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Environmental contamination with dichlorodiphenyltrichloroethane (DDT) has sever effects on the ecosystem worldwide. DDT is a recalcitrant synthetic chemical with high toxicity and lipophilicity. It is also bioaccumulated in the food chain and causes genotoxic, estrogenic, carcinogenic, and mutagenic effects on aquatic organisms and humans. Microbial remediation mechanism and its enzymes are very important for removing DDT from environment. DDT and its main residues dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) can biodegrade slowly in soil and water. To enhance this process, a number of strategies are proposed, such as bio-attenuation, biostimulation, bioaugmentation and the manipulation of environmental conditions to enhance the activity of microbial enzymes. The addition of organic matter and flooding of the soil enhance DDT degradation. Microbial candidates for DDT remediation include micro-algae, fungi and bacteria. This review provide brief information and recommendation on microbial DDT remediation and its mechanisms.

The placenta is the principal regulator of the in utero environment, and disruptions to this environment can result in adverse offspring health outcomes. To better characterize the impact of in utero perturbations, we assessed the influence of known environmental pollutants on the expression of microRNA (miRNA) in placental samples collected from the National Children's Study (NCS) Vanguard birth cohort. This study analyzed the expression of 654 miRNAs in 110 term placentas. Environmental pollutants measured in these placentas included dichlorodiphenyldichloroethylene (DDE), bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), arsenic (As), mercury (Hg), lead (Pb), and cadmium (Cd). A moderated t-test was used to identify a panel of differentially expressed miRNAs, which were further analyzed using generalized linear models. We observed 112 miRNAs consistently expressed in >70% of the samples. Consistent with the literature, miRNAs located within the imprinted placenta-specific C19MC cluster, specifically mir-517a, mir-517c, mir-522, and mir-23a, are among the top expressed miRNA in our study. We observed a positive association between PBDE 209 and miR-188-5p and an inverse association between PBDE 99 and let-7c. Both PCBs and Cd were positively associated with miR-1537 expression level. In addition, multiple let-7 family members were downregulated with increasing levels of Hg and Pb. We did not observe DDE or BPA levels to be associated with placental miRNA expression. This is the first birth cohort study linking environmental pollutants and placental expression of miRNAs. Our results suggest that placental miRNA profiles may signal in utero exposures to environmental chemicals.

Environmental contamination with dichlorodiphenyltrichloroethane (DDT) has sever effects on the ecosystem worldwide. DDT is a recalcitrant synthetic chemical with high toxicity and lipophilicity. It is also bioaccumulated in the food chain and causes genotoxic, estrogenic, carcinogenic, and mutagenic effects on aquatic organisms and humans. Microbial remediation mechanism and its enzymes are very important for removing DDT from environment. DDT and its main residues dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) can biodegrade slowly in soil and water. To enhance this process, a number of strategies are proposed, such as bio-attenuation, biostimulation, bioaugmentation and the manipulation of environmental conditions to enhance the activity of microbial enzymes. The addition of organic matter and flooding of the soil enhance DDT degradation. Microbial candidates for DDT remediation include micro-algae, fungi and bacteria. This review provide brief information and recommendation on microbial DDT remediation and its mechanisms., Competing Interests: The authors declared that they do not have any known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Indoor residual spray (IRS) of insecticides and insecticide-treated bednets (ITNs) are the two most important malaria vector control tools in the tropical world. Application of both tools in the same locations is being implemented for malaria control in endemic and epidemic Africa. The two tools are assumed to have synergistic benefits in reducing malaria transmission because they both act at multiple stages of the transmission cycle. However, this assumption has not been rigorously examined, empirically or theoretically. Using mathematical modelling, we obtained the conditions for which a combination strategy can be expected to improve upon single control tools. Specifically, spraying of dichlorodiphenyltrichloroethane (DDT) in all houses where residents are not using ITNs can reduce transmission of malaria (R(0)) by up to 10 times more than the reduction achieved through ITNs alone. Importantly, however, we also show how antagonism between control tools can arise via interference of their modes of action. Repellent IRS reduces the likelihood that ITNs are contacted within sprayed houses and ITNs reduce the rate at which blood-fed mosquitoes rest on sprayed walls. For example, 80 per cent coverage of ITNs and DDT used together at the household level resulted in an R(0) of 11.1 when compared with an R(0) of 0.1 achieved with 80 per cent ITN coverage without DDT. While this undesired effect can be avoided using low-repellence pyrethroid chemicals for IRS, the extent of the potential benefits is also attenuated. We discuss the impact that this result will likely have on future efforts in malaria control combination strategy.

