Distribution Of Organochlorine Pesticides Research Articles

Persistence, variance and toxic levels of organochlorine pesticides in fluvial sediments and the role of black carbon in their retention

The present study assesses the persistence and variation of organochlorine pesticides (OCPs) and their regulation by total organic carbon (TOC) and black carbon (BC) in freshwater sediment. Sediment samples from the Yamuna River, a major tributary of the Ganges (one of the most populated and intensively used rivers in Asia), had high levels of Σ20OCPs (21.41 to 139.95 ng g(-1)). β-Hexachlorocyclohexane (β-HCH) was the most predominant component. ΣHCH and Σdichloro-diphenyl-trichloroethane (DDT) constituted ~86% of Σ20OCPs. Isomer ratios indicated fresh usage of lindane, DDT and technical-grade HCH. Toxicological comparison with freshwater sediment quality guidelines showed γ-HCH and DDT at high levels of concern. β-HCH, α-HCH, endrin, heptachlor epoxide, dichloro-diphenyl-dichloroethane (DDD), dichloro-diphenyl-dichloroethylene and chlordane were above some of the guideline levels. TOC and BC had mean concentrations of 1.37 ± 0.51% and 0.46 ± 0.23 mg g(-1), respectively. BC constituted 1.25 to 10.56% of TOC. We observed low to moderate correlations of BC with isomers of HCH, p,p'-DDT and methoxychlor while of TOC with Σ20OCPs, γ-HCH, endosulfan sulfate and methoxychlor. Principal component analysis enabled correlating and clustering of various OCPs, BC and TOC. OCP distribution was related with pH, electrical conductivity, soil moisture and finer fractions of sediment. OCPs with similarity in properties that determine their interactions with carbonaceous components of sediment clustered together. A number of factors may, thus, be involved in the regulation of interactive forces between BC and OCPs. BC in this study may be more important than TOC in the retention of some OCPs into fluvial sediments, thereby reducing their bioavailability. The finding is probably the first of its kind to report and emphasises the role of BC in the persistence of OCPs in fluvial sediments.

The investigation of atmospheric deposition distribution of organochlorine pesticides (OCPs) in Turkey

Atmospheric deposition is a significant pollution source leading to contamination of remote and clean sites, surface waters and soils. Since persistent organic pollutants (POPs) stay in atmosphere without any degradation, they can be transported and deposited to clean surfaces. Organochlorine pesticides are an important group of POPs which have toxic and harmful effects to living organisms and environment. Therefore, atmospheric deposition levels and characteristics are of importance to determine the pollution quantity of water and soil surfaces in terms of POPs. This study reports the distribution quantities of atmospheric deposition including bulk, dry, wet and air–water exchange of particle and gas phase OCPs as a result of 1-year sampling campaign. Atmospheric deposition distribution showed that the main mechanism for OCPs deposition is wet processes with percentage of 69 of total deposition. OCP compounds' deposition varied according to atmospheric concentration and deposition mechanism. HCH compounds were dominant pesticide species for all deposition mechanisms. HCH deposition constituted the 65% of Σ10OCPs.

Spatial distribution of persistent organic pollutants in the surface water of River Brahmaputra and River Ganga in India

