Occurrence of priority hazardous PAHs in water, suspended particulate matter, sediment and common eels (Anguilla anguilla) in the urban stretch of the River Tiber (Italy)

Systematic underestimation of polycyclic aromatic hydrocarbon aqueous concentrations in rivers

Polycyclic aromatic hydrocarbons (PAHs) are a widespread group of organic contaminants whose presence in water bodies is cause of severe concern. With few exceptions, the majority of PAHs is hydrophobic, presents a high adsorption affinity, and is thus primarily transported within river systems during high-flow events together with suspended particulate matter (SPM). Evidence exists of analytical challenges related to the incomplete extraction of PAHs adsorbed to solids and thus to a potential negative bias in the chemical analysis of PAHs in bulk water samples with high SPM content. Despite this, partly due to the elevated efforts required to collect representative samples containing sufficient SPM for the separate PAH analysis in this matrix, several investigations rely on the analysis of aqueous samples. This study tests the hypothesis that surveys based exclusively on bulk water may lead to a systematic underestimation of the real contamination level and transport of PAHs in rivers. Six high-turbidity events were examined in three Austrian rivers applying time-integrated sampling and simultaneously analyzing PAHs in total bulk water, filtered water, SPM, and supernatant. Despite an unavoidable degree of uncertainty in such challenging sampling scheme, the results indicate that measurements performed with best available standard methods in bulk water samples determined in average only about 40% of the theoretically expected total PAHs concentrations derived from the analyses in SPM. Such deviation has important implications for the reliable assessment of the compliance with environmental quality standards as well as for surveys aimed to estimate riverine loads, validate emission models, and understand the transport dynamics of PAHs in rivers. Whereas the first objective, e.g., in European countries, is alternatively achieved via monitoring in biota, the latter ones require efforts directed to complement monitoring campaigns with separate sampling of SPM, with monitoring of suspended solids transport to appropriately select and interpret the results of water samples and to improve the chemical analysis of PAHs in bulk water samples with high solids content.

Seasonal variation and concentration of PAHs in Lake Balaton sediment: A study on molecular weight distribution and sources of pollution

The temporal and spatial variations of 16 Polycyclic Aromatic Hydrocarbons (PAHs) were examined at multiple sites around Lake Balaton from February 2023 to January 2024. The results indicated that the concentrations of PAHs in sediment were high during the winter months, 448.35 to 619.77 ng/g dry weight, and low during the summer months, 257.21 to 465.49 ng/g dry weight. The concentration of high molecular weight PAHs (HMWPAHs), consisting of 5-6 rings, was greater than that of low molecular weight PAHs (LMWPAHs), which had 2-3 rings. The total incremental lifetime cancer risk (ILCR) for both dermal and ingestion pathways was high for both adults and children during the four seasons, with the highest records as the following: winter > spring > summer > autumn. The ecological effects of the 16 PAHs were negligible except for acenaphthylene (Acy) and fluorene (Fl), which displayed slightly higher concentrations during the autumn and spring, respectively.

Spatiotemporal distribution, sources apportionment and ecological risks of PAHs: a study in the Wuhan section of the Yangtze River

This study investigated the sources, contamination and ecological risks of polycyclic aromatic hydrocarbons (PAHs) based on their spatiotemporal distribution in aquatic environment in the Wuhan section of the Yangtze River (WYR). The fugacity ratio evaluation indicated that sediment was secondary release sources of two- and three-ring PAHs and sinks of four- and five-ring PAHs. The total concentrations of PAHs (Σ16PAHs) ranged from 2.51 to 102.5 ng/L in water with the dominant contribution of 47.8% by two-ring PAHs. Σ16PAHs in sediments varied from 5.90 to 2926 ng/g with the contribution of 35.4% by four-ring PAHs. The higher levels of PAHs occurred around developed industrial areas during the wet season, which was related to local industrial emissions and influenced by rainfall/runoff. Annual flux of Σ16PAHs was estimated of 28.77 t. The PMF model analysis revealed that petroleum and industrial emissions were the dominant sources in water accounting for 58.5% of the total pollution, although traffic emission was the main source for sediment accounting for 44.6%. Risk assessments showed that PAHs in water were at low risks, whereas about 44% of the sediments were identified as medium risks. Therefore, energy structure adjustment and further implement of regulation and monitoring are necessary to reduce PAH emissions.

Distribution, sources, and health risk of polycyclic aromatic hydrocarbons and their derivatives in the watershed: the case of Yitong River, China

Polycyclic aromatic hydrocarbons (PAHs) and substituted PAHs (SPAHs) are persistent organic pollutants prevalent globally, and SPAHs have received widespread attention in recent years due to their stronger toxicity and carcinogenicity compared to PAHs. There is a lack of systematic examination of PAHs and their derivatives in watersheds. Thus, to clarify the current status, possible sources, and potential risks of PAHs and their derivatives in watersheds, a study was conducted on Yitong River in China. The results showed that the concentrations of ∑PAHs, ∑OPAHs, and ∑NPAHs ranged from 297.9-1158.3 ng/L, 281.1-587.2 ng/L, and 65.7-269.1 ng/L, respectively. Diagnostic ratio analysis showed that the PAHs were mainly derived from petroleum sources, agricultural waste, and coal combustion. Nitrated PAHs (NPAHs) were mainly derived from liquid combustion sources, and oxygenated PAHs (OPAHs) were derived mainly from petroleum source emissions and atmospheric deposition. The exposure risk model of PAHs revealed that 86% of the studied sites would pose carcinogenic risks after dermal contact. The contaminant causing a major carcinogenic risk was DahA, and none of the sites produced non-carcinogenic risks. The lifetime carcinogenic risk of NPAHs was 8.85 × 10^-10-1.44 × 10^-4, and some surface waters presented with potential carcinogenic risks.

Status of different anthropogenic organic pollutants accumulated in sediments from Olt River Basin, Romania: From distribution and sources to risk assessment

Some organic pollutants including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have been banned from production worldwide, but due to their toxicity and persistence are still of concern. Also, unintentional by-products of combustion and industrial processes such as polycyclic aromatic hydrocarbons (PAHs), represent a permanent threat to the safety of the environment and the population. In this study, surface sediment samples from the middle and lower Olt River Basin (ORB), Romania, including dams, the main tributaries and the confluence with Danube River were collected during seasonal sampling campaigns in 2019 and analyzed for 13 OCPs, 12 PCBs and 15 PAHs in order to evaluate the impact of the main anthropogenic activities in the area (industrial activities and agriculture) and the ecological status of the ORB. The registered levels of OCPs, PCBs and PAHs in surface sediments varied from low to significantly polluted environments, indicating a clear spatial distribution between sites based on concentrations and congener profiles correlated with the influence of anthropogenic activities in the surrounding area. Based on some molecular diagnostic ratio and multivariate statistical analysis, both non-point sources and point sources deposition by surface runoff or atmospheric deposition were identified. Overall, the contamination profile of the study area reveals significant amounts of organochlorine compounds, resulting from the industrial production of chlorinated products, including lindane, but also from the long-term agricultural use of both HCHs and DDTs, more than half of the sites having levels that pose a potential risk for benthic organisms. Therefore, levels of POPs in the hot-spots sampling locations raise numerous concerns about the safety of the environment and the population in the region, requiring immediate actions.

Priority Organic Pollutants and Endocrine-Disrupting Compounds in Arctic Marine Sediments (Svalbard Islands, Norway)

The present study investigated the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) and phenolic endocrine-disrupting compounds (PEDCs), including bisphenol A (BPA), 4-nonylphenol (4-NP), and its monoethoxylate (NP1EO) and diethoxylate precursors in marine sediments in an Arctic fjord (Svalbard, Norway). The contribution of different local sources of contamination was also evaluated, together with a risk assessment for the marine environment. Samples were collected during two consecutive summer seasons (2018 and 2019), and target contaminants were analyzed with gas chromatography-mass spectrometry (MS) and high-performance liquid chromatography-MS/MS. The results showed no statistical differences between total PAH concentrations measured in 2018 (mean value 53.7 ± 54.3 ng/g) and 2019 (mean value 58.1 ± 63.6 ng/g). Low-ring (three or four rings) PAHs were the most abundant congeners, and single PAH ratios indicated a predominance of petrogenic sources (i.e., coal and liquid fossil fuel combustion). Nonylphenols and BPA showed a significant decrease in 2019 compared to 2018; 4-NP and NP1EO prevailed in both years, particularly in sediments close to the Ny-Ålesund research village. Overall, the results indicate that local anthropic activities are the major source of contamination in the Kongsfjorden ecosystem, but also melting waters from glaciers in the summer season can play an important role as a secondary source of pollutants previously trapped in ice. Comparison between our data and empirical and mechanistic indices derived from sediment quality guidelines suggests that the occurrence of PAHs and PEDCs in sediments does not currently pose a risk for this Arctic ecosystem, but further investigation is needed on the spread of hazardous contaminants and their effects on these fragile environments. Environ Toxicol Chem 2023;42:953-965. SETAC.

