Spatial variation of DDT and its metabolites in fish and sediment from Cinca River, a tributary of Ebro River (Spain)

Organochlorine residues in muscle of European eels (Anguilla anguilla) from four Spanish Mediterranean wetlands and coastal lagoons

European eels (Anguilla anguilla) are an endangered species throughout their range, and chlorine organic compounds are some of the most important pollutants for marine species. Data on contaminants in eel stocks remain incomplete, so organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in muscle of European eels from four Spanish Mediterranean ecosystems were analyzed. COPs are presents in eels from all areas, but some compounds are not detected: HCH α, β and γ (lindane), endosulfan sulfate, heptachlor, and PCBs 28, 52 and 180. The high percentage of DDT 2,4' in eels from S'Albufera des Grau Natural Park, an ecosystem with good ecological status according to the Water Framework Directive, and the presence of PCBs in S'Albufereta Natural Reserve indicate the need to carry out further studies in the future. The results obtained can improve the management of this species in the studied areas.

Behaviors and trophodynamics of o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT) in the aquatic food web: Comparison with p,p'-DDT

The broad-spectrum insecticide p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) has been banned in most countries since the 1970s on account of its environmental persistence as well as the high biomagnification of its major metabolite 1,1-dichloro-2,2-bis(4-chorophenyl)ethylene (p,p'-DDE). However, the information on the bioaccumulation and behavior of p,p'-DDTs in aquatic organisms is lacking. In this study, all 6 DDT isomers were detected in biota from the food web of the Liaodong Bay, China, and the total concentrations of DDT isomers in Chinese anchovy (Thrissa kammalensis) and Japanese Spanish mackerel (Scomberomrus niphonius) were 223 ± 42 ng/g ww and 242 ± 70 ng/g ww, respectively. In biota, o,p'-DDD dominated among the o,p'-isomers (80.5 ± 17.3%), while p,p'-DDE dominated among the p,p'-isomers (61.8 ± 15.2%). Contrastingly, sediment from the Liaodong Bay contained similar proportions of o,p'-DDT and p,p'-DDTs, suggesting an isomer-specific metabolism of the compounds in biota. A well-controlled laboratory exposure experiment with Japanese medaka (Oryzias latipes) demonstrated that o,p'-DDT was more difficult to metabolize to o,p'-DDE compared with that of p,p'-DDT. Significantly positive regressions were found between trophic levels and lipid equivalent concentrations for both o,p'-DDT and o,p'-DDD, and the trophic magnification factors (TMFs) were estimated as 12.3 and 9.12 (p < 0.05), respectively. The TMFs of o,p'-DDT and o,p'-DDD in the aquatic food web were higher than p,p'-DDT (7.76), p,p'-DDD (4.17), and p,p'-DDE (3.39), which may be explained by the isomer-specific metabolism differences in biota.

Occurrence of organochlorine pesticides and polychlorinated biphenyls in sediment and fish in Cau Hai lagoon of Central Vietnam: Human health risk assessment

This is the first study on polychlorinated biphenyls (PCBs) in fish from the Cau Hai lagoon, a part of the largest coastal lagoon in Southeast Asia. Seven selected PCB congeners and organochlorine pesticides in sediments and edible fish tissues were quantified by GC-MS. The sum of ICES-7 PCB and DDTs concentrations in fish species consumed regularly and of economic value were in ranges 26-43 ng g^-1 lw and 182-277 ng g^-1 lw, respectively. The ratio between the parent DDT compound and the sum of metabolites, DDE and DDD, was most of the time smaller than 1, suggesting primarily an historical contamination of the lagoon. An agglomerative hierarchical clustering indicates sites located in the north-western part of the Cau Hai lagoon were characterized by above-average concentrations of DDE and DDT. Comparing to previous data, a large decrease in ∑DDT residues can be seen over the past 20 years.

