Concentrations Of Dichlorodiphenyltrichloroethane Research Articles

Screening, characterization and optimization of potential dichlorodiphenyl trichloroethane (DDT) degrading fungi

Dichlorodiphenyltrichloroethane is an organo-chlorine insecticide used for malaria and agricultural pest control, but it is the most persistent pollutant, endangering both human and environmental health. The primary aim of the research is to screen, characterize, and assess putative fungi that degrade DDT for mycoremediation. Samples of soil and wastewater were gathered from Addis Ababa, Koka, and Ziway. Fungi were isolated and purified using potato dextrose media. Matrix-Assisted Laser Desorption, Ionization, and Flight Duration The technique of mass spectrometry was employed to identify fungi. It was found that the finally selected isolate, AS1, was Aspergillus niger. Based on growth factor optimization at DDT concentrations (0, 3500, and 7000 ppm), temperatures (25, 30, and 35 °C), and pH levels (4, 7, and 10), the potential DDT-tolerant fungal isolates were investigated. A Box-Behnken experimental design was used to analyze and optimize fungal biomass and sporulation. The highest biomass (0.981 ± 0.22 g) and spore count (5.60 ± 0.32 log/mL) of A. niger were found through optimization assessment, and this fungus was chosen as a potential DDT-degrader. For DDT degradation investigations by A. niger in DDT-amended liquid media, gas chromatograph-electron capture detector technology was employed. DDT and its main metabolites, DDE and DDD, were eliminated from both media to the tune of 96–99 % at initial DDT concentrations of 1750, 3500, 5250, and 7000 ppm. In conclusion, it is a promising candidate for detoxifying and/or removing DDT and its breakdown products from contaminated environments.

Association between prenatal exposure to indoor residual spraying insecticides and infection rates among South African children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE)

In 2021, 53 countries conducted indoor residual spraying (IRS), the application of insecticides such as dichlorodiphenyl trichloroethane (DDT) or pyrethroids to the walls of homes to control malaria. Animal studies show that these insecticides can increase susceptibility to infections but only one human study was conducted in a population from an area where IRS is applied. The aim of the present study was thus to investigate whether maternal exposure to DDT, its breakdown product dichlorodiphenyl dichloroethylene (DDE) or pyrethroid insecticides is associated with symptoms of infection among children living in a region of South Africa were IRS is conducted annually. As part of the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) we measured maternal serum concentrations of DDT and DDE, and urinary concentrations of four pyrethroid metabolites in peripartum samples. Poisson regression models with robust variance estimates were used to investigate associations with the rates of infection symptoms between ages 3.5–5 years among 629 children as assessed based on caregiver interviews. Multiple pyrethroid metabolites were associated with infection symptoms. For instance, cis-DBCA was associated with increased rates of ear infection (Incidence Rate Ratio for a 10-fold increase (IRR10) = 1.4; 95 % Confidence Interval (CI) = 1.0, 2.1) and persistent diarrhea (IRR10 = 2.1; 95 % CI = 1.2, 3.9), trans-DCCA was associated with increased rates of colds in children (IRR10 = 1.3; 95 % CI = 1.0, 1.6) and persistent fever (IRS10 = 1.4; 95 % CI = 1.0, 2.0), and 3-PBA was associated with increased rates of persistent fever (IRR10 = 1.8; 95 % CI = 1.0, 3.0). We found limited evidence of association between maternal DDE and DDT serum concentrations and infection symptoms. Results suggest that prenatal exposure to pyrethroid insecticides may be associated with infections among children from an area where IRS is conducted.

Chlorinated persistent organic pollutants in human breast milk in the Miyagi Prefecture disaster-affected area 1 year after the Great East Japan Earthquake of 2011

