Global scale distribution, seasonal changes and long-range transport potentiality of endosulfan in the surface seawater and air

Endosulfan I, II, and sulfate were detected in the atmosphere and surface seawater on a global scale during three Chinese National Arctic-Antarctic Research Expeditions in 2016 and 2017. Concentrations of the three species displayed seasonal variations in seawater in the Northern Hemisphere but remained steadily low on Antarctic coasts. Endosulfan sulfate was predominant in the Northern Hemisphere, whereas isomer I was more abundant in the Southern Hemisphere. Endosulfan was detected in the atmosphere over the western Pacific Ocean but rarely in the central Arctic and North Atlantic oceans. Its concentration in seawater increased with increasing latitude in the Southern Ocean. Although fugacity ratios indicate a strong potential for deposition of endosulfan, air-seawater exchange may be slow, as suggested by the large differences between atmospheric and seawater concentrations. Ocean current endosulfan loads varied markedly between seasons. Three-day backward trajectories indicate that Northeast Asia is the major source of atmospheric endosulfan in the western Pacific Ocean, whereas the central Arctic and North Atlantic oceans are affected more by local air masses.

Comprehensive assessment of unutilized and obsolete pesticides impact on genetic status and health of population of Almaty region

The group of persistent organic pollutants (POPs) are particularly dangerous for the environment and by consequence for human health because of the risk to be transmitted in the food chain. Among them, the urgent problem of obsolete and forbidden organochlorinated pesticides (OCPs) needs a rigorous management in many countries, including Kazakhstan. The aim of our study was to evaluate the effect of pesticides content in food products on the genetic status and health of the population living on the contaminated areas near destroyed warehouses for OCPs (4 villages of Talgar district and 1 control site, Almaty region). The food products sampled in Taukaraturyk (control site), and in 4 villages where non-utilized obsolete pesticides were discovered: Beskainar, Kyzylkairat, Amangeldy, and Belbulak. The contents of 24 pesticides in food products from plant (apples, pears, tomatoes, cucumbers, sweet peppers) and animal (beef meat, cow milk, honey) origin, that grown in places of localization of non-utilized OCPs, were determined, sometimes in high and unacceptably high concentrations (before 2500 times over MRL). In pears, the pesticides content (especially DDT, γ-HCH, β-HCH, endosulfan, and aldrin pesticide group), was higher than in other fruits. Among vegetables, the highest levels of all groups of pesticide were found in cucumbers. Beef meat samples demonstrated increased contents of β-HCH, γ-HCH, endrin and dieldrin. In cow milk samples only the high concentration of dieldrin was found. The content of pesticides in meat was 4-5 times higher than in milk. The medical examinations, carried out among the cohorts living around the polluted by pesticides territories and control cohort from ecologically favorable village, showed that there were more individuals with high and middle levels of somatic health in the control group than in groups exposed to OCPs. The long-term effect of the pesticide contamination of the environment on genetic status of the population was assessed by chromosomal aberration (CA) frequencies. The highest level of chromosomal aberrations was identified for the examined residents of Kyzylkairat (41%) and Belbulak (38%), a high level in Amangeldy (12%), and middle level in Beskainar (6.5%). The association between the CA frequency, health status and the pesticides contents in food were assessed by a Spearman rank correlation. The low indicators of somatic health status were strictly associated with high levels of CA, and good health status indicates that the CA rates did not exceed the spontaneous level of mutagenesis. The strongest correlation was shown between high levels of chromosomal aberrations and the content of different pesticides in pears (Cr = 0.979-0.467), tomatoes (Cr = 0.877-0.476), cucumbers (Cr = 0.975-0.553) and meat (Cr = 0.839-0.368). The obtained results highlight the need to improve health protection by increasing the public awareness to the security of the storage of obsolete OCPs in order to strengthen food safety by efficient control services.

Nationwide levels and distribution of endosulfan in air, soil, water, and sediment in South Korea

We investigated the levels and distribution patterns of α- and β-endosulfan and endosulfan sulfate in air, soil, water, and sediment samples collected from the South Korean persistent organic pollutants (POPs) monitoring networks. In the air samples, the highest concentrations of the total (Σ₃) endosulfan (50.3-611 pg/m³, mean: 274 pg/m³) were observed during summer. Spearman analysis revealed a good correlation between agricultural land area and atmospheric concentrations of Σ₃ endosulfan except during winter. Regardless of the season, the ratio of the two isomers (α/β) was 3.6-4.9 in the air samples, higher than that observed in technical mixtures (2.0-2.3), possibly due to the higher volatility of α-endosulfan, compared to β-endosulfan. Concentrations of Σ₃ endosulfan in the soil samples (n.d.-13.4 ng/g, mean: 0.8 ng/g) were not significantly different except at some stations adjacent to large areas of farmland. The average levels of Σ₃ endosulfan in the water and sediment samples were 2.1 ng/L and 0.1 ng/g dw, respectively. In analyzing the four largest rivers, it was observed that a few water stations during spring and fall and sediment stations in fall had high concentrations of the two isomers and endosulfan sulfate, particularly around the Yeoungsan and Nakdong Rivers near large areas of agricultural land. Endosulfan sulfate was dominant at most water and sediment sampling stations. This study demonstrates that the endosulfan found in most environmental compartments most probably derives from agricultural areas despite its ban as a pesticide. On the other hand, given that it was also detected in industrial and urban areas, in which pesticide application does not occur, it can be conjectured that endosulfan is aerially transported at higher temperatures and continuously circulates within the environment.