Research progress in human biological monitoring of aromatic hydrocarbon with emphasis on the analytical technology of biomarkers

Aromatic hydrocarbons are unsaturated compounds containing carbon and hydrogen that form single aromatic ring, or double, triple, or multiple fused rings. This review focuses on the research progress of aromatic hydrocarbons represented by polycyclic aromatic hydrocarbons (including halogenated polycyclic aromatic hydrocarbons), benzene and its derivatives including toluene, ethylbenzene, xylenes (o-, m- and p-), styrene, nitrobenzene, and aniline. Due to the toxicity, widespread coexistence, and persistence of aromatic hydrocarbons in the environment, accurate assessment of exposure to aromatic hydrocarbons is essential to protect human health. The effects of aromatic hydrocarbons on human health are mainly derived from three aspects: different routes of exposure, the duration and relative toxicity of aromatic hydrocarbons, and the concentration of aromatic hydrocarbons which should be below the biological exposure limit. Therefore, this review discusses the primary exposure routes, toxic effects on humans, and key populations, in particular. This review briefly summarizes the different biomarker indicators of main aromatic hydrocarbons in urine, since most aromatic hydrocarbon metabolites are excreted via urine, which is more feasible, convenient, and non-invasive. In this review, the pretreatment and analytical techniques are compiled systematically for the qualitative and quantitative assessments of aromatic hydrocarbons metabolites such as gas chromatography and high-performance liquid chromatography with multiple detectors. This review aims to identify and monitor the co-exposure of aromatic hydrocarbons that provides a basis for the formulation of corresponding health risk control measures and guide the adjustment of the exposure dose of pollutants to the population.

Polycyclic aromatic hydrocarbons in aquatic media of Turkey: A systematic review of cancer and ecological risk

Polycyclic aromatic hydrocarbons (PAHs) have gathered worldwide attention due to their carcinogenicity and toxicity. This paper aims to review and extend current knowledge on PAHs in aquatic environments in Turkey, where expansion of the marine industry has caused contamination concerns. To assess cancer and ecological risks associated with PAHs, we systematically reviewed 39 research articles. Mean measured concentrations of total PAHs ranged from 61 to 249,900 ng L^-1 in surface waters, 1 to 209,400 ng g^-1 in sediments, and 4 to 55,000 ng g^-1 in organisms. Estimated cancer risks from concentrations in organisms were higher than those from surface waters and sediments. Negative ecosystem impacts of petrogenic PAHs were estimated to be larger than those of pyrogenic origin, despite the predominance of the latter. Overall, the Marmara, Aegean, and Black seas are highly-polluted and need remedial action, while further study is needed to confirm the status of other water bodies.

Large-scale spatiotemporal variations, sources, and risk assessment of banned OCPs and PAHs in suspended particulate matter from the Negro river, Argentina

Organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) threaten the environment due to their wide environmental resistance. Environmental paradigms coexist along the Negro River (NR) in Argentina, South America, which flows to the sea below the latitude of 40^o S; however, this is the first environmental assessment of OCPs and PAHs in water of the NR for more than 15 years. With 21 sampling sites covering a range of 600 km of river extension, we assessed 16 OCPs and 16 PAHs in suspended particulate material (SPM) with regard to their levels, seasonality, sources, and potential biological risk assessment. Using gas chromatography-mass spectrometry and gas chromatography coupled with electron capture detection, we found an overall mean value for Σ₁₆ OCPs of 648.56 ng. g^-1, d.w. Despite a ban spanning 25 years, an increasing trend of accumulation of hexachlorocyclohexanes (HCHs) and endosulfan was shown in the lower valley. The ɑ-HCH/ɤ-HCH and β-HCH/(ɑ + ɤ)-HCH ratios indicated a prevalent usage of technical HCH over lindane and recent HCH inputs. The most abundant compound, α-endosulfan, averaged 141.64 ng. g^-1, d.w. and DDX (Σ 4,4'-DDE, 4,4'-DDD, and 4,4'-DDT) averaged 99.98 ng. g^-1, d.w. Winter OCP loads in the NR reflected the runoff of the heaviest pesticide application period. We estimated the total discharge of DDT into the Atlantic ocean was 96 g.day^-1, added to 458 g of HCHs and 257 g of endosulfans (ɑ + β + epoxide) adsorbed by the SPM. PAHs occurred widely along the river (38.83 ± 43.52 μg. g^-1) and the highest levels coincided with locations with marked anthropogenic-related activity, such as petroleum/gas exploitation facilities. Risk quotient analysis showed a low risk posed by OCPs, but a high risk of potential effects on biota posed by the PAHs, highlighting the need for mitigation measures.

Characterizing spatiotemporal variations of polycyclic aromatic hydrocarbons in Taihu Lake, China

In this study, we analyzed the concentration distributions of 20 polycyclic aromatic hydrocarbons (PAHs) in 41 water samples which were collected from the northern part of Taihu Lake during 4 field campaigns (201511, 201606, 201702 and 201709). The concentrations were determined with GC-MS, and their spatial and seasonal distribution characteristics were interpreted. The results show that 2-ring PAHs present considerably higher concentrations in warm seasons than cold seasons, but the concentrations of the other higher-ring PAHs are rather stable in warm and cold seasons. The distribution patterns of these PAHs might be mainly attributed to ambient temperature effects on the PAH solubility in the water body. Meanwhile, the spatial distributions of the PAH concentrations in cold seasons were rather various in the sampling area, while the distributions in the warm seasons were homogeneous. The different distributions could result from the water recharge from the Yangtze River during cold seasons, which diluted PAH concentrations in the northeastern part of the lake. Furthermore, via literature review on PAH concentrations in water body, PAHs are in a wide range of levels and their patterns are different among the studies, which should be more effected by local factors instead of general PAH properties. The results from this study also present special characteristics of PAHs in Taihu Lake, which exhibit more insight on PAHs existence in water bodies.

Freshwater suspended particulate matter-Key components and processes in floc formation and dynamics

Freshwater suspended particulate matter (SPM) plays an important role in many biogeochemical cycles and serves multiple ecosystem functions. Most SPM is present as complex floc-like aggregate structures composed of various minerals and organic matter from the molecular to the organism level. Flocs provide habitat for microbes and feed for larger organisms. They constitute microbial bioreactors, with prominent roles in carbon and inorganic nutrient cycles, and transport nutrients as well as pollutants, affecting sediments, inundation zones, and the ocean. Composition, structure, size, and concentration of SPM flocs are subject to high spatiotemporal variability. Floc formation processes and compositional or morphological dynamics can be established around three functional components: phyllosilicates, iron oxides/(oxy)hydroxides (FeOx), and microbial extracellular polymeric substances (EPS). These components and their interactions increase heterogeneity in surface properties, enhancing flocculation. Phyllosilicates exhibit intrinsic heterogeneities in surface charge and hydrophobicity. They are preferential substrates for precipitation or attachment of reactive FeOx. FeOx form patchy coatings on minerals, especially on phyllosilicates, which increase surface charge heterogeneities. Both, phyllosilicates and FeOx strongly adsorb natural organic matter (NOM), preferentially certain EPS. EPS comprise various substances with heterogeneous properties that make them a sticky mixture, enhancing flocculation. Microbial metabolism, and thus EPS release, is supported by the high adsorption capacity and favorable nutrient composition of phyllosilicates, and FeOx supply essential Fe.

Influence of Source Apportionment of PAHs Occurrence in Aquatic Suspended Particulate Matter at a Typical Post-Industrial City: A Case Study of Freiberger Mulde River

Polycyclic aromatic hydrocarbons (PAHs) have received extensive attention because of their widespread presence in various environmental media and their high environmental toxicity. Thus, figuring out the long-term variances of their occurrence and driving force in the environment is helpful for environmental pollution control. This study investigates the concentration levels, spatial variance, and source apportionment of PAHs in suspended particulate matter of Freiberger Mulde river, Germany. Results show that the concentrations of the 16 priority PAHs suggested by USEPA (Σ16PAHs) were in the range of 707.0–17,243.0 μg kg−1 with a mean value of 5258.0 ± 2569.2 μg kg−1 from 2002 to 2016. The relatively high average concentrations of Σ16PAHs were found in the midstream and upstream stations of the given river (7297.5 and 6096.9 μg kg−1 in Halsbrucke and Hilbersdorf, respectively). In addition, the annual average concentration of Σ16PAHs showed an obvious decreasing pattern with time. Positive Matrix Factorization (PMF) receptor model identified three potential sources: coke ovens (7.6–23.0%), vehicle emissions (35.9–47.7%), and coal and wood combustion (34.5–47.3%). The source intensity variation and wavelet coherence analysis indicated that the use of clean energy played a key role in reducing PAHs pollution levels in suspended sediments. The risk assessment of ecosystem and human health suggested that the Σ16PAHs in the given area posed a non-negligible threat to aquatic organisms and humans. The data provided herein could assist the subsequent management of PAHs in the aquatic environment.

