Which persistent organic pollutants can we map in soil using a large spacing systematic soil monitoring design? A case study in Northern France

Persistent organic pollutants (POPs) impact upon human and animal health and the wider environment. It is important to determine where POPs are found and the spatial pattern of POP variation. The concentrations of 90 molecules which are members of four families of POPs and two families of herbicides were measured within a region of Northern France as part of the French National Soil Monitoring Network (RMQS: Réseau de Mesures de la Qualité des Sols). We also gather information on five covariates (elevation, soil organic carbon content, road density, land cover and population density) which might influence POP concentrations. The study region contains 105 RMQS observation sites arranged on a regular square grid with spacing of 16 km. The observations include hot-spots at sites of POP application, smaller concentrations where POPs have been dispersed and observations less than the limit of quantification (LOQ) where the soil has not been impacted by POPs. Fifty nine of the molecules were detected at less than 50 sites and hence the data were unsuitable for spatial analyses. We represent the variation of the remaining 31 molecules by various linear mixed models which can include fixed effects (i.e. linear relationships between the molecule concentrations and covariates) and spatially correlated random effects. The best model for each molecule is selected by the Akaike Information Criterion. For nine of the molecules, spatial correlation is evident and hence they can potentially be mapped. For four of these molecules, the spatial correlation cannot be wholly explained by fixed effects. It appears that these molecules have been transported away from their application sites and are now dispersed across the study region with the largest concentrations found in a heavily populated depression. More complicated statistical models and sampling designs are required to explain the distribution of the less dispersed molecules.     

Adsorption and desorption characteristics of lindane, carbofuran and methyl parathion on various Indian soils

Adsorption and desorption characteristics of three insecticides on four Indian soils were studied. Insecticides used were representative of organochlorine, organophosphate, and carbomate groups. The order of adsorption of pesticides on soils was: lindane > methyl parathion > carbofuran. Compost soil had shown the maximum adsorption capacity. The order of adsorption capacity of various soils were: compost soil > clayey soil > red soil > sandy soil. Adsorption isotherms were better fitted to Freundlich model and K_f values increased with increase in organic matter content of the soils. Thermodynamic parameters indicated favorable adsorption of all the three pesticides in four different soils. Adsorption was exothermic in nature. Distilled water desorbed 30–60% of adsorbed pesticides whereas; organic solvents were able to affect 50–80% of sorbed pesticides. Clay content and organic matter played a significant role in pesticide adsorption and desorption processes. Hysteresis effect was observed in red, clayey and compost soils. Hysteresis effect increased with increase in organic matter and clay content of the soils.     

Estimated daily intake of organochlorine pesticides from dairy products in Brazil

The estimated daily intake (EDI) of organochlorine (OC) pesticides (HCB, α-HCH, lindane, aldrin, p,p′-DDE, p,p′-DDD, and o,p′-DDT) through consumption of dairy products from Rio Grande do Sul State (Brazil) was investigated. Fluid milk and cheese had similar ΣOC levels (26.04 and 26.14 ng g⁻¹ fat, respectively), whereas milk powder had lower levels (2.23 ng g⁻¹ fat). OC levels in UHT milk exhibited a declining trend over time (ΣOC = 27.70 ng g⁻¹ fat in 2000 vs. 1.50 ng g⁻¹ fat in 2009/2010). The EDI of OC pesticides was remarkably higher for children (8.266 ng kg⁻¹ day⁻¹) than for adolescents, adults, and the elderly (ranging from 0.393 ng kg⁻¹ day⁻¹ to 0.614 ng kg⁻¹ day⁻¹). The average EDIs for OC pesticides were below the acceptable daily intakes (ADI), with the exception of aldrin, which greatly exceeded the ADI for children. In addition, some samples (8.8%) exceeded the maximum residue limit for the compounds evaluated.     

Immobilization of laccase from Myceliophthora thermophila on functionalized silica nanoparticles: Optimization and application in lindane degradation

This work is focused on immobilization of laccase from Myceliophthora thermophila expressed in Aspergillus oryzae(Novozym 51003? laccase) on amino modified fumed nano-silica(AFNS) and the possible use in bioremediation. Hereby, for the first time, factors affecting the immobilization of Novozym 51003? laccase on AFNS were investigated for defining the immobilization mechanism and optimizing the utilization of AFNS as support for laccase immobilization. The highest specific activity(13.1 IU·mg~(-1) proteins) was achieved at offered 160 mg per g of AFNS and for the same offered protein concentration the highest activity immobilization yield, reaching68.3% after the equilibrium time, at optimum pH 5.0, was obtained. Laccase immobilization occurs by adsorption as monolayer enzyme binding in 40 min, following pseudo-first-order kinetics. The possible use of obtained immobilized preparation was investigated in degradation of pesticide lindane. Within 24 h, lindane concentration was reduced to 56.8% of initial concentration and after seven repeated reuses it retained 70% of the original activity.     

Hydrodechlorination and hydrogenation of aromatic compounds over palladium on alumina in hydrogen-saturated water

The catalytic transformations of 1,2-dichlorobenzene, chlorobenzene, 4-chlorobiphenyl, γ-hexachlorocyclohexane (Lindane), naphthalene and phenanthrene were studied over palladium on alumina in hydrogen-saturated water (Pd/Al₂O₃/H₂) at room temperature and ambient pressure. The chlorinated benzenes were rapidly hydrodechlorinated and Lindane was dehydrochlorinated to benzene. Partial or complete hydrogenation was observed for biphenyl and the polycyclic aromatic hydrocarbons. The phenanthrene ring was cleaved at the 9,10-position. In general dechlorination reactions were faster than hydrogenation reactions.     

