Adsorption of pesticides (heptachlor epoxide, dieldrin and endrin) onto modified bentonite by Keggin cation Al30O8(OH)56(H2O)2418+ denoted Al30 cation to form composite (Al30/B), has been ...investigated as a possible alternative method for their removal from aqueous solutions. The study was aimed to use a low-cost material as a step towards cleaner environment. Interestingly, these chemical modifications altered the physicochemical characteristics of bentonite in term of morphology, surface area and functionality which has been confirmed by using nitrogen adsorption–desorption isotherm, scanning electronic microscopy (SEM) and X-ray diffraction (XRD). Gas chromatography coupled to mass spectrometry (GC–MS) was used to identify and analyze the pesticides. Different physicochemical parameters were analyzed: contact time, adsorbent dose, pH, and temperature. The results showed that the removal percentage of pesticides on Al30/B was the highest at contact time of 5 h, adsorbent dosage of 25 mg, at pH 7.5, and at optimum temperature of 45 °C. Furthermore, the Kinetic study indicated that the adsorption of pesticides on Al30/B was well adapted to the pseudo-first order kinetic with a correlation coefficient near unity. The results of adsorption were fitted to the Langmuir and Freundlich isotherms. The Freundlich model represented the adsorption process better than Langmuir model, with correlation coefficients (R2) values range from 0.986 to 0.989. The Thermodynamic study suggested that the adsorption of pesticides was chemisorption, spontaneous and endothermic process. Therefore, Al30/B composite can be utilized effectively for removal of pesticides with efficiency up to 98%.
In the present study, we determined the levels of chlorinated pesticide residues in surfacewater samples collected from the Charsadda district (KPK, Pakistan). SPME-GC-ECD with COMBIPAL CTC ...autosampler was used for extraction and analysis of 20 organochlorine pesticides in thecollected water samples. For maximum efficiency of the SPME procedure, several parameters werestudied, including the extraction and desorption time of the fiber, solution pH, agitation of samples,and stirring speed, etc. This method showed good liner response, with R2 values in the range of0.9887 to 0.9999 for all pesticides. This method also provided good percent recoveries at 1 µg L−1(87.5to 106.0%) and at 2 µg L−1(88.5 to 109.2%). Lower limits of detection for all 20 chlorinated pesticideswere found to be lower than their maximum permissible contamination levels. Approximately 50%of the surface water samples collected from the Charsadda district were found to be contaminatedwith the pesticides γ-BHC, heptachlor, aldrin and dieldrin, with maximum concentrations of 0.023,0.108, 0.014 and 0.013 µg L−1, respectively. For adults and children, the cancer risk from water dueto contamination by various pesticides ranged from 0 to 33.29 × 10−6. The non-carcinogenic riskfrom each pollutant in the water samples of the Charsadda district was found to be in the order ofheptachlor > aldrin > dieldrin > γ-BHC. However, the pesticides α-BHC, β-BHC, heptachlor epoxide,chlordane, endrin, 4,40-DDD, endrin ketone, 4,40-DDT, endosulfan sulfate and methoxychlor werenot detected in any of the surface water samples of investigated in the present study.
Antarctica is no longer pristine due to the confirmed presence of anthropogenic contaminants like Persistent Organic Pollutants (POPs). Benthic organisms are poorly represented in contamination ...studies in Antarctica although they are known to bioaccumulate contaminants. Sponges (Phylum Porifera) are dominant members in Antarctic benthos, both in terms of abundance and biomass, and are an important feeding source for other organisms, playing key functional roles in benthic communities. To the best of our knowledge, legacy chlorinated POPs such as polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and dichlorodiphenyltrichloroethane (DDT) and their metabolites have never been investigated in this Phylum in Antarctica. The aim of this work was to evaluate the bioaccumulation of PCBs, HCB, o,p’- and p,p’-DDT and their DDE and DDD isomers in 35 sponge samples, belonging to 17 different species, collected along the coast of Terra Nova Bay (Adèlie Cove and Tethys Bay, Ross Sea), and at Whalers Bay (Deception Island, South Shetland Islands) in Antarctica. Lipid content showed a significant correlation with the three pollutant classes. The overall observed pattern in the three study sites was ΣPCBs>ΣDDTs>HCB and it was found in almost every species. The ΣPCBs, ΣDDTs, and HCB ranged from 54.2 to 133.7 ng/g lipid weight (lw), from 17.5 to 38.6 ng/g lw and from 4.8 to 8.5 ng/g lw, respectively. Sponges showed contamination levels comparable to other Antarctic benthic organisms from previous studies. The comparison among sponges of the same species from different sites showed diverse patterns for PCBs only in one out of four cases. The concentration of POPs did not vary significantly among the three sites. The predominance of lower chlorinated organochlorines in the samples suggested that long-range atmospheric transportation (LRAT) could be the major driver of contamination as molecules with a high long range transport potential (e.g. low chlorinated PCBs, HCB) prevails on heavier ones.
