Persistent organochlorine residues in sediments along the coast of mid-Black Sea region of Turkey

Chronology of trace elements and radionuclides using sediment cores in Golden Horn Estuary, Sea of Marmara

Trace elements and radionuclides are substantial pollutants in marine environment since they are non-biodegradable and can be harmful even in minute concentrations. The Golden Horn estuary, where is an inlet of Bosphorus and two creeks, has been seriously polluted by untreated municipal and industrial dischargers for several decades. Since 1998, a large restoration and rehabilitation efforts have been undertaken in the estuary to mitigate the pollution. In the present study, four sediment cores were taken from the Golden Horn estuary to assess the historical accumulation of trace elements and radionuclides. Radiometric dating was implemented by ²¹⁰Pb and ¹³⁷Cs radionuclides and CRS model. Sedimentation rates were calculated in the range of 0.92-0.97 cm yr^-1 in the estuary. The distribution of radionuclides (⁴⁰K, ²²⁶Ra, and ²²⁸Ra) indicated some slight variations which ascribes to the geological characteristics of sediment along the cores. The concentrations of the anthropogenic elements were relatively higher in the intensive industrialization period. Their concentrations reduced in the latest 15-20 years thanks to the large-scale rehabilitation project in the estuary. The pollution indices, namely EF, Igeo, CF, and PLI showed that the concentrations of Cd, Cr, Cu, Pb, Sb, and Sn were above the world averages. Our results provide an insight on the long-term accumulation trends of trace element in the Golden Horn, which revealed that the estuary remains moderately polluted. We suggest that preventive countermeasures are much more important than post pollution remediation in the case of metallic pollution in the estuaries.

Bacterial communities of the Black Sea exhibit activity against persistent organic pollutants in the water column and sediments

The ability of bacteria to degrade organic pollutants influences their fate in the environment, impact on the other biota and accumulation in the food web. The aim of this study was to evaluate abundance and expression activity of the catabolic genes targeting widespread pollutants, such as polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachloro-cyclohexane (HCH) in the Black Sea water column and sediments. Concentrations of PAHs, PCBs and HCH were determined by gas chromatography (GC) coupled to mass spectrometry (MS) and electron capture (ECD) detectors. bphA1, PAH-RHDα, nahAc, linA and linB that encode biphenyl 2,3 dioxygenase, α-subunits of ring hydroxylating dioxygenases, naphthalene dioxygenase, dehydrochlorinase and halidohydrolase correspondently were quantified by quantitative PCR. More recalcitrant PAHs, PCBs and HCH tended to accumulate in the Black Sea environments. In water samples, 3- and 4-ringed PAHs outnumbered naphthalene, while PAHs with > 4 rings prevailed in the sediments. Congeners with 4-8 chlorines with ortho-position of the substituents were the most abundant among the PCBs. β-HCH was determined at highest concentration in water samples, and total amount of HCH exceeded its legacy Environmental Quality Standard value. bphA1, was the most numerous gene in water layers (105 copies/mL) and sediments (105 copies/mg), followed by linB and PAH-RHDα genes (103 copies/mL; 105 copies/mg). The least abundant genes were linA (103 copies/mL; 104 copies/mg) and nahAc (102 copies/mL; 104 copies/mg). The most widely distributed gene bphА1 was one of the least expressed (10-3-10-2 copies/mL; 10-1 copies/mg). The most actively expressed genes were linB (101-102 copies/mL; 103 copies/mg), PAH-RHDα (101 copies/mL; 102 copies/mg) and linA (10-1-100 copies/mL; 100 copies/mg). Interaction of bacteria with PAHs, PCBs and HCH is evidenced by high copy numbers of the catabolic genes that initiate their degradation. More persistent compounds, such as high-molecular weight PAHs or β-HCH are accumulating in the Black Sea water and sediments, albeit microbial activity is directed against them.

The impact of the marine sewage outfalls on the sediment quality: The Black Sea and the Marmara case

Marine sewage outfalls are the cheapest method of disposal for municipalities with restricted funds, despite their negative effects on marine ecosystems. This study was conducted on the marine sewage outfalls of the Turkish cities Rize (Black Sea) and Yalova (Sea of Marmara). Heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were investigated in the sediments for determine pollution degree. Two of Yalova stations were classified as having high contamination levels (1034.436 and 1476.483 ng/g, respectively) and all the other stations suffered moderate pollution in terms of ∑₁₆PAHs. ∑DTTs in sediments above probable effect levels (PELs), were observed both stations Yalova and Rize. The highest metal concentrations in the sediments from the eight stations ranged from 4.97 to 29.65 mg/kg for Ni; 7.57–44.14 mg/kg for Cr; 9.84–42.76 mg/kg for Cu; and 48.08–103.77 mg/kg for Zn. In sum, examination of pollutant sources provides clear evidence of an anthropogenic effect on the discharge environments.