Occurrence and depositional history of organochlorine pesticides in the sediments of the Zayandehrud River in the arid region of Central Iran

In this study, surface sediments along the Zayandehrud River (14 samples), and two dated core sediments (46 samples) from small artificial urban lakes at the middle section of the Zayandehrud River in the Gavkhooni basin in the central arid regions of Iran were analyzed for residual levels of 20 organochlorine pesticide (OCP) compounds. Total OCP concentrations ranged from 0.1 to 50.1 ng g-1 dry weight and from 1.9 to 51.5 ng g-1 dry weight in surface and core sediments, respectively. Dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) were found to be the predominant OCPs in these sediments. The calculated metabolic and isomeric ratios confirmed the aged nature of residual dichlorodiphenyltrichloroethane (DDT) in sediments. Moreover, the isomeric ratios indicated the aged nature of technical HCH (hexachlorocyclohexane), while the contribution of γ- HCH (lindane) as a main source has increased, especially in the last two decades. Past usage, as well as current usage of endosulfan technical mixture in the Gavkhooni basin, has been found in the last four decades. Analyses of sedimentary cores, as natural archives, have shown the successful ban on the use of organochlorine pesticides (especially DDT) in the Gavkhooni basin, and to some extent, in the central plateau of Iran. In general, it can be concluded that natural factors (i.e., floods and wet years) lead to soil leachate and play an essential role in remobilization and transfer of residual OCPs from soil to inland aquatic ecosystems in the Gavkhooni basin, which is an arid region.

First evaluation of DDT (dichlorodiphenyltrichloroethane) residues and other Persistence Organic Pollutants in soils of Rwanda: Nyabarongo urban versus rural wetlands

This study was the first to evaluate the occurrence, residue levels, spatial distribution and sources of DDT and other Persistence Organic Pollutants (POPs), which can be found in the Nyabarongo lower catchment (NLC) in Rwanda. These include Aldrin, Dieldrin, Endosulfan, Endrin, Hexachlorocyclohexane (HCH), Heptachlor, Heptachlorepoxide, Hexachlorobenzene (HCB), Isodrin, Methoxychlor, Mirex and Polychlorinated biphenyls (PCBs). A total of 108 soil samples were collected in the wetland area, both extracted and eluted with cyclohexane and analysed by GC-MS. The results indicated that DDT isomers and degradation products were major POPs and were detected in 44 samples (40%). Their detection frequency followed the order of 4,4'-DDE > 4,4' -DDT > 4,4' -DDD > 2,4' -DDT > 2,4' -DDD and 2,4' -DDE. Residues varied from non-detected (nd) to 120 μg kg^-1 dry weight (dw), with a mean value of 3.93 μg kg^-1 dw and a high variation (SD = 10.17 μg kg^-1 dw). The degradation ratios confirmed both the historical and recent application of DDT and Dieldrin (0.53-18 μg kg^-1 dw). Other detected POPs included PCBs in Kigali city which ranged from 0.1 to 0.21 μg kg^-1 dw, confirming that the old contamination drifted from electric transformers. Aldrin (0.38-0.59 μg kg^-1 dw); Heptachlor (0.14-0.19 μg kg^-1 dw) residues probably reached the catchment through rain-washout. This study confirms that even though Rwanda banned the use of DDT and other POPs including pesticides (Aldrine, Chlordane, DDT, Dieldrine, Endrine, Heptachlor, Hexachlorobenzene, Mirex, and Toxaphene); Industrial products (Hexachlorobenzene and Polychlorobiphenyl PCBS) and unintentional sub-products, since 2002, some of above products are still used in random areas (e.g: DDT, Dieldrin). The highest residues were detected close to Lake Muhazi and areas surrounding Kigali city. This study recommends full evaluation of human health and ecological risks from exposure to DDT. Additionally, the National Implementation Plan (NIP) for the Stockholm Convention to eliminate POPs should be reinforcement through strengthening the market control and educational programs.