Occurrences, Sources, and Human Health Risk Assessments of Polycyclic Aromatic Hydrocarbons in Marine Organisms From Temperate Coastal Area

The pollution characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in marine organism species (6 species of fishes and 2 species of crustaceans) from the coastal area of the East China Sea were determined. The concentrations of 16 PAHs in the studied organisms ranged from 29.73 to 87.02 ng/g dw and 2- and 3-ring PAHs were the most abundant compounds in the aquatic organisms. The habitat, diet and predator-prey relationship have posed potential effects on the PAH accumulation in marine organisms. The source identification of PAHs was performed by using the molecular diagnostic ratios and principal component analysis (PCA). The results showed that the main sources of PAHs in the marine organisms were coal combustion, followed by mixture of gasoline combustion, oil combustion, crude oil spill and vehicle emissions. The incremental lifetime cancer risk of human via ingestion process of marine organisms in this sea area was also estimated and the assessment showed that it posed an acceptable but non-negligible risk to human health.

Current and Future Trends of Low and High Molecular Weight Polycyclic Aromatic Hydrocarbons in Surface Water and Sediments of China: Insights from Their Long-Term Relationships between Concentrations and Emissions

In this study, we analyzed the temporal trend of polycyclic aromatic hydrocarbons (PAHs) in China using data reported over the past 20 years. We found that the total concentrations of low molecular weight PAHs (C_ΣLPAHs) in surface water and sediments were positively correlated with their total emissions (E_ΣLPAHs), which increased between 2000 and 2008, then decreased until 2017. Additionally, the total concentrations of high molecular weight PAHs (C_∑HPAHs) in surface water and sediments were positively correlated with their total emissions (E_ΣHPAHs), which increased significantly from 2000 to 2014 and then plateaued. Two future scenarios were assessed to explore C_∑LPAHs and C_∑HPAHs in surface water and sediments. PAH emissions were reduced by technological improvement in 2030 for coal consumption in Scenario 1 and for control of biomass burning in Scenario 2. Scenario 1 was more efficient than Scenario 2 in reducing C_∑HPAHs in the surface water and sediments of China for the areas where C_ΣHPAHs in surface water exceeded the annual average standard (i.e., 30 ng L^-1), with reductions of 38 and 24% in Scenarios 1 and 2, respectively. The observed relationships in this study can provide tools for emission reduction policies in the future.

Mutagenicity of the Danube River: The contribution of liquid phase and particulate suspended matter

Bioassays have been used to complement the chemical characterization of aquatic mutagenicity, but the tests sometimes are done only with water liquid phase (LP). Particle-bound mutagens are important because they can be ingested by filtering organisms. Our objective was to evaluate the mutagenicity of organic extracts of the LP and the water suspended particulate matter (SPM) from 13 sites along Danube River with the Salmonella/microsome microsuspension assay using TA98, YG1041, TA1538, and YG5185 strains. A high incidence of mutagenicity was detected, 84% for LP and 92% for SPM samples. The contribution of SPM to the mutagenicity was relatively small when compared with LP however, for five sites SPM was responsible for the whole mutagenicity, highlighting the importance of analyzing SPM when assessing water mutagenicity. YG1041 was the most sensitive strain and should be considered in future water mutagenicity monitoring programs, but it will depend on the main pollution sources.

Pharmaceuticals in water and sediment of small streams under the pressure of urbanization: Concentrations, interactions, and risks

Small streams are crucial but vulnerable elements of ecological networks. To better understand the occurrence of pharmaceutically active compounds (PhACs) in streams, this study focused on the occurrence, distribution, and environmental risk of 111 PhACs and 7 trace elements based on a total of 141 water and sediment samples from small streams located in the urbanizing region of Budapest, Hungary. Eighty-one PhACs were detected in the aqueous phase, whereas sixty-two compounds were detected in the sediment. Carbamazepine (CBZ) was the most frequently identified PhAC in water, and was found in 91.5% of all samples. However, the highest concentrations were measured for lamotrigine (344.8 μg·L^-1) and caffeine (221.4 μg·L^-1). Lidocaine was the most frequently occurring PhAC in sediment (73.8%), but the maximum concentrations were detected for CBZ (395.9 ng·g^-1) and tiapride (187.7 ng·g^-1). In both water and sediment, more PhACs were found downstream of the wastewater treatment plants (WWTPs) than in the samples not affected by treated wastewater, even though no relationship was observed between the total amount of treated wastewater and the number of detected PhACs. The PhAC concentrations were also independent of the distance from the WWTP effluents. PhAC-polluted samples were detected upstream of the WWTPs, thereby suggesting the relevance of diffuse emissions in addition to WWTP outlets. The most frequently detected PhACs in the sediment were usually also present in the water samples collected at the same place and time. The varying concentrations of PhACs and the fluctuating water-sediment properties resulted in a lack of correlation between the general chemical properties and the concentrations of PhACs, which makes it difficult to predict PhAC contamination and risks in urbanized small streams. The environmental risk assessment indicated that diclofenac had the highest risk in the sampling area.

Physiological and histopathological alterations in Capoeta baliki and Squalius pursakensis after caused by some environmental pollutants

The present study was aimed to apply physiological and histological biomarkers of pelagic and benthic fish species as biomonitoring of environmental pollutants. Capoeta baliki and Squalius pursakensis were caught from 5 stations in Kirmir Stream (Turkey). After measuring the total length and weight for condition factor analysis, liver, gill, brain, and kidney tissues of fish were taken for histopathological analysis. Dorsal muscles of fish tissues were analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). The mean condition factor of C. baliki and S. pursakensis were 1.14 and 0.97, respectively. It was indicated that the first one was in good condition than the latter one. According to histopathological observations, the alterations in the tissues may be associated with the environmental pollutants' exposure. The total concentration of PAHs of dorsal muscle of C. baliki and S. pursakensis found ranged from 0.915 to 108.421 µg/kg and 0.601 to 675.248 µg/kg, respectively. The highest total concentrations of OCPs were found as 44.16 µg/kg for C. baliki and as 562.12 µg/kg for S. pursakensis. The PCB 28 (10.83 µg/kg), PCB 52 (10.92 µg/kg), PCB 138 (226.24 µg/kg), and the total concentrations of PBDEs were found as 151.74 µg/kg in only S. pursakensis. The result of the concentrations of the investigated pollutants was generally found higher in S. pursakensis which is a higher trophic level than C. baliki. Histopathological alterations were detected as hyperemia in liver, gill, and brain; as hydrophobic degeneration in liver; hyperplasia in gill; and tubular degeneration in kidney tissues of both species. The obtained result of the study shows that the environmental pollutants may affect the physiological and histological status of fish.

Comprehensive insights into the occurrence, source, distribution and risk assessment of polycyclic aromatic hydrocarbons in a large drinking reservoir system

The resource, environment, and ecological value of drinking reservoirs have received widespread concerns due to the pollution of persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs). Therefore, we comprehensively studied the occurrence, source, distribution, and risk assessment of representative PAHs in Fengshuba Reservoir (FSBR) (large drinking reservoir, China). The total concentrations of 16 USEPA PAHs in the water phase, porewater phase, sediment phase, and soil phase were in ranges of 109.72-393.19 ng/L, 5.75-35.15 μg/L, 364.4-743.71 μg/kg, and 367.81-639.89 μg/kg, respectively. The naphthalene (Nap) was the dominant PAHs in the water phase, while it was Nap and phenanthrene (Phe) in porewater, sediment, and soil phase. The main sources of PAHs in FSBR were biomass combustion. Redundancy analysis indicated that the NTU, NO₂^-, NH₄⁺, Chl-α, and IC were the dominant factors influencing the PAH distribution in water phase, and the PAHs in sediment phase was affected by T and NO₃^-. Pseudo-partitioning coefficients indicated that the PAHs in the porewater phase were more likely to migrate to the sediment phase. Risk assessment indicated that the PAHs both in the water and sediment phases were generally in a low-risk state, while the PAHs in the soil phase were in a moderate-risk state, and the Nap was in a high-risk state, and exposure to the PAHs in FSBR through drinking and skin exposure had little impact on consumers' health. In summary, Nap could be used as a key indicator to evaluate the existence and potential risk of PAHs in FSBR.

