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1.

Purpose

Psychoactive compounds??meprobamate, pyrithyldione, primidone, and its metabolites, phenobarbital, and phenylethylmalonamide??were detected in groundwater within the catchment area of a drinking water treatment plant located downgradient of a former sewage farm in Berlin, Germany. The aim of this study was to investigate the distribution of the psychoactive compounds in anoxic groundwater and to assess the risk of drinking water contamination. Groundwater age was determined to achieve a better understanding of present hydrogeological conditions.

Methods

A large number of observation and production wells were sampled. Samples were analyzed using solid-phase extraction and ultrahigh-performance liquid chromatography?Ctandem mass spectrometry. Groundwater age was estimated using the helium?Ctritium (3He?C3H) dating method.

Results

Concentrations of psychoactive compounds up to 1???g/L were encountered in the contamination plume. Generally, concentrations of phenobarbital and meprobamate were the highest. Elevated concentrations of the analytes were also detected in raw water from abstraction wells located approximately 2.5?km downgradient of the former sewage farm. Concentrations in the final drinking water were below the limit of quantification owing to dilution. The age of shallow groundwater samples ranged from years to a decade, whereas groundwater was up to four decades old at 40?m below ground. Concentrations of the compounds increased with groundwater age.

Conclusions

Elevated concentrations of psychoactive drugs indicate a strong persistence of these compounds in the environment under anoxic aquifer conditions. Results suggest that the heritage of sewage irrigation will affect raw water quality in the area for decades. Therefore, further monitoring of raw and final drinking water is recommended to ensure that contaminant concentrations remain below the health-based precautionary value.  相似文献   

2.

Purpose

Fish farming in barrage pond is a rearing system commonly used worldwide. Obtaining good water quality is essential to improve sustainability of these ecosystems, both for health of fish consumers and environmental considerations. However, ponds are often located in agricultural landscape, but few study reports impact of pesticide pressure on these ecosystems. This study characterizes five sites in Northeastern France. This work establishes an initial framework for pesticide monitoring with the aim to improve understanding of the fate of pesticides in ponds.

Methods

This framework is based on surveys indicating managements and Geographical Information System (GIS) for five ponds and their watersheds (sites: C-0, C-25, C-45, C-75 and C-85) and completes with some analysis of a large spectrum of pesticide residues in surface waters.

Results

Watersheds show a gradient of crop proportion ranging from 0% to 82% of the watershed area, mainly rapeseed, wheat, barley and maize. Ponds were representative of local Northeastern France management. Many pesticides, and also nutrients, were measured in water with concentrations varying between sites and seasons. The sum of quantified molecules ranged from 0.17 ??g/l for site C-0 (March) to 8.81 ??g/l for site C-25 (October). Concentrations of metaldehyde, quinmerac, isoproturon and bentazon were sometimes above 1 ??g/l.

Conclusions

There is a strong connection between pond and watershed, due to water supply throughout the fish production cycle. Sites with small pond/big watershed are the most exposed to acute contamination a few days after spraying because water discharges are not diluted.  相似文献   

3.

Purpose

The quality of fish produced in ponds needs to be ensured. Indeed, pond is often strongly connected to an agricultural watershed, and pesticides are a main health and environmental issue of concern. In this context, the purpose of this study is to highlight the management practices which could impact the pesticide contamination profiles in edible fish and to give recommendations for better practices.

Methods

A principal component analysis, coupled to a hierarchical cluster analysis, was performed to evaluate temporal evolution of contamination profiles and to assess variability among fish species and among sites according to watershed characteristics. The explicative variables correspond to muscular concentrations of pesticides (azoxystrobin, clomazone, diflufenican, carbendazim, isoproturon, metazachlor, napropamid) in three species of fish (Perca fluviatilis, Cyprinus carpio and Rutilus rutilus), caught in five ponds during two sampling campaigns. Management data are added variables in order to discuss about parameters suspected to be implicated in the contamination profiles recorded.