Simultaneous determination of eight neonicotinoid insecticides, fipronil and its three transformation products in sediments by continuous solvent extraction coupled with liquid chromatography-tandem mass spectrometry

Neonicotinoids (NEOs) and fipronil (FIP) are insecticides that are widely used in modern agriculture and have received considerable attention in recent years due to their adverse effects on non-target organisms in the environment. In the present study, a new method to simultaneously detect eight common NEO insecticides and FIP and its three transformation products (FIPs) in sediments was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based on a combined pretreatment of continuous solvent extraction (CSE) and solid phase extraction (SPE). Under optimized conditions, 5.0 g of freeze-dried sediment samples were initially extracted with methanol (20 mL)-methanol (15 mL)-water (20 mL) in sequence, and then the extract was cleaned with hydrophilic-lypophilic balance SPE cartridges, and HPLC-MS/MS analysis was conducted. The established method was validated to be sensitive, linear, accurate, and precise. The limits of detection (LOD) and limits of quantification (LOQ) of target compounds were 0.012-0.055 μg/kg d.w and 0.031-0.091 μg/kg d.w, respectively. Good linearity (R² > 0.990) was observed between 4.0 × 10^-2 and 20.0 μg/kg d.w. The recovery rates of all target insecticides were between 75.5% and 98.5%, and the relative standard deviations (RSD) were all less than 15.0% at the low, medium, and high spiked levels. Finally, the optimized method was applied to analyze 12 target insecticides in the sediments obtained from Jiaozhou Bay of China and its main inflow rivers. Acetamiprid, thiamethoxam, fipronil sulfide, and fipronil sulfone were detected in the river sediment samples at the concentration from <LOQ to 0.197 μg/kg d.w. Thus, the two types of studied insecticides can enter the sedimentary environment. Overall, the proposed method can be used to investigate the contamination status of typical NEOs and FIP insecticides in sediments and provide base data to comprehensively understand their environmental behavior, safety, and fate.

Pollution characteristics and ecological risk assessment of HCHs and DDTs in estuary wetland sediments from the Bohai Bay, North China

Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) tend to persist in the environment for long periods of time. The concentration and distribution of HCHs and DDTs were investigated in surface sediments of Yongdingxinhe wetland and Binhai wetland by gas chromatography-mass spectrometer (GC-MS). All isomers of HCHs and DDTs were detected in all of the samples. The concentrations of total HCHs (ΣHCHs) in two wetland sediments ranged from 69.81 to 379.28 ng · g ^-1, with a mean value of 224.55 ng · g ^-1. The concentrations of total DDTs (ΣDDTs) ranged from 98.32 to 129.10 ng · g ^-1, with a mean value of 113.71 ng · g ^-1. The results of an ecological risk assessment demonstrated that there was high-risk ecological effect of organochlorine pesticides (OCPs) on the estuary wetlands. Lindane and technical DDTs were found to be the main sources of OCPs.

The Environmental Issues of DDT Pollution and Bioremediation: a Multidisciplinary Review

DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane) is probably the best known and most useful organochlorine insecticide in the world which was used since 1945 for agricultural purposes and also for vector-borne disease control such as malaria since 1955, until its banishment in most countries by the Stockholm convention for ecologic considerations. However, the World Health Organization allowed its reintroduction only for control of vector-borne diseases in some tropical countries in 2006. Due to its physicochemical properties and specially its persistence related with a half-life up to 30 years, DDT linked to several health and social problems which are due to its accumulation in the environment and its biomagnification properties in living organisms. This manuscript compiles a multidisciplinary review to evaluate primarily (i) the worldwide contamination of DDT and (ii) its (eco) toxicological impact onto living organisms. Secondly, several ways for DDT bioremediation from contaminated environment are discussed. For this, reports on DDT biodegradation capabilities by microorganisms and ways to enhance bioremediation strategies to remove DDT are presented. The different existing strategies for DDT bioremediation are evaluated with their efficiencies and limitations to struggle efficiently this contaminant. Finally, rising new approaches and technological bottlenecks to promote DDT bioremediation are discussed.