An integrated approach for chemical water quality assessment of an urban river stretch through Effect-Based Methods and emerging pollutants analysis with a focus on genotoxicity

The impact of emerging chemical pollutants, on both status and functionality of aquatic ecosystems is worldwide recognized as a relevant issue of concern that should be assessed and managed by researchers, policymakers, and all relevant stakeholders. In Europe, the Reach Regulation has registered more than 100.000 chemical substances daily released in the environment. Furthermore, the effects related to the mixture of substances present in aquatic ecosystems may not be predictable on the basis of chemical analyses alone. This evidence, coupled with the dramatic effects of climate changes on water resources through water scarcity and flooding, makes urgent the application of innovative, fast and reliable monitoring methods. In this context, Effect-Based Methods (EBMs) have been applied in the urban stretch of the Tiber River (Central Italy) with the aim of understanding if detrimental pressures affect aquatic environmental health. In particular, different eco-genotoxicological assays have been used in order to detect genotoxic activity of chemicals present in the river, concurrently characterized by chemical analysis. Teratogenicity and embryo-toxicity have been studied in order to cover additional endpoints. The EBMs have highlighted the presence of diffuse chemical pollution and ecotoxicological effects in the three sampling stations, genotoxicological effects have been also detected through the use of different tests and organisms. The chemical analyses confirmed that in the aquatic ecosystems there is a diffuse presence, even at low concentrations, of emerging contaminants such as pharmaceuticals, not routinely monitored pesticides, personal care products, PFAS. The results of this study can help to identify an appropriate battery of EBMs for future studies and the application of more appropriate measures in order to monitor, mitigate or eliminate chemical contamination and remediate its adverse/detrimental effects on the ecosystem health.

Determination of Polycyclic Aromatic Hydrocarbons in Batman River by Liquid-liquid and Solid-phase Extractions and the Statistical Comparison of the Two Extraction Techniques

Polycyclic Aromatic Hydrocarbons (PAHs), which have detrimental health effects such as cancer and mutation, abound in rivers. To employ effective mitigation strategies, accurate determination of PAHs in water bodies is essential. In this study, PAHs in the Batman River were investigated. Specifically, the study has two aims: (1) determining whether there are any statistical differences between the Liquid-liquid (LL) and Solid-phase (SP) extraction techniques of PAHs; and (2) investigation of PAH contamination and the potential sources of PAHs in the Batman River. Methodologically, four different samples were collected and one part of each sample was extracted with the LL and the other part with the SP. Later, each extract was analyzed using gas chromatography-mass spectrometry. Subsequently, the analysis results of the LL and SP extracts were statistically compared. PAH concentrations were 85.5 and 76.7 ng/L for the means of the LL and SP extracts, respectively. Based on the t-test, the differences between these two means were not significant (p-value=0.684 > 0.05). Similarly, no statistical differences were observed between the analysis results of the LL and SP extracts for any individual PAHs. As for the source analysis, the results indicated that road vehicles and coal combustion were the possible sources of PAH contamination in the river. This study provides the first data set for PAH contamination in the Batman River.

Legacy and Emerging Pollutants in an Urban River Stretch and Effects on the Bacterioplankton Community

River contamination is due to a chemical mixture of point and diffuse pollution, which can compromise water quality. Polycyclic Aromatic Hydrocarbons (PAHs) and emerging compounds such as pharmaceuticals and antibiotics are frequently found in rivers flowing through big cities. This work evaluated the presence of fifteen priority PAHs, eight pharmaceuticals including the antibiotics ciprofloxacin (CIP) and sulfamethoxazole (SMX), together with their main antibiotic resistant genes (ARGs) and the structure of the natural bacterioplankton community, in an urbanized stretch of the river Danube. SMX and diclofenac were the most abundant chemicals found (up to 20 ng/L). ARGs were also found to be detected as ubiquitous contaminants. A principal component analysis of the overall microbiological and chemical data revealed which contaminants were correlated with the presence of certain bacterial groups. The highest concentrations of naphthalene were associated with Deltaproteobacteria and intI1 gene. Overall, the most contaminated site was inside the city and located immediately downstream of a wastewater treatment plant. However, both the sampling points before the river reached the city and in its southern suburban area were still affected by emerging and legacy contamination. The diffuse presence of antibiotics and ARGs causes particular concern because the river water is used for drinking purposes.

Gene expression analysis on growth, development and toxicity pathways of male Nile tilapia (Oreochromis niloticus), after acute and sub-chronic benzo (α) pyrene exposures

Benzo[α]pyrene (BaP), a lipophilic polycyclic aromatic hydrocarbon (PAH), is a contaminant widely distributed in aquatic systems. Its presence in freshwater organisms is of great concern; particularly in Nile tilapia (Oreochromis niloticus), due to its economic relevance. The aim of this study is to evaluate the effects of acute and sub-chronic BaP exposures on molecular growth/development responses, toxicity to DNA pathways and xenobiotic metabolism. Negative morphometric changes (the growth condition factor, hepatosomatic and gonadosomatic indices), the fluorescent aromatic compounds (FACs) in bile were also studied in order to understand the mechanisms of action of BaP. Genes involved in the growth hormone GH/insulin-like growth factor 1 (IGF-1) were measured, such as IGF1-2 with the growth hormone receptor gene expression GHR1-2, and the endocrine disruption biomarker vitellogenin (VTG). Acute exposure elicited changes in the GH/IGF axis, mainly in the GHR1 and in IGF1 mRNA levels without affecting the GHR2 expression. While sub-chronic exposure had less effect on both GHR and IGF genes. The most notable tissue-specific effects and morphometric endpoints were observed upon sub-chronic exposure, such as changes in key genes involved in detoxification, DNA damage, and altered reproductive morphological endpoints; showing that sub-chronic BaP doses have longer-lasting toxic effects. This study shows that sub-chronic BaP exposure may compromise the health of Nile tilapia and sheds light on the changes of the GH/IGF axis and the biotransformation of the xenobiotics due to the presence of this contaminant.

Octanol-water partition coefficient (logKow) dependent movement and time lagging of polycyclic aromatic hydrocarbons (PAHs) from emission sources to lake sediments: A case study of Taihu Lake, China

Understanding the movement of polycyclic aromatic hydrocarbons (PAHs) from emission sources to sediments is important for achieving long-term pollution control of PAHs in sediments. In this study, by exploring the correlation of individual PAHs concentrations (C_PAHs) in Taihu Lake sediments reported in the past twenty years with their annual emissions (E_PAHs) in the lake region, it was observed that mean concentrations of PAHs with low logK_ow (i.e., logK_ow≤4.00) in Taihu Lake sediments were correlated best with their emissions without lagging between the sediment sampling time and the PAHs emitting time. However, for PAHs with middle logK_ow (i.e., 4.00<logK_ow≤4.57) or high logK_ow (i.e., logK_ow>4.57), their mean concentrations in sediments were correlated best with the emissions of PAHs emitted 1 or 2 years before the sediment sampling time. The longer lagging time of PAHs with middle or high logK_ow from emission sources to lake sediments could be attributed to their retardation in soils and river sediments around the lake. Moreover, the retardation in soils and river sediments is dependent on PAHs logK_ow and degradation half-life, indicating the dependence of PAHs concentration in sediments on their environmental behaviors, including sorption and degradation. K_ow dependent movement and the time lagging observed in Taihu Lake for PAHs from emission sources to sediments could be valuable for developing measures to control PAHs, especially for congeners with high logK_ow.

Emerging and Persistent Pollutants in the Aquatic Ecosystems of the Lower Danube Basin and North West Black Sea Region—A Review

The tremendous impact of natural and anthropogenic organic and inorganic substances continuously released into the environment requires a better understanding of the chemical status of aquatic ecosystems. Water contamination monitoring studies were performed for different classes of substances in different regions of the world. Reliable analytical methods and exposure assessment are the basis of a better management of water resources. Our research comprised publications from 2010 regarding the Lower Danube and North West Black Sea region, considering regulated and unregulated persistent and emerging pollutants. The frequently reported ones were: pharmaceuticals (carbamazepine, diclofenac, sulfamethoxazole, and trimethoprim), pesticides (atrazine, carbendazim, and metolachlor), endocrine disruptors—bisphenol A and estrone, polycyclic aromatic hydrocarbons, organochlorinated pesticides, and heavy metals (Cd, Zn, Pb, Hg, Cu, Cr). Seasonal variations were reported for both organic and inorganic contaminants. Microbial pollution was also a subject of the present review.

