An integrated evaluation of molecular marker indices and linear alkylbenzenes (LABs) to measure sewage input in a subtropical estuary (Babitonga Bay, Brazil)

Relationship between nitrate, heavy metal, and sterols contents in Japanese agricultural soils with risk of groundwater pollution

In Japanese agricultural lands, nitrate-nitrogen contamination of soil and groundwater often occurs due to the application of livestock excrements and compost. Therefore, rural soils in Japan were sampled and analyzed for nitrate-nitrogen leaching, heavy metal content, and sterols associated with livestock excrement and compost to calculate contamination risk indicators. The results were analyzed using self-organizing maps and cluster analysis. Nitrate-nitrogen content using water extraction was detected in most of the sampled soils. In addition, many samples from areas that were already severely contaminated with nitrate-nitrogen showed particularly high concentrations. Coprostanol, an indicator of fecal contamination, was detected in more than half of the samples. The main source of nitrate-nitrogen contamination in these areas is livestock excrement and compost. Self-organization maps showed that areas with high nitrate-nitrogen contamination also corresponded to areas with high copper and zinc soil contents. The self-organization maps and cluster analysis resulted in five clusters: a nitrate-contaminated group mainly originating from livestock excrement and compost, a heavy metal-contaminated group, a general group, a nitrate-contaminated group mainly originating from chemical fertilizers, and a contaminated group with potentially hazardous substances requiring attention. Authorities and decision-makers can use the results to prioritize areas requiring remediation.

Chemical contamination affecting filter-feeding bivalves in no-take marine protected areas from Brazil

Marine protected areas (MPAs) are zones geographically delimited under pre-defined management goals, seeking to reduce anthropogenic threats to biodiversity. Despite this, in recent years reports of MPAs affected by chemical contamination has grown. Therefore, this study addresses this critical issue assessing legacy and current chemical contamination in filter-feeder bivalves obtained in very restrictive no-take MPAs from Brazil. The detected pollutants encompass polycyclic aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs), and persistent organic pollutants (POPs) like dichlorodiphenyltrichloroethane (DDTs) and polychlorinated biphenyls (PCBs). Despite protective measures, bivalves from nine MPAs exhibited high LABs (13.2-1139.0 ng g-1) and DDTs levels (0.1-62.3 ng g-1). PAHs were present in low concentrations (3.1-29.03 ng g-1), as PCBs (0.7-6.4 ng g-1), hexachlorobenzene (0.1-0.2 ng g-1), and Mirex (0.1-0.3 ng g-1). Regardless of the sentinel species, MPAs and management categories, similar accumulation patterns were observed for LABs, DDTs, PAHs, and PCBs. Based on the limits proposed by Oslo Paris Commission, the measured levels of PAHs, PCBs and were below the environmental assessment criteria. Such findings indicate the no biological effects are expected to occur. However, they are higher considering background conditions typically measured in remote or pristine areas and potential simultaneous exposure. Such findings indicate an influence of anthropogenic sources, emphasizing the urgency for monitoring programs guiding strategic management efforts to safeguard these areas.

A comprehensive review of polycyclic aromatic hydrocarbons in Brazilian coastal environments

This study provides an overview of the evaluation of polycyclic aromatic hydrocarbons (PAHs) in the coastal regions of Santos Basin, located in Brazil's Southeast region, the country's most industrialized area. The analysis is based on data compiled from various studies in this area since 2000. A comprehensive literature review was conducted using the SCOPUS database, encompassing peer-reviewed scientific journals from publishers such as Elsevier, Springer, Nature, Wiley, Taylor & Francis, Google Scholar, and ResearchGate. Most of these studies have focused on the sediment compartment due to its role as the primary repository for organic matter and, consequently, PAHs in the marine environment. However, the bioavailability of organic contaminants in sediment is generally lower compared to water and suspended particulate matter, which has received less attention in the context of Santos Basin. The literature search also includes studies evaluating PAH concentrations in organisms to investigate the bioaccumulation rates of these compounds. Data presented in this review primarily originates from coastal and estuarine areas within Santos Basin, with occasional extensions to the continental shelf. The majority of publications are centered on studies conducted in the southeastern Brazilian states of São Paulo and Rio de Janeiro, where the highest levels of PAH contamination across all environmental compartments are typically observed. Santa Catarina, on the other hand, is the coastal region with fewer studies. The regions where most of the studies involving PAHs in the Santos Basin are concentrated in areas where public university research centers are located, a pattern that repeats throughout the Brazilian coast. In areas far from universities, little is known about the environmental status of PAHs.

Biochemical responses in Pacific oysters Magallana gigas (Thunberg, 1793): Tools to evaluate the environmental quality of aquaculture areas

The discharge of sanitary sewage into the bays of the Florianópolis Metropolitan Area (Southern Brazil), has led to the contamination of oyster farms. Consequently, linear alkylbenzenes (LABs) were quantified in the sediment, and the biochemical responses in gills and digestive gland of oysters from six farms were assessed. Our findings revealed elevated levels of LABs in the sediment of the Imaruim and Serraria farms. Additionally, alterations were observed in the antioxidant enzymes: catalase, glutathione peroxidase and superoxide dismutase in both oyster tissue from the Serraria, Santo Antonio de Lisboa and Sambaqui farms. Furthermore, correlation analyses indicated strong and moderate associations between biochemical responses, organic contaminants, and certain physicochemical parameters. Consequently, our results demonstrated the activation of the antioxidant system in oysters, representing a protective response to the presence of sanitary sewage and other contaminants. Therefore, we propose the utilization of biochemical biomarkers for monitoring the environmental quality of farms.

Environmental occurrence and assessment of organic pollutants in surface sediments of South Peninsular Malaysia

Organic pollution continues to be an important worldwide obstacle for tackling health and environmental concerns that require ongoing and prompt response. To identify the LAB content levels as molecular indicators for sewage pollution, surface sediments had obtained from the South region of Malaysia. The origins of the LABs were identified using gas chromatography-mass spectrometry (GC-MS). ANOVA and a Pearson correlation coefficient at p < 0.05 were used in the statistical analyses of the differences between the research locations. Internal to external (I/E) ratio, homologs C13/C12, and long to short (L/S) chains are used to identify the effectiveness of wastewater treatments. According to statistical analysis, the range of LAB level at the stations was 67.4 to 188.7 ng g-1dw. A significant difference was observed between LAB homologs (p < 0.05), with a higher level of C13 in most of the stations. The computed LAB ratio (I/E), which varied from 1.6 to 2.7, revealed the released wastewater from primary and secondary sources. LAB degradation varied between 33 and 49% in the areas that were evaluated. The treatment system of wastewater requires to be further improved, and using LAB markers to track anthropogenic contamination is imperative.