Results

This work shows that high amounts of pesticides applied, short crop rotation durations and bare soil practices led to contamination of sediments and fish and were associated to a “bad” management of watershed. Breeding fish that had low masses and establishing the fishing period at the end of winter seemed to be “bad” management of pond. Aggravating topological parameters were big watershed coupled to small pond and high proportions of sand soils in the watershed.

Conclusions

Reducing amounts of pesticide used (e.g. policy agency plans, farmer acceptance), favouring long-term rotations and inter-cultures, adapting pond creation and fish farming practices to watershed management and topography all could reduce pesticide levels in edible fish and contribute to a better sustainability of the extensive fish farming in pond.  相似文献   

4.

Background, aim and scope

Groundwaters and source waters are exposed to environmental pollution due to agricultural and industrial activities that can enhance the leaching of organic contaminants. Pesticides are among the most widely studied compounds in groundwater, but little information is available on the presence of phthalates, alkylphenols and bisphenol A. These compounds are used in pesticide formulations and represent an emerging family of contaminants due to their widespread environmental presence and endocrine-disrupting properties. Knowledge on the occurrence of contaminants in source waters intended for bottling is important for sanitary and regulatory purposes. So the aim of the present study was to evaluate the presence of phthalates, alkylphenols, triazines, chloroacetamides and bisphenol A throughout 131 Spanish water sources intended for bottling. Waters studied were spring waters and boreholes which have a protection diameter to minimize environmental contamination.

Materials and methods

Waters were solid-phase extracted (SPE) and analysed by gas chromatography coupled to mass spectrometry (GC-MS). Quality control analysis comprising recovery studies, blank analysis and limits of detection were performed.

Results and discussion

Using SPE and GC-MS, the 21 target compounds were satisfactorily recovered (77?C124?%) and limits of quantification were between 0.0004 and 0.029???g/L for pesticides, while for alkylphenols, bisphenol A and phthalates the limits of quantification were from 0.0018???g/L for octylphenol to 0.970???g/L for bis(2-ethylhexyl) phthalate. Among the 21 compounds analysed, only 9 were detected at levels between 0.002 and 1.115???g/L. Compounds identified were triazine herbicides, alkylphenols, bisphenol A and two phthalates. Spring waters or shallow boreholes were the sites more vulnerable to contaminants. Eighty-five percent of the samples did not contain any of the target compounds.

Conclusions

Target compounds were detected in a very low concentration and only in very few samples. This indicates the good quality of source waters intended for bottling and the effectiveness of the protection measures adopted in Spain. None of the samples analysed exceeded the maximum legislated levels for drinking water both in Spain and in the European Union.  相似文献   

5.

Background

A three-dimensional groundwater flow model was used to evaluate the groundwater potential and assess the effects of groundwater withdrawal on the regional water level and flow direction in the central Beijing area. A program of groundwater modeling aimed at estimating current contaminant fluxes to the central area and site streams via groundwater was developed.

Results and discussion

The conceptual model developed for the site attempted to incorporate a complex stratigraphic profile in which groundwater flow and contaminant transport is strongly controlled by a shallow aquifer. Here, a conceptual model for groundwater flow and contaminant transport in central Beijing is presented.

Conclusion

Model simulations indicated that a sharp drop in the hydraulic head occurs at the center of the model area, which generates a cone of depression and a continuous decline of head with respect to time as a result of heavy groundwater abstraction.  相似文献   

6.

Purpose

We evaluate malathion toxicity to Japanese medaka (Oryzias latipes) juveniles by using a mass spectrometry combined with gas chromatography (GC/MS) metabolomics approach.

Methods

Medaka were exposed to low (L) and high (H) concentrations (nominally 20 and 2,000 ??g/L, respectively) of water-borne malathion. Metabolites were extracted from the fish, derivatized, and analyzed by GC/MS. Identified metabolites were subjected to one-way analysis of variance and principal component analysis (PCA). We examined the variations in the amounts of the metabolites during the exposure period.