Accumulation characteristics of endosulfan soil residues in soybean and reduction in their phytoavailability by treatment with powdered activated carbon

Powdered activated carbon (PAC) has been utilized for sorptive remediation of environmental sites contaminated with various organic chemicals. In the present study, time-dependent sorption/desorption characteristics of the α- and β-isomers and a sulfate-metabolite of endosulfan (ED) were investigated in PAC-amended soils to determine the optimal PAC amendment dosage. Subsequently, ED phytoavailability to soybean (Glycine max Merr.) plants were examined in the presence or absence of PAC under restricted laboratory conditions. Based on the results of sorption/desorption tests, the optimal dosage of PAC amendment for ED-contaminated soils was determined as 1% (w/w), and at this dosage, all ED residues were sorbed completely onto the PAC-amended soils without any desorption. In soil amended with 1% PAC, the extents of ED accumulated by soybean plants were reduced by 89.4-100.0% within 20 days compared to those extents observed in unamended controls. Moreover, PAC treatment precluded the formation of the toxic metabolite ED-sulfate in either the soil or soybean plants. Therefore, PAC amendment in ED-contaminated soils could be highly effective for limiting uptake of ED into plants from contaminated soil and may be useful as an alternative method to produce safe food resources from contaminated arable soils.

Polychlorinated biphenyls and organochlorines pesticides in indoor dust: An exploration of sources and health exposure risk in a rural area (Kopawa) of Nepal

While contamination of indoor environment with organochlorine compounds (OCs) is well documented worldwide, only a few studies highlighted the problem of indoor pollution in Indian sub-continent, including Nepal. This study insight the contamination level, distribution pattern, and sources of OCs in indoor dust from a rural area of Nepal. Additionally, daily exposure risk through different intake pathways was estimated in order to mark the potential risk of OCs to local residents. Results indicated the predominance of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in dust. Ʃ₂₆OCPs (median 87 ng/g) in dust was about 7-8 times greater than Ʃ₃₀PCBs (median 10.5 ng/g). DDT was the most abundant chemical among Ʃ₂₆OCPs, followed by HCHs and endosulfan, and accounted for 73%, 7%, and 4% of Ʃ₂₆OCPs, respectively. A relatively high level of ƩDDT than other OCPs suggests the existence of DDT source in the Nepalese environment. Among PCB, tetra-CBs were most prevalent, trailed by penta-CBs, hexa-CBs, and hepta-CBs, and comprised 28%, 21%, 17% and 17% of Ʃ₃₀PCBs, respectively. Dioxin like-PCBs (median 3.48 ng/g) was about two times higher than the total indicator-PCB (median 1.63 ng/g). High p,p-DDT/p,p-DDE ratio (median 2.89) suggested fresh application and minimal degradation of DDT in the local environment of Kopawa. While lower α-/γ-HCH ratio (median 0.75) indicated lindane contamination as the primary sources of HCH. Moreover, the low α-/β-endosulfan ratio (median 0.86) specified the fresh use of commercial endosulfan. Among OCPs, only DDT positively related to total organic carbon (TOC) (Rho = 0.55, p < 0.05) but not black carbon (BC), proposing minimal or zero impact of TOC and BC. For PCBs, PCB-126 was moderately and negatively correlated with TOC (Rho = -0.49, p < 0.05), but not BC. The daily risk exposure (DRE) assessment showed that children are more vulnerable to OCs than the adult. The DRE of OCs in this study were 2-4 order of magnitude lower than their corresponding reference dose (RfD), proposing insignificant risk.

Organochlorine Pesticides and Potentially Toxic Elements in Groundwater from a Protected Reserve in the Maya Region of Hopelchen, Mexico

Water quality degradation by organochlorine pesticides and potentially toxic elements is of worldwide concern. This research explores groundwater conditions, regarding organochlorine pesticides and potentially toxic elements, in Hopelchen, Campeche, which is located in the buffer zone of the Calakmul Biosphere Reserve. Unfortunately, agriculture is allowed and agrochemical use is not monitored and sanctioned. Results show that Heptachlor, Endosulfan, and Dieldrin, all recognized carcinogens, had concentrations above the Mexican normative recommended values. Conversely, Cd and Ni concentrations were below recommended values. These results demonstrate that government intervention involving immediate control over agrochemical use is mandatory. Also, the results underscore the contamination of groundwater in several of the Calakmul Biosphere Reserve's buffer zones by organochlorine pesticides concentrations, posing a probable threat for local inhabitants who consume this water and use it for recreation.

Systematic probabilistic risk assessment of pesticide residues in tea leaves

Multiple pesticide residues are frequently present in tea leaves and while the majority of residues satisfy Taiwan's current health regulations, there are potential health effects from pesticide exposure that are of great concern for tea drinkers. We undertook a systematic probabilistic risk assessment of 59 pesticides in tea leaves from 1629 tea leaf samples obtained by Taiwan's Food and Drug Administration in two monitoring surveys in 2015. Bayesian statistics used a Markov Chain Monte Carlo approach to estimate posterior distributions of pesticide residues in tea leaves, lifetime average daily doses and hazard quotients (HQs) of evaluated pesticides. We classified 95th percentile values of HQs into three categories: 0 < HQ < 0.5, 0.5 ≤ HQ ≤ 1 and 1 < HQ. The 95th percentiles of HQs for triazophos (3.39), carbofuran (2.04) and endosulfan (1.80) exceeded 1 in the adult population; the HQ for 3-OH carbofuran was 0.97 and was less than 0.5 for the remaining 55 pesticides. The health risk posed by pesticide residues for tea drinkers is negligible, if triazophos, carbofuran, endosulfan, and 3-OH carbofuran residues satisfy regulatory standards. However, five legacy pesticides, DDT, methomyl, carbofuran, dicofol and endosulfan, were identified. To reduce uncertainties, this study combined Bayesian statistics with a mode of action approach for systematic risk assessment of co-exposure to multiple pesticide residues in tea leaf samples. Measuring pesticide transfer rates will improve the quality of future risk assessments concerning residues in tea leaves. Appropriate management of pesticides in Taiwanese tea farms and monitoring of pesticide residues in imported tea is warranted to protect Taiwan's tea drinkers.