Bioaccumulation and human health risks of OCPs and PCBs in freshwater products of Northeast China

The levels and spatial distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in freshwater products from Northeast China were investigated by gas chromatography coupled to isotope dilution high-resolution mass spectrometry. All samples were on-spot sampled from main production regions of freshwater products in Northeast China, and these samples were used to systematically assess the potential health risks of OCPs and PCBs associated with consumption of these fishery products. Dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexane (HCHs), hexachlorobenzene (HCB) and PCBs were the major pollutants with 100% detection rates, and their levels ranged from 0.086 to 58, 0.038-3.3, 0.093-4.5 and 0.032-1.4 ng g^-1 wet weight, respectively. The estimated dietary intakes of these contaminants were all below their corresponding acceptable daily intakes. Significant regional differences in the levels of OCPs and PCBs (P ≦ 0.001) were found in samples from Liaoning and Inner Mongolia. The results showed that the concentrations of targeted contaminants in aquatic products had species-specific characteristics, and the levels of targeted pollutants in Oncorhynchus mykiss and Eriocheir sienesis were significantly higher than those in other aquatic product species. Advisories on ten species of aquatic products suggested that consumption of Eriocheir sinensis, Oncorhynchus mykiss and Cyprinus carpio at a rate exceeding 15 meals per month would pose a cancer risk. A health risk assessment indicated that exposure to these pollutants through freshwater products consumption would cause a non-ignorable potential carcinogenic risk to humans.

Indicator polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in seafood from Xiamen (China): levels, distributions, and risk assessment

Indicator polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 289 seafood samples including fishes, crustaceans, and shellfish collected from six administrative regions in Xiamen of China. The residual levels of PCBs, dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs) ranged <LOD-64 (median 1.8) ng g^-1 wet weight (ww), 0.03-88 (median 1.4) ng g^-1 ww, and <LOD-5.5 (median <LOD) ng g^-1 ww, respectively. The most abundant compounds were PCB101, p,p'-DDT, and β-HCH. Significant differences in the amounts of PCBs and DDTs were recorded among the species, whereas no significant differences were observed among the species with regard to HCH concentrations. Within the regions investigated, the concentrations of PCBs were much lower in Haicang than in other regions and HCHs were detected with highest concentration in Siming, while no significant differences were observed in DDT concentrations. Principal component analysis (PCA) showed that PCB and OCP pollutions came from similar sources in Xiamen. But the pollution sources of Xiangan were diverse. The predominance of PCBs might be attributed to the past usage of domestically produced commercial PCB mixtures, and the profiles of OCPs might indicate their current use in agriculture. Results of carcinogenic risk assessment based on the 50th or 95th percentile exposure levels exceeded the threshold, suggesting that the PCBs should be of concern. On the other hand, the hazard quotients (HQs) of noncancer risks were all far below than 1.

The long shadow of our chemical past - High DDT concentrations in fish near a former agrochemicals factory in England

A total of 81 roach (Rutilus rutilus) collected from 13 southern English river sites between 2007 and 2012, were analysed for organochlorine pesticides, PCBs, PBDEs and some metals. Unexpectedly high concentrations of the banned insecticide DDT and its degradation products DDE and DDD (∑DDTs) were found in the 10 fish from the river Lee (or Lea) which averaged 88 ± 70 (standard deviation) μg/kg ww, almost 20 times higher than the average for the remaining sites (4.8 ± 3.1 μg/kg). All fish from that site exceeded the Canadian Tissue Residue Guideline (environmental quality standard) of 14 μg/kg ∑DDTs. Concentrations of the insecticides chlordane and lindane as well as copper, which is often used as a fungicide, were also elevated in fish from the Lee, though not as much as those of DDTs. A likely explanation for these observations was found in a nearby former pesticide factory, which had stopped production about three decades earlier. An extensive review of recent literature data on DDT in wild European fish found that, while levels are now generally low, there were several other hotspots with ∑DDTs levels that may still be of concern.