Results and discussion

At 24 h, control, L, and H groups were separated along PC1, suggesting that the effects of malathion depended on exposure concentration. The PCA results at 96 h suggest that the metabolite profiles variations of the L and H groups differed, and thus that the effects of malathion in groups differed. At 24 h, the amounts of amino acids in both exposed groups were lower than the control group amounts, perhaps owing to accelerated protein synthesis. At 96 h, the amounts of almost all the amino acids increased in the L group but decreased in the H group relative to the control group amounts, suggesting the proteolysis occurred in the L group while protein synthesis continued in the H group, that the high malathion exposure affected the fish. In addition, at 96 h, gluconeogenesis may have been induced in the L group but not in H group.

Conclusions

Malathion exposure may have altered the balance between protein synthesis and degradation and induced gluconeogenesis in medaka. Our results suggest that metabolomics will be useful for comprehensive evaluation of toxicity.  相似文献   

7.

Introduction

The future ??Calanque National Park?? coastlines of the Bouches-du-Rh?ne and Var departments in France, constitute one of the ten biodiversity hot spots identified in the Mediterranean basin that receives industrial and urban wastewaters discharged from Marseille and its suburbs.

Materials and methods

Organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) were measured in sediments collected from 12 sampling sites (C1?CC12) of sewage discharge to the sea from the wastewater treatment plant of Cortiou-Marseille. This study aims to determine the extent of these compounds in the sediments and to establish the possible sources of these contaminants.

Results and discussion

Total pesticides in the sediments ranged from 1.2 to 190.6 ng g-1 dry weight of sediment. The highest value was found at station C1, with a decreasing trend in total OC concentrations seaward. Among these compounds, the concentrations of the sum of dichlorodiphenyltrichloroethane (??DDT) were the highest, ranging from 0.7 to 114.3 ng g-1. PCB concentrations, expressed as equivalent to Arochlor 1260, varied from 9.1 to 226.9 ng g-1. Individually, the dominant coplanar PCB congeners CB-153, CB-138 and CB-101. Generally, PCB concentrations at stations C2, C3, C5 and C7 were higher than those at stations C10, C11 and C12. Through some pollution indices, we showed the long-term contamination input of these OCs (DDT, endosulfan, HCH and heptachlor cases) rather than a recent release resulting from degradation and long-term weathering (dieldrin, aldrin and methoxychlor cases). Occurrence of PCBs might be due to their resistance to degradation processes or/and chronic inputs.

Conclusions

By comparison with available sediment quality guideline (SQG) values, the environmental significance and toxicological implications of PCBs and OCs (i) reveal the probable adverse effects for the sediments from C1, C5, C6, C9 and (ii) confirm the adverse effect for marine biota and more particularly for benthic communities at C2?CC4, C7 and C8.  相似文献   

8.

Purpose

Due to the fast development of industry and the overuse of agrichemicals in past decades, Lake Taihu, an important source of aquatic products for Eastern China, has simultaneously suffered mercury (Hg) contamination and eutrophication. The objectives of this study are to understand Hg transfer in the food web in this eutrophic, shallow lake and to evaluate the exposure risk of Hg through fish consumption.

Methods

Biota samples including macrophytes, sestons, benthic animals, and fish were collected from Lake Taihu in the fall of 2009. The total mercury (THg), methyl mercury (MeHg), ??13C and ??15N in the samples were measured.

Results and discussion

The signature for ??15N increased with the trophic levels. Along with a diet composed of fish, the significant relationship between the ??13C and ??15N indicated that a pelagic foraging habitat is the dominant pathway for energy transfer in Lake Taihu. The concentrations of THg and MeHg in the organisms varied dramatically by ??3 orders of magnitude from primary producers (macrophytes and sestons) to piscivorous fish. The highest concentrations of both THg (100 ng g?1) and MeHg (66 ng g?1), however, were lower than the guideline of 200 ng g?1 of MeHg for vulnerable populations that is recommended by the World Health Organization (WHO). The daily intake of THg and MeHg of 92 and 56 ng day?1 kg?1 body weight, respectively, was generally lower than the tolerable intake of 230 ng day?1 kg?1 body weight for children recommended by the Joint FAO/WHO Expert Committee on Food Additives. Significant relationships between the ??15N and the logarithm of THg and MeHg showed an obvious biomagnification of Hg along the food web. The logarithmic bioaccumulation factor of MeHg in the fish (up to 5.7) from Lake Taihu, however, was relatively low compared to that of other aquatic ecosystems.