Exploring the Environmental Exposure to Methoxychlor, α-HCH and Endosulfan-sulfate Residues in Lake Naivasha (Kenya) Using a Multimedia Fate Modeling Approach

Distribution of pesticide residues in the environment and their transport to surface water bodies is one of the most important environmental challenges. Fate of pesticides in the complex environments, especially in aquatic phases such as lakes and rivers, is governed by the main properties of the contaminants and the environmental properties. In this study, a multimedia mass modeling approach using the Quantitative Water Air Sediment Interaction (QWASI) model was applied to explore the fate of organochlorine pesticide residues of methoxychlor, α-HCH and endosulfan-sulfate in the lake Naivasha (Kenya). The required physicochemical data of the pesticides such as molar mass, vapor pressure, air-water partitioning coefficient (K_AW), solubility, and the Henry's law constant were provided as the inputs of the model. The environment data also were collected using field measurements and taken from the literature. The sensitivity analysis of the model was applied using One At a Time (OAT) approach and calibrated using measured pesticide residues by passive sampling method. Finally, the calibrated model was used to estimate the fate and distribution of the pesticide residues in different media of the lake. The result of sensitivity analysis showed that the five most sensitive parameters were K_OC, logKow, half-life of the pollutants in water, half-life of the pollutants in sediment, and K_AW. The variations of outputs for the three studied pesticide residues against inputs were noticeably different. For example, the range of changes in the concentration of α-HCH residue was between 96% to 102%, while for methoxychlor and endosulfan-sulfate it was between 65% to 125%. The results of calibration demonstrated that the model was calibrated reasonably with the R² of 0.65 and RMSE of 16.4. It was found that methoxychlor had a mass fraction of almost 70% in water column and almost 30% of mass fraction in the sediment. In contrast, endosulfan-sulfate had highest most fraction in the water column (>99%) and just a negligible percentage in the sediment compartment. α-HCH also had the same situation like endosulfan-sulfate (e.g., 99% and 1% in water and sediment, respectively). Finally, it was concluded that the application of QWASI in combination with passive sampling technique allowed an insight to the fate process of the studied OCPs and helped actual concentration predictions. Therefore, the results of this study can also be used to perform risk assessment and investigate the environmental exposure of pesticide residues.

Spatial distribution and sources of pesticidal persistent organic pollutants in the Hooghly riverine sediment

Given the extensive indiscriminate usage in the past and limited ongoing use, organochlorine pesticides (OCPs) have been widely reported in the Hooghly riverine environment. Hence, surface riverine sediment samples were collected along the urban and suburban transects of the Hooghly River and OCPs were quantified in gas chromatography mass spectrometry (GC-MS). Mean concentration of HCH, DDT, and endosulfan was 5 ng g^-1, 10 ng g^-1, and 4 ng g^-1 respectively. DDT was dominant among all the OCPs and contributed nearly 40% to the total OCPs possibly due to the ongoing use of DDT for vector control programs. Diagnostic ratios suggest recent source of lindane, DDT, and endosulfan. Using OCP concentration from previously published data in surface water during the same time frame, sediment-water partitioning of OCPs was estimated. Excluding α-HCH and γ-HCH in few pockets, majority of the OCPs tend to partition more on to sediment. Comparing the sediment concentration with the sediment quality guideline values, risk on ecological integrities was indicated due to DDT and HCH contamination. Suburban sites indicated higher risk than urban sites according to the calculated sediment quality guideline quotient (SQGQ). A brief review on the approach to pesticidal POP pollution management in India revealed that older management approaches should be replaced with a unique, integrated, and holistic system.