DDT concentration in fish from the Tapajós River in the Amazon region, Brazil

DDT and metabolites were measured in six species of fish collected from the Tapajós River in the village of Barreiras, near the town of Itaituba in the Brazilian Amazon region. The selected fish were the most consumed and economically important to the local people. DDT was used frequently in this region for malaria control. Fish samples were analyzed after extraction by microwave-assisted extraction in hexane/acetone (8:2, v/v) by gas chromatography with electron capture detector. Residues of op'-DDT and pp'-DDT and metabolites were detected, including pp'-DDE, pp'-DDD, op'-DDT, and op'-DDE, in 98% of the samples, with a greater abundance of pp'-DDT. Total DDT levels were 7.1-249.5 ng g(-1) wet weight (w.w). The DDE/DDT ratio was low, indicating recent exposure to DDT. The study area that may be related to generated waste used in public health campaigns to combat mosquitos (Anopheles spp.), still present in the Amazon environment, that transmit malaria. DDT levels and metabolites found in fish species do not present risks to human health because they are below acceptable limits for consumption.

Enantiomeric fraction and isomeric composition to assess sources of DDT residues in soils

Chiral pesticides such as o,p'-DDT can undergo enantioselective microbial degradation in soil. Hence, the enantiomeric fraction (EF) of o,p'-DDT was used as an approach to assess potential recent inputs of DDT in the lower part of the Ebro River basin (NE Spain), a region heavily impacted by agricultural and industrial activities, including a dicofol production and a chloro-alkali plants. The EFs of five out of nineteen soils were not different from the racemic value (0.505±0.010), confirming that the Ebro River and some of its tributaries, Segre and Cinca rivers, transported fresh DDT residues despite its ban in Spain during the 90 s. o,p'-DDT/p,p'-DDT ratios in soils suggest that recent use of technical DDT and/or DDT-contaminated dicofol may be responsible for the fresh DDT inputs in the Segre River, while in the Ebro River, they indicate a dominant contribution of technical DDT, likely related to the residues accumulated by the chloro-alkali plant discharges.

Emerging and priority contaminants with endocrine active potentials in sediments and fish from the River Po (Italy)

There is a substantial lack of information on most priority pollutants, related contamination trends, and (eco)toxicological risks for the major Italian watercourse, the River Po. Targeting substances of various uses and origins, this study provides the first systematic data for the River Po on a wide set of priority and emerging chemicals, all characterized by endocrine-active potentials. Flame retardants, natural and synthetic hormones, surfactants, personal care products, legacy pollutants, and other chemicals have been investigated in sediments from the River Po and its tributary, the River Lambro, as well as in four fish species from the final section of the main river. With few exceptions, all chemicals investigated could be tracked in the sediments of the main Italian river for tens or hundreds of kilometres downstream from the Lambro tributary. Nevertheless, the results indicate that most of these contaminants, i.e., TBBPA, TCBPA, TBBPA-bis, DBDPE, HBCD, BPA, OP, TCS, TCC, AHTN, HHCB, and DDT, individually pose a negligible risk to the River Po. In contrast, PBDE, PCB, natural and synthetic estrogens, and to a much lower extent NP, were found at levels of concern either to aquatic life or human health. Adverse biological effects and prohibition of fish consumption deserve research attention and management initiatives, also considering the transport of contaminated sediments to transitional and coastal environments of the Italian river.

Persistent organochlorines in 13 shark species from offshore and coastal waters of Korea: Species-specific accumulation and contributing factors

Data on persistent organochlorines (OCs) in sharks are scarce. Concentrations of OCs such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in the muscle tissue of 13 shark species (n=105) collected from offshore (Indian and Pacific Oceans) and coastal waters of Korea, to investigate species-specific accumulation of OCs and to assess the potential health risks associated with consumption of shark meat. Overall OC concentrations were highly variable not only among species but also within the same species of shark. The concentrations of PCBs, DDTs, chlordanes, hexachlorobenzene, and heptachlor in all shark species ranged from <LOQ (limit of quantification) to 184 (mean: 35.0), <LOQ to 1135 (58.2), <LOQ to 56.2 (4.31), <LOQ to 18.8 (1.64) and <LOQ to 77.5 (1.37)ng/g lipid weight, respectively. The determined concentrations of PCBs and DDTs in shark in our study were relatively lower than those reported in other studies. Aggressive shark species and species inhabiting the Indian Ocean had the highest levels of OCs. Inter-species differences in the concentrations and accumulation profiles of OCs among shark species could be explained by differences in feeding habit and sampling locations. Several confounding factors such as growth velocity, trophic position, and regional contamination status may affect the bioaccumulation of OCs in sharks. Hazard ratios of non-cancer risk for all the OCs were below one, whereas the hazard ratios of lifetime cancer risks of PCBs and DDTs exceeded one, implying potential carcinogenic effects in the general population in Korea. This is the first report to document the occurrence of OCs in sharks from Korea.

