Characterization of chlordecone-tolerant fungal populations isolated from long-term polluted tropical volcanic soil in the French West Indies

The insecticide chlordecone is a contaminant found in most of the banana plantations in the French West Indies. This study aims to search for fungal populations able to grow on it. An Andosol heavily contaminated with chlordecone, perfused for 1 year in a soil–charcoal system, was used to conduct enrichment cultures. A total of 103 fungal strains able to grow on chlordecone-mineral salt medium were isolated, purified, and deposited in the MIAE collection (Microorganismes d'Intérêt Agro-Environnemental, UMR Agroécologie, Institut National de la Recherche Agronomique, Dijon, France). Internal transcribed spacer sequencing revealed that all isolated strains belonged to the Ascomycota phylum and gathered in 11 genera: Metacordyceps, Cordyceps, Pochonia, Acremonium, Fusarium, Paecilomyces, Ophiocordyceps, Purpureocillium, Bionectria, Penicillium, and Aspergillus. Among predominant species, only one isolate, Fusarium oxysporum MIAE01197, was able to grow in a liquid culture medium that contained chlordecone as sole carbon source. Chlordecone increased F. oxysporum MIAE01197 growth rate, attesting for its tolerance to this organochlorine. Moreover, F. oxysporum MIAE01197 exhibited a higher EC₅₀ value than the reference strain F. oxysporum MIAE00047. This further suggests its adaptation to chlordecone tolerance up to 29.2 mg l^?1. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that 40 % of chlordecone was dissipated in F. oxysporum MIAE01197 suspension culture. No chlordecone metabolite was detected by GC-MS. However, weak amount of ¹⁴CO₂ evolved from ¹⁴C₁₀-chlordecone and ¹⁴C₁₀-metabolites were observed. Sorption of ¹⁴C₁₀-chlordecone onto fungal biomass followed a linear relationship (r ²?=?0.99) suggesting that it may also account for chlordecone dissipation in F. oxysporum MIAE01197 culture.     

Evaluation of the ecotoxicological impact of the organochlorine chlordecone on soil microbial community structure,abundance, and function

The insecticide chlordecone applied for decades in banana plantations currently contaminates 20,000 ha of arable land in the French West Indies. Although the impact of various pesticides on soil microorganisms has been studied, chlordecone toxicity to the soil microbial community has never been assessed. We investigated in two different soils (sandy loam and silty loam) exposed to different concentrations of CLD (D0, control; D1 and D10, 1 and 10 times the agronomical dose) over different periods of time (3, 7, and 32 days): (i) the fate of chlordecone by measuring ¹⁴C-chlordecone mass balance and (ii) the impact of chlordecone on microbial community structure, abundance, and function, using standardized methods (-A-RISA, taxon-specific quantitative PCR (qPCR), and ¹⁴C-compounds mineralizing activity). Mineralization of ¹⁴C-chlordecone was inferior below 1 % of initial ¹⁴C-activity. Less than 2 % of ¹⁴C-activity was retrieved from the water-soluble fraction, while most of it remained in the organic-solvent-extractable fraction (75 % of initial ¹⁴C-activity). Only 23 % of the remaining ¹⁴C-activity was measured in nonextractable fraction. The fate of chlordecone significantly differed between the two soils. The soluble and nonextractable fractions were significantly higher in sandy loam soil than in silty loam soil. All the measured microbiological parameters allowed discriminating statistically the two soils and showed a variation over time. The genetic structure of the bacterial community remained insensitive to chlordecone exposure in silty loam soil. In response to chlordecone exposure, the abundance of Gram-negative bacterial groups (β-, γ-Proteobacteria, Planctomycetes, and Bacteroidetes) was significantly modified only in sandy loam soil. The mineralization of ¹⁴C-sodium acetate and ¹⁴C-2,4-d was insensitive to chlordecone exposure in silty loam soil. However, mineralization of ¹⁴C-sodium acetate was significantly reduced in soil microcosms of sandy loam soil exposed to chlordecone as compared to the control (D0). These data show that chlordecone exposure induced changes in microbial community taxonomic composition and function in one of the two soils, suggesting microbial toxicity of this organochlorine.     

