Organochlorine pesticides in Cyprinus carpio from Sidi Salem Dam,north-western Tunisia

Cyprinus carpio (Linnaeus, 1758) caught in Sidi Salem Dam in 2011 were analysed for the levels of organochlorine pesticides (OCPs), including hexachlorobenzene (HCB), aldrin, heptachlor, lindane, dieldrin, endrin, and pp′-DDT and its two main metabolites pp′-DDD and pp′-DDE, in order to evaluate the extent of contamination of the dam. Fish were sampled monthly within the dam during 2011. Muscle, liver and gill tissues were analysed by gas chromatography for the determination of OCPs. Samples had variable concentrations of OCPs, ranging from 2.26 to 17.93 ng g?1, 0.59 to 42.67 ng g?1 and 3.30 to 84.27 ng g?1, which were isolated from gills, muscle and liver, respectively. The organochlorine pesticide levels found posed no threat to human health. The highest OCP levels were found in the liver tissues. The pp′-DDE concentrations and their ratios to ΣDDTs indicate aged DDT pollution and suggests that there has been no recent input of technical DDT from the agricultural areas into Sidi Salem Dam.     

Extraction and recovery of organochlorine pesticides from fungal mycelia

An extraction method was developed to recover organochlorine pesticides (OCPs) associated with live and mercuric chloride-treated fungal mycelia. A Cladosporium sp. was inoculated into potato dextrose broth, DDT (90 mg/l) added and incubated for seven days. The combination of a microextraction procedure for aqueous-phase-associated DDT and a sonication extraction for mycelia-bound DDT, using dichloromethane as the extracting solvent, resulted in the recovery of 31-51% of added DDT. DDT recovery was increased to 62-65% by grinding the fungal mycelia before sonication. Alkali and nitric acid pretreatments were tested to increase the recovery of DDT associated with fungal mycelia, however, these treatments resulted in the production of unidentified DDT transformation products. Pretreating mycelia containing DDT in concentrated hydrochloric acid at 60 degrees C for 2, 4 and 6 h resulted in DDT recoveries of 90-91%, 99% and 101-102% respectively without the production of transformation products. When an OCP mixture (DDT, DDD and DDE) was added to fungal mycelia, between 89% and 96% of DDT, DDD and DDE were recovered from live cultures compared to 85-91% in mercuric chloride-treated cultures using the microextraction/hydrochloric acid pretreatment (60 degrees C/6 h) sonication extraction method.     

Accumulation and degradation of organochorine pesticides in shellfish culture environment in Xiamen sea area

By using GC-ECD, the concentrations of organochlorine pesticides hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) in the shellfish culture environment (sea water, sediments, and culture-shellfishes) in Xiamen sea area were analyzed, and the accumulation and degradation patterns of the HCH and DDT were preliminarily approached. In the sea area, there existed remarkable differences in the accumulation and degradation of HCH and DDT among different shellfish culture environments, being mostly associated with the habitation environment and physiological life habits of shellfish. The accumulated HCH isomers (Rx > 1) were mainly beta-HCH, delta-HCH, and gamma-HCH, whereas the degraded HCH isomers (Rx < 1) were mainly alpha-HCH. The ratio of alpha-HCH to gamma-HCH was less than or equal to 1.0, suggesting that the HCH was come from industrial HCH and lindane, most of the HCH had remained in the culture environment for a longer time, and a small amount of lindane was imported. The DDT in the sea water was aerobically degraded, its main degradation product was DDE, and the ratios of (DDD+DDE) to DDTs (p,p-DDE+p,p-DDD+o,p-DDT+p,p-DDT) was less than 0.5, whereas the DDT in sediments and shellfishes was anaerobically degraded, its main degradation product was DDD, and the ratios of (DDD+DDE) to DDTs was greater than 0.5, suggesting that there was a small amount of DDT newly imported in the sea water, and most DDT in sediments and shellfishes were already degraded and transformed into DDD and DDE. There were definite differences in the degradation rates of HCH isomers in the culture environment, suggesting the conformational change of HCH in its transformation processes in the shellfish culture ecosystem.     