An urban metabolism framework purpose to assess the dynamics of linear alkylbenzenes (LABs) discharge flows and driving forces at the city level in Guangdong province, China

Linear alkylbenzenes (LABs) are a class of molecular markers derived from anthropogenic activities. A comprehensive understanding of the mechanism that determines their entry into anthroposphere, in terms of magnitude and pathway, is the prerequisite to establish effective mitigation measures. This study develops a methodology framework to analyze the source-sink interactions and driving factors of the direct and indirect LAB discharges from production and living activities in Guangdong Province, China from 2004 to 2017. Results indicated that the total LAB discharges of Guangdong into the environment were averaged at 2.9 kt yr-1, of which 61.9% originated from the Pearl River Delta (PRD) urban agglomeration. An average proportion of 76.0% was discharged into water bodies with the remaining released into land bodied. From 2014 to 2017, the LAB discharges increased by seven times, resulting from the steady increase of urban residential sources, while contribution from industrial sources continuously declined during the studied period. Meanwhile, the discharging hotspots expanded from Guangzhou city to other super-cities around it, including Shenzhen and Dongguan. The other cities exhibited a decreasing trend in discharges as a function of distance from these hotspot cities. The multisectoral sources of LABs differed considerably among cities, and the source contribution of each city changed significantly with progressive urbanization. The factor decomposition analysis indicated that LAB discharges in PRD cities primarily contributed by the pollutant concentration and reflected the treatment structure, while peripheral cities of the PRD mainly contributed by the per capita consumption and pollutant discharge per unit of GDP. Overall, our results provide a scientific database and supports for the regional co-remediation of anthropogenic pollution.

Bridging archaeology and marine conservation in the Neotropics

Anthropogenic impacts on tropical and subtropical coastal environments are increasing at an alarming rate, compromising ecosystem functions, structures and services. Understanding the scale of marine population decline and diversity loss requires a long-term perspective that incorporates information from a range of sources. The Southern Atlantic Ocean represents a major gap in our understanding of pre-industrial marine species composition. Here we begin to fill this gap by performing an extensive review of the published data on Middle and Late Holocene marine fish remains along the southern coast of Brazil. This region preserves archaeological sites that are unique archives of past socio-ecological systems and pre-European biological diversity. We assessed snapshots of species compositions and relative abundances spanning the last 9500 years, and modelled differences in species' functional traits between archaeological and modern fisheries. We found evidence for both generalist and specialist fishing practices in pre-European times, with large body size and body mass caught regularly over hundreds of years. Comparison with modern catches revealed a significant decline in these functional traits, possibly associated with overfishing and escalating human impacts in recent times.

Sewage contamination assessment in an urbanized tropical estuary in Northeast Brazil using elemental, isotopic and molecular proxies

The Capibaribe Estuarine System (CES) is a tropical estuary located within a densely populated metropolitan region in the Brazilian Northeast, providing multiple ecosystem services including artisanal fisheries, tourism, and navigation. A significant load of domestic and industrial effluents is causing visible environmental degradation that needs to be characterized. This study evaluated the degree of contamination by domestic sewage and the relative contribution of organic carbon (OC) sources in sediments, measuring carbon-to-nitrogen atomic (C/N)_a ratios, δ¹³C of OC, and linear alkylbenzene concentrations (LAB). The SIAR mixing model indicated that estuarine phytoplankton and sewage contribute 73% and 22% to OC, respectively, based on sedimentary (C/N)_a ratios that varied from 8.5 to 13, and δ¹³C ranging from -25.21 to -21.63‰. This suggests that eutrophication of CES is triggered by sewage inflow. The CES was moderately contaminated by LAB, and the highest concentrations observed in the inner portion, from 287 to 1349 ng g^-1 dry weight, suggests the retention of sewage. The mixing isotopic model indicated a significant dilution process of sewage-derived OC by estuarine phytoplankton. The lowest LAB in the lower estuary (317-320 ng g^-1 dw) probably resulted from marine dilution. Principal component analysis demonstrated that mud regulates sedimentary OC content, and that the sewage plume regulates sedimentary LAB. High degradation of LAB isomers probably reflects the net heterotrophic condition of this system, also suggesting these compounds are introduced into CES partially degraded. Our results pointed out that degraded OM is a result of chronic and long-term sewage input. Considering the implications of sewage pollution to environmental and public health, there is an urgent need of better policies to improve domestic effluent treatment capacity, reducing contamination of estuarine environments.

Monitoring of linear alkyl benzenes (LABs) in riverine and estuarine sediments in Malaysia

The aim of this a pioneering research is to investigate linear alkylbenzenes (LABs) as biomarkers of sewage pollution in sediments collected from four rivers and estuaries of the south and east of Peninsular Malaysia. The sediment samples went through soxhlet extraction, two-step column chromatography purification, fractionation and gas chromatography-mass spectrometry (GC-MS) analysis. Principal component analysis (PCA) with multivariate linear regression (MLR) was used as well for source apportionment of LABs. The results of this study showed that total LAB concentration was 36-1196 ng g^-1dw. The internal to external isomer ratios (I/E ratio) of LABs were from 0.56 to 3.12 indicated release of raw sewage and primary and secondary effluents into the environment of south and east of Peninsular Malaysia. Our research supported that continuous monitoring of sewage pollution to limit the environmental pollution in riverine and estuarine ecosystem.

Tracking the historical urban and rural sources of fecal pollution in a South American tropical semi-arid region using sterols and endocrine-disrupting chemicals

Sterols and endocrine-disrupting chemicals were analyzed in two dated sediment cores collected in the Jaguaribe river to determine the recent decades' influence of urbanization and agropastoral activities on the inputs of fecal pollution in a semi-arid region of Brazil. Stigmasterol and sitosterol were the most abundant of the 6 sterols examined in both cores, indicating an important contribution of organic matter from mangrove forests to the study region. Coprostanol presented a continuous increase in concentrations from the 1930s to the 2000s in one core, however, showing higher concentrations (>100 ng g^-1) in the upper layers of both cores. The sterols diagnostic ratios indicated fecal pollution through both cores, especially from the 1940s to 1970s. The coprostanol levels followed the variations in population growth in the state of Ceará. Estriol and estrone were the most abundant estrogenic hormones found in both cores. These compounds are probably related to the intense livestock activities in the Ceará state, especially after the 1970s. The baseline levels of fecal sterols and estrogen hormones found in this study possibly represent a previous unimpacted scenario and may be used for future evaluations of fecal pollution from urbanization and livestock activities.

Sterol and PAHs fingerprint analysis of organic matter at Southeast Brazilian Bay

Southeast Brazilian bays have been increasingly degraded by untreated organic loads. Therefore, to assess fecal contamination status, sediment quality regarding polycyclic aromatic hydrocarbons (PAHs), and sources of organic matter (OM), we have determined fine-grained and total organic carbon (TOC) content and concentrations of PAHs and sterols in twenty-six surface sediment samples in Sepetiba Bay. The fine-grained (1-26 %), TOC (0.20-3.45 %), PAHs (<LQ - 78.27 ng g^-1) and sterols (0.10-21.58 μg g^-1) results showed a decreasing trend from the internal to the external sector of the study area. The diagnostic ratios of selected PAHs and sterols indicated a mixture with significant contribution from continental and pyrolytic OM in all stations. The fecal contamination is significant to the internal sector of Sepetiba Bay. Considering a site-specific sediment quality guidelines (SQGs) the PAHs levels with more restricted benchmark values indicate the harbor and the internal sector as contaminated.

