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2,312 result(s) for "DDT (pesticide)"
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Microbial degradation of recalcitrant pesticides: a review
Some pesticides such as organochlorines are of critical environmental concern because they are highly persistent due to their stable chemical nature. As a consequence, even after banning, dichlorodiphenyltrichloroethane and endosulfan can be detected at concentrations above permissible limits. Moreover, classical pesticide degradation of these compounds using physiochemical processes is limited. Alternatively, biodegradation using microorganisms isolated in contaminated sites appears promising. For instance, the bacterium Pseudomonas fluorescens degrades aldrin by 94.8%, and the fungus Ganoderma lucidum can bring down the levels of lindane by 75.5%. In addition, the toxicity is reduced by enzymes that perform oxidation, reduction, hydrolysis, dehydrogenation, dehalogenation and decarboxylation. Then, the metabolites are further degraded by mineralisation and cometabolism. The biodegradation process can be manipulated by applying techniques such as bioattenuation, bioaugmentation and biostimulation. This article discusses the latest advances in microbial degradation of recalcitrant pesticides.
Ecotoxicological effects of microplastics on aquatic organisms: a review
Microplastics   ( <5 mm), which are classified based on primary or secondary sources, are widely distributed in the environment and exert significant effects on aquatic life forms; however, evidence regarding the ecotoxicological effects of microplastics on aquatic organisms is still limited. This research aims at filling a knowledge gap regarding generation sources, distribution, physicochemical properties, and biological behavior of microplastics (MP) in aquatic environments and their interaction with aquatic organisms. The literature indicates that concentrations of MPs observed in such environments are higher than the threshold for safe concentration (6650 buoyant particles/m 3 ). MPs having large specific surface area, low polarity, and hydrophobic properties have been shown to absorb dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbon (PAHs), bisphenol A (BPA), polyfluoroalkyl substances (PFAS), antibiotics, and heavy metals. MPs adsorb large amounts of toxic organic chemicals (18,700 ng/g PCBs; 24,000 ng/g PAHs) and heavy metals (0.21–430 μg/g Cr; 0.0029–930 μg/g Cd; 0.35–2.89 μg/g As; 0.26–698,000 μg/g Pb). MPs originating from polystyrene (PS), polypropylene (PP), and polyvinylchloride (PVC) show greater toxicity toward aquatic organisms, with effects on the immune system, reproductive system, nervous system, and endocrine system. Thus, elucidating the cumulative toxic expression of MPs in different polluted environments is critical.
Influence of QuEChERS modifications on recovery and matrix effect during the multi-residue pesticide analysis in soil by GC/MS/MS and GC/ECD/NPD
A QuEChERS extraction followed by GC/MS/MS and GC-μECD/NPD for 216 pesticide and metabolites determination in soil simultaneously were developed and compared. Volume of water, volume and polarity of solvent, and cleanup sorbents (C18, GCB, PSA) were optimized. The QuEChERS with and without purification step were applied to estimate effectiveness of the method. The recovery and matrix effect (ME) were critical parameters within each tested procedure. The optimal method without cleanup was validated. Accuracy (expressed as recovery), precision (expressed as RSD), linearity, LOQ, and uncertainty were determined. The recoveries at the three spiking levels using matrix-matched standards ranged between 65 and 116% with RSD ≤17 and 60–112% with RSD ≤18% for MS/MS and μEC/NP, respectively. The LOQ ranged from 0.005–0.01 mg/kg for MS/MS to 0.05 mg/kg for μEC/NP. The ME for most of pesticides resulted in enhancement of the signal and depended on the analyte and detection system: MS/MS showed ME from −25 to 74%, while μEC/NP from −45 to 96%. A principal component analysis was performed to explain the relationships between physicochemical parameters and ME of 216 pesticides. The QuEChERS protocol without the cleanup step is a promising option to make the method less expensive and faster. This methodology was applied in routine analysis of 263 soil samples in which p,p’ DDT was the most frequently detected (23.5% of samples) and pendimethalin with the highest concentration (1.63 mg/kg).
