DDT Concentrations Research Articles

Spatial Variation in Contaminant Occurrence in Marine Fishes and Prawns from Coastal Tanzania.

There are limited data on organic contaminants in marine biota from coastal Tanzania, especially on the occurrence of industrial-use contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The present study, performed in 2018-2019 in coastal Tanzania and Zanzibar Island, aimed at assessing spatial variation in the occurrence of PCBs; brominated flame retardants (BFRs), including PBDEs; and organochlorine pesticides, including dichlorodiphenyltrichloroethane (DDT), among three locations that differ in degree of anthropogenic activity. Analyzed samples included edible tissues of marine fishes and prawns representing different trophic levels and habitats. The results indicate a mainland-island difference, with fishes and prawns collected on Zanzibar having significantly lower PCB and DDT concentrations but higher concentrations of hexachlorobenzene compared to the two mainland locations. The highest contaminant concentrations were found in fishes and prawns collected around central Dar es Salaam harbor, with median ΣPCBs ranging from 22.3 to 577 ng/g lipid weight and ΣDDTs from 22.7 to 501 ng/g lipid weight, suggesting local sources. Concentrations of PBDEs were similar among locations, suggesting more diffuse sources. None of the "newer-type" BFRs, including compounds introduced as replacements for PBDEs, were detected in the present study. Stable isotope values of carbon (δ13 C) and nitrogen (δ15 N) varied among locations, and the relationship between contaminants and δ15 N varied among locations and habitat (pelagic/demersal). Concentrations measured in the present study are below European guidelines for human consumption of fishes and prawns. However, industrial-use contaminants should be monitored in developing countries because they are contaminants of emerging concern as a result of increasing industrialization and global trade of used products and wastes. Environ Toxicol Chem 2022;41:321-333. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Acute exposure to environmentally relevant levels of DDT alters muscle mitochondrial function in vivo in rats but not in vitro in L6 myotubes: A pilot study

Under insulin-stimulated conditions, skeletal muscle is the largest glucose consumer in the body. Mitochondrial dysfunction and damage to this tissue from oxidative stress are linked to the pathogenesis of type 2 diabetes. Environmental exposure to dichlorodiphenyltrichloroethane (DDT) and its metabolite, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), has been associated with the incidence of type 2 diabetes as well as altered oxidative stress and mitochondrial dysfunction in non-muscle tissues. We hypothesized that energy metabolism and insulin sensitivity in skeletal muscle will be altered with exposure to DDT and DDE. In this pilot study, mitochondrial function was measured in permeabilized muscle fibers from Sprague-Dawley rats after one week of exposure to a single injection of DDT (40 μg/kg), a dose comparable to DDT levels in the diets of the Inuit of Northern Canada. The levels of oxidative phosphorylation chain complexes and ROS detoxification enzymes were measured in muscle tissue from these specimens. This acute in vivo exposure to DDT decreased muscle mitochondrial function by 45% without affecting the levels of mitochondrial oxidative phosphorylation chain complexes nor levels of ROS detoxification enzymes. To isolate the effects of DDT and DDE exposure on muscle, L6 myotubes were exposed to DDT or DDE (0, 10, 100, 1000, 10 000 nM) for 24 h. Only very high concentrations of DDT and DDE (1 000 – 10 000 nM) altered maximal respiration with only DDT altering basal glucose uptake in L6 myotubes. This did not alter levels of ROS detoxification enzymes or malondialdehyde (MDA) in L6 myotubes. Altogether, acute exposure to environmentally relevant doses of DDT resulted in muscle mitochondrial dysfunction in vivo in rats, but not when muscle cells were directly exposed to the pollutant or its metabolite.

The rapid survey method of chemical contamination in floods caused by Typhoon Hagibis by combining in vitro bioassay and comprehensive analysis.