In the Great East Japan Earthquake of 11 March 2011, an earthquake and accompanying tsunami struck the Tohoku region of northeastern Japan. Buildings collapsed and the tsunami spread waste, including hazardous materials. This study aimed to determine the concentrations of persistent organic pollutants (POPs) in the breast milk of mothers living in the disaster-affected area of Sendai 1 year after the earthquake. Temporal trends in the POPs concentrations were evaluated by comparison with previous studies. One hundred breast milk samples were obtained from lactating mothers at a hospital in Sendai in 2012. The results were compared with those from other years to examine whether there were changes in the POPs concentrations after the earthquake. We measured polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as chlordanes, using gas chromatography-mass spectrometer (GC-MS) with negative chemical ionization, and dichlorodiphenyl trichloroethane (DDT) and its metabolites using GC-MS with electron impact ionization. The mean total PCBs (11 congeners), total chlordane, and total DDT concentrations were 76.2 ng/g lipid, 39.8 ng/g lipid, and 73.5 ng/g lipid, respectively. For the samples collected in 2012, the concentrations of POPs in breast milk showed minimal changes compared with results from previous years for samples collected at the same hospital in Sendai. Our study demonstrates that 1 year after the earthquake and tsunami, the concentrations of chlorinated POPs in breast milk had not changed substantially.

Evaluation of the spatiotemporal variations of organochlorine pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the forests of the Himalaya and Hengduan mountains using tree bark and tree core samples

There have been few reports of the large-scale spatial distribution and long-term historical variations of pollutants in high-altitude forests. Tree bark and tree core samples were collected from forests in the Himalaya and Hengduan mountains to determine the spatiotemporal variations of persistent organic pollutants. The average concentrations of dichlorodiphenyl trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in tree bark samples were 9.09, 0.10, 0.13, 0.11and 26 ng/g dry weight, respectively, and 1.30, 0.02, 0.17, 0.07 and 186 ng/g dry weight, respectively, in tree core samples. Higher levels of these pollutants were observed in the forests on the southern slopes of the Himalaya (Nepal) and the southern part of the Hengduan mountains (Yunnan, China). Lower concentrations of these pollutants were found in the interior of the Tibetan Plateau on the northern slopes of the Himalaya as a result of the blocking effect of these mountain ranges. The concentrations of DDTs and HCHs in Himalayan tree cores showed increasing trends from 1956 to 1975 when they were used as pesticide extensively worldwide, especially in India. Peak concentrations of DDTs, HCHs and PAHs in tree cores of Qamdo located in Hengduan Mountains were observed in 2013, which were consistent with the history of industrial and agricultural development in Sichuan. This study provides new insights into the impact of atmospheric pollutants in South and Southeast Asia.

Organic Matter Causes Chemical Pollutant Dissipation Along With Adsorption and Microbial Degradation

Views on the entry of organic pollutants into the organic matter (OM) decaying process are divergent, and in part poorly understood. To clarify these interactions, pesticide dissipation was monitored in organic and mineral soils not adapted to contaminants for 241 days; in groundwater sediment slurries adapted to pesticides for 399 days; and in their sterilized counterparts with and without peat (5%) or compost-peat-sand (CPS, 15%) mixture addition. The results showed that simazine, atrazine and terbuthylazine (not sediment slurries) were chemically dissipated in the organic soil, and peat or CPS-amended soils and sediment slurries, but not in the mineral soil or sediment slurries. Hexazinone was chemically dissipated best in the peat amended mineral soil and sediment slurries. In contrast, dichlobenil chemically dissipated in the mineral soil and sediment slurries. The dissipation product 2,6-dichlorobenzamide (BAM) concentrations were lowest in the mineral soil, while dissipation was generally poor regardless of plant-derived OM, only algal agar enhanced its chemical dissipation. Based on sterilized counterparts, only terbutryn appeared to be microbially degraded in the organic soil, i.e., chemical dissipation of pesticides would appear to be utmost important, and could be the first response in the natural cleansing capacity of the environment, during which microbial degradation evolves. Consistent with compound-specific dissipation in the mineral or organic environments, long-term concentrations of pentachloroaniline and hexachlorobenzene were lowest in the mineral-rich soils, while concentrations of dichlorodiphenyltrichloroethane (DTT) and metabolites were lowest in the organic soils of old market gardens. OM amendments changed pesticide dissipation in the mineral soil towards that observed in the organic soil; that is OM accelerated, slowed down or stopped dissipation.