Low levels of persistent organic pollutants in sediments of the Doce River mouth, South Atlantic, before the Fundão dam failure

The Doce River mouth (DRM) was severely impacted by the rupture of the Fundão Dam in 2015, considered the greatest Brazilian environmental tragedy in terms of tailings volume released (>40 million m³) and traveled distance (~600 km until the Atlantic Ocean). Environmental monitoring has been performed since then, but background levels are scarce or absent to Persistent Organic Pollutants (POPs), making impact assessments difficult. In the current study, we presented the baseline levels, inventories, and risk assessment of the POPs polychlorinated biphenyl (PCBs) and organochlorinated pesticides (OCPs), in surface sediment of the DRM. Samples were collected in December 2010 and July 2011, i.e., four years before the Fundão dam failure. The total PCBs and the OCPs (Aldrin, HCHs, and Chlordanes) were detected in both sampling campaigns, with levels up to 9.50 and 1.64, 0.28, and 0.63 ng g^-1, respectively. The decrease of the Doce River flow was the main factor contributing to seasonal variations in the spatial distribution, and to a slight decline in the levels and frequency of the analyzed POPs in sediments collected in the dry season (July 2011). Environmental risk assessment, inventories, and total mass results suggest a low potential of PCBs and OCPs accumulation before the dam failure. This is the first POPs assessment in the study area that helped identify some unexpected impacts of the Fundão dam failure and contributed to the understanding of POPs cycles in the Southern Atlantic, data that are still scarce in the region.

Macrobenthic community responses to multiple environmental stressors in a subtropical estuary

We assessed how multi- and univariate models reflect marine environmental health based on macrobenthic community responses to three environmental stressor categories: hydrodynamics, organic enrichment and metal contamination. We then compared the models with the benthic index AMBI (AZTI Marine Biotic Index). Macrobenthic community and physicochemical variables were sampled at 35 sites along Babitonga Bay, a subtropical estuary in Southern Brazil. Distance-based linear modelling identified depth, grain size and organic matter as well as Cu and Zn as key stressors affecting the macrobenthos. Using canonical analysis of principal coordinates (CAP), we developed three multivariate models based on the variability in community composition, creating stress gradients. The metal gradient showed better correlation with the benthic community. Sediment quality indices (Geoaccumulation Index and Contamination Factor) showed a low to moderate contamination status, with higher concentrations for Cr, Ni and Zn at the inner areas of the bay. According to AMBI, Babitonga Bay has a “good” environmental health status, and the AMBI values show stronger correlations with the hydrodynamic and organic enrichment gradients (r = 0.50 and r = 0.47) rather than the metal gradient (r = 0.29). Lumbrineridae polychaetes (not included in the AMBI list) and Scoloplos sp. were negatively related to the metal contamination gradient and were considered sensitive, while Sigambra sp., Magelona papillicornis, the gastropod Heleobia australis and species of the crustacean order Mysida were positively related to the gradient and considered tolerant to higher concentrations of metals in the sediment. Despite the inconsistency in the ecological classification provided by AMBI and its relationship with the metal gradient, our results suggest that the environmental quality was satisfactory for the studied gradients. The metal gradient showed the weakest correlation to AMBI. In such cases, the ecological classification of taxa by the index should be evaluated under the perspective of the action of inorganic genotoxic contaminants represented by metals.

Does the environmental condition affect the tolerance of the bivalve Anomalocardia flexuosa to different intensities and durations of marine heatwaves?

Populations of the clam Anomalocardia flexuosa, subjected to different pollution conditions, were experimentally exposed to marine heatwaves of actual and future intensities and varying durations. We measured physiological and biochemical biomarkers and survival rates of the species under simulated heatwave events of 7 and 11 days. We observed that both the response of A. flexuosa to heatwaves and its baseline values of biomarkers were distinct between populations, demonstrating that the previous exposure to contaminants negatively interferes with the thermal tolerance of this bivalve. The duration and intensities of heatwaves here tested represent a considerable challenge for the survival of coastal bivalves. Our results suggest that the predicted increase in the ocean's average temperature and the frequency and intensity of marine heatwaves, as well as urbanization and increasing occupation of coastal regions, are factors that synergistically make A. flexuosa increasingly vulnerable over the decades.

Integrated approach for quantitative estimation of particulate organic carbon sources in a complex river system

Despite receiving a considerable amount of attention in the past, quantitative and systematic estimation of the source contributions for different organic carbons (OCs) in complex river systems is still challenging. In this study, we tested an integrated framework using field data of bulk elements and lipid biomarkers and hydrological modeling (hydrological simulation program FORTRAN, HSPF) for the quantitative estimation of OC loads along different land-use types of a watershed (Geumho River watershed in South Korea). Based on the specific source assignments identified from the lipid biomarker patterns in particulate organic carbon (POC) such as short/long chains of alkanes, fatty acids and alcohols, and coprostanol/cholesterol, spatial variations of the diagnostic lipids could be used as an indicator to discriminate between the contributions of natural (algae, bacteria, and terrestrial plants) and anthropogenic sources (fecal). Based on the integration of HSPF modeling, it was also found that various POC loads might be partially controlled by different water discharges within watersheds. With the increase in POC fluxes, the increase in fecal loads was also noticed, as reflected by the predominant lipid (especially coprostanol normalized by water discharges). As a straightforward approach, we developed a set of indices including fecal index-1, ratios of coprostanol, fatty acids, and alkanes, which strengthened the sensitivity for fecal contamination. Compared with the conventional HSPF results, the variations of these proposed indices were more influenced by the broadened watershed extents with increasing downstream distance, which provided a more accurate estimation of the quantitative contributions of POC loadings in the complex river system.

Biomass-derived carbon nanospheres decorated by manganese oxide nanosheets, intercalated into polypyrrole, as an inside-needle capillary adsorption trap sorbent for the analysis of linear alkylbenzenes

Carbon nanospheres (CNSs) were derived hydrothermally from biomass (orange peels) and decorated by manganese dioxide (MnO₂) nanosheets. The MnO₂/CNSs nanocomposite was intercalated into polypyrrole (PPy) during flow-through in-situ electropolymerization of pyrrole on the surface of the inner wall of a stainless-steel needle to prepare an inside-needle capillary adsorption trap (INCAT) device. The surface morphology, thermogravimetric behavior, sorption characteristics, and structure of the MnO₂/CNSs@PPy nanocomposite were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), nitrogen physisorption by the Brunauer-Emmett-Teller (BET) method, dynamic light scattering (DLS) size distribution, and Fourier-transform infrared spectrometry (FT-IR). The INCAT device was coupled with GC-FID and applied for dynamic headspace analysis of linear alkyl benzenes (LABs) in wastewater samples. The effective experimental variables on the extraction efficiency was optimized using a central composite design (CCD) based on response surface methodology (RSM). Under the optimal conditions, the limits of detection (LODs) were in the range of 0.5-1.0 ng mL^-1. The calibration plots were linear over the range of 0.01-10 μg mL^-1. The relative standard deviations (RSDs%) for intra-day, inter-day, and inter-INCAT precision were calculated 5.3-8.3%, 9.4-13.5%, and 13.6-16.9%, respectively. The developed technique was employed successfully for the analysis of LABs in water and wastewater samples with average recovery values ranging from 92 to 109%. A single INCAT device was used more than 90 times without significant change in its extraction capability.

Fecal sterols as sewage contamination indicators in Brazilian mangroves

Recent sewage contamination in Brazilian mangrove forests was evaluated using fecal sterols as biomarkers and socioeconomic indicators. The sterols were quantified by gas chromatography/mass spectrometry (GC/MS). Total fecal sterol concentrations ranged between 2.50 2.50 and 39.03 μg g^-1 and coprostanol, between 0.23 and 6.97 μg g^-1. Mangroves located in less urbanized regions presented low coprostanol levels and low coprostanol/cholesterol and (5β/5β + 5α) stanol ratios in sediment, while urban mangrove forests presented moderate fecal contamination. In the latter, an intense contribution of untreated domestic effluents associated to metropolitan areas was noted, leading to a significant correlation between coprostanol concentrations and inadequate sanitation, reflecting environmental problems associated to disorderly urbanization processes coupled to the absence of an adequate urban infrastructure. However, even in metropolitan areas, fecal sterol levels did not reach those of highly contaminated regions, probably due to the intense and accelerated degradation process typical of tropical environments. However, this study highlights the importance of fecal contamination assessment in mangrove areas since the presence of untreated sewage in these ecosystems is an issue of public and environmental health.