Organochlorine compounds in surface sediments from the northern coast of Cyprus, Eastern Mediterranean: Levels, possible sources and potential risk

Organochlorines (OCs) were determined in sediments collected from different regions of northern coast of Cyprus. The OCPs and Aroclors had a wide range from 2.78 to 306 and 15 to 325ngg(-1), respectively. The highest level was found at Yedi Dalga site. DDE was the most abundant compound. The ratios of metabolites to parent DDT showed that DDTs were derived mostly from the aged and weathered inputs. Comparing our results with the previous studies showed that POPs in sediments were found to be lower than those in samples for Mediterranean and Black Sea coasts. The SQG implied that, Aroclor1254 exceeded the TEL values, showing that adverse biological effects are expected occasionally at some of the sediment samples. DDTs were dominant and more ecotoxicological concern in the northern Cyprus. Altogether, it may be summarized that DDTs will impose ecologically hazardous impacts in the sedimentary environment at the present.

Determination of organochlorine pesticide concentrations in flathead mullet (Mugil cephalus) caught from the western Black Sea coast of Turkey

The objective of this study was to determine the levels of 14 organochlorine pesticides (OCPs) in flathead mullet (Mugil cephalus) caught from the western Black Sea coast of Turkey. The fish samples were caught from five different locations of the western Black Sea coast of Turkey in August 2009. Organochlorine pesticides were extracted from the liver tissues, and then the levels of OCPs were measured using gas chromatography with an electron capture detector. Organochlorine pesticides were detected in all locations. The levels of total OCPs in fish samples ranged between 0.224 and 1.103 μg g(-1) dry weight in the western Black Sea coast of Turkey. DDT, beta-HCH, and endosulfan I were the dominant OCPs in the fish samples. The levels of DDT in fish samples ranged between 0.081 and 0.186 μg g(-1) dry weight. The levels of total HCH in fish samples ranged between 0.007 and 0.376 μg g(-1) dry weight in the western Black Sea coast of Turkey. Although the usage of OCPs was banned in Turkey, the results of this study clearly indicated the presence of OCPs in the western Black Sea coast of Turkey and exposure of living organisms to these chemicals.

Assessing the relationship and influence of black carbon on distribution status of organochlorines in the coastal sediments from Pakistan

Levels of total organic carbon (TOC) and black carbon (BC) were determined together with those of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the selected eighteen coastal sites (n = 285) along the Arabian Sea from Pakistan. Results showed that the total concentration of TOC, BC, ∑OCPs and ∑26PCBs ranged between 0.3 and 2.9% dw, 0.1-0.2% dw, 0.9-110 ng g(-1) dw and 6.2-1200 ng g(-1) dw, respectively. Correlation analysis of BC (r = 0.26-0.89) and TOC (r = 0.06-0.69) revealed a stronger association with studied compounds. The sedimentary depositional fluxes (D) for ∑OCPs and ∑26PCBs were calculated as 1.7 and 4.9 tons yr(-1), respectively. In the coastal belt of Pakistan, sedimentary mass inventories (I) indicated the presence of 13 and 37 metric tons of ∑OCPs and ∑26PCBs, respectively.

Levels, distribution, and risk assessment of organochlorines in surficial sediments of the Red Sea coast, Egypt

The analyses of environmentally persistent pollutants like polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, and dichlorodiphenyltrichloroethane (DDT) and its metabolites in surficial sediment samples collected from 17 locations along with the coast of the Red Sea in Egypt were carried out using gas chromatography-mass spectrometry. Several potential organic contaminants from agricultural (e.g., DDT and its breakdown products, lindane, endrin, dieldrin, and endosulfan) and industrial (PCBs) sources were measured. The levels of 20 organochlorine pesticides (OCPs) and ten PCB congeners in sediment collected from 17 stations along ~1,200 km were investigated. Concentrations of PCBs, HCHs, DDTs, and cyclodienes ranged from 0.40 to 6.17, 0.01 to 0.09, n.d. to 0.46, and 0.08 to 0.90 ppb dry weight. Two statistical programs were applied on the data (principal component analysis, PCA, and cluster analysis, CA), and it was concluded that it is impossible to predict the distribution patterns of the OCPs in a contaminated area. Risk assessment of the organochlorines contaminated in the sediments of the studied area was investigated.