Are geochemical regime shifts identifiable in river waters? Exploring the compositional dynamics of the Tiber River (Italy)

Rivers are dynamic and sensitive systems that change their chemical composition from source to mouth. This is due to the influence of a set of variables controlled by hydro-litho-eco-atmospheric processes and anthropic pressures which are, in turn, affected by catchment attributes. This work proposes a new way of thinking about river geochemistry focused on environmental interconnections rather than single chemical variables. Abrupt changes in the system state (composition) of a certain environmental media, driven by perturbations, may trigger Geochemical Regime Shifts (GRSs). This eventuality is explored in the Tiber River (central Italy) chemistry by Compositional Data Analysis, robust Principal Component Analysis and score-distance graphs. Data variability and the interlinks between response and forcing variables are investigated for different drained areas. A potential GRS is detected for major elements in the lower reaches resulting from a threshold-like state response caused by lithological forcing. On the contrary, trace elements respond gradually to environmental drivers, showing no abrupt changes. The findings outline mechanisms and factors influencing the river's self-restoring capability at a basin-wide scale, providing a better comprehension of the circumstances controlling the equilibrium dynamics of river water systems.

Application of constructed wetlands in the PAH remediation of surface water: A review

Polycyclic aromatic hydrocarbons (PAHs) pose adverse risks to ecosystems and public health because of their carcinogenicity and mutagenicity. As such, the extensive occurrence of PAHs represents a worldwide concern that requires urgent solutions. Wastewater treatment plants are not, however, designed for PAH removal and often become sources of the PAHs entering surface waters. Among the technologies applied in PAH remediation, constructed wetlands (CWs) exhibit several cost-effective and eco-friendly advantages, yet a systematic examination of the application and success of CWs for PAH remediation is missing. This review discusses PAH occurrence, distribution, and seasonal patterns in surface waters during the last decade to provide baseline information for risk control and further treatment. Furthermore, based on the application of CWs in PAH remediation, progress in understanding and optimising PAH-removal mechanisms is discussed focussing on sediments, plants, and microorganisms. Wetland plant traits are key factors affecting the mechanisms of PAH removal in CWs, including adsorption, uptake, phytovolatilization, and biodegradation. The physico-chemical characteristics of PAHs, environmental conditions, wetland configuration, and operation parameters are also reviewed as important factors affecting PAH removal efficiency. Whilst significant progress has been made, several key problems need to be addressed to ensure the success of large-scale CW projects. These include improving performance in cold climates and addressing the toxic threshold effects of PAHs on wetland plants. Overall, this review provides future direction for research on PAH removal using CWs and their large-scale operation for the treatment of PAH-contaminated surface waters.

Pollution level and health risk assessment of polycyclic aromatic hydrocarbons in marine fish from two coastal regions, the South China Sea

Marine fishes are consumed in large quantities by humans as nutritious food. However, the intake of fish polluted by chemicals may pose a severe threat to human health. This study measured the concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in the muscles of 22 species of marine fish from two coastal regions, i.e., Tanmen and Zhuhai, identified the source of PAHs, and assessed the human health risk by dietary exposure. Total PAH (Σ₁₆PAHs) levels in Tanmen and Zhuhai fish were in the range of 24.29-684.83 ng g^-1 dry weight (dw) and 13.74-42.59 ng g^-1 dw, averaging 161.46 ng g^-1 dw and 31.21 ng g^-1 dw, respectively. Compared with other regions in the world, PAH concentrations in Tanmen fish were at median levels, and Zhuhai fish were at low levels. Low molecular weight PAHs (with 2- and 3-rings) were the predominant compounds detected. Molecular diagnostic ratios suggested that PAHs in Tanmen mainly originated from petrogenic sources such as vessel operations or tanker accidents, while Zhuhai fish were mainly polluted by pyrolytic sources such as combustion of coal and wood. The human health risk assessment results indicated that the risk of PAH intake via fish consumption from Zhuhai was negligible, while five species from Tanmen may pose potential health risks to local residents.

Enhanced degradation of benzo[a]pyrene and toxicity reduction by microbubble ozonation

The microbubble technique has drawn great attention for efficient utilization of ozone for advance oxidation processes. Therefore, in this study, microbubble ozonation was investigated to evaluate the removal efficiency and toxicity reduction of benzo[a]pyrene. Compared with conventional macrobubble ozonation, microbubble ozonation produced higher concentrations of hydroxyl radicals and ozone in aqueous solutions, resulting in more efficient and persistent degradation of benzo[a]pyrene. Moreover, microbubble ozonation completely removed the acute toxicity of benzo[a]pyrene to Daphnia magna, whereas the toxicity reduction by macrobubble ozonation was not consistent owing possibly to toxic degradation products. These findings suggest that microbubble ozonation is a promising technique in terms of both chemical degradation and toxicity reduction of organic pollutants.

Suspended Particulate Matter-A Source or Sink for Chemical Mixtures of Organic Micropollutants in a Small River under Baseflow Conditions?

Suspended particulate matter (SPM) plays an important role in the fate of organic micropollutants in rivers during rain events, when sediments are remobilized and turbid runoff components enter the rivers. Under baseflow conditions, the SPM concentration is low and the contribution of SPM-bound contaminants to the overall risk of organic contaminants in rivers is assumed to be negligible. To challenge this assumption, we explored if SPM may act as a source or sink for all or specific groups of organic chemicals in a small river. The concentrations of over 600 contaminants and the mixture effects stemming from all chemicals in in vitro bioassays were measured for river water, SPM, and the surface sediment after solid-phase extraction or exhaustive solvent extraction. The bioavailable fractions of chemicals and mixture effects were estimated after passive equilibrium sampling of enriched SPM slurries and sediments in the lab. Dissolved compounds dominated the total chemical burden in the water column (water plus SPM) of the river, whereas SPM-bound chemicals contributed up to 46% of the effect burden even if the SPM concentration in rivers was merely 1 mg/L. The equilibrium between water and SPM was still not reached under low-flow conditions with SPM as a source of water contamination. The ratios of SPM-associated to sediment-associated neutral and hydrophobic chemicals as well as the ratios of the mixture effects expressed as bioanalytical equivalent concentrations were close to 1, suggesting that the surface sediment can be used as a proxy for SPM under baseflow conditions when the sampling of a large amount of water to obtain sufficient SPM cannot be realized.

Nitrated and parent PAHs in the surface water of Lake Taihu, China: Occurrence, distribution, source, and human health risk assessment

Nitrated polycyclic aromatic hydrocarbons (NPAHs) have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons (PAHs) and thus have received increasing attention in recent years. In this study, the occurrence, distribution, source, and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry, normal, and flood seasons of 2018. The ΣPAH concentrations ranged from 255 to 7298 ng/L and the ΣNPAH concentrations ranged from not-detected (ND) to 212 ng/L. Among the target analytes, 2-nitrofluorene (2-nFlu) was the predominant NPAH, with a detection frequency ranging from 85% to 90% and a maximum concentration of 56.2 ng/L. The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds. In terms of seasonal variation, the highest levels of the ΣNPAHs and ΣPAHs were in the dry season and flood season, respectively. Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion, whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion. The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model. The carcinogenic risk level of the targets ranged from 2.09 × 10^-7 to 5.75 × 10^-5 and some surface water samples posed a potential health risk.

Estimation of Polycyclic Aromatic Hydrocarbons Pollution in Mediterranean Sea from Volturno River, Southern Italy: Distribution, Risk Assessment and Loads

This study reports the data on the contamination caused by polycyclic aromatic hydrocarbons (PAHs) drained from the Volturno River. The seasonal and spatial distribution of PAHs in water and sediment samples was assessed. The 16 PAHs were determined in the water dissolved phase (DP), suspended particulate matter (SPM), and sediments. A multidimensional statistical approach was used to identify three pollution composite indicators. Contaminant discharges of PAHs into the sea were calculated in about 3158.2 kg/year. Total concentrations of PAHs varied in ranges 434.8 to 872.1 ng g⁻¹ and 256.7 to 1686.3 ng L⁻¹ in sediment samples and in water (DP + SPM), respectively. The statistical results indicated that the PAHs mainly had a pyrolytic source. Considering the sediment quality guidelines (SQGs), the water environmental quality standards (USEPA EQS), and risk quotient (RQ), the Volturno River would be considered as an area in which the environmental integrity is possibly at risk.

Occurrence, distribution and pollution pattern of legacy and emerging organic pollutants in surface water of the Kongsfjorden (Svalbard, Norway): Environmental contamination, seasonal trend and climate change

This work aimed to investigate the contamination pattern in Kongsfjorden marine environment (Svalbard, 79°N 12°E) and to disentangle primary and secondary emissions. Surface seawater, sampled in two seasons, was analysed by GC-MS and LC-MS/MS to detect polychlorobiphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), nonylphenols (NPs), bisphenol A (BPA) and perfluoroalkyl and polyfluoroalkyl substances (PFASs). In summer, average ΣPAHs, BPA, ΣNPs, ΣPFASs and ΣPCBs concentrations were 17.3 ± 11.1 ng/L, 0.9 ± 0.3 ng/L, 10.0 ± 6.9 ng/L, 0.4 ± 0.7 ng/L and 1.8 ± 1.3 pg/L, respectively; while in winter, they were 13.6 ± 10.1 ng/L, 0.5 ± 0.2 ng/L, 6.8 ± 3.3 ng/L, <LOD and 0.6 ± 0.4 pg/L, respectively. The application of generalized linear models (GLMs) highlighted that: PFAS pattern agrees their predominant long-range hydrospheric transport; the additive effect of the distance to glacier and harbour affected PAH, NP and BPA distributions; the additive effect of season and distance from the glacier, but not their interaction, influenced PCBs distribution, indicating melting glaciers as potential secondary POP sources.