Identification of compounds bound to suspended solids causing sub-lethal toxic effects in Daphnia magna. A field study on re-suspended particles during river floods in Ebro River

Identifying chemicals causing adverse effects in organisms present in water remains a challenge in environmental risk assessment. This study aimed to assess and identify toxic compounds bound to suspended solids re-suspended during a prolonged period of flushing flows in the lower part of Ebro River (NE, Spain). This area is contaminated with high amounts of organochlorine and mercury sediment wastes. Chemical characterization of suspended material was performed by solid phase extraction using a battery of non-polar and polar solvents and analyzed by GC-MS/MS and LC-MS/MS. Mercury content was also determined for all sites. Post-exposure feeding rates of Daphnia magna were used to assess toxic effects of whole and filtered water samples and of re-constituted laboratory water with re-suspended solid fractions. Organochlorine and mercury residues in the water samples increased from upstream to downstream locations. Conversely, toxic effects were greater at the upstream site than downstream of the superfund Flix reservoir. A further analysis of the suspended solid fraction identified a toxic component eluted within the 80:20 methanol:water fraction. Characterization of that toxic component fraction by LC-MS/MS identified the phytotoxin anatoxin-a, whose residue levels were correlated with observed feeding inhibition responses. Further feeding inhibition assays conducted in the lab using anatoxin-a produced from Planktothrix agardhii, a filamentous cyanobacteria, confirmed field results. This study provides evidence that in real field situation measured contaminant residues do not always agree with toxic effects.

Separating natural from anthropogenic causes of impairment in Zebra mussel (Dreissena polymorpha) populations living across a pollution gradient

The relationship between the reproductive stage, the total lipid content and eight broadly used biochemical stress responses were used to assess seasonal and pollutant effects across eleven different zebra mussel (Dreissena polymorpha) populations from the Ebro and Mijares river basin, Spain. Biochemical markers included superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione S transferase (GST), multixenobiotic transporter activity (MXR), lactate dehydrogenase (LDH), lipid peroxidation (LPO) and single strand DNA breaks. Principal component analyses of zebra mussel responses across an annual cycle, showed a marked gonad stage component in total lipid content and biochemical responses. The same response pattern was observed across the populations sampled along a broad geographical and pollution gradient. Population differences on the gonad developmental stage were highly correlated with most of the measured responses and unrelated with the pollution gradient. Conversely, bioaccumulation of organic and inorganic contaminant residues was more related to pollution sources than with the reproductive cycle. These results indicate that the reproductive cycle is the major factor affecting the temporal and spatial variation of the studied markers in D. polymorpha.

Evaluation of PCBs and DDTs in endemic Iberian barbel Barbus bocagei (Steindachner, 1864) populations

PCB and DDT levels were evaluated in populations of endemic Iberian barbel (Barbus bocagei) in the Jarama River in Spain via a pollution gradient from well-preserved areas upstream to contaminated downstream areas. Age structure, abundance, recruitment and levels of morphological abnormalities and ectoparasites were assessed. Upstream to downstream PCB concentrations ranged from 3.4 to 101.4 ng/g (ww) and from 0.9 to 19.6 ng/g ww for DDTs. The PCB pattern was dominated by the PCB 153, 138 and 180 congeners, and the less chlorinated ones had a relatively high contribution upstream. Barbels exposed to low PCB and DDT levels had a well-balanced population with a predominant cohort of young fish, indicating good recruitment. The most contaminated sites displayed a disrupted age distribution, where the proportion of young fish was clearly under-represented. Recruitment and total density of barbel populations decreased downstream where the highest PCB and DDT levels were found. In addition, a higher incidence of abnormalities and ectoparasites was observed at these sites. High concentrations of PCBs and DDTs most likely contribute to the reduction of Iberian barbel reproductive performance in the most contaminated sites, as shown by the disrupted age-distribution found in our study.