Impact of Organic Micropollutants Causing Mass Mortality of the Clams (Mactra aequisulcata) Due to Charactersitic Distribution at Karachi Coast, Pakistan


 Mass mortality of bivalve clams along with some other marine fauna was observed during the month of May 2016, mainly consisting of the clams (Mactra aequisulcata) of family Veneridae surfaced over the Clifton coast. The occurrence of mass mortality of the venerid clams Mactra aequisulcata and other marine life has been studied due to the toxicity of chlorinated hydrocarbons (DDTs, HCHs, hexa chloro benzene (HCB), chlordane, dieldrin (4-chlorophenyl), methanol (TCPMOH) and heptachlor epoxide and polychlorinated biphenyls (PCBs). Significant compositional characteristics of PCBs and DDTs were found in all dead clams and other fauna including fish (Johnius carutta), crabs (Portunus pelagicus), gastropods (Babylonia spirata), bivalves (Anadara antiquata), (Mactra aequisulcata) and the pen shell (Atrina pectinata) from Karachi coast, Pakistan. Mean concentrations (ranges) of organochlorine pesticides (OCPs) in crab (Portunus pelagicus) and fish samples were 1.1 (<0.01-1.5), 0.22 (<0.01-1.1) and 0.14 (<0.01-1.3) /µg/g. Those in, bivalves (Anadara antiquata) and pen shell (Atrina pectinata), clams (Mactra aequisulcata) were 0.09 (<0.02-1.2), 0.22 (<0.02-1.3) /µg and 0.13 (<0.01-0.27), respectively. The heptachlor epoxide was found in highest concentration in clam samples (25.00 ± 30.92) µg/g, (wet weight) however, in bivalves, (2.30 µg/g, (wet weight), which were higher than those in other gastropods. Polychlorinated biphenyls (PCBs) concentrations were also measured in the same samples of gastropods (Babylonia spirata), fish (Johnius carutta), crab (Portunus pelagicus), clams (Mactra aequisulcata), bivalves (Anadara antiquata) and the pen shell (Atrina pectinata) to determine the possible cause of mass mortality. The DDT to metabolites (DDD & DDE) concentration ratios exceeded upto 1.0 in the sessile fauna that is clams (Mactra aequisulcata) and the pen shell (Atrina pectinata) from Karachi coast. These organisms also exhibited dichloro diphenyl trichloroethane (DDT) inputs, whereas dichloro diphenyl trichloroethane (DDD) was found to be in degraded component and PCBs were generally in low concentrations. The concentrations of DDTs were higher than the ERL guidelines in the coastal areas of Karachi, suggesting that there is potential of ecological risk present in the prevailing environment.
 

Associations between prenatal exposure to DDT and DDE and allergy symptoms and diagnoses in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), South Africa

Dichlorodiphenyl trichloroethane (DDT) is an organochlorine insecticide that is banned internationally except for use as part of Indoor Residual Spraying (IRS) programs to control malaria. Although animal studies show that DDT and its breakdown product dichlorodiphenyl dichloroethylene (DDE) affect the immune system and may cause allergies, no studies have examined this question in populations where IRS is conducted. The aim of our study was to investigate whether prenatal exposure to DDT and DDE is associated with allergy symptoms and diagnose among South African children living in an area where IRS is conducted. To accomplish this aim, we used data from the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), an ongoing birth cohort study of 752 children born between 2012 and 2013 in the rural Vhembe district of Limpopo, South Africa. We measured maternal peripartum serum concentrations of DDT and DDE, and administered a questionnaire to the caregivers of 658 children aged 3.5 years to collect information on allergy symptoms and diagnoses as well as potential confounders using validated instruments. Using multiple logistic regression models, we found positive associations between DDT and DDE serum concentrations and most of the allergy symptoms and diagnoses. Maternal DDT (Odds Ratio [OR] = 1.5 per 10-fold increase, 95% Confidence interval, CI = 1.0, 2.3) and DDE (OR = 1.4, 95% CI = 0.8, 2.4) serum concentrations were most strongly associated with caregiver report of wheezing or whistling in the chest. Concentrations of DDT and/or DDE were also associated with increased odds of children's chests sounding wheezy during or after exercise, itchy rashes coming and going for at least six months, diagnosis of food allergy, and diagnosis of dust or dust mites allergy but confidence intervals crossed the null. Results suggest that prenatal exposure to DDT, and possibly DDE, is associated with elevated odds of wheezing among children from an IRS area.