Polycyclic aromatic hydrocarbons in surface waters from the seven main river basins of China: Spatial distribution, source apportionment, and potential risk assessment

In this study, we report long-term measurements of Polycyclic Aromatic Hydrocarbons (PAHs) collected from the surface waters of seven river basins across China. The spatial distribution, source apportionment, and potential risk assessment of 16 USEPA designated PAHs were reviewed. Water samples were collected from the Songhua River Basin (SRB), Yangtze River Basin (YtRB), Yellow River Basin (YRB), Pearl River Basin (PRB), Huai River Basin (HuRB), Liao River Basin (LRB), and Hai River Basin (HRB). Our results show that the total PAH concentration in the surface waters from primary river basins ranged from 99.60 to 3805.00 ng/L in the dry season with a geometric mean value of 797.96 ng/L, and from 235.84 to 11,812.20 ng/L in the wet season with a geometric mean value of 820.75 ng/L. In the river basins examined, the geometric concentration of Σ₁₆PAHs ranged from 215.50 ng/L to 1969.91 ng/L, with a median value of 837.73 ng/L. In the decreasing order across seven river basins, the geometric mean Σ₁₆PAHs content varied as: SRB (1969.91 ng/L) > LRB (1155.87 ng/L) > YRB (884.06 ng/L) > PRB (837.73 ng/L) > HuRB (559.10 ng/L) > HRB (261.84 ng/L) > YtRB (215.50 ng/L). Moreover, the total PAH concentration was slightly lower in the dry season than in the wet season. The pollution level of PAHs in North China was higher than in South China. No discernible temporal trend was observed in Σ₁₆PAHs observed in China during the past decade. Overall, PAHs designated for priority control measures were Nap, Phe, and Flu; as 2- and 3-ring PAHs were the dominant compounds in the river basins, accounting for 33.7% and 36.9% of the total PAHs, respectively. Source analysis revealed that coal and biomass combustion were the main contributors to PAHs in the river basins, accounting for about 40% of the total. The geometric mean concentrations of individual PAH, including BaP, BaA, BbF, BkF, Ind, and DaA in some water samples exceeded the environmental quality standards of both China and the United States. According to metrics describing eco-toxicity from water contamination, the river basin was at moderate risk in YtRB, YRB, PRB, HuRB, and HRB, but at high risk in SRB and LRB, suggesting that targeted control measures or remedial actions should be undertaken to decrease PAH contamination in China.

Effects of aging on the skin and gill microbiota of farmed seabass and seabream

Background

Important changes in microbial composition related to sexual maturation have been already reported in the gut of several vertebrates including mammals, amphibians and fish. Such changes in fish are linked to reproduction and growth during developmental stages, diet transitions and critical life events. We used amplicon (16S rRNA) high-throughput sequencing to characterize the skin and gill bacterial microbiota of farmed seabass and seabream belonging to three different developmental age groups: early and late juveniles and mature adults. We also assessed the impact of the surrounding estuarine water microbiota in shaping the fish skin and gill microbiota.

Results

Microbial diversity, composition and predicted metabolic functions varied across fish maturity stages. Alpha-diversity in the seabass microbiota varied significantly between age groups and was higher in older fish. Conversely, in the seabream, no significant differences were found in alpha-diversity between age groups. Microbial structure varied significantly across age groups; moreover, high structural variation was also observed within groups. Different bacterial metabolic pathways were predicted to be enriched in the microbiota of both species. Finally, we found that the water microbiota was significantly distinct from the fish microbiota across all the studied age groups, although a high percentage of ASVs was shared with the skin and gill microbiotas.

Conclusions

We report important microbial differences in composition and potential functionality across different ages of farmed seabass and seabream. These differences may be related to somatic growth and the onset of sexual maturation. Importantly, some of the inferred metabolic pathways could enhance the fish coping mechanisms during stressful conditions. Our results provide new evidence suggesting that growth and sexual maturation have an important role in shaping the microbiota of the fish external mucosae and highlight the importance of considering different life stages in microbiota studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-020-00072-2.

Spatial Distributions, Sources and Risks of Polycyclic Aromatic Hydrocarbons in Sediments from Ziya River System, Northern China

With the development of urbanization and industrialization, Ziya River Plain (ZYRP) had become one of the most polluted regions of polycyclic aromatic hydrocarbons (PAHs) in north China. The distribution of PAHs in sediments were investigated, and then their sources and risks were evaluated. The results showed that the total PAHs varied from 3372 to 92,948 μg/kg, and heavy pollution was found in the upstream. Both the isomer pair ratios of PAH and principal components analysis (PCA) revealed that fossil fuel combustion was the mainly contributes (69.1%), followed by wood and coal combustion (26.7%). The ecological risk for the whole area was moderate, with the highest risk in Niuwei River (NWR). and significant correlation was found between the ecological risk and high-molecular-weight (HMW) of PAHs (r² > 0.99, p < 0.01). Our findings would give insights into the mitigation of sedimentary PAHs pollution in north China.

Introduction to Environmental Harmful Factors

In this Chapter, we systematically and comprehensively described various environmental harmful factors. They were classified into four aspects: physical factors, chemical factors, biological factors, and physiological and psychological stress factors. Their classification, modes of presence, toxicity and carcinogenicity, routes of exposure to human and toxic effects on the female reproductive health were introduced. It is expected that the exposure routes could be controlled and eliminated, and the pathogenic mechanism of environmental harmful factors should be investigated and explained to protect female reproductive health.

Barbecued desi chicken: an investigation on the impact of polluted milieu upon formation and ingestion of polycyclic aromatic hydrocarbons (PAHs) in commercial versus laboratory barbecued organs along with stochastic cancer risk assessments in people from an industrial district of Punjab, Pakistan

8∑PAHs in 2- and 4-month-old desi chicken organs collected from Faisalabad district, Punjab, Pakistan, were examined via high-performance liquid chromatography (HPLC). Exposure doses (A_VDD) of PAHs with consequential lifetime excess cancer risks (L_tECR) were also estimated in people ingesting laboratory barbecued (L_b) and commercially barbecued (C_b) desi meat organs. The results exposed the presence of 8ΣPAH in 2- and 4-month-old L_b and C_b chicken organs: drumsticks (D_s), breast (B_S), and wings (W_s) (0.45, 3.10, 0.97 ng g^-1; 2.52, 4.31, 1.22 ng g^-1; and 10.09, 15.04, and 9.06 ng g^-1 respectively). BαP was found only in C_b organs with the highest concentrations (5.08 ng g^-1) in B_s. It was above the EU's tolerable limit, while it was not detected in all L_b organs. The lowest level of 8ΣPAH was found in 2-month-old desi W_s. A comparative percentage increase in 8ΣPAH levels between all L_b and C_b organs was found in the range of 1500-2416.67%. L_tECR for males and adults were ranging from 1.35 × E^-13 to 4.49 × E^-5 at different consumption rates with A_VDD ranging from 1.08 E^-6 to 6.01 E^-5. In contrast to 2- and 4- month-old chicken meat, 2-month-old desi meat is better having less PAH load. Comparing different organs, W_s of former one displayed abridged PAH levels. In conclusion, L_b desi meat is less carcinogenic relative to C_b. More PAH levels are due to secondary smoke in C_b samples collected from the metropolitan. Ingestion of L_b 2-month-old desi chicken organs could be safe to dine as compared with 4-month-old desi and C_b organs. Graphical abstract.