Abstract Objectives To examine plasma levels of dichlorodiphenyldichloroethene (DDE) and dichlorodiphenyltrichloroethane (DDT) in association with survival among women with breast cancer who participated in a population-based case-control study. Methods Participants included 456 white and 292 black women from the Carolina Breast Cancer Study Phase I who were diagnosed with primary invasive breast cancer from 1993 to 1996, and who had available DDE/DDT and lipid measurements from blood samples obtained on average 4.1 months after diagnosis. Using the National Death Index, we identified 392 deaths (210 from breast cancer) over a median follow-up of 20.6 years. We used Cox regression to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and breast cancer-specific 5-year mortality, and 20-year mortality conditional on 5-year survival, for lipid-standardized DDE and DDT levels. Associations stratified by race and estrogen receptor (ER) status were also examined. Results The highest versus lowest DDE tertile and the highest vs non-detectable DDT quantile were associated with HRs of 1.95 (95% CI = 1.31–2.92) and 1.64 (95% CI = 1.10–2.44), respectively, for 20-year conditional all-cause mortality. DDE levels above versus below the median were associated with a HR of 1.69 (95% CI = 1.06–2.68) for 20-year conditional breast cancer-specific mortality among women overall, and HRs were 2.36 (95% CI = 1.03–5.42) among black women and 1.57 (95% CI = 0.86–2.89) among white women (P Interaction = 0.42), and 3.24 (95% CI = 1.38–7.58) among women with ER− tumors and 1.29 (95% CI = 0.73–2.28) among women with ER+ tumors (P Interaction = 0.03). Conclusion Exposure to DDE/DDT may adversely impact overall and breast cancer-specific survival. DDE exposure may contribute to the racial disparities in breast cancer survival. Highlights • Higher DDE and DDT levels were associated with worse overall survival. • Higher DDE levels were associated with worse breast cancer-specific survival. • Mortality rates were elevated more so among black women than among white women. • Mortality rates were elevated more so among women with ER− than ER+ breast cancer. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this study is to investigate the effects of ionizing radiation on two anticancer drugs, 2,4′-dichlorodiphenyl dichloroethane (DCP) and 6-mercaptopurine monohydrate (MPM), by using electron spin resonance (ESR) spectroscopy. For that purpose the intensity of ESR signals of the samples as a function of the microwave power was investigated in the range of 0.01–100 mW at room temperature. While unirradiated samples presented no ESR signal, irradiated samples exhibited significant ESR spectra. ESR measurements were performed at low and high temperatures to study the dosimetric features of free radicals induced by gamma irradiation. In order to obtain the dose-response curves, samples irradiated with gamma at 1, 5, 10, 15, 20, and 25 kGy dose values were used. Furthermore, the g values of the radicals and the hyperfine coupling constants were also determined. Additionally, the time dependency of the samples was analyzed to study the stability of the radicals. Highlights • Two anticancer drugs were investigated by ESR spectroscopy. • It was concluded that two different radicals were formed in both DCP (ĊHCH and ĊHCl 2 radicals) and MPM (HNĊN and ĊH radicals) samples as a result of irradiation. • The ESR parameters and the structure of the radicals were identified. [ABSTRACT FROM AUTHOR]

Abstract Although the agricultural use of dichlorodiphenyltrichloroethane (DDT) has been banned for decades in many countries around the world, the detection of DDT and its metabolites in soils is very common due to their persistence. DDTs (sum of DDT and its metabolites) in farmland soils can be absorbed by crops at different levels and accumulate in the edible parts of agricultural products, posing threats to the health of human being. However, no information on the species sensitivity distribution (SSD) of crops with regard to DDTs has been reported due to the lack of enough bioavailability data and models to normalize the bioavailability data from different sources. Based on the bioconcentration factors of 17 crop species in Chinese soils obtained from previous studies, the criteria of DDTs in soils was derived according to the quality standard of agricultural products using the SSD method. Corrections for water content and aging time were conducted to normalize the data from different sources. The risk values of agricultural products at different concentration levels of DDTs in soils were also evaluated. It was found that oil crops are able to take up more DDTs than non-oil crops, so the soil criteria were calculated separately for oil crops and non-oil crops, which were 0.083 mg/kg and 0.29 mg/kg, respectively. With the residual concentrations of DDTs in soils at the range of 0.01–0.5 mg/kg, 0–8% of the agricultural products exceeded the permissible limits for DDTs which were set in the National Food Safety Standard of China. The results also demonstrated the feasibility for applying SSDs to derive the soil criteria of DDTs in order to ensure the safety of agricultural products. This work will provide information for the risk assessment and the establishment of soil environmental quality standards to ensure safe agricultural production. Graphical abstract fx1 Highlights • Soil criteria for DDTs were derived using SSD and BCF data from different soils. • The soil criterion for oil crops is far below that of the non-oil crops. • Correction for aging time could avoid excessively conservative soil thresholds. [ABSTRACT FROM AUTHOR]