Conclusion

Health risk of exposure to Hg by consumption of fish for local residents is relatively low in the Lake Taihu area. Dilution of Hg levels in the phytoplankton induced by eutrophication is a possible factor inhibiting accumulation of MeHg in fish in eutrophic Lake Taihu.  相似文献   

9.

Purpose

This research is on the evaluation of biosorption capability of the core of Artocarpus odoratissimus (Tarap), grown in Brunei Darussalam, towards Cd(II) and Cu(II) ions present in synthetic solutions, and to characterize the surface of Tarap particles.

Methods

Thermogravimetric analysis and surface titrations were conducted to characterize the surface of dried Tarap core particles. Atomic absorption spectroscopic measurements were conducted to determine the extent of removal of Cd(II) and Cu(II) under different experimental conditions.

Results

Mass reductions associated with many exothermic reaction peaks were observed beyond 200°C up to 650°C indicating the combustion of organic matter in Tarap. Dried particles of core of Tarap bear a negative surface charge promoting strong interaction towards positively charged ions, such as Cu(II) and Cd(II). Biosorption of the two metal ions on Tarap, which is relatively high beyond pH?=?4, occurs within a short period of exposure time. The extent of biosorption is enhanced by acid treatment of the biosorbent, and further it does not significantly depend on the presence of nonreacting ions up to an ionic strength of 2.0?M.

Conclusion

Strong attraction between each metal ion and the biosorbent is attributed to the negative surface charge on the biosorbent within a broad pH range. Acid treatment of the biosorbent improves sorption characteristics, suggesting that ion exchange plays an important role in the metal ion??biosorbent interaction process.  相似文献   

10.
Twenty-three south-Swedish public supply wells were studied to assess pesticide pollution of regional groundwater resources. Relations between pesticide occurrence, hydrogeology, and land use were analyzed using Kohonen’s Self-Organizing Maps approach. Pesticides are demonstrated to be substantially present in regional groundwater, with detections in 18 wells. Concentrations above the drinking water threshold are confirmed for nine wells. Observations indicate considerable urban influence, and lagged effects of past, less restricted use. Modern, oxic waters from shallow, unconfined, unconsolidated or fracture-type bedrock aquifers appear particularly vulnerable. Least affected waters appear primarily associated with deeper wells, anoxic conditions, and more confined sediment aquifers lacking urban influence. Comprehensive, standardized monitoring of pesticides in groundwater need to be implemented nationwide to enable sound assessments of pollution status and trends, and to develop sound groundwater management plans in accordance with the Water Framework Directive. Further, existing water protection areas and associated regulations need to be reassessed.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0548-1) contains supplementary material, which is available to authorized users.  相似文献   

11.

Purpose

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have emerged as contaminants of environmental concerns because they pose potential risks to human and animal health. The purpose of this study was to investigate the in vitro metabolism of OH-PBDEs and their potential inhibition against 17??-estradiol (E2) metabolism.

Methods

Rat liver microsomes were used as a source of P450 enzymes in an in vitro metabolism study of OH-PBDEs. Inhibition of E2 metabolism and kinetic study were performed by incubating with rat liver microsomes in the presence of OH-PBDEs.