Association of selected persistent organic pollutants in the placenta with the risk of neural tube defects
Persistent organic pollutants (POPs) have been associated with a wide range of adverse health effects. Our case-control study was performed to explore the association between placental levels of selected POPs and risks for neural tube defects (NTDs) in a Chinese population with a high prevalence of NTDs. Cases included 80 fetuses or newborns with NTDs, whereas the controls were 50 healthy, nonmalformed newborn infants. Placental concentrations of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers were analyzed by gas chromatography-mass spectrometry. The medians of PAHs, o,p'-isomers of dichlorodiphenyltrichloroethane (DDT) and metabolites, α- and γ-hexachlorocyclohexane (HCH), and α-endosulfan were significantly higher in case placentas than in controls. PAH concentrations above the median were associated with a 4.52-fold [95% confidence interval (CI), 2.10-9.74) increased risk for any NTDs, and 5.84- (95% CI, 2.28-14.96) and 3.71-fold (95% CI, 1.57-8.79) increased risks for anencephaly and spina bifida, respectively. A dose-response relationship was observed between PAH levels and the risk of NTDs, with odds ratios for the second, third, and fourth quartiles, compared with the first, of 1.77- (95% CI, 0.66-4.76), 3.83- (95% CI, 1.37-10.75), and 11.67-fold (95% CI, 3.28-41.49), respectively. A dose-response relationship was observed for anencephaly and spina bifida subtypes. Similar results were observed for o,p'-DDT and metabolites, α-HCH, γ-HCH, and α-endosulfan, whereas no dose-response relationship was observed for the last two pollutants. Elevated placental concentrations of PAHs, o,p'-DDT and metabolites, and α-HCH were associated with increased risks of NTDs in this population.
The trouble with neonicotinoids
Chronic exposure to widely used insecticides kills bees and many other invertebrates Four decades ago, DDT and other pesticides that cause environmental harm were banned. Since then, newly developed pesticides have had to conform to stricter environmental standards. Yet, recent studies highlight the subtle but deadly impacts of neonicotinoids—the most widely used insecticides in the world—on ecosystems ( 1 – 3 ). In contrast to other insecticides, neonicotinoids are systemic, meaning that they are highly soluble and thus absorbed by the plant. They produce delayed mortality in arthropods after chronic exposure to sublethal doses but are not very toxic to vertebrates. It has taken more than a decade to unravel some of the mechanisms through which neonicotinoids affect the integrity of ecosystems. Although gaps in knowledge remain, there is a strong case for stricter regulation of these pesticides.
Risk of breast cancer and adipose tissue concentrations of polychlorinated biphenyls and organochlorine pesticides: a hospital-based case-control study in Chinese women
Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethylene (DDE) are suspected to be associated with breast cancer risk, but the results are controversial. This study was performed to evaluate the associations between adipose tissue PCB, DDT, and DDE concentrations and breast cancer risk. Two hundred and nine pathologically diagnosed breast cancer cases and 165 controls were recruited from three local hospitals in Shantou city, China, from 2014 to 2016. Concentrations of 7 PCB congeners, p,p′-DDT, and p,p′-DDE were measured in adipose tissues obtained from the breast for cases and the breast/abdomen for controls during surgery. Clinicopathologic information and demographic characteristics were collected from medical records. PCBs, p,p′-DDT, and p,p′-DDE concentrations in adipose tissues were compared between cases and controls. Multivariate logistic regression model was used to analyze the risk of breast cancer by PCBs, p,p′-DDT, and p,p′-DDE concentrations in adipose tissues. Breast cancer cases have relatively higher menarche age, higher breastfeeding and postmenopausal proportion than controls. Levels of PCB-52, PCB-101, PCB-118, PCB-138, PCB-153, PCB-180, total PCBs (∑PCBs), and p,p′-DDE were relatively higher in breast cancer cases than controls. Breast cancer risk was increased in the third tertile of PCB-101, PCB-118, PCB-138, PCB-153, PCB-180, ∑PCBs, and p,p′-DDE as compared with the first tertile in both adjusted and unadjusted logistic regression models (odds ratios [ORs] were from 1.58 to 7.88); and increased linearly across categories of PCB-118 and p,p′-DDE in unadjusted model, and PCB-118 and PCB-153 in the adjusted model with trend (all P  < 0.01). While breast cancer risk was declined in the second tertile of PCB-28, PCB-52, and PCB-101 in both unadjusted and adjusted models, also second tertile of p,p′-DDT and third tertile of PCB-28 in the adjusted models. This study suggests associations between the exposure of PCBs, p,p′-DDT, and p,p′-DDE and breast cancer risk. Based on adjusted models, PCB-118, PCB-138, PCB-153, PCB-180, ∑PCBs, and p,p′-DDE exposures increase breast cancer risk at current exposure levels, despite existing inconsistent even inverse results in PCB-28, PCB-52, PCB-101, and p,p′-DDT. More epidemiological studies are still needed to verify these findings in different populations.