A novel comprehensive assessment system, consisting of a bioassay and chemical analysis, was developed to quickly evaluate the human health risk posed by toxic chemicals discharged due to natural disasters. To analyze samples quickly, a yeast-two-hybrid assay (Y2H) and GC-MS equipped with an automated identification and quantification system (AIQS-GC) were employed for the bioassay and chemical analysis, respectively. Since the analysis of 1000 substances by AIQS could be finished within two days following the Y2H assay for screening, this method would complete the risk assessment within three days. To confirm the applicability of this method in real environmental samples, we examined it using sediments circulated by Typhoon Hagibis. In one sediment sample, a distinctive response was indicated by the Y2H assay, and relatively high DDT concentration was identified by AIQS-GC in the same sediment. Therefore, using the results obtained from this method, a human health risk assessment of DDT was conducted, which indicated that the risk could be ignored. Additionally, the contamination of PAHs and alkanes was suggested as well. In this study, the pollution risk assessment could be completed within three days. Therefore, to our knowledge, this is the first study to demonstrate an assessment system with a rapid combination method for emergencies. Consequently, it is believed that this type of novel system would be needed in the future due to the increasing number of natural disasters predicted worldwide.

Environmental contaminants and the disproportionate prevalence of type-2 diabetes mellitus among Indigenous Cree women in James Bay Quebec, Canada

Indigenous populations are disproportionately affected by type 2 diabetes (T2DM) compared to non-Indigenous people. Of importance, the prevalence of T2DM is greater amongst females than males in First Nations communities, in contrast to higher male prevalence reported in non-Indigenous Canadians. Therefore, in this study we extend our previously published work with respect to females, and the potential association between environmental exposures to organochlorine pesticides, such as dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethylene (DDE) to explain the greater prevalence of T2DM among Indigenous females compared to males. Using data from the Multi-Community Environment-and-Health Study, Principal Component Analysis (PCA), examined 9-polychlorinated biphenyl congeners, 7-organic pesticides, and 4-metal/metalloids. Modified Poisson regression with robust error variance estimated adjusted prevalence ratios (PR) and corresponding 95% confidence intervals (95% CI), regressing prevalent T2DM on the newly derived principal components (PC), adjusting for a priori covariates, including parity. We further examined the relationship between high detection concentrations of DDT and tertials of categorized DDE exposures on T2DM among Indigenous Cree women. Among 419 female participants, 23% (n = 95) had physician-diagnosed T2DM. PCA analysis show that DDT and Lead (Pb) loaded highly on the second axis (PC-2), although in opposite directions, indicating the different exposure sources. As previously published, T2DM was significantly associated with PC-2 across adjusted models, however, after further adjusting for parity in this analysis, T2DM was no longer significantly associated with increasing PC-2 scores (PR = 0.88, 95% 0.76, 1.03). Furthermore, we found that the highest detectable levels of DDT, and tertiles of DDE were significantly associated with prevalent T2DM in the fully adjusted model (PR = 1.93, 1.17, 3.19), and (PR = 3.58, 1.10, 11.70), respectively. This cross-sectional analysis suggests organochlorines, specifically, detectable high exposure concentrations of DDT and DDE are associated with prevalent type 2 diabetes, signifying a possible important link between parity and environmental organochlorines pesticides among Indigenous Cree women.

DDT in Crimea coastal waters and blubber of Black Sea cetaceans

This research is based on the multi-year data on the distribution of organochlorine pesticides of the DDT group in the water of the coastal Black Sea areas of Crimea, obtained in expeditions of the “Professor Vodyanitsky” research vessel from 1999 to 2020. Study of content of DDT and its metabolites (DDTs) in the blubber of three species of Black Sea cetaceans that were astrand on the Black Sea coast from the 1980s to the 2020s was grounded on own and literature data. While there was an overall significant variability in ∑DDT content during the study period, there was a significant downward trend in their concentrations in the water of coastal areas of Crimea. Despite the significantly decreased DDTs pollution of the habitat of the Black Sea marine mammals over the last 10 years, high concentrations of DDTs were accumulated in their blubber, the maximum value of the sum of DDTs concentrations reached (163 µg/g of lipids) in the blubber of adult depleted bottlenose dolphin. The minimum concentrations were determined in the blubber of a newborn harbour porpoise female. In blubber samples up to 70% was of DDE, DDD - from 21 to 24%, and the concentration of the initial DDT varied from 6 to 14%. Based on the analysis of own and literature data, it is assumed that in the modern period, as compared to the 1990s, there is a downward trend in the content of the DDTs in the blubber of Black Sea cetaceans.