A Comparison of Ultrasonication and Soxhlet Methods for DDT Extraction from Soil

The goal of this study was to determine the efficacy of ultrasonication extraction of 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT), 1,1-dichloro-2,2-bis[p-chlorophenyl]ethane (DDD), and 2,2-bis[p-chlorophenyl]1,1-dichloro-ethylene (DDE) residues in soil for the purposes of saving time, minimizing generation of hazardous solvent wastes, and reducing costs associated with monitoring contaminant concentrations at remediation sites. An ultrasonic extraction method was developed for DDT, DDD, and DDE residues in soil, and the efficiency of extraction using an ultrasonic cavitator was compared to the traditional soxhlet method by GC-MS. Un-contaminated soil was spiked with analytes DDT, DDD, and DDE at 0.1,1.0,10.0, and 100.0?mg/ kg. Experiments were performed in triplicate, and recoveries of analytes were determined and statistically compared. Results indicate that ultrasonic extraction is a suitable preparatory method for analysis of DDT, DDD, and DDE residues in soil. For spike concentrations of 1?mg/kg to 100?mg/kg, ultrasonication extraction resulted in recoveries in excess of 80% in all but one case. Most recoveries obtained by ultrasonication extraction were statistically indistinguishable from or slightly lower than recoveries obtained by soxhlet extraction. In addition, the lower temperatures employed in ultrasonication extraction may have reduced the amount of thermal degradation of DDT to DDE, a phenomenon that could occur during soxhlet extraction.     

Withdrawal rates of DDT from chickens treated with diphenylhydantoin.

Male and female chickens of a broiler-type strain were fed, from 1 day old to 5 weeks of age, diets containing 0, 2.5, or 15.0 p.p.m. (mg/kg) 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT). Then the diets with pesticide were withdrawn and the chickens were fed dietary levels of diphenylhydantoin (DPH) at 0, 100, or 250 p.p.m. Adipose-tissue and liver samples were obtained on days 0, 10, 20, and 30 following withdrawal of diets with pesticides to determine DPH effect on DDT, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) levels. DPH had no effect on the concentration of DDT and DDE in adipose tissue; their levels declined at a rate having a half-life value of 16 days. DDD was not detected in adipose tissue. DDT accounted for 87% of the adipose residues on day 0, but 66% of the residues at day 30. DPH had no effect on the concentrations of DDT and DDE in livers of chickens fed 15.0 p.p.m. DDT, but did significantly reduce the levels of DDD by 28 and 54% for levels of 100 and 250 p.p.m. DPH, respectively. The similarity of these data to studies on dairy cows and humans, and the dissimilarity to data from rat studies were discussed.     

Biodegradation of DDT by stimulation of indigenous microbial populations in soil with cosubstrates

Stimulation of native microbial populations in soil by the addition of small amounts of secondary carbon sources (cosubstrates) and its effect on the degradation and theoretical mineralization of DDT [l,l,l-trichloro-2,2-bis(p-chlorophenyl)ethane] and its main metabolites, DDD and DDE, were evaluated. Microbial activity in soil polluted with DDT, DDE and DDD was increased by the presence of phenol, hexane and toluene as cosubstrates. The consumption of DDT was increased from 23 % in a control (without cosubstrate) to 67, 59 and 56 % in the presence of phenol, hexane and toluene, respectively. DDE was completely removed in all cases, and DDD removal was enhanced from 67 % in the control to ~86 % with all substrates tested, except for acetic acid and glucose substrates. In the latter cases, DDD removal was either inhibited or unchanged from the control. The optimal amount of added cosubstrate was observed to be between 0.64 and 2.6 mg C $ {\text{g}}^{ - 1}_{\text{dry soil}} $ . The CO₂ produced was higher than the theoretical amount for complete cosubstrate mineralization indicating possible mineralization of DDT and its metabolites. Bacterial communities were evaluated by denaturing gradient gel electrophoresis, which indicated that native soil and the untreated control presented a low bacterial diversity. The detected bacteria were related to soil microorganisms and microorganisms with known biodegradative potential. In the presence of toluene a bacterium related to Azoarcus, a genus that includes species capable of growing at the expense of aromatic compounds such as toluene and halobenzoates under denitrifying conditions, was detected.     

Dechlorination of 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane by Aerobacter aerogenes: I. Metabolic Products

Whole cells or cell-free extracts of Aerobacter aerogenes catalyze the degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) in vitro to at least seven metabolites: 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE); 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD); 1-chloro-2,2-bis(p-chlorophenyl)ethylene (DDMU); 1-chloro-2,2-bis(p-chlorophenyl)ethane (DDMS); unsym-bis(p-chlorophenyl)ethylene (DDNU); 2,2-bis(p-chlorophenyl)acetate (DDA); and 4,4'-dichlorobenzophenone (DBP). The use of metabolic inhibitors together with pH and temperature studies indicated that discrete enzymes are involved. By use of the technique of sequential analysis, the metabolic pathway was shown to be: DDT --> DDD -->DDMU -->DDMS --> DDNU --> DDA --> DBP, or DDT --> DDE. Dechlorination was marginally enhanced by light-activated flavin mononucleotide.     