The release of persistent organic pollutants from a closed system dicofol production process

High concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) have been found to be produced in chemical processes in which chlorine is a raw material. Samples of workshop air, waste water, waste acid, and the dicofol product were collected from a pesticide factory in China that uses a closed-system dicofol production process, and were analyzed for PCDD/Fs and ΣDDTs. The ΣDDTs concentrations were 1.88-17.53 μg m(-3) in the workshop air samples, 4.85-456 μg kg(-1) in the waste water and waste acid samples, and 4.74 g kg(-1) in the dicofol product. The total estimated daily intakes of ΣDDTs for workers by inhalation in the workplace were in the range of 0.38-3.51 μg kg(-1)bwd(-1) for moderate activities. The annual amounts of ΣDDTs and p,p'-DDT directly released to the environment via the use of dicofol were 9,480 kg and 1,080 kg, respectively. The PCDD/F toxicity equivalent values (I-TEQs) in the waste water and waste acid samples ranged from 1.5 to 122 pg I-TEQ kg(-1) and 86.3 ng I-TEQ kg(-1) in the dicofol sample. The annual amount of PCDD/Fs released to the environment was 0.17 g I-TEQ. From the PCDD/F distribution patterns, it is suggested that the major pathway for PCDD/F formation involves precursor synthesis during the production of dicofol in the closed-system process.

Baseline levels and trophic transfer of persistent organic pollutants in sediments and biota from the Congo River Basin (DR Congo)

The present study aimed to evaluate the occurrence of persistent organic pollutants (POPs: (PCBs, PBDEs, DDTs, HCHs, CHLs and HCB) in sediments and biota from the middle Congo River Basin (CRB) and to investigate their trophic transfer through the aquatic food web using nitrogen stable isotope ratios. To our knowledge, no data on levels of POPs in sediment and biota from the CRB are present in the literature, and studies on trophic transfer and biomagnification profiles of POPs using δ(15)N are scarce in tropical regions. POP levels in the sediment and biota were low, with exception of total PCB levels found in fish from the Itimbiri River (1.4 to 44ng/g ww). Compared to concentrations found in fish from pristine to relatively industrial developed areas, the ∑PCB levels in fish from the Itimbiri were high, indicating the presence of a local PCB contamination source in this catchment. Based on minimum risk level criteria formulated by ATSDR, the consumption of PCB contaminated fish from the Itimbiri river poses a potential risk for humans. The POP levels in biota were not significantly related to the POP levels in sediments, and the BSAF concept (Biota-Sediment Accumulation Factor) was found to be a poor predictor of the bioavailability and bioaccumulation of environmental pollutants in the present study. With increasing trophic levels, a significant increase in PCB 95, 101, 110, 138, 146, 149, 153, 174, 180 & 187 and p,p'-DDT in Itimbiri and BDE 47 & 99 in Itimbiri, Aruwimi & Lomami river basins was observed. Trophic magnification factors were higher than 1, indicating that biomagnification occurs through the tropical food web.

Organochlorine compounds in mussels cultured in the Ría of Vigo: accumulation and origin