Degradation of chlordecone and beta-hexachlorocyclohexane by photolysis, (photo-)fenton oxidation and ozonation

Intensive use of chlorinated pesticides from the 1960s to the 1990s has resulted in a diffuse contamination of soils and surface waters in the banana-producing areas of the French West Indies. The purpose of this research was, for the first time, to examine the degradation of two of these persistent pollutants – chlordecone (CLD) and beta-hexachlorocyclohexane (β-HCH) in 1 mg L^?1 synthetic aqueous solutions by means of photolysis, (photo-) Fenton oxidation and ozonation processes. Fenton oxidation is not efficient for CLD and yields less than 15% reduction of β-HCH concentration in 5 h. Conversely, both molecules can be quantitatively converted under UV-Vis irradiation reaching 100% of degradation in 5 h, while combination with hydrogen peroxide and ferrous iron does not show any significant improvement except in high wavelength range (>280 nm). Ozonation exhibits comparable but lower degradation rates than UV processes. Preliminary identification of degradation products indicated that hydrochlordecone was formed during photo-Fenton oxidation of CLD, while for β-HCH the major product peak exhibited C₃H₃Cl₂ as most abundant fragment.     

Determination of soil content in chlordecone (organochlorine pesticide) using near infrared reflectance spectroscopy (NIRS)

Chlordecone is a toxic organochlorine insecticide that was used in banana plantations until 1993 in the French West Indies. This study aimed at assessing the potential of near infrared reflectance spectroscopy (NIRS) for determining chlordecone content in Andosols, Nitisols and Ferralsols from Martinique. Using partial least square regression, chlordecone content conventionally determined through gas chromatography–mass spectrometry could be correctly predicted by NIRS (Q² = 0.75, R² = 0.82 for the total set), especially for samples with chlordecone content <12 mg kg⁻¹ or when the sample set was rather homogeneous (Q² = 0.91, R² = 0.82 for the Andosols). Conventional measures and NIRS predictions were poorly correlated for chlordecone content >12 mg kg⁻¹, nevertheless ca. 80% samples were correctly predicted when the set was divided into three or four classes of chlordecone content. Thus NIRS could be considered a time- and cost-effective method for characterising soil contamination by chlordecone.     

Organochlorine pesticides and polychlorinated biphenyls in soils surrounding the Tanggu Chemical Industrial District of Tianjin, China

The spatial distribution of persistent organic pollutants (POPs) was examined in soils surrounding the Tanggu Chemical Industrial District in Tianjin, China. The concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzenes (HCBs), and polychlorinated biphenyls (PCBs) were determined in 70 surface soils using accelerated solvent extraction and gas chromatography with electron capture detection. The results showed that the ranges of ∑HCH, ∑DDT, ΣHCB, and ∑PCB concentrations in soils were 2.1–12,549 μg?kg^?1 (average, 965 μg?kg^?1), n.d.–2,033 μg?kg^?1 (average, 88.4 μg?kg^?1), n.d.–1,924 μg?kg^?1 (average, 349 μg?kg^?1), and n.d.–373 μg?kg^?1 (average, 46.2 μg?kg^?1), respectively. Of these, HCHs were the dominant POPs, accounting for 75 % of the total organochlorine pesticide (OCP) residues. Overall, the spatial distribution of OCP concentrations showed a decreasing trend from the center of the Tanggu District to the surrounding areas. Two major pollution sources were Tianjin Dagu Chemical Co., Ltd. in the district center and the Tianjin Chemical Plant in Hangu District. In contrast, PCB concentrations were relatively high in the Haihe estuary to the east and low to the west of the study area. Component analysis of OCPs in these soils showed that they mainly came from industrial point sources. Compared with soils in other regions, soil DDT pollution was at a medium level in the Tanggu Chemical Industrial District, but associated HCH, HCB, and PCB pollution was relatively heavy. By multivariate statistical analyses, Tianjin Dagu Chemical Co., Ltd. was recognized as the main source of POPs, and soil properties were clarified to play an important role on the distribution and composition of POPs, especially the organic carbon content.     