Pesticides of Potential Ecological Concern in Sediment from South Florida Canals: An Ecological Risk Prioritization for Aquatic Arthropods

A two-tier ecological risk assessment was conducted for pesticides monitored in sediment at 36 sampling sites in south Florida freshwater canals from 1990–2002. For tier 1, we identified the chemicals of potential ecological concern (COPECs) as DDT, DDD, DDE, chlordane and endosulfan based on their exceedence of sediment quality standards at 20 sites. For 12 sites with data on the fraction of organic carbon in sediments, whole sediment concentrations of COPECs were converted to pore water concentrations based on equilibrium partitioning. In tier 2, a probabilistic risk assessment compared distributions of pore water exposure concentrations of COPECs with effects distributions of freshwater arthropod response data from laboratory toxicity tests. Arthropod effects distributions included benthic and non-benthic arthropod species for chlordane (n = 9), DDD (n = 12), DDE (n = 5), DDT (n = 48), and endosulfan (n = 26). The overlap of predicted pore water concentrations and arthropod effects distributions was used as a measure of risk. DDE was the most frequently detected COPEC in sediment at the 12 sites. Chlordane was present at only one site. The mean 90th centile concentration for pore water exposure was highest for endosulfan and lowest for DDT. The estimated acute 10th centile concentration for effects was highest for chlordane and lowest for DDD. The probability of pore water exposures of COPECs exceeding the estimated 10th centile concentrations for species sensitivity distributions of arthropod acute toxicity data was between 0 and 1%. The estimated NOEC 10th centile concentration from arthropod chronic toxicity distributions was exceeded by the estimated 90th centile concentration for pore water distributions at three sites. Endosulfan had the highest potential chronic risk at S-178 in the C-111 canal system, based on the probability of pore water exposure concentrations exceeding the arthropod estimated chronic NOEC 10th centile at 41%. The COPEC with the next highest probability of exceeding the chronic NOEC 10th centile was DDD at 17.7% and 19.8% in the Everglades Agricultural Area (at S-2 and S-6). DDT had minimal potential chronic risk. Uncertainties in exposure and effects analysis and risk characterization are discussed.     

Comparative acute toxicity of DDT metabolites among American and European species of planarians

1. DDT metabolism in a North American species of planarian leads to the formation of metabolites more toxic than the parent compound. 2. The increased toxicity of DDT metabolites is similar to acute toxicity data reported previously in a European species. 3. It is suggested that planarians lack a direct mechanism for DDT detoxification, since two North American and one European species are known to metabolize DDT initially to DDE and DDD.     

Tissue Residue Guideline for ∑DDT for Protection of Aquatic Birds in China

DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is a chlorinated hydrocarbon insecticide that has been used worldwide. While the use of DDT has been phased out in many countries, it is still produced in some parts of the world for use to control vectors of malaria. DDE (1,1,-dichloro-2,2-bis(p-chlorophenyl)ethylene) and DDD (1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) are primary metabolites of DDT and have similar chemical and physical properties. DDT and its metabolites (DDE and DDD) are collectively referred to as ∑DDT. The lipophilic nature and persistence of the ∑DDT result in biomagnification in wildlife that feed at higher trophic levels in the food chain. Wildlife in aquatic ecosystems depend on aquatic biota as their primary source of food, which provide the main route of exposure to ∑DDT. Studies about effects of ∑DDT on birds were reviewed. The tissue residue guidelines for DDT (TRGs) for protection of birds in China were derived using species sensitivity distribution (SSD) and toxicity percentile rank method (TPRM) based on the available toxicity data. Risks of ∑DDT to birds were assessed by comparing the TRGs and ∑DDT concentrations in fishes from China. The tissue residue guideline for protection of birds in China is recommended to be 12.0 ng ∑DDT/g food.     