Persistent organic pollutants (POPs) like organochlorine pesticides (OCPs), polychlorinated biphenyles (PCBs) and polyaromatic hydrocarbons (PAHs) are discharged in surface water by various point and nonpoint sources thereby degrading the functioning of the ecosystem and threatening human health. Chlorinated pesticides such as Hexachlorocyclohexane (HCHs) and Dichlorodiphenyltrichloroethane (DDTs) are effective pest control chemicals, used in agriculture and public health activities (malaria eradication, etc.) in India for the past several decades and are still in use. POPs can cause endocrine disruption and food chain biomagnification because of their lipophilicity and environmental persistence. This study aims to assess the environmental occurrence and spatial distribution of OCPs, PAHs and PCBs in the surface water of River Brahmaputra and Ganga ending at the of the Bay of Bengal.The order of organochlorine pesticides is as: heptachlor>HCHs>DDTs>dieldrin>aldrin>endosulfan. Diamond Harbour and Bakkhali were the two places with elevated level of all individual HCH isomers compared to all other sites. β-Endosulfan and α-Endosulfan were high at Dibrugarh than other sampling sites. This is due to the ongoing use of Endosulfan in the tea estates in Assam especially the estates close to the town of Dibrugarh. p,p'-DDT and o,p'-DDT levels indicate the fresh input of DDT in all the sampling sites. Heptachlor has been observed in 57% of the total samples reported in the present study.These reasons may attribute to high deposition of pesticides in the surface water of Ganga and Brahmaputra.In addition the catchments area of the Ganga River is surrounded by agricultural lands so a relatively higher residue of pesticides was prevalent. Σ27 PCBs varied from BDL to 142 (Avg±SD, 3.96±6.71) ng L-1. PCB-18, PCB-52 & PCB-44 showed the highest concentration levels for all the sampling sites. PCB-126 was observed in samples taken from sites close to the city limit of Kolkata and Assam which is an indication of higher toxic effect from this highly toxic congener. PCB-169 was prevalent in most of the sites. The total concentrations of PAHs varied from BDL to 31 (Avg±SD, 0.2±1.5) µg L-1. PAHs concentrations were very low as PAHs are particle bound compounds.

A Case Study on the Long-Term Influence of Historical Intensive Usage of Organochlorine Pesticides on Current Ambient Air

Polyurethane foam disk passive air sampling was performed to investigate the levels and spatial distributions of organochlorine pesticides (OCPs) in the atmosphere of a typical city (Tangshan) in China where unparalleled amounts of OCPs including dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) were used for sanitary purposes following the 1976 Tangshan Earthquake. This study aimed to investigate the long-term influence of historical intensive usage of OCPs during the earthquake on the current ambient air levels. Sampling was performed at seven sites in Tangshan between July and October 2010. The levels of Sigma DDTs and Sigma HCHs were relatively high, with concentrations ranging from 79-254 pg/m(3) and 117-176 pg/m(3), respectively. The concentration of hexachlorobenzene (HCB) was 69-89 pg/m(3). Technical DDTs and HCHs were sprayed for preventing epidemics mainly in the southern region of Tangshan in 1976. In this study, high levels of DDTs and HCHs were found in the southern region, and levels decreased considerably to the north. Unlike DDTs and HCHs, the levels of HCB are very similar for the different sampling sites. This suggests that intensive usage of DDTs and HCHs following the earthquake had a significant effect on the levels of OCPs. Correlations identified between the enantiomers of the OCPs indicated that p,p'-DDTs and HCHs shared the same source, and that o,p'-DDT and HCB may come from similar sources. The signatures of OCPs suggested that the technical DDTs and HCHs used following the earthquake still contribute to their current levels in the atmosphere of Tangshan city.

Distribution of Organochlorine Pesticides along the Qinhe River and Its Risk Evaluation

Distribution of Organochlorine Pesticides along the Qinhe River and Its Risk Evaluation

Sixty-Year Sedimentary Record of DDTs, HCHs, CHLs and Endosulfan from Emerging Development Gulfs: A Case Study in the Beibu Gulf, South China Sea