Dichlorodiphenyltrichloroethane was used on Cape Cod, Massachusetts (USA), for mosquito and gypsy moth mitigation, from 1948 until the insecticide was banned in the 1970s. There are historical accounts of major spray events, and DDT was expected to have remained immobile in the organic-rich sediments of local ponds. We investigated the potential for sediment cores from lakes on Cape Cod to reveal the depositional history of DDT. This compound and its metabolites dichlorodiphenyldichloroethane and dichlorodiphenyldichloroethylene (ΣDDT) were examined in sediment cores from four kettle lakes on Cape Cod that lie between the towns of Brewster and Harwich, where there is a detailed history of aerial spraying. Sediment cores were dated via 210Pb and analyzed for water content, total carbon, total organic carbon, and organochlorine pesticide concentrations. Use of fallout 137Cs to confirm 210Pb dates was unsuccessful, probably because of post-depositional migration of 137Cs. ΣDDT inventories in each lake were determined to be ~ 10 ng cm−2, which represents about 0.1% on an aerial basis of the quantity known to have been sprayed. Compared to the recorded spraying history, the concentration-depth maxima appear decades later than expected. The overall low quantity and unexpected temporal distribution of pesticide residues are probably explained by natural degradation of DDT in the sediment. A novel mathematical correction to DDT concentrations was applied and yielded adjusted inventories close to expected values, and moved the pesticide concentration maxima to the 1950s and 1960s, when they were expected to have occurred. [ABSTRACT FROM AUTHOR]

Objective . The distribution of equal states (DES) quantifies amplitude fluctuations in biomedical signals. However, under certain conditions, such as a high resolution of data collection or special signal processing techniques, equal states may be very rare, whereupon the DES fails to measure the amplitude fluctuations. Approach . To address this problem, we develop a novel threshold DES (tDES) that measures the distribution of differential states within a threshold. To evaluate the proposed tDES, we first analyze five sets of synthetic signals generated in different frequency bands. We then analyze sleep electroencephalography (EEG) datasets taken from the public PhysioNet. Main results . Synthetic signals and detrend-filtered sleep EEGs have no neighboring equal values; however, tDES can effectively measure the amplitude fluctuations within these data. The tDES of EEG data increases significantly as the sleep stage increases, even with datasets covering very short periods, indicating decreased amplitude fluctuations in sleep EEGs. Generally speaking, the presence of more low-frequency components in a physiological series reflects smaller amplitude fluctuations and larger DES. Significance . The tDES provides a reliable computing method for quantifying amplitude fluctuations, exhibiting the characteristics of conceptual simplicity and computational robustness. Our findings broaden the application of quantitative amplitude fluctuations and contribute to the classification of sleep stages based on EEG data., (© 2023 Institute of Physics and Engineering in Medicine.)

Organochlorine pesticides are highly persistent in aquatic ecosystems. Amphibians, specifically anurans, play an intricate part in the aquatic food web, and have very permeable skin which makes them prone to bioaccumulation of persistent pollutants. In this study the bioaccumulation of various legacy organochlorine pesticides (OCPs)—including dichlorodiphenyltrichloroethane (DDT), currently used for malaria vector control (MVC)—was assessed along with a set of biomarker responses in Müller’s clawed frog Xenopus muelleri collected from the lower Phongolo River floodplain in South Africa. Possible relationships between bioaccumulation and biomarkers (of exposure, oxidative stress biomarkers, and cellular energy allocation) alongside their temporal changes were investigated. The OCP concentrations showed a significant increase over time for the duration of the study. The increase correlated negatively with rainfall from the region. DDT levels were well below expected effects levels with p,p-DDE being the main contributing metabolite. The results of this study indicate OCPs actively accumulate at sub-lethal levels in aquatic frogs from the study area, while showing possible relations towards some of the biochemical stress responses measured. Most notable were negative relationships indicated between p,p-DDE and acetylcholinesterase, malondialdehyde, and carbohydrates and protein energy availability. Levels of DDT were not found to be significantly higher than other legacy pesticides in the frog tissue, although evidence of newly introduced DDT in the frog tissue was found. Further investigation about sub-lethal effects of these pesticides on anurans is required to gain better insight into their full impact on animal livelihood. [ABSTRACT FROM AUTHOR]