Air-water exchange of pesticidal persistent organic pollutants in the lower stretch of the transboundary river Ganga, India

The lower stretch of the perennial transboundary river Ganga is known as the Hooghly River (HR) in India. Despite the strict ban, HR has been evidenced with residues of pesticidal persistent organic pollutants (POPs) from primary and secondary sources. Hence surface water sampling and passive air sampling (PAS) were conducted along the urban and suburban transects and discharge points to study the fate of pesticidal (POPs along the HR. Excluding the discharge points, the mean concentration of hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT) and endosulfan (ENDO) were 6 ng/L, 4 ng/L and 36 ng/L in surface water and 888 pg/m³, 1689 pg/m³ and 429 pg/m³ in atmosphere respectively. Percentage composition and diagnostic ratios strongly suggest ongoing use of technical HCH, DDT and endosulfan. Elevated endosulfan in surface water has been related to its usage during fishing. Except for p,p'-DDE, α-Endo and β-Endo, fluxes at the air-water interface showed net deposition from air to water for all the OCPs in urban and suburban transects. The estimated eco-toxicological risk assessment showed risk on lower trophic organisms due to DDT and lindane mostly at the discharge points. Endosulfan can pose potential risk to the edible fishe species in the HR.

Residues of endosulfan in cotton growing area of Vehari, Pakistan: an assessment of knowledge and awareness of pesticide use and health risks

This study is based on self-reported information collected from selected farmers of Vehari District, Punjab, Pakistan, to determine their technical knowledge and awareness about pesticide use and associated environmental and health risks. Moreover, soil contamination by routinely used persistent organochlorine pesticide, endosulfan, was also evaluated. Survey data revealed very low literacy rate (on an average 9th grade education) and technical knowledge (almost missing) of the farmers in Vehari District. The farmers are unable to fully read and understand the instructions about the use of pesticide marked on the containers. They are not fully aware of pesticide persistence and toxicity (73%), unable to identify cotton pests and diseases (86%), and do not know which crop to grow in cotton adjacent fields (100%). Data also revealed that the farmers (100%) do not follow safety measure during pesticide application and are unaware of pesticide toxicity symptoms in human as well as the basic first-aid practices (89%).Poor literacy rate and lack of technical knowledge of farmers in Vehari regarding pesticide use and handling are posing serious environmental and health risks among the local inhabitants, particularly among farmers. Soil analysis results showed that concentration of α- and β-endosulfan ranged from 0-14 to 0-14.64 μg/mg, respectively. Principal component analysis showed that soil organic matter is the key soil parameter controlling the occurrence and fate of endosulfan under sandy loam soil conditions of Vehari District. There is a serious need of improving technical and environmental knowledge of farmer about pesticide risks on human health in the studied area, in particular, and the entire country in general. Findings are of great use for policymaking in Pakistan to minimize pesticide risks in Pakistan.

Degradation of endosulfan by high-energy ball milling with CaO: process and mechanism

Mechanochemical degradation (MCD) technology has shown its remarkable potential in the disposal of persistent organochlorines in a non-combustion manner. In the present study, endosulfan, as the newly listed persistent organic pollutants (POPs) in the Stockholm Convention, was investigated for its feasibility of mechanochemical destruction using high-energy ball milling. Using calcium oxide (CaO) as a co-milling reagent, the degradation efficiency of endosulfan was nearly 100% after ball milling for 60 min, while the dechlorination efficiency and the sulfate formation efficiency were delayed for endosulfan degradation. After ball milling for 120 min, the dechlorination efficiency and sulfate formation efficiency reached 87.55% and 26.28%, respectively. Based on the measurement results from various material characterization approaches, the main degradation pathway of endosulfan was proposed as sequential dechlorination followed by the destruction of hydrocarbon skeleton. The GC-MS analysis confirmed that complete desulfurization and dechlorination had been realized finally. This study provides an option for the way toward the efficient and rapid destruction of endosulfan as a new POPs using mechanochemical technology.

Air monitoring of polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides in West Antarctica during 2011-2017: Concentrations, temporal trends and potential sources

Annual air samples were collected at various sites in the Fildes Peninsula, West Antarctica from December 2010 to January 2018 using XAD-2 resin passive air samplers to investigate concentrations, temporal trends and potential sources of persistent organic pollutants (POPs) in Antarctic air. Relatively low concentrations of polychlorinated biphenyls (PCBs) (Σ₁₉PCBs: 1.5-29.7 pg/m³), polybrominated diphenyl ethers (PBDEs) (Σ₁₂PBDEs: 0.2-2.9 pg/m³) and organochlorine pesticides (OCPs) (Σ₁₃OCPs: 101-278 pg/m³) were found in the atmosphere of West Antarctica. PCB-11, BDE-47 and hexachlorobenzene (HCB) were the predominant compounds in the atmosphere. The concentrations of PCBs, HCHs, DDTs and endosulfans were found to show decreasing temporal trends, whereas uniform temporal trends were observed for HCB. The atmospheric half-life values for PCBs, HCHs, DDTs and endosulfans in Antarctic air were estimated for the first time, using regressions of the natural logarithm of the concentrations versus the number of years, obtaining the values of 2.0, 2.0, 2.4 and 1.2 year, respectively. An increasing ratio of α-HCH/γ-HCH indicated long residence time for α-HCH and possible transformation of γ-HCH to α-HCH in the atmosphere. The ratios of p,p'-DDT/p,p'-DDE were mostly lower than unity in this study, which could be attributed to aged sources. It was found that long-range atmospheric transport was still considered to be the main contributing factor to the atmospheric levels of the POPs in West Antarctica whereas the contribution of human activities at the Chinese Great Wall Station was minor. The results of this study give a view on the most recent temporal trends and provide new insights regarding the occurrence of various POPs in the Antarctic atmosphere.

