Evaluation of Organochlorine Pesticides (OCPs) and Polychlorinated Biphenyls (PCBs) Concentrations in the River and Marine Sediments of Samsun Coastline

Risk assessment and contaminant characterization of PCBs, PAHs, and heavy metals in Pichavaram mangrove sediments, Tamil Nadu, India

The coastal region of Pichavaram, Tamil Nadu, India, is a critical ecological zone that supports diverse marine life and local livelihoods; however, it faces significant environmental challenges due to contamination from persistent toxic substances (PTSs) and heavy metals, which pose serious ecological and human health risks. In the present study, sediment samples collected from the mangrove environment were tested for polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals. The results revealed elevated concentrations of ∑PCBs (6-124 ng/g) and ∑PAHs (3.19-37.8 ng/g), alongside heavy metals such as Pb (11-26 μg/g), Cd (0.3-0.87 μg/g), Cu (below detectable levels, bdl)-31 μg/g), Ni (bdl-119 μg/g), and Zn (27-109 μg/g), indicating significant environmental contamination. The total PCB concentrations surpassed the guideline values, indicating potential risks to aquatic life. Elevated naphthalene levels in Kodipallam suggest petrogenic inputs from oil spills and urban runoff. Carcinogenic PAHs, including benzo[a]pyrene, are found at high levels in industrial zones such as Killai, and pose moderate ecological risks. Heavy metals such as As (68-140 μg/g), Cr (25-120 μg/g), and Mn (94-471 μg/g) often exceeded the threshold effect levels (TEL) and probable effect levels (PEL), indicating significant ecological risks and potential human health impacts. Coastal sediment contamination, driven by discharges from chemical industries, oil refineries, metal manufacturing, and agricultural runoff, poses long-term risks to marine life and human health through the bioaccumulation of persistent pollutants in the food chain. This study provides crucial baseline data for future monitoring and emphasizes the need for stricter regulatory measures and pollution management strategies. Recommendations include regular sediment quality monitoring, public awareness campaigns on pollution sources, and sustainable practices to mitigate risks, thereby protecting the coastal environment and local communities.

Pesticides under the category of persistent organic pollutants and emerging contaminants in surface sediments of an Arctic Fjord and nearby lakes

This study focuses on the distribution of some selected organochlorine pesticides and emerging contaminants within the surface sediments of an Arctic fjord, Kongsfjorden and nearby lakes. Organochlorine pesticides (OCPs) such as dicloran, p,p'-DDT, p,p'-DDE, p,p'-DDD were studied along with five emerging contaminants namely diuron, chlorpyrifos, dicofol, pendimethalin and bifenthrin. The highest values of OCPs recorded among the fjord and lake environments during the time of study was 0.3355 ng/g (dicloran), 0.0152 ng/g (p,p'-DDT), 0.0117 ng/g (p,p'-DDE), and 0.0137 ng/g (p,p'-DDD). Except dicofol, all other pesticides were found in both the years (2018 & 2019) with an elevated concentration during 2019. The presence of fresh as well as past input of contaminants was obtained from the values of DDTs ratio. The sediment quality guidelines of DDTs confirm that the fjord and lakes are clean to marginally polluted in which the adverse effects can rarely occur at this present juncture.

Monitoring of environmental persistent organic pollutants in hair samples of cats and dogs

This study investigated 32 persistent organic pollutants, including 9 organochlorine pesticides, 15 polychlorinated biphenyls, 6 polycyclic aromatic hydrocarbons, and 2 organophosphate pesticides in the hair samples of domestic cats and dogs living in an urban area in Samsun, Turkiye. Hair samples were collected from 35 cats and 38 dogs, grouped by sex and age (<3 or >3 years old). Samples were extracted using a liquid-liquid extraction method and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). The results revealed the presence of organochlorine pesticides (n = 58, 468.65 ± 92.30 ng/g), polycyclic aromatic hydrocarbons (n = 57, 15.65 ± 3.91 ng/g), polychlorinated biphenyls (n = 55, 54.11 ± 9.47 ng/g), and organophosphate pesticides (n = 25, 568.43 ± 113.17 ng/g) in the samples. PCBs 81, 118, 128, 208, and 2,4-DDE were not detected in any samples. Only one sample did not contain any of the searched compounds. Fluorene was the most frequently detected pollutant (n = 53, 72.6 %), followed by β-hexachlorocyclohexane (n = 34, 46.6 %). The highest maximum concentration was observed for hexachlorobenzene (2748.03 ng/g), followed by aldrin (2313.45 ng/g) and fenitrothion (2081.13 ng/g). Pollutant concentrations did not differ between cats and dogs, sexes, and ages (p > 0.05). This study highlights the significant threat that urban areas pose to pets, and therefore, POPs should be monitored periodically in hair and other samples. To the best of our knowledge, this is the first report to investigate POP levels in hair samples from cats and dogs in Turkiye.

Ecotoxicological risk assessments and components of persistent organic pollutants and metals in the historical settlement area (Iznik (Nicea) lake) large water resource sediments

The main objectives of this study are to measure permanent organic and inorganic pollutants in detail in an area that hosts historical structures underneath and feeds the huge ecosystem with water, to reveal risk values. Total PAH concentrations in the samples ranged from 43.41 to 202.7 ng/g. Total OCP concentration ranged from 5.15 to 17.98 ng/g, while total PCB concentration ranged from 0.179 to 0.921 ng/g. PCB 28/31, 138, and 153 are the highest detected PCBs. It was found that the lake sediment reached toxic equivalent quotient (TEQ) values of 29.21 for total PAHs and 28.90 for carcinogenic PAHs. Negligible concentration risk quotient had a low to moderate ecological and toxicological risk between 12.91 and 64.42. Highest pollution index value was found 3.81 and the risk index value reached 417.4. It has been revealed that toxicologically risky components accumulate over many years even in the best-protected water resources.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.