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There is a scarcity of data on the amount and distribution of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolites in intermediate and deep ocean water masses. Here, the distribution and inventories of DDTs in water of the Arctic shelf seas and the interior basin are presented. The occurrence of ∑6DDT (0.10-66 pg L-1) in the surface water was dominated by 4,4′-DDE. In the Central Arctic Ocean increasing concentrations of DDE with depth were observed in the Makarov and Amundsen basins. The increasing concentrations down to 2500 m depth is in accordance with previous findings for PCBs and PBDEs. Similar concentrations of DDT and DDEs were found in the surface water, while the relative contribution of DDEs increased with depth, demonstrating a transformation over time and depth. Higher concentrations of DDTs were found in the European part of the Arctic Ocean; these distributions likely reflect a combination of different usage patterns, transport, and fate of these compounds. For instance, the elevated concentrations of DDTs in the Barents and Atlantic sectors of the Arctic Ocean indicate the northbound Atlantic current as a significant conveyor of DDTs. This study contributes to the very rare data on OCPs in the vast deep-water compartments and combined with surface water distribution across the Arctic Ocean helps to improve our understanding of the large-scale fate of DDTs in the Arctic. [ABSTRACT FROM AUTHOR]

Background Dichlorodiphenyldichloroethene ( p,p´ -DDE), the main metabolite of dichlorodiphenyltrichloroethane (DDT), has been associated with changes in human thyroid hormone levels. Maternal thyroid hormones are essential for adequate fetal neurodevelopment during the first half of pregnancy. Objective To evaluate the association between maternal p,p´ -DDE concentration and the maternal thyroid profile during the first half of pregnancy. Materials and Methods We analyzed the information of 430 pregnant women from a Mexican floriculture area, with a gestational age ≤16 weeks. By questionnaire, we obtained sociodemographic, reproductive, and life-style, information. Serum concentrations of thyroid stimulating hormone (TSH), and total and free T3 and T4 were determined by means of Enzyme-Linked ImmunoSorbent Assay (ELISA). p,p´ -DDE was analyzed by Gas Chromatography. The association between p,p´ -DDE and thyroid profile was assessed through linear and logistic regression models. Results Thirty eight percent of women had p,p´ -DDE levels below the Limit of Detection and 12.3% below the Limit of Quantification. Within the quantifiable range, median was 53.03 ng/g. TSH >2.5 mIU/L was present in 9.3% of women; 47.7% had isolated hypothyroxinemia; 3.5% had subclinical hypothyroidism, and 5.8% had overt hypothyroidism. We observed a significant positive association between quantifiable p,p´ -DDE and total T3 serum levels in comparison with those with concentrations below the Limit of Detection (β=0.19; 95% CI=0.06, 0.34). There were no significant associations with other hormones of the thyroid profile or with clinical diagnosis. Conclusions Our findings suggest that p,p´ -DDE exposure, even at low concentrations, could disrupt thyroid homeostasis during pregnancy. [ABSTRACT FROM AUTHOR]

Sulfonated poly(arylene ether sulfone) (SPAES) composite membranes were prepared using antioxidant grafted graphene oxide as a filler for polymer electrolyte membrane fuel cell (PEMFC) applications. SPAES was synthesized via condensation polymerization of 4,4′-dihydroxybiphenyl, 4,4′-dichlorodiphenylsulfone and 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone. The antioxidant grafted graphene oxide was prepared by grafting hindered amine, 4-amino-2,2,6,6-tetramethylpiperidine, onto the surface of graphene oxide (GO). The SPAES composite membrane containing the antioxidant grafted GO showed improved physicochemical properties such as mechanical strength, chemical and thermal stabilities, and proton conductivity compared to pristine SPAES membrane. In particular, the antioxidant grafted GO was much more effective in enhancing the chemical stability of SPAES than GO without the antioxidant. For example after Fenton's test, the SPAES composite membrane with grafted antioxidant showed smaller decrease of both the weight and proton conductivity values than the pristine SPAES and SPAES composite membrane with GO. The enhanced chemical stability of SPAES composite membrane with antioxidant grafted GO can be explained by the combined antioxidant effect of both grafted antioxidant functional groups and GO. [ABSTRACT FROM AUTHOR]