The temporal distribution of organochlorine pesticides (OCPs) was examined in the (210)Pb dated sediment core from the Beibu Gulf, South China Sea. The total OCPs concentrations were in the range of 0.93-26.6 ng g(-1) dry weight. Dichlorodiphenyltrichloroethanes (DDTs) (0.17-24.8 ng g(-1)), Hexachlorocyclohexanes (HCHs) (0.04-0.51 ng g(-1)), Chlordane related compounds (CHLs) (0.22-1.72 ng g(-1)) and endosulfan (n.d.-0.91 ng g(-1)) were the predominant compounds. Similar to most Chinese coastal areas, the levels of DDTs in the Beibu Gulf became elevated since the early 1990s, especially since 2000 despite the ban in 1983 in China. This suggests that the concentrations of DDTs were controlled by several processes, such as land reclamation and soil runoff. The isomer ratios of (p,p'-DDE + p,p'-DDD)/p,p'-DDT, p,p'-DDT/DDTs along with construction land expansion indicated that economic activities, land reclamation, soil runoff and the use of DDT-containing antifouling paints might be responsible for the input of DDT. The ratios of α-HCH/γ-HCH (and γ-HCH/HCHs) and trans-chlordane/cis-chlordane (TC/CC) indicated fresh inputs of lindane and chlordane, respectively. In addition, CC was found to be degraded faster than TC under anaerobic conditions in sediments from the Beibu Gulf.

Soil concentrations and soil-air exchange of organochlorine pesticides along the Aba profile, east of the Tibetan Plateau, western China

Mianzhu—Aba profile, east of the Tibetan Plateau, was selected to study the occurrence of organochlorine pesticides (OCPs) along an altitudinal gradient. Dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and Aldrin, Dieldrin and Endrin (Drins) in surface soils were detected in winter (March) and summer (July). Soil concentrations (ng·g−1, dw) in winter and summer ranged as follws: DDTs, 0.37–179.16 and 0.32–42.57; HCHs, 0.14–10.76 and 0.55–32.71; Drins, N.D-3.99 and 0.02–6.93, respectively. Main soil OCPs were p,p′-DDT, p,p′-DDE, β-HCH and Drins, among which Drins were rarely reported in current literature of the Tibetan Plateau. Higher OCP concentrations in the profile were attributed close to the agricultural fields of the Sichuan Basin, current lindane and nondicofol DDTs inputs, and also long-range atmospheric transport from abroad. Soil OCP concentrations underwent obvious seasonal variation, with higher DDTs in winter and higher HCHs and Drins in summer. It may be caused by climatic conditions, summer monsoon type, and physico-chemical properties of such contaminants. Though “rest” phenomenon occurred in some sampling sites, HCHs and Drins showed an increasing trend with increasing altitude, while DDTs showed an evident decrease with increasing altitude. The altitudinal distributions of OCPs were all consistent with previous findings in other mountainous regions. A primary fugacity analysis on OCPs soil-air exchange indicated that the profile may be secondary sources for HCHs and Endrin. As with Aldrin, Dieldrin, and DDTs, the profile may be both secondary sources and sinks.

PBDEs, PCBs and organochlorine pesticides distribution in edible fish from Negro River basin, Argentinean Patagonia

DDTs, endosulfans, HCHs, chlordanes, PCBs and PBDEs levels were determined in different tissues of patagonian silverside (Odontesthes hatcheri) from the Upper (UV), Middle (MV) and Lower (LV) valleys of the Negro River, Argentina. Results showed a direct relation between pollutant levels in fish and land uses along the basin. All tissues showed decreasing levels from headwaters (UV) to downstream (LV). A significant predominance of organochlorine pesticides (306–3449ngg−1 lipid) followed by ΣPCBs (65–3102ngg−1 lipid) and ΣPBDEs (22–870ngg−1 lipid) was observed in all tissues and valleys, suggesting agriculture as the main source of pollutants in this basin. Pesticides were dominated by DDTs (90% pp′-DDE) followed by endosulfan (α->β->sulfate), γ-HCH and γ-chlordane showing the prevalence of legacy compounds. Endosulfan levels point out the current use of technical endosulfan in the surrounding areas. The highest PCBs and PBDEs concentrations observed in fish from UV were associated to hydroelectric power plants and industries established upstream. PCB fingerprint presented a prevailing contribution of hexa-CBs (66±7%) and penta-CBs (27±9%), with a similar composition to Aroclor 1254–1260. The predominance of BDE-47 (69±17%) among PBDEs, followed by BDE-100 and BDE-99, suggests possible debromination processes. These results were similar to worldwide trends found in fishes and environmental compartments. PCBs levels in silverside muscles along the Negro River exceeded the maximum limits for safe consumption, suggesting a possible human health risk related to silverside ingest. Therefore, a continued long-term monitoring of organic contaminants in fishes is needed in order to assess the potential risk for human health.