Bioaccumulation and toxic potencies of polycyclic aromatic hydrocarbons in freshwater biota from the Ogbese River, Nigeria

Samples of fish and shellfish (periwinkles, mussel, and snail) collected from the rapidly contaminated Ogbese River, Ondo State, Nigeria, were analyzed for their polycyclic aromatic hydrocarbon (PAH) levels by gas chromatography-mass spectrometry after cleanup using solid-phase extraction. The rank order of concentration of ΣPAHs in fish follows: gills >> eggs >>> muscle. The dry weight concentrations (μg/g) of total PAHs ranged from < 0.001 to 2.06, 0.01 to 18.67, 0.01 to 9.56, and 0.01 to 8.28 in fish muscle, periwinkle, snail, and mussel respectively. Accumulation levels of PAHs in the biota were used to calculate biota-sediment (or porewater) accumulation factors (BSAF (BPwAF)) and bioaccumulation factor (BAF). The lower molecular weight PAHs constitute major components (≥ 87% in each case) of PAH congener profiles. Bioaccumulation was greatest for PAHs with log K_ow values between 5.0 and 5.6. However, the study did not show a good correlation between log K_ow of individual PAH and the corresponding BSAFs/BPwAF for the biota. The study indicates that significantly greater (p < 0.05) BSAFs for ΣPAHs were observed in the three bottom dwellers than in fish muscle which suggests that the sediment-feeding behavior largely affected the extent of PAH bioaccumulation in the aquatic organisms. The calculated potency equivalent concentration (PEC) of total PAHs was above the recommended screening value (SV) in US EPA guidelines, suggesting great concern for human consumption. However, estimated excess cancer risk (ECR) induced by dietary exposure only suggests potential cancer risk. The study suggests urgent remediation of the river to safeguard public health.

Occurrence, environmental implications and risk assessment of Bisphenol A in association with colloidal particles in an urban tropical river in Malaysia

Phase distribution of emerging organic contaminants is highly influential in their presence, fate and transport in surface water. Therefore, it is crucial to determine their state, partitioning behaviour and tendencies in water environments. In this study, Bisphenol A was investigated in both colloidal and soluble phases in water. BPA concentrations ranged between 1.13 and 5.52 ng L⁻¹ in the soluble phase and n.d-2.06 ng L⁻¹ in the colloidal phase, respectively. BPA was dominant in the soluble phase, however, the colloidal contribution ranged between 0 and 24% which implied that colloids can play a significant role in controlling BPA’s transportation in water. Urban and industrial areas were the main sources of BPA while forest areas displayed lower levels outside the populated domains. pH levels were between 6.3 and 7.4 which might have affected BPA’s solubility in water to some extent. The particle size distribution showed that the majority of the particles in river samples were smaller than 1.8 µm in diameter with a small presence of nanoparticles. Zeta potential varied between − 25 and − 18 mV, and these negative values suggested instability of particles. Furthermore, BPA was positively correlated with BOD, COD and NH₃–N which might indicate that these organic compounds were released concurrently with BPA. RQ assessment showed low levels of risk towards algae and fish in the study area.

Removal of polycyclic aromatic hydrocarbons from aqueous media using modified clinoptilolite

Carcinogenic polycyclic aromatic hydrocarbons (PAHs) are widespread in the environment. In this study, the removal of PAHs from aqueous media was assessed using samples of clinoptilolite, a natural zeolite, pre-treated with 1 mol/L of NaCl, (Na pre-treated clinoptilolite, NC). Samples (10 g) of NC were separately modified with 5, 2, 2, and 20-mmol/L solutions of cetylpyridinium chloride (CPC), didodecyldimethyl ammonium bromide (DDAB), hexadecyltrimethylammonium bromide (HDTMA), and tetramethyl ammonium chloride (TMA) surfactants as potential cost-effective adsorbents. The kinetics, optimal sorbent dosage, and competitive effects were evaluated through batch adsorption tests using deionised water spiked with five PAHs (anthracene (50 μg/L), fluoranthene (100 μg/L), fluorene (100 μg/L), phenanthrene (100 μg/L), and pyrene (100 μg/L)). The surfactant non-modified (NC) and TMA-MC (modified clinoptilolite) exhibited PAH removal of <66% from the spiked concentration in aqueous solution, while CPC-MC, DDAB-MC, and HDTMA-MC achieved removal rates of >93% for the five PAHs after 24 h at a solid:liquid ratio of 1:100. The remaining concentrations of anthracene and fluoranthene were below 3 μg/L, and that of fluorene was <6 μg/L, lower than the water quality criteria of British Columbia, Canada, for protecting aquatic life. However, HDTMA-MC retained >83% of the fluorene. Over 80% of all PAHs were absorbed within 15 min for the CPC-MC and DDAB-MC, and the maximum adsorption was reached in <2 h. Three kinetic models were applied assuming pseudo-first-order, pseudo-second-order, and intra-particle equations, and the results were well-represented by the pseudo-second-order equation. The PAH sorption results indicated that the adsorption mechanism is based on PAH hydrophobicity, and π-π electron-donor-acceptor interaction with surfactant. CPC and DDAB with two long chain hydrocarbons had more PAH adsorption than HDTMA with one, and TMA with no long chain hydrocarbons (DDAB-MC > CPC-MC > HDTMA-MC ≫ TMA-MC > NC). With a solid:liquid ratio of 1:200, over 90%, 80%, and 70% of the anthracene, fluoranthene, and pyrene were adsorbed by the CPC-MC, DDAB-MC, and HDTMA-MC, respectively.

Pollution characteristics and underlying ecological risks of primary semi-volatile organic compounds (SVOCs) in urban watersheds of Shanghai, China

We investigated the pollution characteristics of ninety semi-volatile organic compounds (SVOCs) in the rivers and lakes of Shanghai. Total concentrations of Σ₉₀SVOCs in water and sediment samples from 30 sites ranged from 1.47 to 19.5 μg/L and 2.38 to 9.48 mg/kg, respectively. PAEs and PAHs were the major contaminant compounds found in all samples. OCPs accounted for less than 3% of the total concentrations of Σ₉₀SVOCs and other SVOCs were either not detected or only detected in trace amounts. Our results indicated that domestic swage, industrial wastewater, petroleum products, and other human activities were the pollutant sources to the water and sediment. It is noteworthy that products that contain the banned chemicals HCH and DDT are still under use within the studied areas. Ecological and health risk assessment results showed that dieldrin and BBP have the potential to cause adverse effects on the environment, while B(a)p and DBP have high carcinogenic risks to humans.

Effect of anthropogenic activities on the occurrence of polycyclic aromatic hydrocarbons in aquatic suspended particulate matter: Evidence from Rhine and Elbe Rivers

As carcinogenic and pervasive pollutants, polycyclic aromatic hydrocarbons (PAHs) in surface water are crucial to environmental policies, and the understanding of their trends and influencing factors is critical for achieving a good chemical and ecological status of water bodies. Based on long-term monitoring data from 1998 to 2017, this study systematically evaluated the spatiotemporal distribution, multimedia transport, fate, and source apportionment of PAHs adsorbed on suspended particulate matter (SPM) in Rhine and Elbe Rivers. The results of the Mann-Kendall test indicated that pollution levels of PAHs decreased from 2.81×10⁵μg⋅s^-1 to 9.80×10⁴μg⋅s^-1 on average in the Rhine and from 1.60×10⁵ μg⋅s^-1 to 5.21×10⁴ μg⋅s^-1 in the Elbe in the last 20 years. Spatially, SPM near urban areas had higher PAH mass fluxes (Rhine:3.07×10⁵μg⋅s^-1, Elbe: 1.73×10⁵μg⋅s^-1) and greater rates of decrease (slopes for Rhine and Elbe: -409, -323) than those near rural areas (Rhine:1.41×10⁵ μg⋅s^-1, Elbe: 9.35×10⁴μg⋅s^-1; slopes for Rhine and Elbe: -128, -89), indicating the significant influence of anthropogenic activities. Wavelet analysis showed that the pollution level of PAH had significant periodic oscillations for the Rhine and Elbe, and revealed several abrupt change points for the two rivers. A multimedia fugacity model demonstrated that impervious surfaces had the highest concentration (Rhine: 1.84g⋅m^-3, Elbe: 0.15g⋅m^-3), while soil (Rhine: 8.33×10⁷g, Elbe: 2.53×10⁶g) and sediments (Rhine: 4.85×10⁶g, Elbe: 1.31×10⁶g) had higher masses of PAHs. Furthermore, source apportionment computed using a self-organizing map and positive matrix factorization model suggested that the major sources of PAHs were vehicular emissions and coal combustion, which accounted for 51.86% of the total mass in the Rhine and 62.92% in the Elbe. The data revealed that the long-term trends of PAH variation were associated with changes in energy consumption and the implementation of vehicular emission standards. Therefore, the substitution of coal and petroleum with renewable energies could assist strategies of PAH mitigation in the environment and gradual reduction of pollution levels.