Influence of plant growth promoting rhizobacterial strains Paenibacillus sp. IITISM08, Bacillus sp. PRB77 and Bacillus sp. PRB101 using Helianthus annuus on degradation of endosulfan from contaminated soil

Endosulfan is a broad spectrum insecticide used in agriculture for protection of various food and non-food crops. It is persistent in nature and hence found in soil, air and water. The potential use of plants and microorganisms for the removal of endosulfan from soil was studied. Helianthus annuus plant was grown in soil spiked with 5, 10, 25 and 50 mg kg^-1 concentrations of endosulfan and inoculated with plant growth promoting rhizobacterial strains Paenibacillus sp. IITISM08, Bacillus sp. PRB77 and Bacillus sp. PRB101 for 40, 80 and 120 days. Potential of plant for endosulfan uptake was evaluated by investigating the endosulfan levels in plant tissues (root and shoot). The results indicated that endosulfan accumulation followed the pattern of root > shoot as well as decrease in uptake of endosulfan in root and shoot of a plant grown in bacterial inoculated soil as compared to un-inoculated soil. Bacterial inoculation had a positive effect on endosulfan degradation. Maximum degradation of 92% at 5 mg kg^-1 of endosulfan in soil was observed on inoculation with PRB101 after 120 days of inoculation. The results showed that plant growth promoting bacteria enhances plant biomass production. Lipid peroxidation was also estimated by determining the malondialdehyde (MDA) production, which is a biomarker of oxidative damage. Decrease in MDA formation by root and leaves of plants grown in the bacteria inoculated plant was also observed. The results suggested the effectiveness of plant growth promoting rhizobacteria to boost accumulation potential, biomass production and enhance remediation of endosulfan contaminated soil.

Review of the analysis of insecticide residues and their levels in different matrices in Ghana

This review reports on how Ghanaian scientists analyse insecticide residues in various matrices in their laboratories as well as the levels of insecticides found in Ghana. It covers different sample preparation methods such as solid-liquid and liquid-liquid extraction. The main technique used for this analysis was gas chromatography (GC) with various detectors such as electron capture, flame photometric, nitrogen phosphorus, and mass spectrometric detection. Liquid chromatography (LC) with mass spectrometric detection was sometimes used to determine the levels of very polar insecticide residues. From the articles reviewed 74% of the insecticides detected were organochlorines with DDTs, lindanes, and endosulfans as most abundant ones. Levels of the insecticides of interest analysed, varied from below the detection limits to clearly above the safety limits. The lowest detected concentration of insecticide residues reported in fruits and vegetables was δ-lindane in pawpaw (0.06 mg/kg) while the highest was fenvalerate (25.6 mg/kg). Insecticide residues reported in sediment were predominantly organochlorines with concentrations ranging from 9.68 ng/kg to 10.98 µg/kg. Endosulfan and its metabolites were the main insecticides found in water bodies with concentrations ranging from 0.036 µg/L to 62.3 µg/L. DDT and its metabolites were the dominant insecticides found in human fluids.

Insight into occurrence, profile and spatial distribution of organochlorine pesticides in soils of solid waste dumping sites of Pakistan: Influence of soil properties and implications for environmental fate

Waste dumping sites are considered as significant disposal pathway for waste contaminants including pesticides. In the present study OCPs were analyzed in soils of waste dumping sites of Pakistan. The mean concentrations of OCPs were in the order: ∑DDTs>∑HCHs>∑Endosulfan>∑HCB>Heptachlor. Order of overall ∑OCPs contamination with respect to location was Lahore>Sukkur>Karachi>Kamoki>Faisalabad>Hyderabad>Losar>Gujrat>Peshawar. Distribution of OCPs in solid waste dumping site was mainly influenced by textural classes, input history and pollution source. Soil texture was the dominant factor for retention of OCPs, whereas TOC and black carbon has not significantly impacted the concentrations of OCPs. Diagnostic ratios indicated the historical input, anaerobic degradation pathway and use of technical mixtures of DDTs in majority of waste dumping sites whereas for HCHs recent as well as past usage of technical mixture was prevalent in most of the areas. Regression analysis revealed a weak positive correlation of OCPs with socioeconomic indices (HDI, Population, waste generation) which is linked with history of use of these contaminants in the respective areas. Forecasted waste generation quantity for the year 2026 showed that waste generation amount will get doubled by the year 2026 suggesting the need properly designed waste management system.