Aquatic biota as potential biological indicators of the contamination,bioaccumulation and health risks caused by organochlorine pesticides in a large,shallow Chinese lake (Lake Chaohu)

Aquatic biota have long been recognized as bioindicators of the contamination caused by hydrophobic organic contaminants (HOCs) in aquatic environments. The primary purpose of the present study is to identify which species of aquatic biota are the most sensitive to organochlorine pesticides (OCPs) in Lake Chaohu and can therefore serve as indicators of the lake's health and assist in the assessment of OCPs risks to human health. OCP levels in eight species of aquatic biota were measured using GC–MS, and the relationships between the biota and OCP levels in the water and suspended solids were studied. DDTs pose potential human health risks and were the predominant OCP components found in the aquatic biota. DDT had the highest mean bioaccumulation factor (BAF) and biota suspended solids accumulation factor (BSSAF) of all of the studied OCP components. The food web magnification factors (FWMF) for p, p′-DDT were greater than 1, implying that biomagnification occurred. This finding indicates that DDTs still pose a serious threat to the ecosystem and human health in Lake Chaohu, even though the agricultural application of DDT powder has been officially banned since 1983. There were significant positive relationships between OCPs levels in Culter erythropterus and those in both water and suspended solids, as well as between OCPs levels in Protosalanx hyalocranius and those in suspended solids. This finding suggests that C. erythropterus and P. hyalocranius are the most sensitive aquatic biota to OCPs and may serve as the most effective bioindicators for monitoring OCP contamination in the water and suspended solids of Lake Chaohu. Megalobrama amblycephala, which contained the highest wet weight mean OCP concentration, is the most sensitive OCP indicator and can be used to assess the human carcinogenic risk of OCPs in Lake Chaohu.     

Bioremediation of DDT in soil by genetically improved strains of soil fungus Fusarium solani

Bioremediation of DDT in soil by genetically improved recombinants of the soil fungus Fusarium solani was studied. The parent strains were isolated from soil enriched with DDD or DDE (immediate anaerobic and aerobic degradation products of DDT), as further degradation of these products are slow processes compared to the parent compound. These naturally occurring strains isolated from soil, however, are poor degraders of DDT and differed in their capability to degrade its metabolites such as DDD, DDE, DDOH and DBP and other organochlorine pesticides viz. kelthane and lindane. Synergistic effect was shown by some of these strains, when grown together in the medium containing DDD and kelthane under mixed culture condition. No synergism in DDE degradation was observed with the strains isolated from enriched soil. DDD-induced proteins extracted from individual culture filtrate (exo-enzyme) when subjected to SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE) showed complementary polypeptide bands in these strains i.e., each strain produced distinct DDD degrading polypeptide bands and the recombinant or hybrid strains produced all of the bands of the two parents and degraded DDD better than the parental strains. Recombinant hybrid strains with improved dehalogenase activity were raised by parasexual hybridisation of two such complementary isolates viz. isolate 1(P-1) and 4(P-2) showing highest complementation and are compatible for hyphal fusion inducing heterokaryosis. These strains are genetically characterised as Kel⁺Ben^RDBP^-Lin^- and Kel^-Ben^rDBP⁺Lin⁺ respectively.Recombinants with mixed genotype, i.e., Kel⁺Ben^RDBP⁺Lin⁺ showing superior degradation quality for DDT were selected for bioremediation study. Recombination was confirmed by polypeptide band analysis of DDD induced exo-proteins from culture filtrate usingSDS-Polyacrylamide Gel Electrophoresis (PAGE) and RAPD (Random Amplified Polymorphic DNA) of genomic DNA using PCR (Polymerase Chain Reaction) technique. SDS-PAGE showed combination of DDD induced polypeptide bands characteristic of both the parents in the recombinants or the hybrids. PCR study showed the parent specific bands in the recombinant strains confirming gene transformation.     

Effects of DDT on the Fish Eagle Haliaeetus vocifer population of Lake Kariba in Zimbabwe

Twenty clutches were collected from nests of Fish Eagles Haliaeetus vocifer at Lake Kariba, Zimbabwe, and a small dam nearby in 1989-90. Unaltered DDT, and metabolites DDD and DDE, were found in every egg. Mean levels of σDDT(= DDT + DDD + DDE) generally varied from 14 to 49 mg/kg dry weight per clutch, but 113–223 mg/kg dry weight were found in clutches from the eastern end of the lake and the mouth of the Sengwa River. SDDT and DDE levels were significantly correlated with the Ratcliffe Index of eggshell thickness. Comparison with museum specimens showed that the Ratcliffe Index has declined by 11% since 1936-41 due to a significant fall in shell weight. Eggshell thinning exceeded 20% at the eastern end of the lake.
Aerial surveys in 1987 and 1990 found that hatching success along the southern lakeshore exceeded 72%, but chicks were seen in fewer than half the nests at the eastern end. However, the density of breeding pairs was greatest here.
Residue levels have increased by about 8% since 1980, rising more steeply in areas recently sprayed for tsetse fly control and falling in others. The threat from DDT may now be receding as regional use has declined and will end, for tsetse fly control, by 1995. None was used for this purpose in 1991. Mercury levels in adult birds were very high and may pose a significant risk.
The breeding population may be limited by availability of safe nest sites. Chicks are sometimes eaten by people. Settlement along the lakeshore is increasing and safe sites are becoming scarcer as dead trees in the lake collapse and large trees onshore are destroyed by elephants.     