Occurrence and fate of linear alkylbenzenes and their potential as environmental molecular markers in highly urbanized river systems

Rapid industrialization, urbanization, and population growth have led to the common occurrence of black-stinking urban rivers. Assessing regional anthropogenic influences is beneficial to develop effective remediation strategies. This study comprehensively investigated the occurrence and fate of linear alkylbenzenes (LABs) as molecular markers of anthropogenic influences in three media (filtered water, suspended particulate matter (SPM), and sediment) in a highly urbanized river (Baihaimian River) in Guangzhou, South China. The concentrations of LABs ranged from 41 to 215 ng/L in the dissolved phase, from 7122 to 46,640 ng/g dry weight in the SPM phase, and from 73 to 3650 ng/g dry weight in surface sediments (0-10 cm depth). The spatial distribution of LABs was probably affected by the surrounding environment, river flux, and sediment properties. No biotransformation of LABs in water samples and a slight biotransformation in sediments were observed. Significant correlations were found between total nitrogen, ammonia nitrogen, and LABs in river water, indicating the same domestic wastewater sources. The positive correlation between total organic carbon (TOC) and LABs in sediments suggested that TOC worked as the controlling factor for the redistribution of LABs and that local sewage discharge was the dominant TOC input. The total mass inventory of LABs in sediment in Baihaimian River was 21 kg. The total mass of LABs released into Baihaimian River was 183 kg per year, among them, 63% was discharged into the adjacent Liuxi River.

Tracking the sources of allochthonous organic matter along a subtropical fluvial-estuarine gradient using molecular proxies in view of land uses

Sedimentary sterols and linear alkylbenzenes associated with allochthonous organic matter (AOM) inputs were studied in surface sediments along the Tubarão riverbed, South Brazil. These markers were analysed in terms of concentrations, diagnostic ratios and by using multivariate analyses to identify the main organic matter sources. It was necessary to integrate all these factors to distinguish the sources and determine sewage contamination. Phytosterols predominated over faecal sterols, but the contributions of livestock waste along the river (determined in 50% of the sites) were confirmed by the fingerprint analysis. Raw sewage contamination was verified at one site, according to the increased levels of sewage molecular markers and confirmed by the multivariate analyses and diagnostic ratios calibrated to this region. A possible synergistic effect between inorganic nanoparticles from coal mine waste and organic contaminants related to AOM input was suggested and should not be ignored since both activities severely contribute to the environmental changes in much of this fluvial-estuarine gradient from the South Atlantic.

Steroid Fingerprint Analysis of Endangered Caspian Seal (Pusa caspica) through the Gorgan Bay (Caspian Sea)

The profile of steroid congeners was evaluated in Caspian seals Pusa caspica by age, sex, and tissue-specific bioaccumulation, and compared with that of abiotic matrices (seawater, surface sediment, and suspended particulate materials, SPMs) from Miankaleh Wildlife/Gorgan Bay, (Caspian Sea, Iran). To identify the level of human fecal contamination, ∑25 sterol congeners were measured in all abiotic/biotic samples, revealing coprostanol, a proxy for human feces, as the most abundant sterol (seawater: 45.1-20.3 ng L^-1; surface sediment: 90.2-70.3 ng g^-1 dw; SPMs: 187.7-157.6 ng g^-1 dw). The quantification of ∑25 sterols in seals followed the order of brain > liver > kidney > heart > blood > spleen > muscle > intestine > blubber > fur, and in both sexes coprostanol level (8.95-21.01% of ∑25s) was higher in blubber and fur, followed by cholesterol in brain, liver, kidney, heart, and blood, cholestanone in intestine and muscle, and β-sitosterol in spleen. Though no age/sex differentiation was observed, the mean concentration of ∑25s was higher in male than females and pup. Different diagnostic ratios revealed sterols originating from human and nonhuman sewage sources. Findings pinpoint the urgent necessity to investigate the ecotoxicity of fecal sterols in mammals, and consequent implications for human health.

Linear alkylbenzenes in surface sediments of an estuarine and marine environment in peninsular Malaysia

Linear alkylbenzenes were determined in the surface sediments of Muar River and Pulau Merambong, Peninsular Malaysia. The concentrations ranged from 87.4 ng g^-1 to 188.1 ng g^-1 and from 67.4 ng g^-1 to 98.2 ng g^-1 of dry weight, respectively. The composition profiles of LABs were characterized, and sewage treatment levels were identified. The ratios of internal to external isomers (I/E ratios) of the linear alkylbenzenes in Muar River sediments ranged from 1.7 to 2.2, whereas those of Pulau Merambong sediments ranged from 1.6 to 1.7. The calculated LAB ratios indicated that the study areas received primary and secondary sewage effluents. The degradation of linear alkylbenzenes in Muar River ranged from 33% to 43%, and that in Pulau Merambong ranged from 33% to 34%. The higher degradation indices in Muar River are a sign of improvement in wastewater treatment.

Use of sterols and linear alkylbenzenes as molecular markers of sewage pollution in Southeast Asia

Southeast Asia has undergone rapid developments in terms of urbanization, economic and population growth. The progress in sewerage treatment infrastructure has not kept pace with such developments. The inadequacy and inefficiency of sewerage systems has prompted the release of untreated sewage into the aquatic environment of Southeast Asia causing many waterborne illnesses since surface water is utilized for recreational, agricultural and aquaculture purposes and, above all, as a source of water intake in Southeast Asia. This paper will review the current data on molecular markers of sewage pollution including sterols and linear alkylbenzenes (LABs) in Southeast Asian aquatic environment to clarify the state of sewage pollution and the competence of sewage treatment plants (STPs) in this area. Despite the importance of sewage pollution research in the region, the number of studies using molecular markers to trace the sources of sewage pollution is limited. So far, indicators of sewage pollution have been investigated in aquatic environments of Indonesia, Vietnam, Malaysia, the Philippines, Thailand, Cambodia and Brunei among Southeast Asian countries. The concentrations and diagnostic ratios of faecal sterols and LABs show the release of untreated and primary treated urban waste into water bodies of these countries. Further studies are required to fill the data gaps in Southeast Asia and come to a better understanding of the trends of sewage pollution in this part of the world. Graphical abstract.