Organochlorine pesticides in soil, water and sediment along the Jinjiang River mainstream to Quanzhou Bay, southeast China

Residue levels of organochlorine pesticides (OCPs) in multiple compartments (water, soil and sediment) along the Jinjiang River mainstream to Quanzhou Bay were monitored to elucidate sources and fate. The concentrations of OCPs in surface soil of the watershed of the Jinjiang River (2.44 ± 1.97 ng/g for hexachlorocyclohexanes (HCHs) and 11.4 ± 8.46 ng/g for dichlorodiphenyltrichloroethanes (DDTs)) and the Quanzhou Bay (1.81 ± 2.15 ng/g for HCHs and 9.72 ± 14.66 ng/g for DDTs) were comparable. The concentrations of HCHs and DDTs in dissolved phase were 55-94% for the total HCHs and ten to sixteen percent for the total DDTs in the Jinjiang River. High correlations of OCPs between suspended particulate matter (SPM) and sediment (p<0.01) were found in this study, which demonstrated that OCPs absorbed onto SPM was the major source in the sediment of Quanzhou Bay. The use of lindane was the major source of HCHs in the study region. Dicofol pollution was found in water of the Jinjiang River and sediment of Quanzhou Bay. Based on the sediment quality guidelines, DDTs pose more ecotoxicological risk in environment of the Jinjiang River and Quanzhou Bay.

Levels of organochlorine pesticide residues in butter samples collected from the Black Sea Region of Turkey

The aim of the present study was to evaluate the levels of 9 organochlorine compounds (aldrin, hexachlorobenzene, 2,4-DDE, 4,4-DDE, 2,4-DDT, 4,4-DDT, and α-, β-, and γ-HCH) in butter samples collected in the Eastern, Middle and Western Black Sea Regions of Turkey between October 2009 and June 2010. The liquid-liquid extraction method was used to extract the organochlorine compounds from the samples and the measurements were performed by using a gas chromatograph-electron capture detector system. DDT metabolites, aldrin, hexachlorobenzene (HCB), and α-, and γ-HCH were not detected in the samples but β-HCH was detected in 3 of a total of 88 samples. In the first period, only one sample from the West Black Sea Region was β-HCH positive (0.014 mg kg(-1)). The other β-HCH positive samples collected in Middle and West Black Sea Regions in the second period had a concentration of 0.066 and 0.019 mg kg(-1), respectively. All concentrations of the detected compounds exceeded the legal limits of 0.003 mg kg(-1) for β-HCH, as prescribed by the Turkish Food Codex, and therefore pose a potential health risk for consumers. The contamination detected is most likely due to the past usage of β-HCH in agriculture and its long term persistence in the environment. These results strongly suggest that further research should be focused on the detection of pesticide residues in agricultural areas across the nation.

Occurrence and distribution of organochlorine residues in surface sediments of the Candarli Gulf (Eastern Aegean)

The residual levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in surface sediments collected from Candarli Gulf. Total concentrations of OCPs and PCBs in sediments ranged from 10.2 to 57.3 and 2.8 to 205 ng g⁻¹ dwt, respectively. DDTs in sediments were derived from the aged and weathered agricultural soils in 61% of the sampling stations while 39% of the sites originated from the recent DDT inputs. Their concentrations appeared to be relatively low by global standards and only sediments receiving the impact from the Bakircay River and petrochemical industry approached the sediment quality guidelines for PCBs and DDTs. Based on ERL/ERM guidelines, DDT and PCBs posed ecological risk to the bottom-dwelling consumers.

Distribution and ecological risk of organochlorine pesticides and polychlorinated biphenyls in surficial sediments from the Eastern Aegean

Organochlorine pesticides and polychlorinated biphenyls were determined in sediment with three replicates collected from the Eastern Aegean coast in 2008. Total concentrations of OCPs and PCBs in sediments ranged from bdl to 17.8, bdl to 26.1 ng g(-1) dwt, respectively. The results indicated that DDTs were the predominant contaminant in sediments. p,p'-DDE was the most often found OCP at all stations except Dardanelles Strait Entrance. DDTs may be derived from the aged and weathered agricultural soils and transported by surface run off from the rivers. OCPs and PCBs were present in noticeably higher concentrations at Izmir Inner Bay than the other sites. According to established sediment quality guidelines, DDTs at four sites and heptachlor at two sites would be more concerned for the ecotoxicological risk in the Eastern Aegean. In addition, the risk of adverse biological effects from the levels of PCBs at sites Candarli and Izmir Inner Bay should be significant.