Organochlorine pesticides (HCH and DDT) in blubber of spotted seals (Phoca largha) from the western Sea of Japan

In 2014–2019, a total of 31 blubber samples were collected from spotted seals (Phoca largha) in the western Sea of Japan. The samples were analyzed by gas chromatography to determine level of organochlorine pesticides (OCPs). The concentration of hexachlorocyclohexane and its isomers (∑HCH) ranged from 389 to 50,070 ng/g lipid weght; the concentration of dichlorodiphenyltrichloroethane and its metabolites (∑DDT), ranged from 62,720 to 1,110,930 ng/g lipid wt. Transfer of HCH and DDT from mother to pup during pregnancy and lactation was documented. The OCP concentration in blubber of spotted seals from the western Sea of Japan is one to two orders of magnitude higher than in spotted seals inhabiting waters off the Japan coast. Organochlorines detected in the western Sea of Japan likely come from some countries of Southeast Asia still using OCPs in the agriculture sector.

Maternal peripartum urinary pyrethroid metabolites are associated with thinner children at 3.5 years in the VHEMBE birth cohort (Limpopo, South Africa)

Pyrethroids are the most widely used insecticides globally for domestic, agricultural, and malaria vector control. In 10 countries, dichlorodiphenyl trichloroethane (DDT) is also used for the latter. Thus, high exposure to pyrethroids and DDT have been reported among women and children from rural and/or malaria-endemic areas. Experimental studies suggest that fetal exposure to pyrethroids, particularly cypermethrin, and DDT may have sex-specific growth effects. However, epidemiologic investigations are scarce and inconsistent and have not considered postnatal environment or susceptibility factors. In 665 mother-child dyads participating in the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE), a rural South African birth cohort with high insecticide exposure, we examined associations of maternal peripartum uri-nary pyrethroid metabolites and serum DDT concentrations with child anthropometrics at 3.5 years using multivariable linear regression. We investigated effect modification by child sex, maternal nutrition and HIV status, and household poverty. Pyrethroid metabolites cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis-DBCA), cis-3-(2,2,-dicholorvinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis-DCCA), trans-DCCA, and 3-phenoxybenzoic acid (3-PBA) were quantified in nearly all mothers. A 10-fold increase in cis-DCCA concentration was associated with 0.21 kg/m2 lower body mass index (95% confidence interval = -0.41, -0.01), with similar estimates for other cypermethrin or permethrin metabolites (trans-DCCA and 3-phenoxybenzoic acid). In stratified analyses, stronger associations were observed with lower weight, body mass index, arm circumference, and weight-for-height among boys relative to girls. Associations with cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid, a metabolite specific to deltamethrin, were weaker or absent. No substantial associations were observed with DDT. In a population with ubiquitous pyrethroid exposure, maternal concentrations of metabolites of cypermethrin and permethrin were associated with thinness at 3.5 years.

Lake sediment records of persistent organic pollutants and polycyclic aromatic hydrocarbons in southern Siberia mirror the changing fortunes of the Russian economy over the past 70 years

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) have previously been detected in the surface sediments, water, and endemic organisms of Lake Baikal, a UNESCO World Heritage Site. The Selenga River is the primary source of freshwater to Lake Baikal, and transports pollutants accumulating in the Selenga River basin to the lake. Sources of POPs and PAHs in the Selenga River basin grew through the 20th century. In the present study, temporal changes in the concentrations of PAHs and POPs were reconstructed from two lakes in the Selenga River basin over the past 150 years using paleolimnological techniques. Increased concentrations in PAHs and PCBs were recorded initially in the 1930s. The 1940s–1980s was the period of greatest exposure to organic contamination, and concentrations of dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs) and many PAHs peaked between the 1960s and 1980s in the two lakes. Declines in concentrations and fluxes were recorded for most PAHs and POPs in the 1980s and 1990s. Temporal trends in concentrations of total and individual compounds/congeners of PAH, PCBs, and polybrominated diphenyl ethers (PBDEs) indicate the contribution of both local and regional sources of contamination in the 20th and 21st centuries. Temporal variations in contaminants can be linked to economic and industrial growth in the former USSR after World War II and the economic decline of Russia in the late-1980s and early-1990s, as well as global trends in industrialization and development during the mid-20th century.