Contamination of marine fauna by chlordecone in Guadeloupe: evidence of a seaward decreasing gradient

Chlordecone is an organochlorine pesticide, used in the Lesser Antilles from 1972 to 1993 to fight against a banana weevil. That molecule is very persistent in the natural environment and ends up in the sea with runoff waters. The objective of the present study is to evaluate the level of contamination in several trophic groups of marine animals according to their distance from the source of pollution. Samples of suspended matter, macroalgae, herbivorous fishes, detrivorous crustaceans, zooplanktivorous fishes, first- and second-order of carnivorous fishes, and piscivorous fishes have been collected in two sites, located downstream the contaminated sites (Goyave and Petit-Bourg), in three marine habitats (coastal mangroves, seagrass beds located 1.5 km from the shoreline, and coral reefs at 3 km offshore). Animals collected in mangroves were the most contaminated (mean concentrations 193 μg kg^?1 in Goyave and 213 μg kg^?1 in Petit-Bourg). Samples from seagrass beds presented intermediate concentrations of chlordecone (85 μg kg^?1 in Goyave and 107 μg kg^?1 in Petit-Bourg). Finally, samples from coral reefs were the less contaminated (71 μg kg^?1 in Goyave and 74 μg kg^?1 in Petit-Bourg). Reef samples, collected 3 km offshore, were two to three times less contaminated than those collected in mangroves.     

Residues levels of organochlorine pesticide in cow's milk from industrial farms in Hidalgo,Mexico

A survey was carried out from 2008 to 2010 to determine the concentrations of 16 organochlorine pesticide residues (OPRs) from Tizayuca, Hidalgo, Mexico. Organochlorine residue determinations were made from milk fat, using chromatographic cleanup and analysis by gas chromatography with an electron capture detector. The OPR concentrations found were from below the detection limit (DL) to 0.91 ng g^?1 in 2008, DL to 0.38 ng g^?1 in 2009 and DL to 0.59 ng g^?1 in 2010. In general concentrations of organochlorine pesticides were higher in the wet season (3.37 ng g^?1 and 4.79 ng g^?1) than the dry season (1.92 ng g^?1 and 2.71 ng g^?1) for 2009 and 2010, due to control of pests in the pasture and sheds. According to Codex Alimentarius regulations, individual pesticides did not exceed the permissible limits, which for example were 10 μg kg^?1 for alpha hexachlorocyclohexane (HCH) and endosulfan I, 20 μg kg^?1 for p,p’-DDT, and 6 μg kg^?1 for dieldrin, endrin and heptachlor. A reduction of organochlorine pesticide concentrations in cow's milk was noted, indicating that the Mexican government has achieved reduction or elimination of some organochlorine pesticides in response to global agreements on persistent organic pollutants.     

High-performance liquid chromatography (HPLC) as a tool for monitoring the fate of fluazinam in soil

Fluazinam is a widely used pesticide employed against the fungal disease late blight in potato cultivation. A specific, repeatable, and rapid high-performance liquid chromatography (HPLC) method utilizing a diode array detector (DAD) was developed to determine the presence of fluazinam in soil. The method consists of acetonitrile (ACN) extraction, clean-up with solid-phase extraction (SPE), and separation using a mobile phase consisting of 70% ACN and 30% water (v/v), including 0.02% acetic acid. HPLC was performed with a C18 column and the detection wavelength was 240 nm. The method was successfully applied to an incubation experiment and to soil samples taken from potato fields where fluazinam had been applied two to three times during the on-going growing season. In the 90-day incubation experiment, analytical standard fluazinam and the commercial fungicide Shirlan^® were added to soil samples that had never been treated with fluazinam, and were then extracted with ACN and 0.01 M calcium chloride (CaCl₂). Fluazinam was not extractable with CaCl₂, indicating that it does not leach to watercourses in the dissolved form. Recovery with ACN extraction for sandy soils was 72–95% immediately after application and 53–73% after 90 days of incubation. Out of the eight potato field soil samples, fluazinam was found in two samples at concentrations of 2.1 mg kg^?1 and 1.9 mg kg^?1, well above the limit of quantification (0.1 mg kg^?1).     