Distribution and sources of organochlorine pesticides in sediments of the coastal East China Sea

Forty-two surface sediment samples collected from the southern coastal East China Sea (ECS) were analyzed for organochlorine pesticides (OCPs). The results showed high concentrations of DDTs and parent DDT fractions in the nearshore area, suggesting that there is still a fresh input of these species from non-point sources, probably due to the recent usage of relevant products. However, for HCHs, the high concentrations with elevated β-HCH fraction were focused at the local major river estuaries, indicating that soils-released HCH input was mainly from the major river runoffs. The distribution and composition of OCPs in the coastal ECS could be more prominently controlled by the direct regional inputs rather than the general natural sorption process on particulate organic carbon. DDTs and chlordane are more important for their potential ecotoxicological risk on neighboring benthic community in the nearshore region and the local major river estuaries.

Seasonal variation of organochlorine contaminants in bonito (Sarda sarda L. 1758) and anchovy (Engraulis encrasicolus L. 1758) in Black Sea region, Turkey

The concentrations of indicator polychlorinated biphenyls (PCBs) and organochlorine insecticides were determined in bonito (Sardasarda L. 1758) and anchovy (Engraulisencrasicolus L. 1758) from the Black Sea, Turkey. Concentrations of total indicator PCBs ranged between <1-17.0 in bonito, and <1-17.5 ng/g fresh weight in anchovy, and total of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane and its metabolites' (DDTs) concentrations ranged between 13.4-26.3, and 2.96-19.0 ng/g fresh weight in bonito and anchovy respectively. PCB 52, p,p'-DDE and endosulfan (α+β) were found dominant in both of the fish species. Except endosulfan, and some DDT metabolites, none of the studied organochlorine pesticides was detected in the fish samples. Concentrations of PCBs in anchovy were found higher than those in bonito, whereas DDT and endosulfan concentrations were found similar in both of the fish species. All of the fish samples had residue concentrations below the maximum residue limits (MRL) recommended by FAO/WHO Codex Alimentarius Commission.

Organochlorine pesticides in soils from a typical alluvial plain of the Yangtze River Delta region, China

Residues of organochlorine pesticides (OCPs), dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH), their risks and affecting factors in 544 representative soils collected from a typical alluvial plain of the Yangtze River Delta region, China, were investigated. Mean concentrations of ΣDDT and ΣHCH in soils were 88.8 and 99 ng/g, respectively. Historical application of DDT and HCH were the major sources of their residues in soils. Concentrations of DDT in soils had relative greater levels of contamination, while concentrations of HCH were almost at safe levels. Residues of DDT and HCH in soils were affected by soil types as well as soil textures.

The sorption behavior of DDT onto sediment in the presence of surfactant cetyltrimethylammonium bromide

The sorption behavior of p,p'- and o,p'-dichlorodiphenyltrichloroethane (DDT) in the presence of a cationic surfactant cetyltrimethylammonium bromide (CTAB) on sediment was studied. Batch experiments were carried out to investigate the kinetics and thermodynamics of the process. The kinetic behavior of these three chemicals on sediment was described by pseudo-second-order kinetic equations, and the isotherms followed the Freundlich model well. The presence of CTAB was able to remarkably accelerate and enhance the sorption of DDT, whereas DDT showed no effect on the sorption of CTAB in our considered concentration ranges. The thermodynamic parameters, such as standard enthalpy change (ΔH0), standard entropy change (ΔS0) and standard Gibbs free energy change (ΔG0) showed that the sorption process of p,p'- and o,p'-DDT was physical, spontaneous and exothermic, and the randomness at the solid-liquid interface increased during the process. In the presence of CTAB, the sorption of DDT showed significantly negative ΔG0 and ΔH0 values.

Distribution of organochlorine pesticides in sediments and mussels from the Istanbul Strait

This study was conducted to determine the status and trends of organochlorine pesticide (OCP) compounds in the sediment and mussel samples collected along the Istanbul Strait and from the coasts of an island in the Marmara Sea. The total concentrations of OCPs were found in the range of 40-13,852 pg g(-1) dry weight for sediments and 5,195-12,322 pg g(-1) wet weight for mussels. The levels of OCPs in both sediments and mussels were dominated by DDTs and HCHs; β-HCH, 4,4(')-DDD and 4,4(')-DDE were the major pollutants. The degree of sediment pesticide contamination was more severe in the inner part of the strait. OCP concentrations in sediments and mussels were compared with the sediment guideline values and legal limits for human health, respectively. The results showed that OC pesticide contamination in the strait might not pose a serious threat to the health of the marine inhabitants at most of the stations.