Exposure to DDT and hypertensive disorders of pregnancy among South African women from an indoor residual spraying region: The VHEMBE study

Indoor Residual Spraying (IRS), the use of insecticides inside residences for malaria control, may cause elevated exposure to insecticides such as dichlorodiphenyl trichloroethane (DDT). Evidence suggests that DDT exposure may increase blood pressure but no study has investigated associations with hypertensive disorders of pregnancy (HDP) in an IRS area. We measured the serum concentration of DDT and its breakdown product dichlorodiphenyl trichloroethylene (DDE) at the time of delivery among 733 rural South African women participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE). We also collected data on HDP diagnosis through questionnaires administered to participants and medical record abstraction. We used multiple logistic regression models to examine the relation between DDT/E and HDP. p,p′-DDT and p,p′-DDE serum concentrations were associated with HDP based on self-report (OR = 1.50; 95%CI = 1.10, 2.03 for p,p′-DDT and OR = 1.58; 95%CI = 1.09, 2.28 for p,p′-DDE) and medical records (OR = 1.32; 95%CI = 0.99, 1.75 for p,p′-DDT and OR = 1.47; 95%CI = 1.03, 2.09 for p,p′-DDE). p,p′-DDE was also associated with gestational hypertension (OR = 1.44; 95% CI = 1.00, 2.07). Exposure to DDT and DDE may be associated with elevated risks of HDP in South African women residing in an area sprayed for malaria control.

Bioremediation of soil contaminated by dichlorodiphenyltrichloroethane with the use of aerobic strain Rhodococcus wratislaviensis Ch628

The concentration of dichlorodiphenyltrichloroethane (DDT) was determined in a sandy soil of specially Protected Natural Area Osinskaya Lesnaya Dacha (Perm region) 45 years after the last application of the insecticide in this area. The concentration of DDT in the soil exceeded the maximum permissible concentration by 250 times and reached 25.05 mg/kg of soil. Under the conditions of model experiment, efficient decontamination of the soil was recorded in the system with the introduced strain Rhodococcus wratislaviensis Ch628; the DDT concentration decreased by 99.7% and equaled 0.07 mg/kg. The process of DDT degradation proceeded slower in the model soil system with autochthonous microbial complex. In this case, 58.2% DDT degraded in 70 days, and the final concentration was 10.47 mg/kg. The soil lost its toxicity for animal and plant test objects by the end of the experiment only in the model system containing the R. wratislaviensis Ch628 strain.

Changes over time in persistent organic pollutants (POP) concentrations in human milk in the Republic of Moldova

ABSTRACTPersistent organic pollutants (POP) in human milk originating from various sources are used as environmental exposure markers. Further, mothersmilk is a predominant pathway for human exposure for suckling infants to POP. The aim of present study was to provide baseline and time trend information on human milk POP concentrations in the Republic of Moldova. A pooled sample of breast milk was analyzed in 2009 and 2015 and health risk evaluated by comparing reference values of humans' daily intake with estimated daily intake (EDI). Results showed decreases for concentrations of dichlorodiphenyltrichloroethane, hexachlorobenzene, dieldrin, heptachlor, α and β-hexachlorocyclohexane, polychlorinated biphenyls, dioxin-like polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans between sampling periods. Regardless of the decrease, EDI was higher than reference values for dioxins toxic equivalents, polychlorinated biphenyls and β-hexachlorocyclohexane in both phases. However, increased levels were detected for polybrominated diphenyl ethers (twofold) and hexabromocyclododecane (threefold) from 2009 to 2015, but the EDI in both phases is much lower than the reference. The decline in certain POP levels may be attributed to coordinated efforts undertaken by national and international entities to regulate these compounds. The basis for the elevated levels of polybrominated diphenyl ethers and hexabromocyclododecane remains unknown but raises concerns regarding lactational exposure.