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•First data about legacy chlorinated POPs in Antarctic sponges are reported.•Antarctic sponges are suitable organisms for legacy POPs contamination studies.•Sponges showed levels of contamination comparable to other benthic organisms.•DDTs and HCB concentrations in sponges: South Shetland Island > Ross Sea.
From 2005 to 2019, three gadoid species, Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and saithe (Pollachius virens), were sampled approximately every third year in the ...northeastern part of the North Sea. Liver samples were analyzed to investigate levels and temporal trends of six groups of persistent organic pollutants (POPs): polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its degradation products, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), trans-nonachlor (TNC), and polybrominated diphenyl ethers (PBDEs). Some of the highest average concentrations were found in cod, the levels otherwise being similar between the three species and mostly below established threshold values. The levels of all the contaminants except HCB and TNC were higher than previously reported for cod and haddock in the Barents Sea. Significantly decreasing levels were found for Σ7PCBs, ΣDDTs, ΣHCHs and Σ15PBDEs in all three species, and for TNC in haddock and saithe, while there was no significant trend for TNC in cod. HCB levels increased significantly in cod and haddock and showed only a minor decrease in saithe. The observed time trends of legacy POPs demonstrate the persistence of some of the studied pollutants despite efforts to eliminate them from the marine environment.
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•Levels of four POPs show a significant decrease in Atlantic cod, haddock and saithe.•The most recently banned group of POPs, Σ15PBDEs, shows the strongest decrease.•HCB shows a significant increase in cod and haddock, and a weak decrease in saithe.•Differences in time trends between the species are due to their diet and behavior.•The levels are higher than in the Barents Sea for four out of six groups of POPs.
Chlorinated pesticides have been used in pest control for several decades in the world. These compounds are still applied in many regions, and their continuous usage has resulted in their ...bioaccumulation and residue in the food chain. These residues could transfer to food products and accumulate in fat tissues. Undoubtedly, the breast milk could be a significant biomarker for estimation of these residues in the human body. This study was conducted to review and compile the results of the studies undertaken in the world which surveyed the organochlorine pesticides residue in breast milk.
A total of 710 national and international articles and texts related to the focused subject were extracted from the virtual databases using the following key words: Chlorinated pesticides, residue and breast milk. Thirty articles published between 1980 and 2013 were selected and reviewed.
The majority of the reviewed articles indicated the presence of two or more organochlorine pesticides in the collected samples of breast milk. Based on the reviewed studies, dichlorodiphenyltrichloroethane (DDT) had the highest level of concentration in the collected samples of breast milk. Moreover, there was a statistically significant positive correlation between mother's age, her multiparty and concentration of chlorinated pesticides in breast milk.
The organochlorine pesticides are still applied in some developing countries including some regions of Iran. Thus, it seems essential to inform the community about the adverse effects of this class of pesticides; and most importantly the governments should also ban the use of such compounds.
Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) have been important monitoring targets in the atmosphere due to their deleterious ...biological effects. Pine needles have been used to monitor atmospheric pollutants. An analytical method was developed to measure 21 PAHs, 14 alkyl PAHs, 7 PCBs, and 23 OCPs in pine needles using ultrasonically assisted extraction and gas chromatography‐tandem mass spectrometry (GC–MS/MS). The ranges of the lower limits of detection of PAHs, PCBs, and OCPs were 0.01–0.05, 0.02–0.06, and 0.01–0.07 μg/kg, respectively. The feasibility of the proposed method was validated by analyzing dust standard reference materials of the samples, which gave satisfactory results with a precision of 0.83%–7.80% (PAHs), 0.93%–4.78% (PCBs), and 0.73%–4.71% (OCPs), and an accuracy of 89.2%–102% (PAHs), 94.6%–109% (PCBs), and 99.4%–102% (OCPs). The PAHs, PCBs, and OCPS were determined from real pine needle samples using the developed method.
Treated wastewater (TWW) is a well recognized source of organic pollutants (OPs) that may accumulate during irrigation. For the first time, data on the occurrence of polycyclic aromatic hydrocarbons ...(PAHs), polychlorinated biphenyles (PCBs) and organochlorinated pesticides (OCPs) in wastewater irrigated soil in Nabeul (Tunisia) are reported. 13 PAHs, 18 PCBs and 16 OCPs were analyzed in soil samples collected at 0–10 and 10–20 cm depth before each and every irrigation and after the irrigation period expanding from June to October. Soil was extracted with an accelerated solvent extractor and analyzed by a tandem gas chromatograph in selected reaction monitoring mode (GC/MS/MS/SRM). OPs residues were detected before irrigation and accumulated at the end of the season for some of them. The total concentration of PAHs varied between 120.01 and 365.18 μg kg−1 dry weight (dw) at 0–10 cm depth before and at the end of irrigation, respectively. The total concentration of PCBs varied between 11.26 and 21.89 μg kg−1 dw at 0–10 cm, being higher than those reported for 10–20 cm. The six indicator PCB congeners (28, 52, 101, 138, 153, 180) were predominant. OCPs concentrations ranged between 12.49 and 21.81 μg kg−1 at 0–10 cm and between 74.03 and 310.54 μg kg−1 at 10–20 cm depth. DDT was predominant accounting for more than 94% of the total OCPs. In view of the present results, OPs are relevant to the agricultural environment, calling for more research on their persistence and potential transfer to plants and/or groundwater while taking into account farmers’ practices.
•13 PAHs, 18 PCBs and 16 OCPs were analyzed in soil irrigated with treated wastewater.•PAHs, PCBs, and OCPs were detected and accumulate in soil during the course of irrigation.•4 rings PAHs were dominant accounting for more than 74% of the total concentration.•Six indicator PCBs (non dioxin-like-PCBs) were predominant in soil samples.•OCPs content are higher in 10–20 cm depth compared to 0–10 cm, especially DDT; the latter being the predominant OCP detected in wastewater irrigated soil.
This study was conducted to investigate the removal efficiency of heptachlor from aqueous solutions using bimetallic iron/copper (Fe/Cu) nanoparticles. The highest removal efficiency of 99.3% for ...heptachlor compounds was achieved at pH 7.0, bimetallic Fe/Cu dosage 0.33 g/L, initial heptachlor concentration 2 µg/L, contact time 30 min, and stirring rate 250 rpm. The adsorption data of heptachlor fitted well to Koble-Corrigan isotherm and Avrami kinetic model. Artificial neural network r
2
: 0.9567) was more precise than the response surface methodology (r
2
: 0.774) in simulating the adsorption of heptachlor onto the bimetallic Fe/Cu nanoparticles. This study indicated that bimetallic Fe/Cu could be employed as an efficient adsorbent for the removal of heptachlor compound.