DIFFERENCES CONCENTRATION DISTRIBUTION AND SOURCE OF IN ORGANOCHLORINE PESTICIDES IN WATER AND SEDIMENT IN JAKARTA BAY WATERS DURING TRANSITION SEASON

Study on the distribution and sources of organochlorine pesticide concentrations in water samples and sediments from the Jakarta Bay was conducted in April 2011 (transition season I) and June 2011 (dry season). The purpose of this study was to determine the distribution of pesticide concentrations in water and sediments and to identify possible sources of organochlorine pesticides. The concentrations of organochlorine pesticides was measured by the GC/ECD (electron capture detection) HP 5890 series II. Concentrations found in the water column during transition I season ranged from 11.596 to 74.338 ng/l (average=41.998 ng/l) and in dry season varied from 4.554 to 19.119 ng/l (average=7.741 ng/l). In sediment samples, concentrations found in transition I season varied from 0.936 to 2.816 ng/g (average=1.782 ug/g), and in dry season about 0.7691 to 7.138 ug/g, (average=2.722 ug/g). In the water column, the average concentration in transition I was higher than that found in dry season, whereas levels in sediment during transition season I was lower. The average levels of pesticides in the water column was higher than those found in sediments. These results suggested that the seasons played a role in the distribution of organochlorine pesticides in the water column and sediments. Source of organochlorine pesticides were suggested from agricultural activities in the mainland Cisadane. Keywords: organochlorine pesticides, DDT, BHC, Jakarta Bay waters.

DIFFERENCES CONCENTRATION DISTRIBUTION AND SOURCE OF IN ORGANOCHLORINE PESTICIDES IN WATER AND SEDIMENT IN JAKARTA BAY WATERS DURING TRANSITION SEASON

<p>Study on the distribution and sources of organochlorine pesticide concentrations in water samples and sediments from the Jakarta Bay was conducted in April 2011 (transition season I) and June 2011 (dry season). The purpose of this study was to determine the distribution of pesticide concentrations in water and sediments and to identify possible sources of organochlorine pesticides. The concentrations of organochlorine pesticides was measured by the GC/ECD (electron capture detection) HP 5890 series II. Concentrations found in the water column during transition I season ranged from 11.596 to 74.338 ng/l (average=41.998 ng/l) and in dry season varied from 4.554 to 19.119 ng/l (average=7.741 ng/l). In sediment samples, concentrations found in transition I season varied from 0.936 to 2.816 ng/g (average=1.782 ug/g), and in dry season about 0.7691 to 7.138 ug/g, (average=2.722 ug/g). In the water column, the average concentration in transition I was higher than that found in dry season, whereas levels in sediment during transition season I was lower. The average levels of pesticides in the water column was higher than those found in sediments. These results suggested that the seasons played a role in the distribution of organochlorine pesticides in the water column and sediments. Source of organochlorine pesticides were suggested from agricultural activities in the mainland Cisadane.</p> <p>Keywords: organochlorine pesticides, DDT, BHC, Jakarta Bay waters.</p>

Residues, sources and tissue distributions of organochlorine pesticides in dog sharks (Mustelus griseus) from Zhoushan Fishing Ground, China

Ten dog sharks (Mustelus griseus) collected from Zhoushan Fishing Ground, China, were analysed for organochlorine pesticides in various tissues, including muscle, liver, skin, gill and fin, with the aim to study the residues, sources and tissue distributions of these chemicals in high trophic level marine fishes. The concentrations of DDTs, HCHs, and chlordanes varied from 7.27–26.62, 2.67–3.35, and 0.54–0.61ng/g wet weight, respectively, with the estimated daily intake far below the acceptable daily intake and Chinese edible hygienic criteria. Data from the tissue distribution suggested a tendency of DDTs and chlordanes to accumulate in the liver, but for HCHs, direct gill penetration may be an important means of entrance. In addition, the compositional profiles indicated that the residues of HCHs and chlordanes mainly originated from the historical usage of these chemicals. However, the predominant maternal compounds and the o,p′-DDT/p,p′-DDT ratios reflected a recent use of dicofol.