The present study explored short-term temporal variations in circulating concentrations of 3 legacy organochlorines with different physicochemical properties (polychlorinated biphenyl 153 [PCB-153], p,p′-dichlorodiphenyldichloroethylene [DDE], and hexachlorobenzene [HCB]) in breeding kittiwakes ( Rissa tridactyla) in a colony in Svalbard (78°N), Norwegian Arctic. Concentrations were measured in blood of a large number ( n = 412-521 blood samples, depending on the data analyses) of prebreeding, incubating, and chick-rearing birds over a period of 5 yr (2007-2011). The PCB-153 concentrations were equal in male and female blood in the prebreeding period, whereas females had significantly lower concentrations during incubation and chick rearing, probably because of their ability to eliminate organochlorines through egg laying. A similar temporal pattern was observed with DDE, although the lower concentrations in incubating females were not significant. Males and females had similar concentrations of HCB over all reproductive stages. The concentrations of all 3 compounds varied greatly between years. The concentrations of PCB-153 tended to decline over the study period, whereas concentrations of HCB showed an increasing trend, especially among chick-rearing males late in the season. Concentrations of PCB-153 increased approximately 2.5 times from the prebreeding to the chick-rearing period, concurrent with mobilization of body lipids (reduced body mass). A similar, but less pronounced trend was found for HCB. For DDE, however, kittiwakes had the highest concentrations in the prebreeding period, suggesting relatively high exposure in their winter areas. The present study documented large variations in circulating concentrations of legacy organochlorines among and within breeding seasons in kittiwakes, but the alterations within seasons were relatively consistent from year to year. Environ Toxicol Chem 2017;36:442-448. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Gas chromatography-triple quadrupole mass spectrometry (GC-QqQMS) was applied for the determination of eight organochlorine pesticides (OCPs) in human serum. OCPs were extracted from the serum sample by solid phase extraction (SPE) and analyzed by gas chromatography mass spectrometry (GC–MS) or gas chromatography tandem mass spectrometry (GC–MS/MS). Electron ionization (EI) and negative chemical ionization (NCI) under two data acquisition modes, namely selected ion monitoring (SIM) and multiple reaction monitoring (MRM), were compared. The use of MRM generally provided higher selectivity and sensitivity because less interference from the sample matrix existed. The EI mode is more suitable for less electronegative compounds such as dichlorodiphenyldichloroethanes (DDDs) with detection limits ranging from 0.0060 to 0.060 ng/mL. In the NCI mode, MRM analysis provided good and lower detection limits (0.0011–0.0030 ng/mL) for pesticides containing more chlorines. The methods were validated by analyzing the pesticides in spiked serum at different levels with recoveries ranged from 83% to 116% and relative standard deviations of less than 10%. The developed method was applied for the determination of the OCPs in real human serum samples. [ABSTRACT FROM AUTHOR]

Binary copolymerization of 4-methyl-1,3-pentadiene ( 4MPD) with styrene, butadiene and isoprene promoted by the titanium complex dichloro{1,4-dithiabutanediyl-2,2′-bis[4,6-bis(2-phenyl-2-propyl)phenoxy]}titanium activated by methylaluminoxane is reported. All the copolymers are obtained in a wide range of composition and the molecular weight distributions obtained from gel permeation chromatographic analysis of the copolymers are coherent with the materials being copolymeric in nature. The copolymer microstructure was fully elucidated by means of 1H NMR and 13C NMR spectroscopy. Differential scanning calorimetry shows an increase of glass transition temperature ( Tg) with the amount of 4MPD in the copolymers with butadiene and isoprene, while in the copolymers with styrene Tg is increased on increasing the amount of styrene. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Awareness of the direction of the body's (longitudinal) axis is fundamental for action and perception. The perceived body axis orientation is strongly biased during body tilt; however, the neural substrates underlying this phenomenon remain largely unknown. Here, we tackled this issue using a neuropsychological approach in patients with hemispheric stroke. Thirty-seven stroke patients and 20 age-matched healthy controls adjusted a visual line with the perceived body longitudinal axis when the body was upright or laterally tilted by 10 degrees. The bias of the perceived body axis caused by body tilt, termed tilt-dependent error (TDE), was compared between the groups. The TDE was significantly smaller (i.e., less affected performance by body tilt) in the stroke group (15.9 ± 15.9°) than in the control group (25.7 ± 17.1°). Lesion subtraction analysis and Bayesian lesion-symptom inference revealed that the abnormally reduced TDEs were associated with lesions in the right occipitotemporal cortex, such as the superior and middle temporal gyri. Our findings contribute to a better understanding of the neuroanatomy of body-centred spatial coding during whole-body tilt., (© 2023. The Author(s).)