Analysis of organochlorine DDT residue along with its metabolites in dry fishes from some selected markets of Dhaka city

A study was investigated to estimate the current status of health hazardous organochlorine insecticide DDT and its metabolites DDE and DDD in different species of dry fish. To achieve the goal of this experiment, ten different sun-dried fish samples were collected from different markets of Dhaka city. The concentration of DDT, DDE and DDD was determined using the capillary column coupled to Gas Chromatograph with Electron Captured Detector (GC-ECD). Most of the dry fishes, seven out of ten samples, were found to be contaminated with DDT along with its metabolites DDE and DDD ranging from 0.029-1.22 mg/kg which is a serious concern because of the nature of long persistency and bioaccumulation of DDT in the environment. The highest concentration of DDT (1.22 mg/kg) was observed in Pampus chinensis dry fish whereas low concentration was detected in Otolithoides pama (0.029 mg/kg). Asian Australas. J. Food Saf. Secur. 2021, 5 (2), 79-84

Bioaccumulation and maternal transfer of two understudied DDT metabolites in wild fish species

While the secondary metabolites of DDT such as 2,2-bis(chlorophenyl)-1-chloroethylene (DDMU) and 2,2-bis(chlorophenyl)methane (DDM) have been detected in the environment for several decades, knowledge is extremely limited on their bioaccumulation characteristics. Here, we reported the bioaccumulation and maternal transfer of p,p′-DDMU and p,p′-DDM in two wild fishes, i.e., the northern snakehead (Channa argus) and crucian carp (Carassius auratus), from a DDT contaminated site in South China. The hepatic concentrations of p,p′-DDMU and p,p′-DDM in the fish were up to 549 and 893 ng/g lipid weight, contributing 5.3% and 3.2% in average to ΣDDXs (the sum concentrations of DDT and its 6 metabolites), respectively. The residues of p,p′-DDMU and p,p′-DDM in the fish exhibited interspecific and intraspecific variations, resulting from the differences in lipid content, sex, and body sizes (length and mass) between or within species. Both p,p′-DDMU and p,p′-DDM were consistently detected in the fish eggs, demonstrating their maternal transfer in female fish. The mean eggs to liver lipid-normalized concentration (E/L) ratios of p,p′-DDMU and p,p′-DDM were 0.98 and 1.77 in the northern snakehead, 0.35 and 0.01 in crucian carp, respectively; which were comparable to or even exceeded those of DDT and its major metabolites calculated in the same individual. Statistical analyses of the data showed that the E/L ratios were positively correlated with body sizes of the fish, but negatively correlated with the hepatic concentrations of p,p′-DDMU and p,p′-DDM in females; suggesting the influences of fish sizes and the mother body residues on their maternal transfer efficiencies.

Legacy organochlorines in estuarine sediment in relation to socioeconomic pattern in multi-coastal watersheds.

Estuarine sediment quality is highly associated with anthropogenic activities in watersheds. This study attempts to couple socioeconomic patterns with estuarine sediment quality via legacy organochlorines in 14 Chinese coastal watersheds. Sedimentary concentrations of HCHs, DDTs, and PCBs showed a significant spatiality in estuary, up to 48.7 ± 15.1, 89.0 ± 46.4, and 54.5 ± 17.2ngg-1, which were predominated by β-HCH, p,p'-DTs, and tri- to penta-PCBs, respectively. Ecological risk of organochlorines was negligible except few moderate risks for DDTs and PCBs against the first class quality of the marine sediment quality guidelines of China. Sedimentary DDT and PCB concentrations were significantly delineated by an environmental Kuznets curve model as a function of non-agricultural GDP per capita in watersheds, while HCHs by an increasing linear model. Findings of this study provide a tool to quantify the contribution of anthropogenic development in watershed to environmental change in estuary across the world.