Concentrations and distribution of organochlorine pesticides in pine needles of typical regions in Northern Xinjiang

The residues of organochlorine pesticides (OCPs) in 29 pine needle samples of typical regions (including Shihezi, Beitun, and Kanas) in Northern Xinjiang was determined with a gas chromatograph equipped with an electron capture detector. Total OCPs concentrations in pine needles ranged from 2.94 to 186 ng/g dry weight, with a mean concentration of 39.63 ng/g. The results indicated that Beitun was the most polluted region while Kanas was the least polluted one. Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the predominant species in samples. Analysis of the sources of contamination showed that HCHs in the needles were derived from an old mixed source of technical HCHs or lindane. For DDTs, it was suspected to have recent application at some sites, which were derived mainly from a mixture of technical DDTs and dicofol containing DDT impurities. Categorical principal component analysis was performed in finding out more about the degradation behavior of DDTs and HCHs, which was identical with the results of source analysis.

Assessment of Argentinean Patagonia pollution: PBDEs, OCPs and PCBs in different matrices from the Río Negro basin

This work reports the occurrence and distribution of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in soil, sediment, suspended particle matter (SPM), streamwater and macrophytes, along the Río Negro basin, Argentinean Patagonia. The clear predominance of OCPs among all matrices indicates the impact of agriculture on the watershed. The highest levels were found for pp′-DDE which represented up to 95% in agricultural soils (42.0–1.27x103ng/g d.w) from the Upper Valley (upstream), where long and historical intensive fruit cultures have been settled and represent a hot spot of legacy pesticides for the environment. The insecticide endosulfan, currently in use, was also found in all matrices. Levels ranged between 0.3 and 708.0ng/g d.w, being the highest concentrations those of SPM from the Middle Valley, just before the delta area, where pesticides would be retained leading to lower concentrations as was observed downstream. PCB (#153, 138, 110, 101) and PBDE (BDE-47) levels were directly related with the presence of hydroelectric power plants, dams and dumping sites, mainly settled in the Upper Valley (0.8ng/g and 15.1ng/g d.w for PBDEs and PCBs, respectively). Although there was a decreasing gradient of these pollutant concentrations through the river flow, downstream urban areas enhanced PCB concentrations in the aquatic environment. More efforts and monitoring programs are highly required to control and reduce soil erosion in order to prevent the availability of forbidden pollutants in the environment.

Concentrations, potential sources and behavior of organochlorines and phenolic endocrine-disrupting chemicals in surficial sediment of the Shaying River, eastern China

Levels and distributions of organochlorine pesticides (OCPs) and phenolic endocrine-disrupting chemicals (EDCs) in surficial sediments of the Shaying River, the largest tributary of the Huaihe River in eastern China, were investigated to understand their relationship with the hydrodynamics. Concentrations of total hexachlorocyclohexane isomers (ΣHCHs) and dichlorodiphenyltrichloroethanes (ΣDDT) were in the range of 26.7–119 and 9.64–214 ng g−1 with mean values of 104 and 80.7 ng g−1, respectively. Residues of HCHs in sediments can be considered as originating from the application of both technical mixtures and lindane in the past. According to the spatial distribution of (DDD + DDE)/ΣDDT ratios, the influence of recent DDT inputs was dominant upstream, whereas DDD prevailed downstream, due to anaerobic degradation. Concentrations of total phenolic EDCs (ΣEDCs) including nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA) ranged widely from 425 to 3,953 ng g−1 with the highest level occurring in the middle reach. This accumulation could be attributed to the retransfer of surficial sediment from upstream, where the main sources are located. Spatial distribution of contaminants indicated that riverine hydrodynamics can significantly affect their behavior and fate in sediment. This evidence was further verified by multivariate statistical techniques such as Cluster Analysis (CA), Principle Component Analysis (PCA) and Discriminant Analysis (DA). The CA identified three distinct clusters reflecting the large complexity of river system like geography setting, hydrodynamic condition, etc. This finding was also confirmed by the DA. Furthermore, a PCA demonstrated that about 80.8 % of total spatial variance can be explained by the first three factors, which also indicated that contaminant spatial distributions are driven by local inputs, biodegradation and riverine hydrodynamics.