Aunque en España se han realizado estudios sobre concentraciones en medios biológicos humanos de compuestos tóxicos persistentes (CTP) desde hace varias décadas, no se ha llevado a cabo una revisión sistemática. Los objetivos fueron: a) identificar los estudios realizados en España en los últimos 30 años que hubiesen determinado concentraciones en humanos de diclorodifeniltricloroetano (DDT), diclorodifenildicloroeteno (DDE), hexaclorobenceno (HCB), hexaclorociclohexanos (HCH) y policlorobifenilos (PCB), y b) sintetizar las principales características y resultados de cada estudio. Los estudios son sumamente heterogéneos y la mayoría carece de representatividad poblacional. Las concentraciones de DDT y DDE parecen haber decrecido moderadamente en los últimos 20 años. Hay numerosas fluctuaciones en los valores de HCB, HCH y PCB, en algún caso compatibles con un estancamiento. Se observan grandes diferencias en los valores detectados en los distintos estudios y dentro de un mismo grupo: las concentraciones de CTP de algunos individuos pueden llegar a ser más de 200 veces superiores a los de otros. La magnitud real de la contaminación humana por CTP y sus tendencias a lo largo del territorio español, así como su diversidad geográfica y social, siguen siendo ampliamente desconocidas.No systematic review is available on studies conducted in Spain on human concentrations of persistent toxic substances (PTS). The objectives were: to identify studies conducted in Spain in the past 30 years that determined concentrations in humans of dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDE), hexachlorobenzene (HCB), hexachlorocyclohexane (HCH) and polychlorinated biphenyls (PCBs); and to summarize the main characteristics and results of each study. Studies are highly heterogeneous and most lack population representativeness. Concentrations of DDT and DDE might have decreased moderately in the last 20 years. Numerous fluctuations are apparent in levels of HCB, HCHs and PCBs, in some instances compatible with some stagnation. There are enormous differences in levels detected across and within studies: PTS concentrations of some individuals may be over 200-fold higher than those of others. The actual magnitude of human contamination by PTS and their trends across Spain -as well as the geographic and social heterogeneity- remain largely unknown.

We collected and analyzed 128 surface soil samples from Xiangfen County for dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE). Total DDT concentrations (DDTs; sum of p,p′ -DDD, p,p′ -DDE, and p,p′ -DDT) ranged from ND to 427.81 ng g −1 (dry weight, dw), with a mean of 40.26 ng g −1 (dw). Among the three compounds, p,p′ -DDD was the most dominant. The DDTs in Xiangfen County soils mainly originated from historical DDT use, but there were also new inputs likely related to dicofol use. The DDTs in Xiangfen County soils were mainly degraded under anaerobic conditions, and direct degradation to DDD was the main degradation route. Regions with relatively high concentrations of DDTs were mainly located in North and South Xiangfen County. In these regions, many soil samples contained p,p′ -DDT as the predominant pollutant, suggestive of extensive new inputs of DDT. A health risk assessment revealed that there are no serious long-term health impacts of exposure to DDTs in soil, for adults or children. [ABSTRACT FROM AUTHOR]