Easy and fast extraction methods to determine organochlorine pesticides in sewage sludge,soil, and water samples based at low temperature

Organochlorine pesticides present in sewage sludge can contaminate soil and water when they are used as either fertilizer or agricultural soil conditioner. In this study, the technique solid–liquid extraction with low temperature purification was optimized and validated for determination of ten organochlorine pesticides in sewage sludge and soil samples. Liquid–liquid extraction with low temperature purification was also validated for the same compounds in water. Analyses were performed by gas chromatography-mass spectrometry operating in the selective ion monitoring mode. After optimization, the methods showed recoveries between 70% and 115% with relative standard deviation lower than 13% for all target analytes in the three matrices. The linearity was demonstrated in the range of 20 to 70 µg L^?1, 0.5 to 60 µg L^?1, and 3 to 13 µg L^?1, for sludge, soil, and acetonitrile, respectively. The limit of quantification ranged between 2 and 40 µg kg^?1, 1 and 6 µg kg^?1, and 0.5 µg L^?1 for sludge, soil, and water, respectively. The methods were used in the study of pesticide lixiviation carried out in a poly vinyl chlorine column filled with soil, which had its surface layer mixed with sludge. The results showed that pesticides are not leached into soil, part of them is adsorbed by the sewage sludge (4–40%), and most pesticides are lost by volatilization.     

Long-term pollution by chlordecone of tropical volcanic soils in the French West Indies: A simple leaching model accounts for current residue

Chlordecone was applied between 1972 and 1993 in banana fields of the French West Indies. This resulted in long-term pollution of soils and contamination of waters, aquatic biota, and crops. To assess pollution level and duration according to soil type, WISORCH, a leaching model based on first-order desorption kinetics, was developed and run. Its input parameters are soil organic carbon content (SOC) and SOC/water partitioning coefficient (K_oc). It accounts for current chlordecone soil contents and drainage water concentrations. The model was valid for andosol, which indicates that neither physico-chemical nor microbial degradation occurred. Dilution by previous deep tillages makes soil scrapping unrealistic. Lixiviation appeared the main way to reduce pollution. Besides the SOC and rainfall increases, K_oc increased from nitisol to ferralsol and then andosol while lixiviation efficiency decreased. Consequently, pollution is bound to last for several decades for nitisol, centuries for ferralsol, and half a millennium for andosol.     

Characterization of Cd-, Pb-, Zn-resistant endophytic Lasiodiplodia sp. MXSF31 from metal accumulating Portulaca oleracea and its potential in promoting the growth of rape in metal-contaminated soils

The aim of this study was to characterize the features of a Cd-, Pb-, and Zn-resistant endophytic fungus Lasiodiplodia sp. MXSF31 and to investigate the potential of MXSF31 to remove metals from contaminated water and soils. The endophytic fungus was isolated from the stem of Portulaca oleracea growing in metal-contaminated soils. The maximum biosorption capacities of MXSF31 were 3.0?×?10³, 1.1?×?10⁴, and 1.3?×?10⁴ mg kg^?1 for Cd, Pb, and Zn, respectively. The biosorption processes of Cd, Pb, and Zn by MXSF31 were well characterized with the pseudo-second-order kinetic model. The biosorption isotherm processes of Pb and Zn by the fungus were fitted better with the Langmuir model, while the biosorption processes of Cd was better fitted with the Freundlich model. The biosorption process of MXSF31 was attributed to the functional groups of hydroxyl, amino, carbonyl, and benzene ring on the cell wall. The active biomass of the strain removed more Cd, Pb, and Zn (4.6?×?10⁴, 5.6?×?10⁵, and 7.0?×?10⁴ mg kg^?1, respectively) than the dead biomass. The inoculation of MXSF31 increased the biomass of rape (Brassica napus L.), the translocation factor of Cd, and the extraction amount of Cd by rape in the Cd?+?Pb-contaminated soils. The results indicated that the endophytic fungus strain had the potential to remove heavy metals from water and soils contaminated by multiple heavy metals, and plants accumulating multiple metals might harbor diverse fungi suitable for bioremediation of contaminated media.     

Comparative sorption,desorption and leaching potential of aminocyclopyrachlor and picloram