Substantial Decrease in Contaminant Concentrations in the Sediments of the Venice (Italy) Canal Network in the Last Two Decades—Implications for Sediment Management

The Venice canal network requires periodic intervention to remove sediments that progressively accumulate. The most recent dredging operation was carried out in the second half of the 1990s and early 2000s. These sediments had accumulated over a period of more than 30 years and were highly contaminated with Cd, Cu, Hg, Pb, Zn and PAHs. Sediments deposited after the dredging work were investigated in 2005, 2009, 2014 and 2017 by analysing sediment cores collected from three sites in the canal network. Arsenic, heavy metal and PAH concentrations were observed to be much lower than past values, although Cu, Hg and PAH levels were still relatively high. The high Cu concentrations (mean 161 mg kg−1) are partly due to the widespread use of Cu-based antifouling paint. Current Italian regulations forbid the disposal of dredged sediments with these concentrations inside the lagoon, thereby increasing the cost of canal network maintenance.

Analyzing Particle-Associated Pollutant Transport to Identify In-Stream Sediment Processes during a High Flow Event

Urban areas are a leading source of polycyclic aromatic hydrocarbons (PAHs) that result from combustion processes and are emitted into rivers, especially during rain events and with particle wash-off from urban surfaces. In-stream transport of suspended particles and attached PAHs is linked strongly to sediment turnover processes. This study aimed to identify particle exchange processes that contribute to the transport of suspended particles during flood events. An urban high-flow signal was tracked in high temporal resolution at two sampling sites in the Ammer River (South-western Germany). Samples were analyzed for turbidity, total suspended solids concentrations (TSS), particle-size distribution, organic carbon, and PAH. Maximum discharge and the highest TSS occurred nearly simultaneously at the upstream sampling site, whereas a temporally shifted course was observed for downstream. The total load of particles was similar, yet a decrease of PAH mass (~28%) and an increase of the particulate organic carbon (POC) content (~3.5%-points) occurred. Coarser particles (≥26 µm) dominated at the beginning of the event at both sampling sites. The signal of remobilized riverbed sediment increases downstream and leads to well-established, robust linear correlations between TSS and PAHs. This study highlights that riverbed sediment acts as intermediate storage for contaminated particles from upstream sources that shape, together with the fresh urban input, the “particle signature” of suspensions moving through catchments during high discharge conditions.

Polycyclic aromatic hydrocarbons (PAHs) in marine organisms from two fishing grounds, South Yellow Sea, China: Bioaccumulation and human health risk assessment

Sediment and marine organism samples collected from Haizhou Bay and Lusi fishing ground in South Yellow Sea, China were analysed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of 16 PAHs in marine organisms ranged from 127.43 to 350.53 ng/g dry weight (dw, Haizhou Bay fishing ground) and from 86.37 to 213.02 ng/g dw (Lusi fishing ground). The dominant compounds were 2- and 3-ring PAHs in marine organism tissues. The main PAH sources were found to be coal combustion. Specific habitat, feeding habit, trophic level and environmental differences may affect the PAH levels in marine organisms in our study area. The biota-sediment accumulation factor (BSAF) decreased with increasing PAH log K_ow and BSAF values might differ in response to various environmental conditions and species. The excess cancer risk from PAH-contaminated seafood consumption was slightly higher than the guideline value (10^-6), but much lower than the priority risk level (10^-4).

Health risk assessments based on polycyclic aromatic hydrocarbons in freshwater fish cultured using food waste-based diets

Two farmed freshwater fish species Nile tilapia (Oreochromis niloticus) and jade perch (Scortum barcoo) were cultured with food waste-based diets and compared with commercial formulated control diet for a period of six months. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) in the diets and cultured fish meat were tested by gas chromatography-mass spectrometry. No significant differences of ∑PAHs were observed between Nile tilapia and jade perch fed with food waste-based diets and control diet (p > 0.05). However, there were significantly higher concentration of ∑PAHs in market fish compared with the same species of fish fed by food waste-based diets (p < 0.05). Thus, the food waste-based diets have a potential to lower the PAH concentrations in farmed fish when compared with market fish. Based on the PAH concentrations, a human health risk assessment was made. The results indicated there were no non-cancer and very low cancer risks of consuming fish cultured with food waste-based diets at the 95th centile (Nile tilapia: hazard index (HI _adult) = 0.343 × 10^-3, HI _children = 0.614 × 10^-3 and cancer risk value = 0.943 × 10^-6; jade perch: HI _adult = 0.456 × 10^-3, HI _children = 0.814 × 10^-3 and cancer risk value = 0.291 × 10^-6). In general, the fish fed with food waste-based diets were unlikely to cause adverse health effects, based on the concentrations of PAHs. There is great potential for using food waste-based diets as an alternative to commercial feeds for cultivating freshwater fish.

Polycyclic Aromatic Hydrocarbons in Sediment and Health Risk of Fish, Crab and Shrimp Around Atlas Cove, Nigeria

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are toxic contaminants and pose health risks to humans and the ecosystem due to their persistence in the environment.

OBJECTIVES

This study determined the concentrations of PAHs in sediment, two species of fish (Drepane africana and Pomadasys jubelini), crabs (Callinectes amnicola) and shrimps (Penaeus notialis) around the Atlas Cove jetty, Lagos, Nigeria.

METHODS

Polycyclic aromatic hydrocarbons were extracted from fish, shrimp, and crabs that were purchased from local fishermen. Sediments were collected at five locations impacted by ship movement and cargo offloading around the Atlas Cove jetty during the period of June to August 2016, using standard methods. Potential toxicity of PAHs in the sediments on the surrounding aquatic organisms was assessed. The PAHs were analyzed using gas chromatography-mass spectrometry. Human health risk assessment was calculated from biota using dietary daily intake and carcinogenic potencies of individual PAH concentrations.

RESULTS

A total of 17 PAH congeners were detected in sediment samples and ten were detected in biota samples. Concentrations of total PAHs obtained in sediment and fish samples ranged from 2.15 - 36.46 mg/kg and 11.89 - 71.06 mg/kg, respectively. The total PAHs concentration pattern follow the order of P. notialis > C. amnicola > P. jubelini (whole) > D. africana (whole) > D. africana (fillet) > P. jubelini (fillet) > sediment. Concentrations of total PAHs were higher in whole fish than in fillet samples (muscle) in both fish species. High values of PAHs were recorded in the dietary intake (0.10 - 2.33 mg/kg body weight/day) of the organisms. Toxic equivalent quotient values (0.01 to 0.10 mg/kg) were observed to be higher than the screening values (0.0014 to 0.0599 mg/kg). In the muscle of Drepane africana and Pomadasys jubelini, splitting and atrophy of the muscle bundles were observed.

CONCLUSIONS

The concentrations of PAHs in analyzed sediment and organisms were higher than the maximum permissible limit of the United State Environmental Protection Agency (USEPA). Most of the detected PAHs were of petrogenic origin, which is an indication that anthropogenic activities were influencing PAH concentrations.

COMPETING INTERESTS

The authors declare no competing financial interests.

Occurrence, distribution, bioaccumulation, and ecological risk of bisphenol analogues, parabens and their metabolites in the Pearl River Estuary, South China

Bisphenol analogues and alkyl esters of p-hydroxybenzoic (parabens) can be defined as emerging endocrine-disrupting compounds (EDCs) due to their similar characteristics. This study analyzed eight bisphenol analogues, six parabens, and five paraben metabolites in seawater (including aqueous and suspended particle matter (SPM)), as well as organism samples from the Pearl River Estuary, in order to determine their occurrence, distribution, bioaccumulation, and ecological and human health risk in South China's marine environment. The aggregation concentrations of bisphenol analogues, parabens, and paraben metabolites were 106 ng/L, 4.53 ng/L, and 231 ng/L in aqueous samples, 868 ng/g, 173 ng/g, and 9320 ng/g in SPM samples, 41.6 ng/g, 6.46 ng/g, and 460 ng/g in marine organisms, respectively. This study identified significantly higher concentrations of paraben metabolites than their parent parabens in the marine environment, which has not yet been reported in previous studies. These findings call for greater attention on the contamination of paraben metabolites in marine environments. Moreover, the median values of the logarithm of bioaccumulation factors (BAF) for the detected 20 target compounds ranged from 0.11 to 5.07. Bisphenol analogues including bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), bisphenol P (BPP), and Fluornen-9-bisphenol (BPFL) (3.3 < lg BAF < 3.7), and three paraben metabolites including 4-hydroxybenzoic acid (4-HB) (3.3 < lg BAF < 3.7), methyl protocatechuate (OH-MeP), and ethyl protocatechuate (OH-EtP) (Log BAF > 3.7), exhibited varying degrees of potential bioaccumulation effect in the majority of organism samples. Furthermore, all tested chemicals in this study were at low risk quotient (RQ) levels for acute and chronic toxicity in seawater. However, the target hazard quotient (THQ) values of two paraben metabolites, 4-HB and benzoic acid (BA), were higher than 1, which indicates that paraben metabolites have the potential to adsorb into organisms, and their associated human health risks should be of great concern. Overall, the study results suggest that the occurrence and risks of emerging EDCs in coastal waters are deserving of further studies, especially in densely populated regions of the world.