This paper analyzes the influence of mussel physiological conditions on bioaccumulation of organochlorine pollutants. A direct relationship between reproductive stage, lipid content and accumulation of PCBs, DDTs and HCHs was observed. The organochlorine compounds accumulated by mussels cultured in the Ría of Vigo show levels below the limits set by the European legislation for human consumption, ranging between 12.50-58, 2.21-10.80 and 0.50-2.69 μg kg(-1) dry weight for PCBs, DDTs and HCHs, respectively. Other organochlorine pesticides normally present in estuarine areas, such as hexachlorobenzene (HCB), aldrin, chlordane and nonachlor were not detected. The proportion of PCBs, between 2 and 7 times higher than OCPs, indicates a pollution of predominantly industrial origin in the sampling area. Several molecular indices were used to identify the source of accumulated OCPs by Mytilus, showing recent inputs of technical DDT, mainly in summer-autumn, and continued discharges of lindane. On the other hand, other pesticides containing DDT impurities, such as dicofol, can contribute to DDT pollution in the Ría of Vigo. Multivariate analysis suggests the usefulness of including physiological parameters such as the gonad condition index and lipid content of sentinel organisms in environmental biomonitoring of lipophilic pollutants, as well as in the determination of their origin.

Organochlorine pesticides (OCPs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) in edible fish from Lake Volta, Lake Bosumtwi and Weija Lake in Ghana

Organochlorine pesticides (OCPs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) were measured by a high resolution gas chromatograph-high resolution mass spectrometer (HRGC/HRMS) in selected edible fish from three freshwater bodies, Lake Volta, Lake Bosumtwi and Weija Lake in Ghana. The levels of organochlorine pesticides measured in this study were generally low. The highest concentration of OCPs was measured for dichlorodiphenyltrichloroethane compounds (DDTs) (p,p'-DDT, o,p'-DDT, p,p'-DDE, o,p'-DDE, p,p'-DDD and o,p'-DDD), followed by chlordane compounds (CHLs) (trans-chlordane, cis-chlordane, trans-nonachlor and cis-nonachlor), hexachlorobenzene (HCB) and gamma-hexachlorocyclohexane (γ-HCH). The relatively high ratio of p,p'-DDT/p,p'-DDE in tilapia and catfish with an extremely high value in catfish purchased from a local market at Madina, a suburb of Accra, however, suggests the fresh contamination of technical DDT in Ghana. Although PCDD/Fs and dl-PCBs showed relatively low levels, the concentrations are, however, comparable with recent data of some developed countries. There is a potential health risk from DDTs, PCDD/Fs and dl-PCBs for the general population of Ghana because fish is one of their important protein sources. It is therefore necessary to estimate the total intake of DDTs, PCDD/Fs and dl-PCBs, and to assess the health risks for the general population of Ghana.

Human health risk assessment of environmental exposure to organochlorine compounds in the Catalan stretch of the Ebro River, Spain

In this study, the environmental impact and human health risks associated with exposure to organochlorine compounds (OCs) through soils and tap water in the Catalan stretch of the Ebro River, Spain, were investigated. The concentrations of polychlorinated biphenyls, hexachlorocyclohexanes, as well as DDT and derivates, were determined. Relatively low levels of these pollutants were observed, with mean concentrations ranging between 0.51-315.8 lg/kg and 0.05-74.6 ng/L in soil and tap water, respectively. These values are similar to those found in a number of recent surveys over the world. In spite of the presence of a chlor-alkali plant located upstream the Ebro River, which could mean a potential source of pollution, the current levels of OCs should not mean significant additional health risks for the local population.

DDT and metabolites in fish from Lake Edward, Uganda

This paper presents results based on determination of residue levels of 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) and its metabolites in five fish species from Rwenshama landing site on Lake Edward, Uganda. The residue levels were analysed by using a GC-ECD and confirmed by GC-MS. The DDT residues detected in fish samples from Lake Edward were p,p'-DDT, o,p'-DDT, p,p'-DDE, o,p'-DDE, p,p'-DDD and o,p'-DDD. All the analysed samples of fish presented mean DDT residues ranging from non-detectable levels to 68 microg kg(-1) fresh weight. High levels of p,p'-DDT were detected in comparison to the metabolites (p,p'-DDE and p,p'-DDD). The detection of higher levels of p,p'-DDT than p,p'-DDE and p,p'-DDD, in most fish samples, suggests recent exposure of fish to DDT. Generally, most of the fish samples had residue levels below the maximum residue limits (MRL) recommended by FAO/WHO Codex Alimentarius Commission.