Assessment of Organochlorine Pesticides in Phreatic Aquifer of Pampean Region, Argentina

This work evaluates the factors affecting the presence of organochlorine pesticides in Pampeano aquifer in the Quequén Grande River watershed, Buenos Aires Province, Argentina. Eighteen sampling sites were selected in order to have representatives of different type of wells and types of soil. Among the analyzed compounds, endosulfan showed the highest concentrations (4.75 ng l^- 1 mean), which could be related to use in the recent past. Others important pesticides groups detected were HCHs (1.1 ng l^- 1 mean) and heptachlors (2.17 ng l^- 1mean). The analysis of the results show that the thickness of the unsaturated zone is the main factor related to the concentrations of pesticides and there were no differences according to wells or soil types. Although agricultural use of most OCPs has been banned in Argentina from more than 30 years ago, their residues are still detected in groundwater of the region, indicating their high persistence.

Structure-based design and application of an engineered glutathione transferase for the development of an optical biosensor for pesticides determination

In the present work, a structure-based design approach was used for the generation of a novel variant of synthetic glutathione transferase (PvGmGSTU) with higher sensitivity towards pesticides. Molecular modelling studies revealed Phe117 as a key residue that contributes to the formation of the hydrophobic binding site (H-site) and modulates the affinity of the enzyme towards xenobiotic compounds. Site-saturation mutagenesis of position Phe117 created a library of PvGmGSTU variants with altered kinetic and binding properties. Screening of the library against twenty-five different pesticides, showed that the mutant enzyme Phe117Ile displays 3-fold higher catalytic efficiency and exhibits increased affinity towards α-endosulfan, compared to the wild-type enzyme. Based on these catalytic features the mutant enzyme Phe117Ile was explored for the development of an optical biosensor for α-endosulfan. The enzyme was entrapped in alkosixylane sol-gel system in the presence of two pH indicators (bromocresol purple and phenol red). The sensing signal was based on the inhibition of the sol-gel entrapped GST, with subsequent decrease of released [H+] by the catalytic reaction, measured by sol-gel entrapped indicators. The assay response at 562 nm was linear in the range pH = 4-7. Linear calibration curves were obtained for α-endosulfan in the range of 0-30 μΜ. The reproducibility of the assay response, expressed by relative standard deviation, was in the order of 4.1% (N = 28). The method was successfully applied to the determination of α-endosulfan in real water samples without sample preparation steps.

Kinetic field dissipation and fate of endosulfan after application on Theobroma cacao farm in tropical Southwestern Nigeria

Endosulfan, 6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano,2,4,3-benzodioxathiepin-3-oxide, is still a pesticide of choice for most cocoa farmers in Southwestern Nigeria, in spite of its persistence, bioaccumulative, toxicological properties, and restriction. A single treatment of 1.4 kg ai/ha (0.5% ai) of technical grade endosulfan (Thiodan, 35EC) was applied to 0.0227 ha of cultivated Theobroma cacao L. (Cocoa) farm at the Cocoa Research Institute of Nigeria (CRIN). Levels of parent endosulfan (α-, β-endosulfan) and major metabolite (endosulfan sulfate) were determined in vegetation and surrounding matrices at days 0, 7, 14, 21, 28, 42, and 60 using GC-MS. Their kinetic variables were determined. Order of ∑endosulfan distribution at day 0 was dry foliage > fresh foliage > bark > pods > soil (0-15 cm). No residual endosulfan was found in cocoa seeds and subsurface soil (15-30 cm). Low residual levels in pods on day 0 may be due to endogenous enzymatic breakdown, with α-isomer more susceptible and α/β-endosulfan ratio being 0.90. Fell dry foliage as mulch was predominantly the receiving matrix for non-target endosulfan sprayed. Volatilization was key in endosulfan dissipation between days 0 and 7 from foliage surfaces (> 60% loss), while dissipation trend was bi-phasic and tri-phasic for vegetation and soil, respectively. ∑endosulfan loss at terminal day ranged between 40.60% (topsoil) and 99.47% (fresh foliage). Iteratively computed half-lives (DT'₅₀) ranged from 6.48 to 30.13 days for ∑endosulfan in vegetation. Endosulfan was moderately persistent in pods-a potential source for cross contamination of seeds during harvest. Iteratively determined DT'₅₀ and initial-final day DT₅₀ are highly correlated (R = 0.9525; n = 28) and no significant difference (P = 0.05) for both methods.

Assessment of organochlorine pesticides in the Himalayan riverine ecosystems from Pakistan using passive sampling techniques