Spatial distribution and historical input of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in sediments from a subtropical estuary (Guaratuba Bay, SW Atlantic)

This study evaluated the occurrence and distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in 22 surface sediment samples and one core collected in Guaratuba Bay, a large and well-preserved estuary in Southern Atlantic, Brazil. The concentration of PCBs in the superficial sediment samples ranged from <LQ (below the limit of quantification) to 5.62ngg−1, while the concentration of OCPs ranged from <LQ to 0.74ngg−1. The spatial distribution of the organochlorine compounds (OCs) suggested that the sources of these contaminants are located outside the bay and are related to human activities on the margins of the two main rivers that discharge in the region. The OCs in the sediment core ranged from <LQ to 0.52ngg−1 and from <LQ to 1.52ngg−1 for PCBs and OCPs, respectively. Despite their usage worldwide, the low concentrations of OCs in Guaratuba Bay suggest low input levels, which may represent the background levels for this region.

Influence of long-term sewage irrigation on the distribution of organochlorine pesticides in soil–groundwater systems

Serious shortage of water resources is one of the major factors restricting the sustainable development of cropland and pasture land in northern and northwestern China. Although the reuse of wastewater for agricultural irrigation becomes a well established practice in these regions, many contaminants have been also introduced into the soil–groundwater systems such as persistent organochlorine pesticides (OCPs). To study the influence of long-term sewage irrigation on the distribution of OCPs in soil–groundwater systems, the groundwater flow field was investigated and 31 topsoil samples, 9 boreholes, 11 sewage effluents and 34 groundwater samples were collected in Xiaodian, Taiyuan city, one of the largest sewage irrigation districts, China. During sampling, three representative types of regions were considered including effluent-irrigated area, groundwater-irrigated area served as the control field and no-irrigated area as reference “background”. The results showed over-exploitation of groundwater had changed the flow field of groundwater and wherever in soil or in groundwater, the concentration of OCPs in effluent-irrigation area presented the highest value, which indicated that the sewage irrigation had a strong influence on the distribution of OCPs in soil–groundwater systems. Principal component analysis for OCPs content in groundwater showed that the major influence factors on the occurrence and distribution of OCPs in groundwater systems attribute to the flow field of groundwater and to the current pesticide use.

Organochlorine pesticides in air and soil and estimated air–soil exchange in Punjab, Pakistan

This study provides the first systematic data on the distribution of organochlorine pesticides (OCPs) in the soils and atmosphere of the Punjab province, Pakistan. Atmospheric concentrations of OCPs were estimated by using the polyurethane foam passive air sampling (PUF-PAS) technique. DDTs (dichlorodiphenyltrichloroethane), HCHs (hexachlorocyclohexane) and chlordane were the dominant OCPs found in both soil and air samples. The average concentrations of DDTs, HCHs and chlordane were 350, 55 and 99pgm−3 in air and 40, 7.8 and 3.8ngg−1 in soils, respectively. Air–soil exchange of OCPs was estimated by calculating the fugacities in soil and air. Fugacity fraction (ff) values indicate that soils are acting as a secondary source to contaminate the atmosphere at certain sampling stations.