Exposure of infants to organochlorine pesticides from breast milk consumption in southwestern Ethiopia

Breast milk is often used as an environmental bioindicator since it serves as an important medium to accumulate organochlorine pesticides. The main aim of this study is to determine the level of organochlorine pesticides in human breast milk collected from three districts of southwestern Ethiopia (Asendabo, Deneba, and Serbo) at three times points baselines (1st month), midline ( six months), and end line (12 months) and risk of infants’ exposure. A longitudinal study was conducted to assess pesticide residues in human breast milk samples and evaluate the risk-exposure of infants to these pesticides from consumption of mother’s milk in Ethiopia. Breast milk samples were collected from 168 mothers at three time points and pesticides were extracted using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The level of pesticide residues in human milk samples and exposure of infants to the pesticides was evaluated by calculating the estimated daily intake and compared with the provisional tolerable daily intake of the pesticides under study. The results indicated that, from the eight organochlorine pesticides analyzed in 447 breast milk samples at three sampling times, DDT and its metabolites were detected. p,p′-DDE and p,p′-DDT were detected in all (100%) of the breast milk samples while, p,p-DDD, and o,p-DDT were detected in 53.9%, and 42.7%, respectively. The mean concentration of total DDT at three time points(baseline, midline and endline) were 2.25, 1.68 and 1.32 µg/g milk fat, respectively. The mean concentration of total DDT from the three districts was 1.85 µg/g milk fat which is above the maximum residue limit (MRL = 0.02 µg/g milk fat set by FAO/WHO). The mean ratio of DDT/DDE for the three areas was calculated less than five (< 5) indicates historical DDT use in the study area. The estimated daily intake of infants at the first month of breastfeeding was 11.24 µg/kg-BW/day, above the provisional tolerable daily intake (PTDI) for total DDT set by FAO/WHO, which is 10 µg/kg body weight. An intake of OCPs is a big concern for infants' health in Ethiopia and countries with a similar condition, particularly at the first month of lactation. Strict regulations of the health-threatening pesticide by the regulatory body (Environment, Forest and Climate Change Commission) at the country and regional levels is advocated.

Occurrence of Pesticides Associated with an Agricultural Drainage System in a Mediterranean Environment

Surface water pollution (as a result of pesticides) is a major problem, due to the negative impact on human health and ecosystems. The excessive use and persistence of surface water pollution in the environment may present a notable risk. In this article, DDT and its metabolite DDE hereafter, DDT–DDE), and a commonly used pesticide (herbicide) glyphosate, were analyzed in agricultural drainage waters; afterward, a spatial analysis was applied to identify potential areas of high pesticide occurrence in an agricultural Mediterranean coastal floodplain. The spatial distribution of banned (Directive 79/117/EEC), yet highly persistent pesticides in the environment, such as DDT (and metabolites), was compared with the (currently and mostly used) glyphosate. A sequence of various point patterns, spatial analysis methods, and non-parametric statistics, were computed to elucidate the pesticide pollution hotspots. As a reference value, almost 70% of the water samples were above the World Health Organization (WHO) guideline for DDT (and metabolites) for drinking water (1 µg/L), with a maximum of 6.53 µg/L. Our spatial analysis approach revealed a significantly high concentration of DDT–DDE clusters close to wetlands in natural parks, where mosquitos are abundant, and pesticides persist and flow to the surface waters from soil and groundwater pools. Conversely, glyphosate concentrations were below WHO guidelines; their spatial patterns were related more toward current agricultural uses in the southern sector of the study area.