Organochlorine pesticides (OCPs) pose a considerable threat to human and environmental health. Despite most OCPs have been banned, they are still reported to be used in developing countries, including Pakistan. We aimed to identify the distribution, origin, mobility, and potential risks from OCPs in three major environmental compartments, i.e., air, water, and soil, across Azad Jammu and Kashmir valley, Pakistan. The sums of OCPs ranged between 66 and 530 pg/g in soil, 5 and 13 pg/L in surface water, and 14 and 191 pg/m3 in air, respectively. The highest sum of OCPs was observed in the downstream zone of a river that was predominantly influenced by peri-urban and urban areas. The OCP isomers ratios (α-HCH/γ-HCH and o,p'-DDT/p,p'-DDT) indicate use of lindane and technical DDTs mixture as a source of HCH and DDT in the riverine environment. Similarly, the ratios of DDE and DDD/the sum of DDTs, α-endosulfan/β-endosulfan, and cis-chlordane/trans-chlordane indicate recent use of DDTs, endosulfan, and chlordane in the region. The air-water exchange fugacity ratios indicate net volatilization (fw/fa > 1) of α-endosulfan and trans-chlordane, and net deposition (fw/fa < 1) of β-endosulfan, α-HCH, γ-HCH p,p'-DDD, p,p'-DDE, and p,p'-DDT. Based on the risk quotient (RQ) method, we consider the acute ecological risks for fish associated with the levels of OCPs as negligible. However, more studies are recommended to evaluate the chronic ecological risks to other riverine-associated aquatic and terrestrial species as well as human health risks to the POPs exposure through food chain transfer in forthcoming years.

Mercury and Organochlorines in the Terrestrial Environment of Schirmacher Hills, Antarctica

We report the levels of mercury (Hg) and nine organochlorine pesticides [OCPs: α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, δ-HCH, α-Endosulfan, β-Endosulfan, Endosulfan sulfate, p,p'-dichlorodiphenyldichloroethylene (DDE) and p,p'-dichlorodiphenyldichloroethane (DDD)] in the terrestrial environment (moss and soil) and water (OCPs only) of Schirmacher Hills, Antarctica. This area has never been studied for mercury and not for OCPs since 1988. Mercury levels in moss, 66 ± 37 ng/g dry weight (dw), are comparable to other Antarctic locations. Levels of α-HCH, below detection to 4.48 ng/g dw, and p,p'-DDE, below detection to 31 ng/g dw, in mosses are lower or marginally higher than other Antarctic locations. No other OCPs were detected in moss. None of the OCPs were detected in soil. This suggests that Schirmacher Hills may be considered as a background site with respect to mercury and analyzed OCPs, despite the operation of two old research stations (Maitri, est. 1989, and Novolazarevskaya, est. 1961) in the region.

Persistent organic pollutants in sediments, intertidal crabs, and the threatened Olrog's gull in a northern Patagonia salt marsh, Argentina

Persistent organic pollutants (POPs) are of great concern for the environment. In this study we (a) determine levels and distribution of OCPs, PCBs, and PBDEs in sediments and two crab species (Neohelice granulata and Cyrtograpsus altimanus), (b) assess bioaccumulation in crabs, and (c) explore the occurrence of POPs in the Near Threatened Olrog's gull (Larus atlanticus) chicks and eggs in one of the most important salt marsh environments in the South West Atlantic. Sediments, crabs, and gull chicks and eggs showed POPs presence at low levels; being α-endosulfan, PCB-153, and BDE-47 the most represented compounds. In sediments, pollutant concentrations were lower than those reported in Canadian guidelines for the protection of the aquatic life. POP bioaccumulation was recorded in crabs, suggesting a risk to upper trophic level predators. Further studies are needed to understand the trophic effects of POPs in San Blas bay, particularly on the threatened Olrog's gull.

Air contamination by legacy and current-use pesticides in Brazilian mountains: An overview of national regulations by monitoring pollutant presence in pristine areas

In the last decades, research regarding the dynamics of pesticides has grown, even in remote regions. Due to long-range atmospheric transport, environmental persistence and toxicological potential of organochlorine pesticides (OCPs), similar characteristics of current-use pesticides (CUPs) and their massive use in Brazil, these contaminants have become a major concern for environmental and human life. Thus, this study aimed to evaluate subgroups or individual chemicals of OCPs and CUPs, which could have travelled over two Conservation Unit sites in the Rio de Janeiro state. The study was carried out for 24 months, (2013-2015), in Itatiaia National Park (INP) and in the Serra dos Órgãos National Park (SONP), at ∼2400 and ∼2200 meters above sea level, respectively. The study was based on atmospheric passive sampling (polyurethane foam disks). Target pesticides were detected by means of gas chromatography device coupled with mass spectrometry (GC-MS). Significantly higher concentrations were measured in SONP when compared to INP. However, in broad terms, the contamination profile was quite similar for both national parks: The highest concentrations of endosulfan (INP - 1275 pg m^-3 and SONP - 3202 pg m^-3) were followed by cypermethrin (INP - 148 pg m^-3 and SONP - 881 pg m^-3) and chlorpyrifos (INP - 67 pg m^-3 and SONP - 270 pg m^-3). In agreement with previous studies, the atmospheric concentrations of legacy OCPs showed background air levels. The decrease of endosulfan over the years was highlighted with a parallel increase of chlorpyrifos, suggesting a collateral effect of the national bias of permissive and massive use of agrochemicals. CUPs seemed to behave like pseudo-persistent pollutants (pseudo-POPs). This is the first report of atmospheric concentrations of pyrethroids in Brazilian mountain regions, and possibly the first to investigate them in the air in South America or in any mountain region in the world.