Organic contamination of beached plastic pellets in the South Atlantic: Risk assessments can benefit by considering spatial gradients

Microplastics are important vectors for the transport and accumulation of persistent organic contaminants in coastal and marine environments. We determined the concentration of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) associated with microplastic pellets collected along a 39-km stretch of Brazil's South Atlantic coastline to understand the spatial dynamics and potential risk posed by these contaminants. Total PAH concentrations ranged from 1,454 to 6,002 ng g^-1 and regularly exceeded the threshold effect level (TEL) for sediments defined by the United States Environmental Protection Agency. Sampling stations, spaced evenly along the coastline (i.e., 3-km intervals) exhibited a general north-to-south decline in the concentrations of some PAHs, but this spatial gradient was complicated by small-scale differences in the concentrations and composition of associated contaminants. Similarly, analysis of individual isomer ratios revealed further complexity driven by differences in the contribution of petrogenic versus pyrolytic inputs which pose different levels of risk to marine organisms. PCB concentrations ranged from 0.8 to 104.6 ng g^-1 and were dominated by low chlorinated congeners likely to have originated from major industrial areas to the north. Overall, this study highlights the challenge of directly linking microplastic pollution with the potential toxicological effects of organic contaminants in coastal waters. We recommend that monitoring programs should explicitly consider both the origin (i.e., pellet sources and dispersal pathways) and nature of organic contamination (i.e., concentration and composition) when assessing the risks for biota and human health.

Tracking the historical sewage input in South American subtropical estuarine systems based on faecal sterols and bulk organic matter stable isotopes (δ13C and δ15N)

Faecal sterols and stable isotopes (δ¹³C and δ¹⁵N) from bulk organic matter (OM) were analysed in three sedimentary cores collected in two subtropical bays located in the South Atlantic to evaluate historical trends in the sewage input and to track possible changes in the bulk isotopic composition of OM in recent decades. The values of δ¹³C and δ¹⁵N ranged from -27.4 to -25.0‰ and from 0.5 to 3.9‰, respectively, without a clear trend in the variation over the whole period covered by sediment cores and with no conclusive interpretation of a specific range value typically related to the sewage input for these areas. The maximum coprostanol concentration was 0.19 μg g^-1 in the upper 4 cm of one core, which was not considered contaminated by evaluation of the sterols diagnostic ratios. Even at low levels, the coprostanol concentrations followed variations in urban and economical regional development. Baseline values for faecal sterols (in average between 0.03 and 0.05 μg g^-1), which may represent a previous non-impacted environment scenarios, were calculated for use in comparative perspectives for future evaluations of the sewage input and contamination.

Environmental health in southwestern Atlantic coral reefs: Geochemical, water quality and ecological indicators

Climate change, pollution and increased runoff are some of the main drivers of coral reefs degradation worldwide. However, the occurrence of runoff and marine pollution, as well as its ecological effects in South Atlantic coral reefs are still poorly understood. The aim of the present work is to characterize the terrigenous influence and contamination impact on the environmental health of five reefs located along a gradient of distance from a river source, using geochemical, water quality, and ecological indicators. Stable isotopes and sterols were used as geochemical indicators of sewage and terrigenous organic matter. Dissolved metal concentrations (Cu, Zn, Cd, and Pb) were used as indicators of water quality. Population density, bleaching and chlorophyll α content of the symbiont-bearing foraminifer Amphistegina gibbosa, were used as indicators of ecological effects. Sampling was performed four times during the year to assess temporal variability. Sediment and water quality indicators showed that reefs close to the river discharge experience nutrient enrichment and sewage contamination, and metals concentrations above international environmental quality guidelines. Higher levels of contamination were strongly related to the higher frequency of bleaching and lower density in A. gibbosa populations. The integrated evaluation of stable isotopes, sterols and metals provided a consistent diagnostic about sewage influence on the studied reefs. Additionally, the observed bioindicator responses evidenced relevant ecological effects. The water quality, geochemical and ecological indicators employed in the present study were effective as biomonitoring tools to be applied in reefs worldwide.

Sterol biomarkers and fecal coliforms in a tropical estuary: Seasonal distribution and sources

The Sergipe River estuary has been subjected to a range of anthropogenic activities including food, plastic, textile, ceramic and metallurgical production plants along with domestic sewage inputs, all of which are of environmental concern. In this study, the levels of fecal coliforms (FC) in surface water samples and sterols in superficial sediment samples collected from the Sergipe River estuary were determined. Based on the FC concentrations, 58% of the water samples were considered Water Potentially Unusable (WPU) according to the United States Environmental Protection Agency (USEPA). Concentrations of coprostanol ranged from 13 to 1072 ng g^-1, indicating a significant input of sewage at some points in the estuary. Principal Component Analysis (PCA) showed that there is no clear correlation between the coprostanol and coliform data, which may be due to the high resistance to degradation of coprostanol in sediments and to recent inputs of sewage at the water sample collection points.

Emerging and traditional organic markers: Baseline study showing the influence of untraditional anthropogenic activities on coastal zones with multiple activities (Ceará coast, Northeast Brazil)

Molecular markers are useful tools to characterize natural and anthropogenic impacts on coastal zones. Distribution of n-alkanes showed that the Pacoti River was predominantly influenced by terrigenous input. Distribution of polycyclic aromatic hydrocarbon (PAH) indices showed a mix of natural sources, especially pyrogenic influences. Sterol and hormone levels showed sewage discharge. Integrated geographic assessment showed that pyrogenic process and sewage discharge are predominant along the river because of natural and different anthropogenic activities. The upstream region is influenced by rural activities such as livestock and discharge from the sewage treatment plant, whereas the estuarine region is influenced by urban and industrial activities, predominantly the discharge of treated or untreated sewage, vehicle traffic, and manufacture of red ceramics. On the other hand, on the river mouth, there is the predominance of aquaculture activities. Traditional anthropogenic markers are not sufficient for producing a comprehensive assessment of anthropogenic impacts in areas with multiple activities.

Emerging and Traditional Organic Markers in Areas with Multiple Anthropogenic Activities: Development of an Analytical Protocol and Its Application in Environmental Assessment Studies

This work describes the development of an analytical protocol combining cleanup by liquid-solid extraction and GC-MS for the determination of emerging and traditional multi-molecular markers. The procedure was used for the environmental assessment of a coastal region with multiple human activities. Global recovery rates ranged from 45.49% to 119.4% for the 46 substances analyzed: pesticides (73.7%-97.7%), PAHs (52.5%-93.7%), sterols (66.7%-119.4%) and natural and synthetic hormones (45.5%-119.1%) and the rates were compared to those reported in studies on both individual classes and multi-classes of contaminants. The analytical protocol demonstrated satisfactory efficiency and could be used successfully in environmental assessments and source assignment studies. The environmental assessment study revealed that the Acaraú River in northeastern Brazil is influenced by the combination of urban and rural activities. The sources of PAHs are vehicular traffic and the burning of biomass; pesticides stem from pest control in agribusiness and public health campaigns; sterols and hormones stem from a combination of natural inputs, human sewage (treated and raw) and animal husbandry activities.

Pollution status of marine protected areas worldwide and the consequent toxic effects are unknown

Chemical pollution is considered a factor that may threaten marine protected areas (MPAs), and recent studies have found contamination and associated biological effects in some MPAs. However, organized data on this topic are lacking. This study reviewed the literature on pollution in MPAs in order to compile data, determine whether MPAs are influenced by pollution and, whenever possible, describe how they are being affected by contaminants. The results show that the pollution status is unknown in most MPAs worldwide. When any information is available, it is often insufficient to diagnose the threats to biodiversity or to support further actions. More robust and extensive information is available on a small number of MPAs, and much less information is available regarding the negative effects of pollution. More than 80% of the areas studied exhibited evidence of contamination at potentially toxic concentrations or were found to have a status that produced toxic effects on the biota. The scientific community is encouraged to study pollution in MPAs worldwide.