Results

The obtained data clearly demonstrated that OH-PBDEs, especially those congeners with lower bromination, could be metabolized to bromophenol and diOH-PBDEs. The less metabolic rate of OH-PBDEs was observed with the increasing number of bromine substituents. OH-PBDEs with hydroxyl group and bromine adjacent to the ether bridge showed faster metabolic rates. In addition, the results showed non-competitive inhibition of E2 metabolism by OH-PBDEs with IC50 values in the range from 13.7 to 55.2???M. The most potent OH-PBDE inhibitor was found to be 3??-OH-BDE-100. The inhibitory potencies for OH-PBDEs were significantly higher than those of parent PBDE and methoxylated metabolites, providing the evidence that PBDEs exerted estrogenic activity in part by their hydroxylated metabolites.

Conclusions

OH-PBDEs exhibited large differences in their capacity to be metabolized and to inhibit E2 metabolism in rat liver microsomes. The finding might increase our understanding of healthy risk associated with PBDEs in human and wildlife.  相似文献   

12.

Background and purposes

The pathways used by microorganisms for the metabolism of every xenobiotic substrate are specific. The catabolism of a xenobiotic goes through a series of intermediate steps and lower intermediates (metabolites) appear in sequence. The structure of the metabolites can be similar to the parents due to kinship. The purposes of this study were to examine if the degradation pathways that were developed for a parent xenobiotic are effective to degrade the parent??s lower metabolites, and if the reverse is true.

Materials and methods

The xenobiotic substrates, 2,4-dichlorophenoxyacetic acid (2,4-D, the parent xenobiotic) and its metabolite 2,4-dichlorophenol (2,4-DCP), were independently subjected to acclimation and degradation tests by the biomasses of mixed-culture activated sludge and a pure culture of Arthrobacter sp.

Results

Activated sludge and Arthrobacter sp. that were acclimated to 2,4-D effectively degraded 2,4-D and the lower metabolites of 2,4-D, typically 2,4-DCP. During the degradation of 2,4-D, accumulations of the lower metabolites of 2,4-D were not found. The degradation pathways acquired from acclimation to 2,4-D are effective for all the metabolites of 2,4-D. However, pathways acquired from acclimation to 2,4-DCP are not effective in the degradation of the parent 2,4-D.

Conclusions

Microorganisms acclimated to 2,4-D evolve their degradation pathways by a scheme that is different from the scheme the microorganisms employ when they are acclimated to the metabolites of 2,4-D.  相似文献   

13.

Background

In this paper, batch removal of hexavalent chromium from aqueous solutions by Araucaria heterophylla leaves was investigated. The batch experiments were conducted to study the adsorption of metal species and effect of different pH, contact time, metal concentration, biosorbent concentration, and adsorption capacity.

Method

Freundlich and Langmuir??s isotherm model were used to describe the adsorption behavior, and the experimental results fitted Freundlich model well.

Results

The adsorption efficiency observed for all chromium concentrations, i.e., 1, 3, 5, and 10?mg/L was 100% and the equilibrium was achieved in 30?min for 1 and 3?mg/L, whereas for 5 and 10?mg/L, it was less than 60?min. FTIR spectra was taken to identify functional groups involved in the biosorption.

Conclusion

Thus, Araucaria leaves can be considered as one of the cheap and efficient biosorbent for toxic hexavalent chromium removal from natural or wastewaters.  相似文献   

14.
The unsustainable life cycle management of pesticides in the last 60 years has created large pesticide stockpiles. The two major working areas of the International HCH and Pesticide Association (IHPA; www.ihpa.info) address a part of these legacies and are shortly introduced here: (1) The assessment and support of the management of the worlds single largest POPs stockpile: the globally dumped 4 to 7 million tonnes hexachlorocyclohexane (HCH) wastes from lindane production, and (2) the support for the management of the obsolete pesticides legacy in Eastern Europe, the Caucasus and Central Asia (EECCA) countries of ~240,000 t, leaving these pesticides in unregulated storages without adequate safety control being a huge risk to the environment and human health. The integrative approach IHPA takes—promoting international cooperation and the exchange of knowledge and experiences—is shortly explained. IHPA has developed various supporting tools for its work: the IHPA web page and newsletter informing on the threats and challenges, but also on the progresses of managing pesticide stockpiles; the joint GIZ-PAN-IHPA exhibition on awareness of the pesticide stockpile challenge; and the ‘International HCH and Pesticides Forum’ as most important tool to progress the integrative work and mission of IHPA. Finally, a summary of the 11th International HCH and Pesticides Forum held in Gabala, Azerbaijan is given which brought together more than 120 scientists, policy-makers, non-governmental and international organisations, industry and students from more than 40 countries to progress the obsolete pesticides and hazardous chemical waste challenge in EECCA countries. The event finished with adoption of ‘Gabala Declaration’, which aims to mobilise efforts of all stakeholders for prevention and elimination of POPs, obsolete pesticides, and hazardous chemical waste in the region.  相似文献   