Distribution and sources of organochlorinated contaminants in sediments from Izmir Bay (Eastern Aegean Sea)

Eighteen surface sediment samples representative of the entire Izmir Bay were analyzed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). This was in order to provide extensive information concerning the recent deposition of these compounds in this area, together with levels, distribution, possible sources and potential biological risk. Sites that were contaminated by high concentrations of organochlorine compounds were associated with dense population, such as the harbour and the Gediz River estuary. Relatively higher ΣDDT concentrations and high DDT/DDE+DDD ratios in the Gediz River estuary indicated DDT usage, probably linked to public health emergencies. According to the established guidelines for sediment quality, the risk of adverse biological effects from such levels of OCPs and PCBs as recorded at most of the study sites was insignificant. But the higher concentrations in Inner bay and in the Gediz River estuary could cause biological damage.

The level and distribution of selected organochlorine pesticides in sediments from River Chenab, Pakistan

Organochlorine pesticides (OCPs), viz. β-hexachlorocyclohexane (β-HCH), γ-HCH, aldrin, dieldrin, endrin, heptachlor, endosulfan-I, endosulfan-II, heptachlor endoepoxide, heptachlor exoepoxide, mirex, dicofol, o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT), p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyltrichloroethylene (DDE) and 12 other physicochemical parameters were measured in surface sediments from River Chenab during two sampling seasons (summer and winter, 2007) to evaluate spatial and temporal trends of sediment pollution. Hierarchical agglomerative cluster analysis identified three groups of sites based on spatial similarities in physicochemical parameters and OCP residual concentrations. Spatial discriminant function analysis (DFA) segregated 14 parameters, viz. dicofol, endosulfan-I, heptachlor endoepoxide, dieldrin, DDD, DDE, endosulfan-II, o,p'-DDT, p,p'-DDT, pH, electrical conductivity (EC), Cl⁻¹, total P (%), and silt, which explained 96% of total variance between spatial groups. γ-HCH was the most frequently detected (63%) pesticide, followed by DDD (56%). The ratio of DDTs to their metabolites indicated current input and anaerobic biodegradation. Temporal DFA highlighted aldrin, heptachlor endoepoxide, Cl⁻¹, total P, and EC as important variables which caused variations between summer and winter. DDTs were relatively more prevalent as compared to other OCPs in the sediments samples during both seasons. DDT metabolites were detected at greater frequencies and concentrations in winter, whereas DDT isomers were more prevalent in summer sediment samples. Factor analysis identified agricultural and industrial activities as major sources of sediment OCP contamination. Concentrations of γ-HCH, heptachlor endoepoxide, dieldrin, and DDTs (isomers and metabolites) in all sediment samples were well above interim sediment quality guidelines (ISQGs) and probable effect limits (PEL) given by Canadian Sediment Quality Guidelines (CSQGs).

Organochlorine residual concentrations in cattle egret from the Punjab Province, Pakistan

In this study, residual concentration of organochlorine pesticides (OCPs) in the sediments, prey, and eggs of Bubulcus ibis were measured from three breeding heronries from the Punjab province of Pakistan. Pattern of contamination in eggs followed the order: DDTs>HCHs>heptachlor>aldrin. Overall, pesticide residual concentrations were greater in eggs of cattle egrets collected from heronry on the River Ravi. Among HCHs, γ-HCH was more prevalent in eggs, whereas DDTs followed the order: DDD>DDE>p,p'-DDT>o,p'-DDT. Eggshell thinning was detected which showed negative relationship with residual concentration of DDE. In prey samples, residual concentration of POPs followed the order: DDTs>HCHs>dicofol>heptachlor; however, contamination pattern in sediments followed a slightly different order: DDTs>heptachlor>dicofol>HCHs>dieldrin>aldrin. Concentration of β-HCH was more prevalent in sediments and comparatively greater concentrations of POPs were measured in sediments collected from the River Ravi. Dicofol was found for the very first time in the biological samples from Pakistan, and its concentration was measured as relatively high in eggs from heronry from the River Chenab. Residual concentrations measured in eggs were below the levels that could affect egret populations. Biomagnification of the total OCPs through the food chain was evident in three breeding heronries. The concentration of DDE measured in eggs of the cattle egret suggests the need for monitoring this contaminant in other bird species at different trophic levels.