Atmospheric concentrations of organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and neutral per- and polyfluoroalkyl substances (PFAS) have been measured at Villum Research ...Station, Station Nord (North Greenland) in the period 2008–2013. Atmospheric concentrations of OCPs at the same site have been previously reported for the years 2008–2010. The detection frequency and the average concentrations of OCPs have not significantly changed since the previous study. PBDE congeners (∑13PBDEs) were measured for the first time in North Greenland at concentrations similar to those observed for other remote sites, confirming that these compounds are ubiquitous in the Northern Hemisphere. The ∑13PBDEs concentration ranged from not detected (n.d.) to 6.26 pg m−3. The BDE congeners found in more than 30% of the samples were BDE-17, BDE-28, BDE-47, BDE-71, BDE-99 and BDE-100. Also for neutral PFAS we present for the first time a multiyear series of measurements for North Greenland. The average sum of the seven measured neutral PFAS (∑7PFAS) ranged from 1.82 to 32.1 pg m−3. The most abundant compound was 8:2 FTOH (44% of ∑7PFAS), followed by 6:2 FTOH and 10:2 FTOH. Perfluoroalkyl sulfonamides (FOSA) and perfluoroalkyl sulfonamidoethanols (FOSE) were also detected but at much lower concentrations than FTOHs.
Temporal trends were investigated for all measured compounds but no significant trend in concentration was observed. Monthly average concentrations for the six years were calculated for each compound and the seasonal variation was investigated. Some OCPs and FTOHs showed seasonal variations, and in most cases a maximum was found during summer.
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•PBDEs and neutral PFASs are reported for the first time in the atmosphere of North Greenland.•Atmospheric concentrations of POPs do not show any trend in the period 2008–2013.•Some compounds showed seasonal variations, and in most cases a maximum was found during summer.•Temperature dependency was observed for a few of the investigated compounds.
Chlorinated pesticides, polybrominated- and polyfluorinated compounds have been measured in the atmosphere of North Greenland in the years 2008–2013.
The feasibility and effectiveness of iron turning waste as low cost and sustainable permeable reactive barrier (PRB) media for remediating dieldrin, endrin, dichlorodiphenyltrichloroethane (DDT), and ...lindane individually (batch system) and combined (continuous flow column) in water were investigated. After 10 min of reaction in a batch system, removal of endrin, dieldrin, and DDT was higher (86–91 %) than lindane (41 %) using 1 g of iron turning waste in 200 mL of pesticide solution (20 μg/L for each pesticide). Among the studied pesticides, only lindane removal decreased substantially in the presence of nitrate (37 %) and magnesium (18 %). Acidic water environment (pH = 4) favored the pesticide removal than neutral and basic environments. For the column experiments, sand alone as PRB media was ineffective for remediating the pesticides in water. When only iron turning was used, the removal efficiencies of lindane, endrin, and dieldrin were 83–88 % and remained stable during 60 min of the experiments. DDT removal was less than other pesticides (58 %). Sandwiching the iron turning waste media between two sand layers improved DDT removal (79 %) as well as limited the iron content below a permissible level in product water. In a long-term PRB column performance evaluation, iron turning waste (150 g) removed all pesticides in water (initial concentration of each pesticide = 2 μg/L) effectively (≥94 %) at a hydraulic retention time of 1.6 h. Iron turning waste, which was mainly in the form of zerovalent iron (Fe0), was oxidized to ferrous (Fe2+) and ferric (Fe3+) iron during its reaction with pesticides, and electrons donated by Fe0 and Fe2+ were responsible for complete dechlorination of all the pesticides. Therefore, it can be used as inexpensive and sustainable PRB media for groundwater remediation especially in developing countries where groundwater contamination with pesticides is more prevalent.
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•Iron turning waste efficiently treated chlorinated pesticides in water.•Iron turning waste completely dechlorinated all studied chlorinated pesticides.•Except for lindane, pesticide removal was not affected by minerals in groundwater.•Low water pH favored the removal of pesticides compared to neutral conditions.•This study provides sustainable media for remediation of pesticides in groundwater.
Main finding: Iron turning waste has shown its ability as potential permeable reactive barrier media for remediating and completely degrading the organochlorine pesticides in water at a laboratory scale to meet the U.S. drinking water standards and/or World Health Organization health significance values. Iron turning waste is much more affordable than nano-zerovalent iron (nZVI), a similar material typically used for groundwater remediation. Iron turning waste can be used in developing countries that cannot afford nZVI for remediation of contaminants, especially organochlorine pesticides.
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