Theoretical study of γ-hexachlorocyclohexane and β-hexachlorocyclohexane isomers interaction with surface groups of activated carbon model

Activated carbon (AC) is employed in drinking water purification without almost any knowledge about the adsorption mechanism of persistent organic pollutants (POPs) onto it. Hexachlorocyclohexane (HCH) is an organochlorinated contaminant present in water and soils of banana crops production zones of the Caribbean. The most relevant isomers of HCH are γ-HCH and β-HCH, both with great environmental persistence. A theoretical study of the influence of AC surface groups (SGs) on HCH adsorption is done in order to help to understand the process and may lead to improve the AC selection process. A simplified AC model consisting of naphthalene with a functional group was used to assess the influence of SGs over the adsorption process. The Multiple Minima Hypersurface (MMH) methodology was employed to study γ-HCH and β-HCH interactions with different AC SGs (hydroxyl and carboxyl) under different hydration and pH conditions. The results obtained showed that association of HCH with SGs preferentially occurs between the axial protons of HCH and SG's oxygen atom, and the most favorable interactions occurring with charged SGs. An increase in carboxylic SGs content is proposed to enhance HCH adsorption onto AC under neutral pH conditions. Finally, this work presents an inexpensive computer aided methodology for preselecting activated carbon SGs content for the removal of a given compound.     

Increasing serum levels of non-DDT-derivative organochlorine pesticides in the younger population of the Canary Islands (Spain)

Organochlorine pesticides are a lipophilic class of chemicals that persist in the environment and tend to accumulate in human tissues for years. They came into widespread use in the late 1940s. Because of their capacity to bioaccumulate and biomagnify in food chains and their toxic effects, most of them were banned in industrialized countries, among them Spain, in the late 1970s and 1980s. In 1998 organochlorine pesticides were determined in a representative sample of a Spanish population (around 690 serum samples from people 6 to 75years old from the Canary Islands). Serum levels of lindane aldrin, dieldrin and endrin, were determined. Our results showed that a high percentage of samples presented detectable levels of some of the organochlorines measured, endrin being the most frequently detected (72%) and at highest concentration (mean 136.7ng/g fat). Mean concentrations of the main cyclodiene evaluated, dieldrin, was lower to those found in other Western populations. However, serum levels of lindane were higher than those described in North European populations. Influence of geographical and sociodemographic factors was evaluated. Urban populations showed the highest levels of dieldrin, while non-urban population showed the highest serum values of lindane, aldrin and endrin. Unexpectedly, serum values of lindane, aldrin and dieldrin were higher in younger than in older people. Subjects under 18years showed almost twice as high serum levels of lindane, aldrin and dieldrin than subjects of 65-75years. These results may well suggest that people living in the Canary Islands have been and are currently exposed to non-DDT-organochlorine pesticides. The type and source of exposure could vary between islands and type of habitat. Contaminated food and/or the environment could be related with this situation.     

2000年湖北省膳食样品有机氯农药六六六和DDT残留溯源分析

为了解湖北省食品中有机氯农药六六六和DDT残留情况，对2000年湖北省总膳食中的单个食品进行了分析及溯源，发现鳊鱼HCH(六六六)残留量为555．88μg／kg，其中γ-HCH占HCH异构体构成比例的98．29％；鸭蛋中DDT残留量为541．78μg／kg，以pp′-DDE为主要存在形式。鳊鱼中HCH和鸭蛋中DDT的残留量均超过新提出的食物中HCH和DDT允许限量修订标准。此溯源结果提示违规使用林丹的现象依然存在。     

Behaviour of pesticides lindane and methyl parathion during manufacture, ripening and storage of feta cheese

The behaviour of the pesticides lindane and methyl parathion during the manufacture, ripening and storage of feta cheese was investigated. Pasteurization of milk at 63–65°C for 30 min did not affect the concentrations of either pesticide. Lindane and methyl parathion at concentrations of 0.10 mg/kg and 16.66 mg/kg of milk, respectively, did not affect the activity of the starter culture. The concentration of lindane in the cheese and in whey/brine did not change significantly during ripening (up to 240 days). The concentration of methyl parathion in the cheese increased progressively up to 120 days of ageing, but decreased significantly (P < 0.05) from 120 up to 240 days. Methyl parathion might be bound to casein, in particular to the seryl and phosphoseryl groups of casein. Changes of brine to decontaminate the feta cheese from methyl parathion and lindane residues did not affect their concentrations in the cheese.     

Removal Of Pesticides By Use Of Ozone Or Hydrogen Peroxide/Ozone

This article deals with the efficiency of an ozonation step in drinking water treatment plants remove pesticides. These tests are carried out with a laboratory technique, the “OZOTEST” method, which simulates operating conditions on site and allows a complete oxidation assessment.

Efficiency of the two oxidant systems – ozone and ozone coupled with hydrogen peroxide – is evaluated for 11 pesticides commonly analyzed in control laboratories. Comparison of the two systems is made in terms of pesticide removal, but also in terms of ozone consumption. Matrix effects and contact time are also taken into account, and an order of reactivity for each system considered is suggested.