HCH and DDT in sediments from marine and adjacent riverine areas of North Bohai Sea, China

Residues of organochlorine pesticides (OCPs), hexachlorocyclohexanes (HCHs), and dichlorodiphenyltrichloroethanes (DDTs) and their environmental risks in surface sediments collected from marine and adjacent riverine/estuarine areas in the northern Bohai Sea, China, were investigated. Concentrations of SigmaHCH and SigmaDDT in sediments ranged from below detection (<LOD) to 1964.97 ng g(-1) dry wt (dw; mean, 92.51 ng g(-1) dw) and <LOD to 86.46 ng g(-1) dw (mean, 9.23 ng g(-1) dw), respectively. Concentrations of HCH and DDT were generally higher in marine than riverine sediments. Concentrations of HCH and DDT residues found in the present study were higher than those reported in marine and river/estuary sediments from other areas of the world. The source of HCH in sediments could be explained by the large amount of historical use, while DDT seemed to be a combination of erosion of the weathered soils and long-range atmospheric transport. Concentrations of HCH in sediments from the study areas did not exceed sediment quality guidelines (SQGs), with the exception of gamma-HCH. However, risks posed by concentrations of DDT observed in sediments were found to be moderate to high compared with those posed by consensus-based SQGs. Although the mean sedimentary concentrations of HCH and DDT found in the area of the northern Bohai Sea, China were lower than suggested SQGs in general, their concentrations in some locations were close to or above the SQGs for adverse effects in benthic organisms and, thus, remain a cause for concern.

Distribution and bioaccumulation of organochlorine pesticides in surface sediments and benthic organisms from Taihu Lake, China

The spatial distribution and bioaccumulation of organochlorine pesticides (OCPs) in surface sediments and benthic organisms from Taihu Lake were studied. OCPs were detected in all sediment samples with total concentrations ranging from 4.22 to 461 ng g(-1) dry weight (dw). The ratios of certain metabolites to their parent compounds indicated there are still new inputs of parent DDT (dichlorodiphenyltrichloroethane) to Taihu Lake, while the highest residues of HCHs (hexachlorocyclohexanes) mainly came from earlier usage and fresh gamma-HCH (lindane). No positive correlation was found between the distribution of OCPs and organic matter contents in sediments. Concentrations of OCPs and lipids in typical large benthic organisms, Bellamya aeruginosa (B. aeruginosa) and Corbicula fluminea (C. fluminea), increased with body weight. HCHs, DDTs, chlordanes and heptachlors were the dominant compounds detected in organisms and C. fluminea accumulated much more OCP than B. aeruginosa. Higher values of biota-sediment accumulation factor (BSAF) were detected in C. fluminea, which was both affected by biological characteristics of the organisms and physicochemical properties of the compounds.

Distribution and bioaccumulation of organochlorine pesticides along the Black Sea coast

Sediment, mussel, and seawater samples were collected three times during 2001-2003 at nine sampling stations along the mid-Black Sea coast of Turkey. The samples were analyzed with GC-ECD for contents of various organochlorine pesticides (OCPs) in the environment. DDT and its metabolites were detected at concentrations significantly above the detection limits. The highest concentrations of DDT metabolites measured in the sediment and mussel samples were 35.9 and 14.0 ng/g wet weight respectively. Considerable levels of aldrin, dieldrin, endrin, heptachlor epoxide, lindane, endosulfan sulphate, and HCB were also detected in the sediment, mussel, or seawater samples. Although these persistent toxic compounds have been banned for some years in Turkey, they may still be used illegally in some regions, contributing to their significant levels in the environment. The biota-sediment accumulation factor (BSAF) estimated for DDT and its metabolites in mussels was 2.9, which is nearly two times higher than the benchmark of 1.7. In spite of such high BSAF values observed for these toxic compounds, their levels in mussels were significantly below the international legal limits recommended by the Food and Agriculture Organization of the United Nations. Edible biota from the waterbodies examined may thus still be considered safe for human consumption at this time. However, as pollutants can biomagnify through the food chain over time, further routine sampling and analysis of biota along the Black Sea coast are warranted in order to better assess the threat of OCPs to public health in the region.

Determination of selected polychlorinated biphenyls in soil by miniaturised ultrasonic solvent extraction and gas chromatography-mass-selective detection

Miniaturised ultrasonic solvent extraction procedure was developed for the determination of selected polychlorinated biphenyls (PCBs) in soil samples by gas chromatography-mass-selective detection by using 2(3) factorial experimental design. Recoveries of PCBs from fortified soil samples are over 90% for three different fortification levels between 40 and 120 microg kg(-1), and relative standard deviations of the recoveries are below 7%. The limits of detection (LODs) ranged from 0.003 to 0.006 microg kg(-1). The performance of the proposed method was compared to traditional shake flask extraction method on the spiked real soil sample and extraction methods showed comparable efficiencies. Proposed miniaturised ultrasonic solvent extraction offers several advantages, i.e., reducing sample requirement for measurement of target compound, less solvent consumption and reducing the costs associated with solvent purchase and waste disposal.