Differential Effect of DDT,DDE, and DDD on COX‐2 Expression in the Human Trophoblast Derived HTR‐8/SVneo Cells

The purpose of this study was to investigate the effect of 1,1,1‐trichloro‐2,2‐bis‐(chlorophenyl)ethane (DDT), 1,1‐bis‐(chlorophenyl)‐2,2‐dichloroethene (DDE), and 1,1‐dichloro‐2,2‐bis(chlorophenyl)ethane (DDD) isomers on COX‐2 expression in a human trophoblast‐derived cell line. Cultured HTR‐8/SVneo trophoblast cells were exposed to DDT isomers and its metabolites for 24 h, and COX‐2 mRNA and protein expression were assessed by RT‐PCR, Western blotting, and ELISA. Prostaglandin E₂ production was also measured by ELISA. Both COX‐2 mRNA and protein were detected under control (unexposed) conditions in the HTR‐8/SVneo cell line. COX‐2 protein expression and prostaglandin E₂ production but not COX‐2 mRNA levels increased only after DDE and DDD isomers exposure. It is concluded that DDE and DDD exposure induce the expression of COX‐2 protein, leading to increased prostaglandin E2 production. Interestingly, the regulation of COX‐2 by these organochlorines pesticides appears to be at the translational level. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:454‐460, 2012; View this article online at wileyonlinelibrary.com . DOI 10:1002/jbt.21444     

Metabolism of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane in the mouse

The metabolites of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) found in the urine of female Swiss mice are reported. The metabolites of DDT are DDD, 1-chloro-2,2-bis(p-chlorophenyl)ethene (DDMU), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (DDE), 2,2-bis(p-chlorophenyl)acetic acid (DDA), 2-hydroxy-2,2-bis(p-chlorophenyl)acetic acid (αOH-DDA) and 2,2-bis(p-chlorophenyl)ethanol (DDOH), while DDD afforded DDMU, DDE, DDA, αOH-DDA and DDOH. The relative excreted levels of DDA and DDOH and the absence of 2,2-bis(p-chlorophenyl)acetaldehyde (DDCHO) are not consistent with the generally accepted path way for DDA formation, which involves sequential metabolism of DDT and DDD via DDOH to afford DDA. The quantitative results are interpreted to mean that DDA is formed by hydroxylation at the chlorinated sp³-side chain carbon of DDD to give 2,2-bis(p-chlorophenyl)acetyl chloride (DDA-Cl), which in turn is hydrolyzed to DDA. The excretion of αOH-DDA from both DDT- and DDD-treated mice has never been previously observed. It is suggested that this metabolite arises from the initial epoxidation of DDMU, a metabolite of DDT and DDD, to yield 1,2-epoxy-1-chloro-2,2-bis(p-chlorophenyl)ethane (DDMU-epoxide). This chloroepoxide is then hydrolyzed and oxidized to produce the αOH-DDA.     

Concentrations of contaminants in muscle of the American alligator in Florida

Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues.     

Inupiat Health and Proposed Alaskan Oil Development: Results of the First Integrated Health Impact Assessment/Environmental Impact Statement for Proposed Oil Development on Alaska’s North Slope