Background The aim of this study was to assess the association between postnatal exposure to multiple persistent organic pollutants (POPs) measured in breast milk samples and early behavioral problems using statistical methods to deal with correlated exposure data. Methods We used data from the Norwegian HUMIS study. We measured concentrations of 24 different POPs in human milk from 612 mothers (median collection time: 32 days after delivery), including 13 polychlorinated biphenyls (PCB) congeners, 6 polybrominated diphenyl ethers (PBDE) congeners and five organochlorine compounds. We assessed child behavioral problems at 12 and 24 months using the infant toddler symptom checklist (ITSC). Higher score in ITSC corresponds to more behavioral problems. First we performed principal component analysis (PCA). Then two variable selection methods, elastic net (ENET) and Bayesian model averaging (BMA), were applied to select any toxicants associated with behavioral problems. Finally, the effect size of the selected toxicants was estimated using multivariate linear regression analyses. Results p,p ′-DDT was associated with behavioral problems at 12 months in all the applied models. Specifically, the principal component composed of organochlorine pesticides was significantly associated with behavioral problems and both ENET and BMA identified p,p ′ - DDT as associated with behavioral problems. Using a multiple linear regression model an interquartile increase in p,p ′ - DDT was associated with a 0.62 unit increase in ITSC score (95% CI 0.45, 0.79) at 12 months, corresponding to more behavioral problems. The association was modified by maternal education: the effect of p,p ′ - DDT was strongest in women with lower education (β=0.59; 95%CI: 0.38, 0.81) compared to the mother with higher education (β=0.14; 95%CI: −0.05, 0.34) ( p -value for interaction=0.089). At 24 months, neither selection method consistently identified any toxicant associated with behavioral problems. Conclusion Within a mixture of 24 toxicants measured in breast milk, p,p ′-DDT was the single toxicant associated with behavioral problems at 12 months using different methods for handling numerous correlated exposures. [ABSTRACT FROM AUTHOR]

Although approximately 123 million people may be exposed to high levels of insecticides through the use of indoor residual spraying (IRS) for malaria control, few studies exist on indoor insecticide contamination due to IRS and its relationship with human exposure. In the present study, we developed a sampling method to collect undisturbed dust from 50 homes in Limpopo, South Africa, a region where dichlorodiphenyltrichloroethane (DDT) has been used in IRS programs to prevent malaria for ~ 70 years. We quantified DDT and its degradation products, dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) in dust samples to determine dust loading levels and compared these levels to paired serum concentrations of p , p ′-DDT and p , p ′-DDE in women residents. p , p ′-DDT and p , p ′-DDE had the highest detection frequencies in both dust (58% and 34% detection, respectively) and serum samples (100% detection). Significantly higher detection frequencies for o , p ′-DDT, p , p ′-DDE, and p , p ′-DDD were observed in dust samples collected in buildings that had been previously sprayed for malaria control. We also observed a significant, positive association between dust loading and serum concentrations of p , p ′-DDT and p , p ′-DDE (Spearman's rho = 0.68 and 0.54, respectively). Despite the low detection frequency in dust, our results indicate that undisturbed dust may be a good metric to quantify long-term home exposure to DDT-related compounds and that contamination of the home environment may be an important determinant/source of DDT and DDE exposure. [ABSTRACT FROM AUTHOR]

Dichlorodiphenyltrichloroethane (DDT), one of the persistant organic pollutants, was degraded by using nano-size zero valent iron (NZVI) and NZVI with Cu. The Box Behnken Design of Experiments was used to determine the effects of four factors: namely, initial DDT concentration (Co), metal loading, %Cu (M), and pH of test solution, on the degradation of DDT. Experiments were conducted at room temperature. The response was expressed as mg DDT degraded per g of metal particles. Among four factors, the metal loading and initial DDT concentration were the most significant. Increasing the initial DDT concentration increased the amount of DDT degraded per unit amount of metal particles. According to the effect of metal loading, only a small amount of metal particles is necessary to effect DDT degradation. The degradation of DDT was different with NZVI alone and bimetallic NZVI/Cu. However, only the addition of Cu up to 5% of the total metal loading improved DDT degradation significantly. DDT degradation was the most favorable at pH 3 and the least was pH 2. The mg DDT degraded per g metal particles could be modeled by the equation R= 7.60 + 2.63Co -- 4.2M + 1.21pH. The optimum DDT degradation condition was also observed. [ABSTRACT FROM AUTHOR]

Between the 1940s and 1990s, immeasurable amounts of organochlorine pesticides (OCPs) were used in endemic disease control campaigns and agriculture in the tropical semi-arid regions of Brazil. The present study evaluated the legacy of banned OCP usage, considering the levels, ecological risk and dependence on sediment physicochemical properties for the fate and distribution in the Jaguaribe River. The sum concentration of OCPs (Σ OCPs ) ranged from 5.09 to 154.43 ng·g − 1 , comparable to the levels found in other tropical and subtropical regions that have traditionally used OCPs. The environmental and geographical distribution pattern of p , p -DDT, p , p -DDD and p , p -DDE shows that the estuarine zone contained more than 3.5 times the levels observed in the fluvial region, indicating that the estuary of the Jaguaribe River is a sink. The temporal pattern indicates application of dichloro-diphenyl-trichloroethanes (DDTs) in the past; however, there is evidence of recent input of these pesticides. High ecological risk was observed for levels of γ-hexachlorocyclohexanes (γ-HCH) and heptachlor, and moderate ecological risk was observed for levels of DDTs in sediments from the Jaguaribe River. The heptachlor, γ -HCH and hexachlorobenzene (HCB) concentrations depend on the organic and inorganic fractions of sediment from the Jaguaribe River, whereas the p , p- DDE, p , p -DDD, p , p -DDT and α-endosulfan concentrations depend solely on the organic fraction of the sediment. [ABSTRACT FROM AUTHOR]