Organochlorinated pesticide multiresidues in surface sediments from Beijing Guanting reservoir

For the analysis of organochlorine pesticides (OCPs) in sediments and water, a multiresidue analysis method based on gas chromatography with electron capture detection (GC/ECD) was developed. Solid-phase extraction (SPE) using Oasis HLB cartridges was also applied in sample extraction. Mean recoveries were satisfactory with 72-103% and 71-103% for water and sediment, respectively. Twenty-one OCPs were analyzed in water and surface sediment samples from Beijing Guanting reservoir. Total concentrations of 21 OCPs were 16.7-791 ng/l (mean 234 ng/l), 275-1,600 ng/l (mean 644 ng/l), 5250-33,400 ng/kg (mean 13,000 ng/kg) in surface water, pore water and sediment (dry weight), respectively. P, p'-DDE, delta-HCH, aldrin, gamma-HCH and beta-HCH are the most abundant compounds in water while p, p'-DDE, o, p'-DDT, beta-HCH, delta-HCH, p, p'-DDT and aldrin accounted for about 85% of total 21 OCPs in sediment in Beijing Guanting reservoir. Concentrations of OCPs were high both in water and sediment samples in Beijing Guanting reservoir for municipal water supply. The data provides information on the levels and sources of OCPs in Guanting reservoir. The study indicated that measures should be taken to decrease OCPs residues in order to improve the quality of municipal water supply in Beijing.

Screening 31 endocrine-disrupting pesticides in water and surface sediment samples from Beijing Guanting reservoir

For screening 31 potential or suspected endocrine-disrupting pesticides in water and surface sediments, a multiresidue analysis method based on gas chromatography with electron capture detection (GC/ECD) was developed. Solid phase extraction (SPE) technology with Oasis HLB cartridge was also applied in sample extraction. The relevant mean recoveries were 70-103% and 71-103% for water and sediment, respectively. Relative standard deviations (RSD) are 2.0-7.0%, 4.0-8.0% for water and sediment, respectively. Thirty one pesticides (alpha-HCH, beta-HCH, gamma-HCH, delta-HCH, hexachlorobenzene (HCB), aldrin, heptachlor, endosulfan I & II, p,p'-DDD, o,p'-DDT, p,p'-DDT, p,p'-DDE, endrin aldehyde, endosulfan sulphate, methoxychlor, hepachlor epoxide, alpha-chlordane, gamma-chlordane, dieldrin, endrin, dicofol, acetochlor, alachlor, metolachlor, chlorpyriphos, nitrofen, trifluralin, cypermethrin, fenvalerate, deltamethrin) in water and surface sediment samples from Beijing Guanting reservoir were analyzed. Concentrations of pesticides ranged from 7.59 to 36.0 ng g(-1) on a dry wt. basis for sediment samples, from 279.3 to 2740 ng l(-1) for pore waters and from 48.8 to 890 ng l(-1) for water samples, respectively, with a mean concentration of 10.7 ng g(-1) in sediment, 735 ng l(-1) in pore water and 295 ng l(-1) in water, respectively. The data obtained provides information on the levels and sources of endocrine-disrupting pesticides in Guanting reservoir. These results underscore the need to improved environmental protection measures in order to reduce the exposure of the population and aquatic biota to these endocrine-disrupting compounds.

Organochlorinated pesticides in sediments from the Lake Albufera of Valencia (Spain)

Bottom sediment samples from 121 sites of the Lake Albufera of Valencia were analyzed. Dieldrin, endrin, heptachlor and op'-DDT were not detected (<0.01 ng g(-1)) in 88-93% of the sites. Aldrin and HCB concentration ranges were between <0.01 and 0.1 ng g(-1) in 86% and 94% of the sites, respectively. Heptachlor-epoxide and lindane 95% confidence intervals were 0.2-0.5 and 0.06-0.12, respectively. The greatest average concentration corresponds to pp'-DDE, pp'-DDD and pp'-DDT. The sum of six isomers and derivatives of the DDT average concentration reaches 2.1 ng g(-1), as opposed to 2.7 ng g(-1) for the sum of 13 pesticides considered. In the site with a major contamination, 27.0 ng g(-1) of pp'-DDD and 12.8 ng g(-1) of pp'-DDT were accumulated. The DDE:DDT proportion average was 0.37, indicating an aged DDT contamination. Concentrations of pesticides in sediments were compared to three sediment quality guidelines, and indicated that a low biological effects level can be expected in either sediments or aquatic organisms.