Contamination, spatial distribution, and source contribution of persistent organic pollutants in the soil of Guiyang city, China: a case study.

The contamination of persistent organic pollutants (POPs), including dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and polycyclic aromatic hydrocarbon (PAH), is the most studied environmental issue. In 2020, a total of sixty soil samples collected from ten locations in Guiyang were analyzed to assess the presence of four DDTs and HCHs and sixteen PAHs. The concentrations of total DDTs, total HCHs and Σ16PAHs in the soil were between 0.26 and 12.76, 0.23 and 51.80μg/kg, and 10.02 and 1708.86μg/kg, respectively. The mean and median concentrations of total DDTs, total HCHs and Σ16PAHs in the soil were 1.04 and 0.26μg/kg, 4.32 and 0.23μg/kg, 139.14 and 98.98μg/kg, respectively. p,p'-DDT, p,p'-DDD and γ-HCH the dominant organochloride pollutants in the soil, while 4-ring PAHs were the dominant PAHs, occupying 41.1-53.6% of the total PAHs in the soil. The highest levels of PAHs in the soil were observed in areas of Guiyang with relatively larger population densities and more developed heave industries. Various diagnostic tools were used to identify the potential sources of the POPs in the soil. The data indicated that DDTs and HCHs were from past and recent common inputs and that mixtures of several combustion activities (biomass, coal and petroleum combustion, diesel, gasoline, and vehicular emissions) were the major sources of PAHs in the Guiyang soil. The results provide information for the assessment of the extent of POP pollution in the Guiyang soil and can help authorities establish environmental protection regulations and soil remediation techniques.

Environmental chemicals and cross-sectional cognition among adults in the National Health and Nutrition Examination Survey

BACKGROUND AND AIM: Cognitive impairment among older adults is a growing public health challenge and environmental chemicals may be modifiable risk factors. A wide array of chemicals has not been tested for association with cognition in an environment-wide association framework. METHODS: In the US National Health and Nutrition Examination Survey (NHANES) 1999-2002 and 2011-2014 cross-sectional cycles, cognition was assessed using the Digit Symbol Substitution Test (DSST, scores 0-117) among participants 60 years of age and older. Concentrations of environmental chemicals were measured in blood or urine. Chemicals with at least 50% of measures greater than the limit of detection were included (nchemicals=124, nclasses=16). We tested for differences in cognition by natural log transformed concentration of each chemical using parallel multivariable linear regression models accounting for age, sex, race/ethnicity, and educational attainment. We calculated false discovery rates (FDR). RESULTS:Participants with complete cognition/demographic measures and at least one chemical measure (n=5,670) were mean age 70.3 years, 51% female, 43.7% college educated, and 53.2% non-Hispanic White. The mean DSST score was 43.6 (18.1 standard deviation) and 24.2% were cognitively impaired (DSST28). In adjusted analyses, 75% higher lipid adjusted blood concentration of the pesticide DDT was associated with 1.4 points lower DSST score (95% Confidence interval (CI):-2.1,-0.7, FDR:0.0001). Similarly, 75% higher heptachlor concentration was associated with 0.9 points lower DSST score (95%CI:-1.6,-0.1, FDR:0.02). For metals, we observed 75% higher blood cadmium levels were associated with 0.7 points lower DSST score (95%CI:-1.1,-0.4, FDR:5*10-5) and 75% higher blood lead levels were associated with 0.6 points lower DSST score (95%CI:-0.9,-0.2, FRD:0.002). Among perfluoroalkyl substances, 75% higher urinary concentration of perfluoroundecanoic acid was associated with 0.5 points lower DSST score (95%CI:-1.0,0.07, FDR: 0.09). CONCLUSIONS:Exposure to environmental chemicals, particularly pesticides and metals, may be modifiable factors for reduced cognition among older adults. KEYWORDS: cognition, exposome, environment-wide association study, dementia