Hydrocarbon and sewage contamination near fringing reefs along the west coast of Havana, Cuba: A multiple sedimentary molecular marker approach

Organic contamination is a major environmental concern in coastal regions, and it can be evaluated by the determination of aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), faecal sterols and linear alkylbenzenes (LABs). The concentrations of these organic markers were obtained from nine surface sediment samples to evaluate a possible contamination near a fringing reef on the west coast of Havana, Cuba. The AH levels ranged from 1.24 to 135.6 μg g^-1, the PAH levels were up to 2133 ng g^-1, the faecal sterol levels ranged from 0.03 to 1.54 μg g^-1, and the total LAB levels were up to 22.7 ng g^-1. The highest concentrations were obtained at sites close to Havana Bay and at the sources of untreated sewage input. A decreasing concentration gradient was observed from Havana Bay to the outer sites. Although only two sites presented high levels of contamination, untreated sewage discharged close to the fringing reef may affect its environment.

Insights about sources, distribution, and degradation of sewage and biogenic molecular markers in surficial sediments and suspended particulate matter from a human-impacted subtropical estuary

The molecular markers sterols and linear alkylbenzenes (LABs) were analyzed in the surficial sediments and suspended particulate matter (SPM) of a subtropical estuary in South Atlantic (Paranaguá Estuarine System). The purpose of this study was identify the spatial distribution of sewage and the input of biogenic organic matter (OM) and to provide comparative insights about their behavior, compositions, and sources. The concentration of coprostanol ranged from < DL (detection limit) to 2.67 μg g^-1 in SPM and from < DL to 0.94 μg g^-1 in sediments. Total LABs ranged from 43.8 to 480.0 ng g^-1 in SPM and from < DL to 21.0 ng g^-1 in sediments. LABs homologs composition varied between the two matrices. The local hydrodynamic pattern may promote water column homogenization, dispersion, and dilution of sewage particles, and preferential sedimentation in fluvial and mixture zones. Results suggest that SPM is a good matrix for larger spatial and short time scale evaluation while sediments may help to define hot spot areas of input and final deposition of sewage particles. Marine sterols predominated in SPM while no dominance patterns of marine/terrestrial sterols occurred in surficial sediments. The higher degradation rates of sterols and LABs in the water column must be the main factor for the sharp drop in concentration towards the sediment and the variation of the preferential composition of these markers between compartments.

Ecological risk assessment of sedimentary hydrocarbons in a subtropical estuary as tools to select priority areas for environmental management

The concentration, distribution, and ecological risk of hydrocarbons, as well as bulk parameters, were determined in surface sediments of the Babitonga Bay, a subtropical human-impacted estuary in South Atlantic. Total aliphatic and polycyclic aromatic hydrocarbons (PAHs) ranged between 0.8 and 201.2 μg g^-1 and from 8.7 to 5489 ng g^-1, respectively. Saguaçú Lagoon, the region near the ferry boat and the vicinity of São Francisco harbour (SFH), presented high hydrocarbon concentrations. Despite the low accumulation trend in this region, the SFH and city may act as a punctual hydrocarbon source. The inner portion of the estuary had the finest sediment grains and the highest concentrations of carbon, nitrogen, and sulphur, indicating its importance as a depositional and cumulative area. The occurrence of unresolved complex mixture suggested chronic oil contamination. Petrogenic (based on the high percentage of alkylated PAHs) and pyrolytic (according to the diagnostic ratios of PAH isomer pairs) sources were confirmed. Ecological risk assessment was evaluated by the risk quotient (RQ). All samples had at least one priority PAH present at above the negligible concentration, including naphthalene, which was observed in all samples. Only the sites near the ferry boat and at the Saguaçú Lagoon contained compounds with concentrations above their maximum permissible concentrations, while all other sampling sites are classified as "Low-risk." The spatial distribution of RQs coincides with PAHs distribution, indicating that the regions near SFH, ferry-boat, and the Saguaçú Lagoon should be considered to be priority areas when making environmental monitoring policies.

Using fecal sterols to assess dynamics of sewage input in sediments along a human-impacted river-estuary system in eastern China

Sedimentary fecal sterols and other sterol biomarkers, combined with bulk total organic carbon (TOC) and its stable carbon isotope were applied to characterize the sewage contamination across a ca. 280 km transect from the Xiaoqing River to the Laizhou Bay, a typical river-estuary system subjected to extensive anthropogenic stress due to rapid regional urbanization and industrialization in eastern China. Two sampling events were performed in both spring and summer seasons in the Laizhou Bay adjacent to the Xiaoqing River in order to assess the potential seasonal variation. Fecal sterols such as coprostanol and epicoprostanol, which are typical indicators of anthropogenic sewage input, displayed high concentrations of up to 63.2 μg g^-1 dry weight (dw) and 13.1 μg g^-1 dw, respectively. Results suggested that most of the stations along the Xiaoqing River were severely contaminated by fecal inputs with a decreasing trend from the river to the estuary that was mainly explained by the increasing distance from the diffuse sewage sources and the gradual dilution by sea water. Although there was no significant difference in fecal sterol concentrations between spring and summer in the Laizhou Bay, suggestive of no significant difference in sewage abundance, significantly higher average epicoprostanol/coprostanol and lower coprostanol/epicoprostanol ratios were observed in spring than summer, indicative of different sewage sources (e.g., human vs. non-human). Seasonal discharge and land-runoff, air temperature related to microbial activity differences and different extend of animal manure irrigation during agricultural planting could be additional reasons and need further investigation. Nevertheless, fecal sterol concentrations, distributions and diagnostic ratios should all be taken into consideration to better understand sewage inputs and source dynamics in river-estuary ecosystems.

Organic contamination as a driver of structural changes of hydroid's assemblages of the coral reefs near to Havana Harbour, Cuba

Hydroid assemblage's responses to organic contamination were evaluated using sedimentary sterols as explanatory variables. At seven coral reef sites in the Havana west coast, hydroids were collected along three 10 m × 1 m, 10 m deep transects. Five sterols were analysed, i.e., coprostanol, an indicator of faecal contamination, and cholestanol, cholesterol, stigmasterol and brassicasterol, indicators of biogenic organic matter inputs. The sampling sites were classified by level of contamination. A total of 65 species comprised the hydroid assemblages. Hydroids community abundance and richness decreased in the contaminated sites. Coprostanol had the highest relative importance for these variables and also for Plumularia floridana and Clytia gracilis abundances. Obelia dichotoma and Halecium bermudense were relatively abundant in the contaminated sites. The results indicate that faecal contamination negatively affected the hydroid assemblages, highlighting the importance of integrated biological and chemical indicators to evaluate the environmental conditions of the Havana coral reef.

Testing biomarker feasibility: a case study of Laeonereis culveri (Nereididae, Annelida) exposed to sewage contamination in a subtropical estuary

The feasibility of biomarkers to accurately detect pollution in estuaries and coastal areas appears to be overestimated in the scientific literature, and is likely stemming from a bias towards publishing only positive results. Herein, we test the applicability of antioxidant capacity and lipid peroxidation to detect potential in situ sewage impacts on a subtropical estuary. We experimentally assessed variation in malondialdehyde (MDA, an indicator of lipid peroxidation) and total antioxidant capacity against peroxyl radicals (ACAP) through transplantations of the worm Laeonereis culveri from control to sewage-polluted areas. Variations in biomarkers were more related to natural environmental variability and small-scale heterogeneity among areas than to experimental exposure to sewage. Use of oxidative stress biomarkers is promising but further experimental work under real-life conditions is necessary to further validate and establish their accuracy and feasibility for practical purposes.