15.

Background

Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited.

Methods

The exposed site with a history of over 20 years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50 km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender?Cage matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2??-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed.

Results

Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43 ??g/l; well water: 14.20 vs. 0.79 ??g/l, pond water: 135.68 vs. 0.37 ??g/l, cultivated soil: 13.07 vs. 0.81 mg/kg, p?p?p?Conclusions The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers.  相似文献   

16.

Introduction and purpose

The objective of this study is to determine children??s blood lead levels and identify sources of lead exposure. Childhood lead exposure constitutes a major pediatric health problem today in China. A blood lead screening survey program for children in the age group of 2?C12?years residing in Pearl River Delta region, south of China, was carried out from Dec 2007 to Jan 2008.

Methods

Blood lead levels and lead isotope ratios of a total of 761 participants were assessed by inductively coupled plasma mass spectroscopy. Measurements of urban environmental samples for source identification of children lead exposure were also performed.

Results and conclusions

The geometric mean value of the children??s blood lead levels was 57.05???g/L, and 9.6% of them were higher than 100???g/L. The blood lead levels were still much higher than those in developed countries. Based on the data of environmental lead source inventories, lead isotopic tracing revealed that there is about 6.7% past used gasoline Pb embedded in Shenzhen residential dust and about 15.6% in Guangzhou dust, respectively.  相似文献   

17.

Background

Contamination with heavy metals is among the most hazardous environmental concerns caused by mining activity. A valuable tool for monitoring these effects is the use of sentinel organisms. Particularly, small mammals living inside mine tailings are an excellent study system because their analysis represents a realistic approach of mixtures and concentrations of metal exposure.

Purpose

We analyzed metal tissue concentrations and DNA damage levels for comparison between genders of a sentinel (Peromyscus melanophrys) and a nonsentinel (Baiomys musculus) species. Also, the relationship between DNA damage and the distance from the contamination source was evaluated.

Methods

This study was conducted in an abandoned mine tailing at Morelos, Mexico. Thirty-six individuals from both species at the exposed and reference sites were sampled. Metal concentrations in bone and liver of both species were analyzed by atomic absorption spectrophotometry, and DNA damage levels were assayed using the alkaline comet assay.

Results

In general, concentrations of zinc, nickel, iron, and manganese were statistically higher in exposed individuals. A significant effect of the organ and the site on all metal tissue concentrations was detected. Significant DNA damage levels were registered in the exposed group, being higher in B. musculus. Females registered higher DNA damage levels than males. A negative relationship between distance from the mine tailing and DNA damage in B. musculus was observed.

Conclusions

We consider that B. musculus is a suitable species to assess environmental quality, especially for bioaccumulable pollutants??such as metals??and recommend that it may be considered as a sentinel species.  相似文献   

18.

Purpose

Hexachlorocyclohexane (HCH) isomers (??-, ??- and ??- (Lindane)) were recently included as new persistent organic pollutants (POPs) in the Stockholm Convention, and therefore, the legacy of HCH and Lindane production became a contemporary topic of global relevance. This article wants to briefly summarise the outcomes of the Stockholm Convention process and make an estimation of the amount of HCH waste generated and dumped in the former Lindane/HCH-producing countries.