Distribution of organochlorine pesticides and polychlorinated biphenyls in two spices of fish from Danube

The distribution and contents of organochlorine pesticides (OCPs) and congeners of polychlorinated biphenyls (PCBs) were analyzed in Bream (Blicca bjoerkna) and Barbel (Barbus barbus) from the Danube River, near Batajnica. The analysed compounds were 16 OCPs (α-Hexachlorocyclohexane (α-HCH), β-Hexachlorocyclohexane (β-HCH), Hexachlorobenzene (HCB), γ-Hexachlorocyclohexane (γ-HCH), δ-Hexachlorocyclohexane (δ-HCH), Heptachlor, Aldrin, cis-Heptachloroepoxide (cis-HCE), trans-Heptachloroepoxide (trans-HCE), γ-Chlordane, p,p'-Dichlorodiphenyldichloroethylene (p,p'-DDE), α-Chlordane, Dieldrin, Endrin, p,p'-Dichlorodiphenyldichloroethane (p,p'-DDD), p,p'-Dichlorodiphenyltri-chloroethane (p,p'-DDT)) and 7 PCB congeners (IUPAC numbers 28, 52, 101, 138, 153, 180, 118). Determination and quantification of OCPs and PCBs were performed by a GC-ECD method. The proximate composition of fish fillets was determined by applying standard SRPS ISO methods. The statistically significant difference (p < 0.05) was found between the OCPs content in Bream and Barbel, as well as between PCBs content in the analyzed fish filets. Among all analyzed pesticides, both fish contained the highest amounts of ΣDDT (expressed as sum of p,p'-DDT + p,p'-DDE + p,p'-DDD), (13.8 ng/g fish - Bream, 2.6 ng/g fish - Barbel). The sum of PCB congeners in Bream filets (40.8 ng/g fish) was significantly higher than in Barbel filets (7.2 ng/g fish). Results of Student's t-test (p = 0.05) showed the differences in the content of lipids, moisture, ash and calculated energy value between the analyzed fish filets. Four times higher fat content in Bream (4.25%) than in Barbel (1.07%) is one of the main reasons for higher content of OCPs and PCBs in Bream compared to Barbel, which were taken from the same location (The Danube River, Batajnica).

Organochlorine pesticide (OCP) residues in mountain soils from Tajikistan

The concentrations and spatial distribution of organochlorine pesticides (OCPs) in surface soils of different altitudes (570–4656 m) from Tajikistan were determined. OCPs were detected in all samples with concentrations in the range 52.83–247.98 ng g(-1) dry weight (ng g(-1) dw). Aldrins were the most predominant compounds followed by chlordanes, hexachlorocyclohexanes (HCHs) and endosulfans, while dichlorodiphenyltrichloroethanes (DDTs) and methoxychlor were detected at much lower concentrations. Composition analysis indicated that OCPs mainly came from the atmospheric transport of historically used pesticides. OCP residues in the west and northwest parts of Tajikistan were higher than the east and the southeast due to the proximity to the potential sources and anthropogenic activity intensities around. Additionally, correlation analysis between OCPs and altitudes indicated that the more volatile pollutants, such as HCH isomers, seemed to become enriched more easily in regions with higher altitudes relative to the less volatile ones, such as DDTs.

Levels and Distribution of Organochlorine Pesticides and Polychlorinated Biphenyls in Water and Sediment from the International Anzali Wetland, North of Iran

Organochlorine pesticides (OCPs) and PCBs were determined in water and sediment from the Anzali Wetland, north of Iran. The total concentrations of OCPs were 71.75-315.16 ng/l, 1.8-12.68 ng/g dry wt in water and sediments respectively, and those of polychlorinated biphenyls (PCBs) in the two phases were: nd-141.09 ng/l and 0.39-2.64 ng/g dw, respectively. Also, the results indicated that β-HCH, DDE were the most common organochlorine pesticides contaminants. In this study, the ∑PCB/∑DDT reflect the relative importance of agricultural than industrial sources in this area. a significant difference was observed between the stations. Station number 3 showed the highest range of the pollutants studied.