Determination of PCDD/F and DL-PCB pollution levels, source appointment and risk assessment of surface sediments in dam lakes in Istanbul, Türkiye

The current situation of the water resources of Istanbul, which is one of the important metropolises of Europe, should be known and constantly monitored by the reasons of the rapid increase in the city population, the acceleration of production-related industrial activities, the expansion of the city with construction activities, and the decrease in precipitation. The purpose of this study was to reveal the situations of surface sediments collected from Istanbul water reservoirs in terms of PCDD/Fs and DL-PCBs, to identify possible sources, and to conduct their ecological risk assessment. Total PCDD/Fs and DL-PCBs concentrations varied between 28.13 and 457.4 pg/g (average 136.8 pg/g) and 12.19-340.1 pg/g (average 72.09 pg/g). The corresponding TEQ values of PCDD/Fs and DL-PCBs were between 0.53 and 5.37 pg TEQ/g (average 2.23 pg TEQ/g) and 0.02-0.44 pg TEQ/g (average 0.12 pg TEQ/g), respectively. Octachlorodibenzo-p-dioxin (OCDD) is the dominant congener by constituting about 75% of the total PCDD/Fs on average, while congener distributions of DL-PCBs showed the dominance of PCB-118 and PCB-105. The sediments taken from Kazandere dam have the lowest pollution levels for both PCDD/Fs and DL-PCBs. The highest PCDD/F and DL-PCB amounts were measured in sediments of Alibey and Elmalı dams (closest to highly populated settlements of Istanbul), which are most affected by the air pollution caused by the traffic, commercial/industrial combustion (like waste incineration facility) and combustion for residential heating. Almost all the sediments have total dioxin-like toxicity levels higher than the safe threshold level (with two exceptions) of 0.85 pg TEQ/g dw, proposed for ecological risk. Health risk assessment shows that levels of dioxin-like compounds would result in a total intake of 0.33 pg TEQ/kg bw/day even in the worst-case scenario, not exceeding the tolerable daily intake value of 1 pg TEQ/kg bw/day. Among exposure pathways, consumption of fish constitutes almost all the total intake, while contributions of other pathways are minimal.

Spatial distribution, source identification and ecological risk assessment of POPs and heavy metals in lake sediments of Istanbul, Turkey

Istanbul needs to be protected and constantly monitored water resources due to its increasing population and the decrease in precipitation. This study aims to comprehensively reveal surface sediments collected from reservoirs that supply water to Istanbul concerning POPs (PAHs, PCBs, and OCPs) and heavy metals; to identify possible sources of PAHs, and conduct their ecological risk assessment. Pollution indices in this study were used as contamination degree (CD) contamination factor (CF), geoaccumulation index (I_geo), pollution load index (PLI) and Sediment Quality Guidelines (SQGs). Total PAH concentrations of surface sediments at the sampling points ranged from 46.29 ng/g (A7) to 403.9 ng/g (A15). Benzo(b)fluoranthene (5.647-59.42 ng/g), Pyrene (3.625-83.10 ng/g), Fluoranthene (3.363-66.48 ng/g), Phenanthrene (3.115-52.48 ng/g), Chrysene (3.532-43.98 ng/g), Naphthalene (6.606-36.20 ng/g), Benzo(g,h,i)perylene (3.316-41.73 ng/g) and Indeno(1,2,3-c,d)pyrene (3.453-38.84 ng/g) are the dominant PAH compounds. PAH pollution may be caused by the village-town settlements near the dam and the O7-D020 highway. Total OCP concentration ranged from 2.233 ng/g (A12) to 7.337 ng/g (A1), while total PCB concentration ranged from 0.246 ng/g (A13) to 3.708 ng/g (A1). The lowest total OCP and PCB concentrations were found in surface sediments taken from Kazandere, Papuçdere and Alibey Dam lakes. DDT p,p (0.072-5.177 ng/g) has the highest concentration among all sediment samples. While the most dominant OCP compounds in the samples were DDT p,p, DDE p,p and DDD p,p, HCH alpha, HCH beta, respectively, PCB 153, 138 and 180 were the highest detected PCB congeners in the same samples. Total heavy metal concentration varied from 77,812 mg/kg to 267,072 mg/kg. According to PAH diagnostic analysis, the surface sediments of Terkos, Büyükçekmece, Elmalı, Darlık, Sazlıdere, Alibey and Ömerli Dams were polluted by petrogenic sources, while the surface sediments of Kazandere and Papuçdere Dams were affected by pyrogenic sources. None of the levels of POPs in the samples exceeded the ERM values. Slight and moderate contamination of heavy metals, such as Pb and Zn, were present in most of the sampling points according to CD, CF, PLI and I_geo values. The quality criteria of heavy metals showed that almost all of the sampling points had Cd, Pb and Hg concentrations below the ERL values. The Ni concentrations at most of the sampling points significantly exceeded the ERM values. The concentrations of As, Cr, Cu and especially Ni and Zn exhibit a significant toxic risk to aquatic organisms to sediment quality criteria.