Results

In a preliminary assessment, the countries and the respective amount of HCH residues stored and deposited from Lindane production are estimated. Between 4 and 7 million tonnes of wastes of toxic, persistent and bioaccumulative residues (largely consisting of alpha- (approx. 80%) and beta-HCH) are estimated to have been produced and discarded around the globe during 60 years of Lindane production. For approximately 1.9 million tonnes, information is available regarding deposition. Countries are: Austria, Brazil, China, Czech Republic, France, Germany, Hungary, India, Italy, Japan, Macedonia, Nigeria, Poland, Romania, Slovakia, South Africa, Spain, Switzerland, Turkey, The Netherlands, UK, USA, and former USSR. The paper highlights the environmental relevance of deposited HCH wastes and the related POPs?? contaminated sites and provides suggestions for further steps to address the challenge of the legacy of HCH/Lindane production.

Conclusion

It can be expected that most locations where HCH waste was discarded/stockpiled are not secured and that critical environmental impacts are resulting from leaching and volatilisation. As parties to the Stockholm Convention are legally required to take action to stop further POPs pollution, identification and evaluation of such sites are necessary.  相似文献   

19.

Purpose

The main objective of this work was to develop and test a pilot scheme for decontaminating pesticide-containing water derived from pesticide mixtures used to protect vineyards, in which the scheme comprises adsorption by an organoclay and includes a system where an enhanced or rapid microbial degradation of the adsorbed residues can occur.

Methods

In laboratory experiments, the Freundlich adsorption coefficients of formulations of two fungicides, penconazole and cyazofamid, onto the organoclay Cloisite 20 A were measured in order to predict the efficiency of this organoclay in removing these fungicides from the waste spray-tank water. Subsequently, the adsorption tests were repeated in the pilot system in order to test the practical operation of the depuration scheme.

Results

The adsorption tests with the pilot system show 96% removal of both fungicides over a few hours, similar to the efficiency of removal predicted from the laboratory adsorption tests. The formulation type may influence the efficiency of clay recovered after adsorption. Regarding the waste disposal, for instance, the organoclay composted after the treatment, cyazofamid showed significant dissipation after 90?days, whereas the dissipation of penconazole was negligible.

Conclusion

The depuration scheme developed showed to be efficient for decontaminating pesticide-containing water derived from vineyards, but additional treatments for the adsorbed residues still appear to be necessary for persistent pesticides. However, future decontamination research should be attempted for water contaminated with pesticides containing antifoaming agents in their formulations, in which case the present pilot system could not be applied.  相似文献   

20.

Purpose

Removal of malathion from agricultural runoff was studied using novel copper-coated chitosan nanocomposite (CuCH)??a biopolymeric waste obtained from marine industry.

Methods

Synthesis and characterization of the adsorbent using different spectral techniques like Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface analyzer have been carried out. Equilibrium studies have been carried out to optimize the dose rate, pH, and the reaction time. Parathion and methyl parathion removal were also evaluated by CuCH in the batch mode. Using gas chromatography?Cmass spectrometry (GC?CMS) and FTIR studies suitable mechanism for adsorption has been suggested.

Results

The particle size of the adsorbent ranged from 700 to 750?nm. The surface area was found to be 20?m2?g-1 with a pore volume of 0.11?cc?g-1. The maximum adsorption capacity of malathion by CuCH was found to be 322.6?±?3.5?mg?g-1 at an optimum pH of 2.0. Presence of copper ions enhanced the adsorption capacity of the adsorbent. The reaction was found to follow pseudo second-order kinetics with a rate constant of 0.53?g?mg-1?min-1. Evidence from FTIR indicated that copper ions form a dithionate complex with malathion during the adsorption stage. The adsorbent was found to remove malathion completely from spiked concentration of 2?mg?l-1 in the agricultural run-off samples. It was also found that CuCH removed other organophospurous pesticides like methyl parathion and parathion under prevailing conditions.

Conclusions

The results indicated that CuCH could be applied for the removal of organophosphorous pesticides.  相似文献   

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