DDTs and other organochlorine pesticides in tissues of four bird species from the Rift Valley region, Ethiopia

Despite the presence of a wide variety and number of birds, there is exceedingly little data on organochlorine pesticide (OCP) residues in birds inhabiting in Africa. In the present study, concentrations of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes, drins, cyclodienes, and hexachlorobenzene were measured in liver, kidney, heart and brain of 4 bird species from the Rift Valley region, Ethiopia. Indoor residual spraying of DDT for malaria vector control, and indiscriminate and illegal use of pesticides underline the relevance of this study. Levels of ΣOCPs ranged from 1.87 to 4586ng/g wet weight, and the scavenger bird species Leptoptilos crumeniferus had the highest level in liver. In all tissues, contamination profiles of OCPs within the species were similar, with DDTs≫other OCPs. Among the DDTs, p,p'-DDE was the most abundant compound and had significantly a higher burden in all tissues. The risk characterization demonstrated potential risks to the studied birds associated with DDE exposure. Maximum hepatic levels of p,p'-DDE exceeded the levels reported to trigger adverse effects. The detection of p,p'-DDT in all bird tissues suggests the release of fresh DDT to the environment. This is the first study to assay OCPs in different tissues of birds from the Ethiopian Rift Valley region, and henceforth the data will serve as a reference data for future studies.

Are Biometric Parameters Helpful to Assess the Health Risk of Consuming Organochlorine Compounds Contaminated Silver European Eel (Anguilla anguilla)?

Several organochlorine compounds (OCs) were measured in European eels from the Tevere river (Italy). It followed that some of them are still important chemical contaminants. Concentrations of dichlorodiphenyltrichloroethanes (DDTs) are hazardous for the consumer health; those of the 6 indicator polychlorinated biphenyls (PCBs) are often close to the current European maximum residue limit and always higher than the former limit. The relationship between OC concentrations, biometric parameters and the lipid content was then investigated. A strong positive correlation with eel size emerged for the indicator PCBs and DDTs concentrations expressed on wet weight basis. This is explained by the corresponding higher lipid percentage that characterizes bigger eels and the absence of a dilution effect for compounds of main concerns. On the basis of the PCB-TDI threshold for a 70 kg person, we suggest that 1 should consume no more than 2 eels per week each weighing about 100 g. Thus, we conclude that eel consumption should be limited and restricted to eels relatively shorter and lighter.

Levels and Spatial Distribution of Persistent Organic Pollutants in the Environment: A Case Study of German Forest Soils

The Of/Oh-horizons of 447 forest stands in Germany were evaluated for concentrations and spatial distribution of selected polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). While concentrations of dichlorodiphenyltrichloroethane (DDT) and PCBs show similar spatial distribution patterns for all measured compounds within each compound class, significantly different distributions were identified for concentrations of low-molecular-weight PAHs [2- and 3-ring PAHs plus fluoranthene (FLA) and pyrene (PYR)] in contrast to high-molecular-weight PAHs (4-6-ring PAHs without FLA and PYR). Maxima of persistent organic pollutant (POP) concentrations could be mostly explained by specific locatable sources. Because of the slow degradation rates of these target substances, this is especially relevant for historic contamination sources, such as extensive 1980s DDT usage in the former German Democratic Republic and industrial facilities that produced hexachlorobenzene (HCB) or PCBs. A contribution of ubiquitous background pollution derived from long-range atmospheric transport is likely for some compounds in the studied area, e.g., DDT in the western part of Germany and dieldrin. However, most target compounds appear to be mainly sourced from local or regional emissions. This is supported by the absence of clear dependencies between POP concentrations and most evaluated environmental and local parameters. We suggest that these results generally reflect the distribution of POPs in densely populated and industrialized countries located in temperate regions.

Organochlorine pesticides in fish from Taihu Lake, China, and associated human health risk assessment

Because contaminants and nutrients always coexist in fish, the risk from contaminants and the benefit from nutrients, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are also concomitant via fish consumption. To investigate the risk and benefit via fish consumption, concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs) in the whole- and portion-muscles of fish from Taihu Lake, China, were measured. Based on the contaminant data and nutrients from our previous study, and the associated risk and benefit via fish consumption were estimated. The concentrations of DDTs and HCHs in the whole-muscles ranged from 7.8×102 to 3.4×103pgg−1ww, and from 67.3 to 300pgg−1ww, respectively. Of DDTs and HCHs measured, p,p′-DDE and β-HCH were respectively the most abundant pesticides. The composition profiles of DDTs and HCHs suggested that the pesticides were mainly historical residues. The benefit–risk quotient (BRQ) of EPA+DHA vs. POPs (persistent organic pollutants including data of DDTs, HCHs, and those of polychlorinated biphenyls and polybrominated diphenyl ethers cited from our previous study) via consumption of fish from Taihu Lake was calculated. As a result, to achieve the recommended EPA+DHA intake of 250mgd−1 for a healthy adult, the consumption of most fish species from the lake can cause cancer and non-cancer risks. However, the fish consumption at the rates of 44.9gd−1 by Chinese would not lead to the risks for most of the species. The results also suggested that the risk of consuming silver carp was generally lower than other fish species, and those of dorsal muscles were lower than ventral and tail muscles.