Distribution of linear alkylbenzenes as a domestic sewage molecular marker in surface sediments of International Anzali Wetland in the southwest of the Caspian Sea, Iran

Due to directly receiving high volume of untreated urban and industrial sewage and in turn transferring the pollutants to fish and back to humans, the International Anzali Wetland has been considered to be urgently registered in the Montreux Record. Hence, the present study was aimed to determine the spatial distribution of the linear alkylbenzenes (LABs) in surface sediments of the wetland and its sewage contamination situation. The surface sediments (sampling stations = 167) were collected from the western, eastern, southwest, and central regions of the wetland. The samples were extracted, fractioned, and then analyzed using gas chromatography-mass spectrometry (GC-MS). The concentration of LABs in the sediment samples revealed a range from 394.12 to 109,305.26 ng g^-1 dw. The concentrations of ΣLABs in the eastern region were significantly higher than that in the other regions. The occurrence of low ratio of internal to external isomers (I/E ratio) of LABs (from 0.65 to 1.30) and D% (from - 0.07 to 24.13) implied effluent row or poorly untreated sewage into the wetland. No correlation was observed between the detected LAB concentrations with total organic carbon (TOC) and grain size. Taken together, regional anthropogenic inputs are the controlling factors for the observed spatial distributions of ∑LABs in the International Anzali Wetland. The findings suggested that LABs are powerful indicators to trace anthropogenic sewage contamination and also highlighted the necessity of sewage treatment plants to be founded around the International Anzali Wetland, especially in the vicinity of the eastern and central regions.

An integrated evaluation of some faecal indicator bacteria (FIB) and chemical markers as potential tools for monitoring sewage contamination in subtropical estuaries

Sewage input and the relationship between chemical markers (linear alkylbenzenes and coprostanol) and fecal indicator bacteria (FIB, Escherichia coli and enterococci), were evaluated in order to establish thresholds values for chemical markers in suspended particulate matter (SPM) as indicators of sewage contamination in two subtropical estuaries in South Atlantic Brazil. Both chemical markers presented no linear relationship with FIB due to high spatial microbiological variability, however, microbiological water quality was related to coprostanol values when analyzed by logistic regression, indicating that linear models may not be the best representation of the relationship between both classes of indicators. Logistic regression was performed with all data and separately for two sampling seasons, using 800 and 100 MPN 100 mL^-1 of E. coli and enterococci, respectively, as the microbiological limits of sewage contamination. Threshold values of coprostanol varied depending on the FIB and season, ranging between 1.00 and 2.23 μg g^-1 SPM. The range of threshold values of coprostanol for SPM are relatively higher and more variable than those suggested in literature for sediments (0.10-0.50 μg g^-1), probably due to higher concentration of coprostanol in SPM than in sediment. Temperature may affect the relationship between microbiological indicators and coprostanol, since the threshold value of coprostanol found here was similar to tropical areas, but lower than those found during winter in temperate areas, reinforcing the idea that threshold values should be calibrated for different climatic conditions.

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in sediments from an urban- and industrial-impacted subtropical estuary (Babitonga Bay, Brazil)

Babitonga Bay is a large estuary, which has been under pressure from anthropogenic activities coexisting with a natural area of Atlantic rainforest and mangrove systems. The concentration of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was determined to evaluate the contamination status and the determine possible pollution sources in the estuary. The ∑DDT (sum of DDT, DDE and DDD concentrations) was the predominant OCP group, with concentrations ranging from <DL (below detection limit) to 122ng g^-1. The exceptionally high concentration of p,p'-DDT (80%) found near São Francisco harbour exceeded SQG limits indicating highly toxic conditions in the area that may be attributed to a recent contamination from some local input. In contrast, other sites in the estuary presented higher concentration of the metabolite p,p'-DDE (34%). The results suggest strongly anthropogenic impact in specific sites of this estuary, which need further investigation.

Lipid biomarkers and spectroscopic indices for identifying organic matter sources in aquatic environments: A review

Understanding the dynamics of organic matter (OM) and the roles in global and local carbon cycles is challenging to the fields of environmental sciences and biogeochemistry. The accurate identification of OM is an essential element to achieve this goal. Lipids, due to their ubiquitous presence and diagenetic and chemical stability, have long and successfully been used as molecular makers in assessing the sources and the fate of OM in natural environments. In parallel, optical properties of dissolved organic matter (DOM) have been suggested as efficient tools in tracing OM sources. In this review, three representative lipid biomarkers and several common spectroscopic indices were compared for their capabilities to identify OM sources in various aquatic environments. Spectroscopic indices present various benefits in term of the high sensitivity, easy and rapid analysis, and a low cost, providing reliable information on major sources (i.e., autochthonous, allochthonous and anthropogenic) of DOM in given systems investigated. However, for further understanding the associated biogeochemistry (e.g., diagenetic changes in sources), using biomarkers is preferable due to their abilities to identify a wide spectrum of different sources simultaneously as well as their high resolution for mixed OM sources. Thus, a complementary use of both tools is highly recommended for accurately tracking OM sources and the dynamics in aquatic systems, particularly in a watershed affected by multiple sources. Nevertheless, future studies need to be carried out (1) to refine the accuracy of the source assignments in a wide range of settings along with the development of an extensive database encompassing various sources, environmental factors, and geographical locations and (2) to understand how biogeochemical processes reflect the biomarkers and the spectroscopic indices used.

Occurrence of cocaine and benzoylecgonine in drinking and source water in the São Paulo State region, Brazil

The occurrence of illicit drugs in natural waters (surface, source and drinking water) is of interest due to the poor sanitation coverage and the high consumption of drugs of abuse in Brazil. In addition, little is known about the effects of these compounds on aquatic organisms and human health. This work investigates the occurrence of cocaine (COC) and its major metabolite, benzoylecgonine (BE), in surface and drinking water collected in rivers from a populated geographic area in Brazil. Surface water samples were collected in 22 locations from 16 different rivers and one dam from São Paulo State, whereas drinking water samples were collected in 5 locations. Samples were collected during the dry and wet season. Among the 34 surface water samples analyzed, BE was detected above the LOD in 94%, while COC in 85%. BE concentrations ranged from 10ngL^-1 to 1019ngL^-1 and COC concentrations from 6ngL^-1 to 62ngL^-1. In the drinking water samples analyzed, BE and COC were found in 100% of the samples analyzed. For BE, concentrations were found in the range from 10ngL^-1 to 652ngL^-1, and COC was quantified in concentrations between 6 and 22ngL^-1. These concentrations are one of the highest found in urban surface waters and may pose some risk to aquatic species. However, no human health risk was identified using the Hazard Quotient. BE is proposed as a reliable indicator of sewage contamination in both source and drinking water.

Evaluation of anthropogenic contamination using sterol markers in a tropical estuarine system of northeast Brazil

The São Francisco River estuarine system, located in the Northeast coast of Brazil, has great economic, tourist and social importance. Its waters are used for activities such as agriculture, aquaculture, navigation and fishery, which supplies the surrounding communities. In this study, sterols markers were determined in twenty-eight sediment samples from São Francisco River estuary by gas chromatography - mass spectrometry (GC-MS). Sterol analysis was useful to distinguish between anthropogenic and biogenic organic matter (OM) sources in the studied area. Six sterols were quantified, suggesting different sources. Concentrations of fecal sterol (coprostanol) were lower than 500ngg(-1), suggesting no indicative of severe sewage contamination.However, two stations showed concentrations around 100ngg(-1) and the values for the coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios indicates sewage contamination. The results in this study may be considered as baseline concentrations to be used as future reference for monitoring programs to prevent anthropogenic impacts.