It has been hypothesized that environmental exposures at key development periods such as in utero play a role in childhood growth and obesity. To investigate whether in utero exposure to endocrine-disrupting chemicals, dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethane (DDE), is associated with childhood physical growth, we took a novel statistical approach to analyze data from the CHAMACOS cohort study. To model heterogeneity in the growth patterns, we used a finite mixture model in combination with a data transformation to characterize body mass index (BMI) with four groups and estimated the association between exposure and group membership. In boys, higher maternal concentrations of DDT and DDE during pregnancy are associated with a BMI growth pattern that is stable until about age five followed by increased growth through age nine. In contrast, higher maternal DDT exposure during pregnancy is associated with a flat, relatively stable growth pattern in girls. This study suggests that in utero exposure to DDT and DDE may be associated with childhood BMI growth patterns, not just BMI level, and both the magnitude of exposure and sex may impact the relationship. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) have been measured in surplus serum collected in 2009 from a convenience sample of 300 Texas children (boys and girls) in the birth to 13 years of age range. Serum concentrations of traditional persistent organic pollutants such as 2,2',4,4',5,5'- hexachlorobiphenyl (PCB-153) and p,p'-DDE did not change consistently with age. By contrast, serum concentrations of tetra-, penta-, and hexa-BDEs were lowest in the youngest children (birth to two year old) and increased 3.0 to 7.9 times, depending on the analyte, for children in the >4 to 6 years of age group. From the apex concentration to the 10 to 13 years of age group, concentrations decreased significantly except for 2,2',4,4',5,5'-hexabromodiphenyl ether (PBDE- 153), which also had a longer apex concentration of >4 to 8 years of age. This concentration trend for PBDE-153 is most likely due to a longer half-life of PBDE- 153 than of other PBDE congeners. The observed PBDEs concentration patterns by age may be related, at least in part, to ingestion of residential dust containing PBDEs through hand-to-mouth behavior among toddlers, preschoolers, and kindergarteners. Further studies to characterize young children's exposure to PBDEs are warranted and, in particular, to determine the lifestyle factors that may contribute to such exposures. [ABSTRACT FROM AUTHOR]

The present study work was aimed at to monitor the residue level of some selected pesticides (Dichloro diphenyl tricthloro ethane, Dichloro diphenyl dichloro ethylene, endosulfan, aldrin, cypermethrin, deltamethrin, permethrin, and bifenthrin) in milk samples collected from the cotton growing belt of the Punjab province. The residue level of these pesticides in dairy milk samples was analyzed on High Performance Liquid Chromatography (HPLC) system. About 70% of the collected samples were found contaminated with either of the analyzed pesticides. Aldrine was detected in 35% samples with mean concentration level of 0.68µg/ml, ranged between 0.32 µg/ml and 5.19µg/ml. However, DDT, DDE, and endosulfan prevailed comparatively in lower percentage such as 10%, 9%, and 7%, respectively. DDT ranges between .003µg/ml and 0.40µg/ml, with mean concentration level of 0.01 µg/ml. Whereas DDE is present with mean residue level of 0.04µg/ml, ranging from 0.15µg/ml to 1.23µg/ml. Lower level of DDT residues in milk indicates that the further application of DDT has been ceased which is also reported by other monitory studies conducted in most of the countries. Mean concentration level of the Endosulfan in milk was 0.13µg/ml. Among pyrethroids pesticides detected in milk samples, bifentrhin was present with the highest mean concentration level of 1.68µg/ml followed by permethrin with mean residue level of 1.24µg/m. The mean residue level of cypermethrin and deltamethrin was 0.23µg/ml and 0.21µg/ml respectively. The results also indicated that 23%, 21%, 18% and 7% of the milk samples were contaminated with cypermethrin, bifenthrin, permethrin and detlamethrin, respectively. [ABSTRACT FROM AUTHOR]