Population characteristics of young African women influencing prenatal exposure to DDT (Manhiça, Mozambique)

The concentrations of dichlorodiphenyltrichloroethane (DDT) compounds in cord blood of 214 children born between 2003 and 2006 in Manhiça (Mozambique) have been determined. In this time interval, corresponding to the period before DDT reintroduction for indoor residual spraying, the observed values averaged 0.8 and 0.4 ng/ml for 4,4'-dichlorodiphenyldichloroethylene (4,4'-DDE) and 4,4'-DDT, respectively, and were similar to those found in western countries. However, the 4,4'-DDT/4,4'-DDE ratio was high indicating that the inputs of these compounds arriving to children in utero originated from recent uses of the insecticide. The strongest factor affecting DDT concentration was parity. A well-defined decreasing concentration trend was observed for the cord blood concentrations in the period of study. The trend was also observed for multiparae and primiparae mothers independently. Children from multiparae women showed much lower concentrations than primiparae women. Children from mothers with secondary school level exhibited lower concentrations of these pesticides than mothers with lower degree of education.

Persistent organic pollutants in coastal sediment off South China in relation to the importance of anthropogenic inputs

Surface sediments collected from the coastal region off South China were analyzed for persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs). The concentrations of BDE-209, Σ(12)PBDE, Σ(15)PAH, Σ(7)PAH, and Σ(11)OCP were 0.22 to 26.3, 0.01 to 0.77, 13.9 to 271, 6 to 133, and 0.9 to 104 ng/g, respectively. The spatial distribution patterns of PBDEs and PAHs suggested that the eastern coastal region was slightly more contaminated than the western coast. In addition, the concentrations of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs) were highly variable, with the highest level found at a site in Zhanjiang Bay, which might have been reflective of the impact of antifouling paints mainly used in boat maintenance in harbor areas. The predominance of BDE-209 in the study region was consistent with the usage pattern of penta-, octa-, and deca-BDEs in China, whereas sediment PAHs appeared to have been derived largely from coal or wood and petroleum combustion. Preliminary assessments indicated that terrestrial inputs, such as atmospheric transport and riverine runoff, may have been the major input pathways for PBDEs and PAHs, respectively, to accumulate in coastal sediment off South China. Conversely, residues of DDT-containing antifouling paints associated with shipping activities and boat maintenance accounted for most of the accumulated sediment DDTs.

Detection of health hazard insecticide dichlorodiphenyltrichloroethane (DDT) in some common marine dry fish samples from Bangladesh

Objectives: The general purpose of this study is to detection and determination of the concentration level of dichlorodiphenyltrichloroethane (DDT) in some commercially available marine dry fishes and to investigate the contamination status of dichlorodiphenyltrichloroethane (DDT) of these dry fishes. Methods: Samples were collected from six largest dry fish markets (three from Chittagong district and three from Cox’s Bazar district) and four types of dry fishes were taken in this study are Ribbon fish (Lepturacanthus savala), Sin Croaker (Johnius dussumieri), Bombay duck (Harpodon nehereus) and Shrimp (mixed species). Total numbers of samples were 24 that were analyzed in the laboratory. Results: The results of the study show that the mean concentrations of dichlorodiphenyltrichloroethane (DDT) in the samples of Ribbon fish, Bombay duck and Sin croaker were ranged between 130.85 - 153.47ppb, 125.21 - 181.4ppb and 119.86 – 208.65ppb respectively. The mean concentrations of dichlorodiphenyltrichloroethane (DDT) were found at a lower amount in shrimp sp. than the other. Conclusions: This result indicates that the concentration of dichlorodiphenyltrichloroethane (DDT) in dry fish samples from Bangladesh are higher and may causes chronic disease and potential long-term risk for human health.