Organochlorine pesticides in the drinking water of Merida and its Metropolitan Zone, a Karst Region

ABSTRACT This study was conducted to evaluate the quality of drinking water in 28 homes of Merida and 7 municipalities of its Metropolitan Zone, in Yucatan, Mexico. The organochlorine pesticides (OCP) were investigated since it represents important health risks. The karst groundwater in Yucatan is vulnerable due to the easy infiltration of contaminants. The use of prohibited OCP in agriculture and livestock production as well as the minimal infrastructure for drinking water sanitation also pose important public health risks. Samples were analyzed by GC-ECD. The concentrations of lindane (0.01896 ppm), heptachlor (0.09741 ppm), endosulfan (0.05796 ppm), DDT (0.00519 ppm), and endrin (0.00125 ppm) were above the international standards. Samples were analyzed for physicochemical parameters such as pH, electrical conductivity, CaCO3, MgCO3, hardness, Na+, K+, SO4˭, and Cl−. Total hardness (405–646 mg/L) were above of international criterion. Adequate infrastructure to obtain safe drinking water for human consumption is strongly recommended.

Organochlorine pesticide residues in tea and their potential risks to consumers in Ethiopia

Tea is the most frequently consumed drink in the sphere; next to the water. However, tea can be contaminated by different pesticides particularly those outdated pesticides which have been familiar as one of the main difficulties in Ethiopia and contaminate the food commodities. From a study done in south west of Ethiopia, Dichlorodiphenyltrichloroethane (DDT) and endosulfan were detected in commonly consumed food items. Therefore, the main aim of this study was to analyze the residue of organochlorine pesticides (OCPs) in tea collected from the market and assessing their risks to consumers. 19 different tea samples were randomly collected from supermarkets in Jimma town and Addis Ababa city. In the analytical procedure, QuEChERS (Quick, Easy, Cheap, Rugged, and Safe) method was applied for the extraction of tea samples. The finding of the study revealed that, five OCPs (aldrin, γ-chlordane, DDT, endrin, and dibutylchlorepoxide) were detected at a concentration of 0.1465, 0.167, 0.2044, 0.3067 and 0.4089 mg kg−1 in domestic tea, respectively, while endosulfan sulfate, methoxychlor, and heptachlor epoxide were detected at a concentration of 0.258, 0.458 and 1.427 mg kg-1 in imported tea samples respectively. From the pesticides detected, the mean concentration of DDT (0.292–0.825 mg kg−1) is above the Maximum Residue Limits (MRLs) established by China (0.2 mg kg−1). The estimated daily intake (EDI) of γ-chlordane and endrin were above the acceptable daily intakes (ADIs), this indicates that there is a health risk for tea consumers. The detection of pesticide residues in tea reveals that there is the widespread use of OCPs in the study area for agricultural purposes or as vector control. Therefore, strict regulation of pesticides during production, importing, sale, and application in the field is important for Ethiopia.

Health Risk Assessment of Liza parsia Fish Lipids: Heavy Metals and DDTs Contaminations

Background: Fish is a source of nutrition; however, toxic substances and heavy metals may enter human body due to consuming contaminated fish. The aim of this study was to investigate the levels of heavy metals and DDTs in Liza parsia, a fish species, and assess the health risk of the contaminants in the fish samples. Methods: The extracted fish lipid was added with n-hexane and H2SO4 and was kept for long time. The upper organic part was collected for the analysis of DDTs by gas chromatography equipped with electron capture detector. The fish samples were homogenized by wet digestion method, and the heavy metal contents were analyzed, using an atomic absorption spectrophotometer. The health risks of the fish samples were assessed based on target hazard quotient and target cancer risk. Results: The pesticide contents of DDT, DDD, DDE and DDTs in the fish samples were 0.0414, 0.000253, 0.015 and 0.0567ng/g, respectively. Also, the mean concentrations of Mn, Fe, Cu and Zn were 35.42±10.05, 318.75±242.45, 41.67±4.78 and 281.25±5.42 mg/kg, respectively. Of note, the Cd and Pb contents were below the detection limits. The concentrations of other heavy metals were above the reference limits, which can cause various disease processes. Conclusion: The contents of four heavy metals and DDTs in the samples were above the limits. The main sources of these substances are likely due to human anthropogenic activities. Fish and other edible aquatic animals should be monitored regularly and the heavy metal levels be determined and declared to the public.