Sterol ratios as a tool for sewage pollution assessment of river sediments in Serbia

In this work, source pollution tracing of the sediments of the Danube River and its tributaries in Serbia was performed using sterol ratios. Improved liquid chromatography-tandem mass spectrometry method, which enabled complete chromatographic separation of four analytes with identical fragmentation reactions (epicoprostanol, coprostanol, epicholestanol and cholestanol), was applied for the determination of steroid compounds (hormones, human/animal and plant sterols). A widespread occurrence of sterols was identified in all analyzed samples, whereas the only detected hormones were mestranol and 17α-estradiol. A human-sourced sewage marker coprostanol was detected at the highest concentration (up to 1939 ng g(-1)). The ratios between the key sterol biomarkers, as well as the percentage of coprostanol relative to the total sterol amount, were applied with the aim of selecting the most reliable for distinction between human-sourced pollution and the sterols originated from the natural sources in river sediments. The coprostanol/(cholesterol + cholestanol) and coprostanol/epicoprostanol ratios do not distinguish between human and natural sources of sterols in the river sediments in Serbia. The most reliable sterol ratios for the sewage pollution assessment of river sediments in the studied area were found to be coprostanol/(coprostanol + cholestanol), coprostanol/cholesterol and epicoprostanol/coprostanol. For the majority of sediments, human-derived pollution was determined. Two sediment samples were identified as influenced by a combination of human and natural biogenic sources.

The occurrence of PAHs and faecal sterols in Dublin Bay and their influence on sedimentary microbial communities

The source, concentration, and potential impact of sewage discharge and incomplete organic matter (OM) combustion on sedimentary microbial populations were assessed in Dublin Bay, Ireland. Polycyclic aromatic hydrocarbons (PAHs) and faecal steroids were investigated in 30 surface sediment stations in the bay. Phospholipid fatty acid (PLFA) content at each station was used to identify and quantify the broad microbial groups present and the impact of particle size, total organic carbon (%TOC), total hydrogen (%H) and total nitrogen (%N) was also considered. Faecal sterols were found to be highest in areas with historical point sources of sewage discharge. PAH distribution was more strongly associated with areas of deposition containing high %silt and %clay content, suggesting that PAHs are from diffuse sources such as rainwater run-off and atmospheric deposition. The PAHs ranged from 12 to 3072ng/g, with 10 stations exceeding the suggested effect range low (ERL) for PAHs in marine sediments. PAH isomer pair ratios and sterol ratios were used to determine the source and extent of pollution. PLFAs were not impacted by sediment type or water depth but were strongly correlated to, and influenced by PAH and sewage levels. Certain biomarkers such as 10Me16:0, i17:0 and a17:0 were closely associated with PAH polluted sediments, while 16:1ω9, 16:1ω7c, Cy17:0, 18:1ω6, i16:0 and 15:0 all have strong positive correlations with faecal sterols. Overall, the results show that sedimentary microbial communities are impacted by anthropogenic pollution.

Complex spatial and temporal variation of subtropical benthic macrofauna under sewage impact

To better understand variation in sewage-impacted benthic macrofauna from subtropical tidal flats over time and space, we applied a five-factor linear model at a hierarchy of spatial (Condition - Contaminated or Non-Contaminated, Tidal Flat and Plot) and temporal scales (Season and Fortnight). The Contaminated site showed high levels of coprostanol and the presence of Paranais cf frici as markers or indicators of organic enrichment. Differences between Seasons were more pronounced for the faunal variation patterns than for the other parameters, with lower species richness and abundance in summer. There were significant interactions between Fortnight and Tidal Flat for most variables, reflecting marked heterogeneity within Tidal Flats. Benthic community has significantly changed over short periods of time. These rapid changes may lead to erroneous interpretations and mask the true sources of variation. Our results clearly demonstrate the need to better understand benthic temporal variability even at small scales.

Quantification of Sterol and Triterpenol Biomarkers in Sediments of the Cananéia-Iguape Estuarine-Lagoonal System (Brazil) by UHPLC-MS/MS

Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananéia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananéia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve.

Assessment of anthropogenic contamination with sterol markers in surface sediments of a tropical estuary (Itajaí-Açu, Brazil)

The Itajaí-Açu estuarine region is one of the most important estuarine systems of south Brazil, due to the location of the Itajaí Harbor, which is the major route of international trading of the state and the largest national fishing pole landing. In addition, industries as well as urban and tourism activities are potential sources of pollution in this area. In the present study, sediment samples from 12 stations along the estuarine system were collected and extracted followed by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis. Eight sterols were identified and quantified, indicating natural and anthropogenic sources. Coprostanol concentrations ranged from <4 up to 8930 ng g(-1) of dry weight sediment with higher values being observed in the area next to the Itajaí Harbor and under influence of Itajaí-Mirim River flow, which receives wastewater from several cities. Concentrations and selected sterol ratios were useful tools used to distinguish anthropogenic and biogenic organic matter (OM) sources in the studied area, where coprostanol concentrations higher than 500 ng g(-1) were observed in 42% of the stations analyzed, indicating strong sewage contamination. Factor analysis with principal component analysis (FA/PCA) has distinguished two different groups of samples, with high and low total sterol concentrations. FA/PCA results revealed that the stations located in the estuary were separated by PC1 because they are clearly contaminated by sewage, also pointed by coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios and by the higher concentrations of fecal sterols.

Sewage contamination of sediments from two Portuguese Atlantic coastal systems, revealed by fecal sterols

Fecal sterols in sediments were used to assess the degree of sewage contamination in Ria de Aveiro lagoon and Mondego River estuary for the first time. Coprostanol, the major fecal sterol, averaged 1.82 ± 4.12 μg g(-1), with maxima of 16.6 μg g(-1). The northwestern sector of the Ria and a marina at Mondego estuary showed the highest level of sewage contamination. This scenario was confirmed by several diagnostic ratios based on fecal sterols and other phytosterols. Our data revealed that in spite of the improvements achieved in the last decades, there is still a need for control the organic inputs into the aquatic environment in the studied regions.

Baseline distribution and sources of linear alkyl benzenes (LABs) in surface sediments from Brunei Bay, Brunei

Sewage pollution is one of major concerns of coastal and shoreline settlements in Southeast Asia, especially Brunei. The distribution and sources of LABs as sewage molecular markers were evaluated in surface sediments collected from Brunei Bay. The samples were extracted, fractionated and analyzed using gas chromatography- mass spectrometry (GC-MS). LABs concentrations ranged from 7.1 to 41.3 ng g(-1) dry weight (dw) in surficial sediments from Brunei Bay. The study results showed LABs concentrations variably due to the LABs intensity and anthropogenic influence along Brunei Bay in recent years. The ratio of Internal to External isomers (I/E ratio) of LABs in sediment samples from Brunei Bay ranged from 0.56 to 2.17 along Brunei Bay stations, indicating that the study areas were receiving primary and secondary effluents. This is the first study carried out to assess the distribution and sources of LABs in surface sediments from Brunei Bay, Brunei.