Long-term relationships among pesticide applications, mobility, and soil erosion in a vineyard watershed
Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice. Many studies have addressed the question of their possible remobilization as a result of global change. In this article, we present a retro-observation approach based on lake sediment records to monitor micropollutants and to evaluate the long-term succession and diffuse transfer of herbicides, fungicides, and insecticide treatments in a vineyard catchment in France. The sediment allows for a reliable reconstruction of past pesticide use through time, validated by the historical introduction, use, and banning of these organic and inorganic pesticides in local vineyards. Our results also revealed how changes in these practices affect storage conditions and, consequently, the pesticides' transfer dynamics. For example, the use of postemergence herbicides (glyphosate), which induce an increase in soil erosion, led to a release of a banned remnant pesticide (dichlorodiphenyltrichloroethane, DDT), which had been previously stored in vineyard soil, back into the environment. Management strategies of ecotoxicological risk would be well served by recognition of the diversity of compounds stored in various environmental sinks, such as agriculture soil, and their capability to become sources when environmental conditions change. Significance A record of lake sediment spanning approximately 100 years allowed us to reconstruct the long-term succession of herbicide, fungicide, and insecticide treatments in a vineyard catchment in France. This record of pesticide deposition is consistent with the historical onset and banning of these chemical substances by French and European environmental agencies. We also present evidence of the effects of postemergence herbicides, such as glyphosate, on soil erosion and evidence of the release of banned remnant pesticides, such as dichlorodiphenyltrichloroethane (DDT), that are stored in vineyard soil back into the environment. These results indicate that the sink–source dynamics of pesticides, which are crucial in ecotoxicological risk assessment, should take into account the effects of a changing environment on pesticide storage.
Off-target pesticide movement: a review of our current understanding of drift due to inversions and secondary movement
Pesticide drift has been a concern since the introduction of pesticides. Historical incidences with off-target movement of 2,4-D and dichlorodiphenyltrichloroethane (DDT) have increased our understanding of pesticide fate in the atmosphere following aerial application. More recent incidences with dicamba have brought to light gaps in our current understanding of aerial pesticide movement following ground application. In this paper, we review the current understanding of inversions and other weather and environmental factors that contribute to secondary pesticide movement and raise questions that need to be addressed. Factors that influence volatility and terminology associated with the atmosphere, such as cool air drainage, temperature inversions, and radiation cooling will be discussed. We also present literature that highlights the need to consider the role(s) of wind in secondary drift in addition to the role in physical drift. With increased awareness of pesticide movement and more herbicide-resistant traits available than ever before, it has become even more essential that we understand secondary movement of pesticides, recognize our gaps in understanding, and advance from what is currently unknown. Nomenclature: dicamba; 2, 4-D; dichlorodiphenyltrichloroethane
Serum levels of Organochlorine Pesticides and Breast Cancer Risk in Iranian Women
Breast cancer is a multifactorial disease and its etiology is linked to multiple risk factors. There are shreds of controversial evidence that exposure to organochlorine pesticides (OCPs) are important in the etiology of breast cancer. The present study aimed to determine the circulating levels of OCPs in patients with breast tumors in Southeastern of Iran. This case–control study included 27 patients with malignant breast tumors (MBT), 31 patients with benign breast tumors (BBT), and 27 healthy women as a control group. Serum OCPs levels, including α-hexachlorocyclohexane (α-HCH), β-HCH, γ-HCH, 2,4-dichlorodiphenyltrichloroethane (2,4-DDT), 4,4-DDT, 2,4-dichlorodiphenyldichloroethylene (2,4-DDE), and 4,4-DDE, were measured using gas chromatography. Our data revealed significantly higher concentrations of 2,4-DDT in MBT and BBT groups compared with control ones (P < 0.001 for both comparisons). Patients with breast cancer suffered significantly higher accumulation levels of 4,4-DDE compared with control subjects (P = 0.04). Significant correlations were found among organochlorine compounds with each other in both patients’ groups. There was a significant positive correlation between body mass index and serum levels of 2,4-DDT in BBT group (r = 0.407, P = 0.02). The present findings suggest that the serum levels of 4,4-DDE and 2,4-DDT are associated with an increase in the risk of breast cancer in Southeastern women of Iran.
Pesticide regulations and their malpractice implications on food and environment safety
Although pesticides have a positive effect on plant health in terms of insect pests and diseases control, increased productivity and improved crop storage, their malpractice impacts on food safety negatively. Pesticide residues and corresponding metabolites are left as runoff to the environment affecting non-targeted organisms like fish, bees, butterflies, birds and other beneficial organisms in soil and water bodies. Moreover, the application of pesticides in non-agriculture activities goes unnoticed, such as spraying for anopheles mosquito to control malaria. Human health effects caused by pesticide residues in food include headache, vomiting, itching and skin irritation, restlessness, dizziness, breathing difficulties, neurotoxicity and chronic poisoning-related diseases such as cancer and death incidences. Maximum residue limits are the maximum pesticide residues limit in food considered safe to human as set by the Codex Alimentarius Commission and the joint Food and Agriculture Organization/World Health Organization meeting on pesticide residues. The residues of dichlorodiphenyltrichloroethane and chlorpyrifos are reported in various foods globally. Additionally, food safety is largely obstructed by illegal use of pesticides and the presence of counterfeit pesticides in the market. This review provides detail on pesticide control and regulations, residues in food, their health impacts and link approaches like good agricultural practices for ensuring sustainability on safe food production.