Event loading drives distribution of the organochlorine pesticide metabolite DDE in a sub-tropical river system, Brisbane River, Australia

Past catchment practices can contribute to environmental impacts for decades following their cessation. We examine the distribution of the prevalent organochlorine pesticide, dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDE, DDD) in the sediments of a sub-tropical river system (Brisbane River, Australia). This study aimed to identify sources of DDT, DDE, DDD into the lower reaches of the Brisbane River. Annual sediment sampling of the lower Brisbane River over a period of 15 years (2001–2015) revealed a significant increase in sediment DDT, DDE and DDD content following major floods. A regional survey detected elevated sediment DDT, DDE and DDD content at 32 of 79 sites sampled; however, these were generally below guideline trigger values. DDE was the sole fraction at all but one site with creek systems dominated by intensive cropping practices identified as legacy sources and major flood events as a driver of elevated sediment DDE content in the lower reaches.

The Benthic Trophic Corner Stone Compartment in POPs Transfer from Abiotic Environment to Higher Trophic Levels—Trichoptera and Ephemeroptera Pre-Alert Indicator Role

Persistent organic pollutants (POPs) have been at the forefront of environmental contamination research even before their ban in 2001 at the Stockholm Convention. Their relation to different compartments of the environment (biotic and abiotic) has been thoroughly investigated. This article aims to identify whether the benthos could represent a reliable indicator of environmental contamination with POPs and to highlight its potential transfer role between abiotic and upper trophic compartments—benthos feeders. In this regard, we determined that the Ephemeroptera samples have higher concentrations (p &lt; 0.05) of ΣPCB, ΣHCH, and ΣDDT than sediment samples while Trichoptera samples have higher concentrations (p &lt; 0.05) only in the case of ΣPCB and ΣDDT. This, along with the fact that the frequency of detection for POPs is similar between the sample types (sediments, Trichoptera, and Ephemeroptera), makes the benthos samples valuable indicators of contamination with sediment samples working as complementary information about how recent the contamination is.

Occurrence of Pesticide Residues in Freshwater and Estuarine Fishes of Thamirabarani River

Background: Studies pertaining to the presence of OCP residues in the freshwater and marine ûshes caught from the Thamirabarani river basin region are not available to analyze the extent of bioaccumulation to assess their safety for human consumption. Hence, this study was undertaken as a maiden work to examine the OCP residues in the fishes collected from ûve sites spanning from the source to mouth region of the Thamirabarani river system, along with other related niches to examine the effect of environment pollution.Methods: Pesticides from fish muscle and their organs were extracted as per AOAC 2007.01 using QuEChERS method. A Gas Chromatograph model Perkin Elmer - equipped with Ni Electron Capture Detector of activity 15 MCi was used for the analysis. A volume of 1.0µl of the extracts was injected. The operating conditions were capillary column Elite-5 capillary column, 60m x 0.25mm, 1.00µm temperature programme: 70ºC (2 min) to 180ºC (I min) 25ºC/min to 300ºC 5ºC/min, Injection temperature: 270ºC, Detector temperature: 300ºC, Carrier gas: Nitrogen at 1.0 mL/min, Make up gas: Nitrogen at 29 mL/min.Result: Among fishes, rohu accumulated maximum of 0.4014 to 0.605 ug/kg of DDT in station IV and V respectively. Dhananjayan and Muralidharan (2010) reported OCPs in 156 fishes sample from Kaveri river. The average concentration of DDT ranged between 0 and 0.605 ug/kg. Bhuvaneshwari and Babu rajendran (2012) also reported 2.8 ug/g of DDT in fishes from Kaveri river. The low occurrence of DDT in the presence study is mainly due to their rapid degradation with living organisms.