We report on the first Health Impact Assessment (HIA) for proposed oil and gas development in Alaska’s North Slope region. Public health is not generally analyzed in the Environmental Impact Statement (EIS) process in the U.S. We conducted an HIA for proposed oil development within the National Petroleum Reserve - Alaska in response to growing concerns among North Slope Inupiat communities regarding the potential impacts of regional industrial expansion on their health and culture. We employed a qualitative HIA methodology, involving a combination of stakeholder input, literature review, and qualitative analysis, through which we identified potential health effects. The possible health outcomes identified include increases in diabetes and related metabolic conditions as a result of dietary change; rising rates of substance abuse, domestic violence, and suicide; increased injury rates; more frequent asthma exacerbations; and increased exposure to organic pollutant, including carcinogens and endocrine disruptors. There are also potential benefits, including funding for infrastructure and health care; increased employment and income; and continued funding of existing infrastructure. Based on these findings, we recommend a series of public health mitigation measures. This project represents the first formal effort to include a systematic assessment of public health within the U.S. EIS process. The inclusion of public health concerns within an EIS may offer an important and underutilized avenue through which to argue for environmental management strategies that focus on public health, and may offer communities a stronger voice in the EIS process. An erratum to this article can be found at     

Elucidation of Contaminant-Induced Toxic Responses in the Biota of Lake Vembanad,Kerala, India

This study investigates the spatial distribution of various organochlorine insecticides (OCIs) and heavy metals in both sediment and a bivalve, Villorita cyprinoides var. Cochinensis, collected from three pristine areas of Lake Vembanad. The detected concentrations of OCIs in the bivalve and sediment are in the order DDT > Heptachlor > BHC and BHC > DDD > heptachlor, respectively. However the DDT concentration (28.5 ng/g) in the bivalve at Chambakkara exceeded the limit suggested by the U.S. Geological Survey's National Water-Quality Assessment Program (NWQAP) and indicated an anthropogenic input source for the parent DDT. The maximum potential contamination indices for Zn and Ni in the bivalve were 267.8 mg/kg and 22.3 mg/kg, respectively. The Enrichment Factor (EF) and geoaccumulation index (I_geo) values of sediment indicated that Cd showed high pollution status and the Biota Sediment Accumulation Factor value of heavy metals suggested that Zn, Cu, and Cd were bioaccumulated in the bivalve's tissue. The concentrations of Zn and Cd were above the threshold levels and regarded as harmful according to the international standard for metals in mollusc compiled by the Food and Agriculture Organization. Therefore, they create great health risk for mussel consumers.     

The Health and Ecological Impacts of Organochlorine Pesticide Pollution in China: Bioaccumulation of Organochlorine Pesticides in Human and Fish Fats

The levels of organochlorine pesticides (OCPs) in the environment and foods have declined significantly in China since 1983, the year when their use in agriculture was officially banned. The levels today of these contaminants in soil, water, and agricultural products are well below 50 μg/kg in many parts of China. Yet in spite of such a decline, the current levels of pollution still pose a significant health risk to many people in China because OCPs are highly persistent and bioaccumulative substances. This preliminary study was conducted to monitor the levels of hexachlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) in human and fish fats from southeast China in an effort to corroborate the above health concern. The data reconfirmed that pollution by HCH and DDT, which are the major components of OCPs, is a serious ecological problem in the study region, and likely in other parts of China as well. The HCH contents in the human samples were between 0.25 and 2.20 mg/kg, with an average of 0.90 mg/kg. The DDT contents in these human samples were much higher, between 0.54 and 9.22 mg/kg with an average of 3.50 mg/kg. The major isomers found in the human samples were β-HCH and p, p′-DDE, representing 94.9 to 99.5% of total HCH and 72.3 to 96.7% of total DDT, respectively. The HCH and DDT content in the grass carp samples averaged 0.03 and 0.67 mg/kg, respectively. The levels of bioaccumulation reflected in these human and fish samples were considered substantial, particularly when residents in the study region continue to be exposed to the OCPs remaining so persistently in their environment. It is therefore important for the health authorities to launch a large-scale investigation into the potential health and ecological impacts of OCP pollution in China. The data also suggested that the current national standards might need to be lowered for the levels of OCPs in the environment in China.     

Residues of chlorinated hydrocarbons in tissues of raptors in Florida

Dead or moribund raptors (n = 75) representing 11 species were collected between 1971 and 1981 from various locations in Florida. Samples of bran, muscle, liver and adipose tissue were analyzed for DDT, DDE, DDD, dieldrin, and PCB's. Detectable concentrations of DDT or its metabolites were found in 100% of all samples of muscle and liver, and 77% all samples of brain. Dieldrin was determined to be present in 91%, 93%, 87% and 78% of all samples of brain, muscle, liver and adipose tissue, respectively. Lethal or hazardous concentrations of dieldrin were found in brain samples from three birds, but DDT and PCB's were present at sublethal concentrations. When species were grouped according to their dietary habits, it was not possible to identify any trends in pesticide concentrations.