Ecological risk of chlorinated organic pollutants in a semi-enclosed bay impacted by aquaculture

Semi-enclosed bays are used for critical economic activities such as ports, aquaculture, and human settlement due to their topography and ocean connectivity. However, the role of these geomorphological characteristics on the accumulation of chlorinated organic pollutants in semi-enclosed bays is poorly understood. We investigated the spatiotemporal distribution and potential ecological risk of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in sediments from Shantou Bay, a semi-enclosed bay. The ∑PCB concentration was 258–1297 ng g−1 and 59.6–651 ng g−1 in the dry season and wet season, respectively. Sediments collected downstream and upstream the aquaculture farms had significantly lower DDT concentrations than those collected close to the aquaculture discharge points. The ratio of DDT and its metabolites indicated that there was possible fresh input of DDTs into Shantou Bay. However, no significant spatial trend was observed in the PCB profiles. The concentrations of PCBs and OCPs in Shantou Bay were above the China Marine Sediment Quality Class I suggesting remediation was essential to ensure the aquatic systems could be safely used for fisheries, swimming, or as marine protected areas. Furthermore, the potential ecological risk of DDTs was high as it exceeded the effects thresholds at all sites. Seasonal variations in human activities, resuspension of historical contaminants due to physical oceanographic, climatic and hydrological factors, and contaminant trapping probably contributed to the changes in organic pollutant distribution in the semi-enclosed bay.

Developmental exposure to DDT or DDE alters sympathetic innervation of brown adipose in adult female mice

BackgroundExposure to the bioaccumulative pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) has been associated with increased risk of insulin resistance and obesity in humans and experimental animals. These effects appear to be mediated by reduced brown adipose tissue (BAT) thermogenesis, which is regulated by the sympathetic nervous system. Although the neurotoxicity of DDT is well-established, whether DDT alters sympathetic innervation of BAT is unknown. We hypothesized that perinatal exposure to DDT or DDE promotes thermogenic dysfunction by interfering with sympathetic regulation of BAT thermogenesis.MethodsPregnant C57BL/6 J mice were administered environmentally relevant concentrations of DDTs (p,p’-DDT and o,p’-DDT) or DDE (p,p’-DDE), 1.7 mg/kg and 1.31 mg/kg, respectively, from gestational day 11.5 to postnatal day 5 by oral gavage, and longitudinal body temperature was recorded in male and female offspring. At 4 months of age, metabolic parameters were measured in female offspring via indirect calorimetry with or without the β3 adrenergic receptor agonist, CL 316,243. Immunohistochemical and neurochemical analyses of sympathetic neurons innervating BAT were evaluated.ResultsWe observed persistent thermogenic impairment in adult female, but not male, mice perinatally exposed to DDTs or p,p’-DDE. Perinatal DDTs exposure significantly impaired metabolism in adult female mice, an effect rescued by treatment with CL 316,243 immediately prior to calorimetry experiments. Neither DDTs nor p,p’-DDE significantly altered BAT morphology or the concentrations of norepinephrine and its metabolite DHPG in the BAT of DDTs-exposed mice. However, quantitative immunohistochemistry revealed a 20% decrease in sympathetic axons innervating BAT in adult female mice perinatally exposed to DDTs, but not p,p’-DDE, and 48 and 43% fewer synapses in stellate ganglia of mice exposed to either DDTs or p,p’-DDE, respectively, compared to control.ConclusionsThese data demonstrate that perinatal exposure to DDTs or p,p’-DDE impairs thermogenesis by interfering with patterns of connectivity in sympathetic circuits that regulate BAT.Graphical abstract