Sorption and desorption of aminocyclopyrachlor (6-amino-5-chloro-2-cyclopropylpyrimidine-4-carboxylic acid) were compared to that of the structurally similar herbicide picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) in three soils of differing origin and composition to determine if picloram data is representative of aminocyclopyrachlor behavior in soil. Aminocyclopyrachlor and picloram batch sorption data fit the Freundlich equation and was independent of concentration for aminocyclopyrachlor (1/n = 1), but not for picloram (1/n = 0.80–0.90). Freundlich sorption coefficients (K _f) for aminocyclopyrachlor were lowest in the eroded and depositional Minnesota soils (0.04 and 0.12 μmol ^(1–1/n) L^1/n kg^?1) and the highest in Molokai soil (0.31 μmol ^(1–1/n) L^1/n kg^?1). For picloram, K _f was lower in the eroded (0.28 μmol ^(1–1/n) L^1/n kg^?1) as compared to the depositional Minnesota soil (0.75 μmol ^(1–1/n) L^1/n kg^?1). Comparing soil to soil, K _f for picloram was consistently higher than those found for aminocyclopyrachlor. Desorption of aminocyclopyrachlor and picloram was hysteretic on all three soils. With regard to the theoretical leaching potential based on groundwater ubiquity score (GUS), leaching potential of both herbicides was considered to be similar. Aminocyclopyrachlor would be ranked as leacher in all three soils if t_1/2 was > 12.7 days. To be ranked as non-leacher in all three soils, aminocyclopyrachlor t_1/2 would have to be <3.3 days. Calculated half-life that would rank picloram as leacher was calculated to be ～15.6 d. Using the current information for aminocycloprachlor, or using picloram data as representative of aminocycloprachlor behavior, scientists can now more accurately predict the potential for offsite transport of aminocycloprachlor.     

Development and validation of LC-MS/MS method for the determination of Ochratoxin A and its metabolite Ochratoxin α in poultry tissues and eggs

The objective of this study was to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of Ochratoxin A (OTA) and Ochratoxin α (OTα) in poultry tissues and eggs. The two toxins were extracted by a mixture of acetonitrile/water, purified with a reversed phase C18 solid phase extraction column (SPE) and determined by LC-MS/MS. The LC-MS/MS method performances were evaluated in terms of linearity in solvent and in matrix (ranged from 0.5 to 15.10 µg L^?1 for OTA and from 0.60 to 17.85 µg L^?1 for OTα), limit of detection (LOD), limit of quantitation (LOQ), specificity, accuracy and precision in repeatability conditions. Recovery experiments were performed by spiking poultry liver, kidney, muscle and eggs around 1 µg kg^?1 and 10 µg kg^?1. LODs were 0.27 and 0.26 µg kg^?1 while LOQs were fixed at 1.0 and 1.2 µg kg^?1 for OTA and OTα, respectively. Main recoveries for OTA ranged from 82 to 109% and for OTα ranged from 55 to 89%. The values of within-laboratory relative standard deviation (RSD_r) were equal to or below 20%. Considering the results obtained and that all analytical performance criteria were fulfilled, the new extraction and purification method developed for OTA and OTα determination in animal tissues and eggs was found appropriate for control laboratories and research activities designed to ensure food safety.     

Influence of soil and hydrocarbon properties on the solvent extraction of high-concentration weathered petroleum from contaminated soils

Petroleum ether was used to extract petroleum hydrocarbons from soils collected from six oil fields with different history of exploratory and contamination. It was capable of fast removing 76–94 % of the total petroleum hydrocarbons including 25 alkanes (C₁₁–C₃₅) and 16 US EPA priority polycyclic aromatic hydrocarbons from soils at room temperature. The partial least squares analysis indicated that the solvent extraction efficiencies were positively correlated with soil organic matter, cation exchange capacity, moisture, pH, and sand content of soils, while negative effects were observed in the properties reflecting the molecular size (e.g., molecular weight and number of carbon atoms) and hydrophobicity (e.g., water solubility, octanol–water partition coefficient, soil organic carbon partition coefficient) of hydrocarbons. The high concentration of weathered crude oil at the order of 10⁵ mg kg^?1 in this study was demonstrated adverse for solvent extraction by providing an obvious nonaqueous phase liquid phase for hydrocarbon sinking and increasing the sequestration of soluble hydrocarbons in the insoluble oil fractions during weathering. A full picture of the mass distribution and transport mechanism of petroleum contaminants in soils will ultimately require a variety of studies to gain insights into the dynamic interactions between environmental indicator hydrocarbons and their host oil matrix.     

Mineral constituents in Leccinum scabrum from lowland locations in the central Europe and their relation to concentration in forest topsoil

Leccinum scabrum is an edible mushroom common in European regions in the northern hemisphere. Macro and trace mineral constituents such as Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, P, Rb, Sr and Zn were studied in L. scabrum and in the top soil collected from the same location underneath soil substratum. The “pseudo-total” and labile (extractable fraction of minerals) were measured to get insight into the levels, distribution between the morphological parts of fruiting bodies, potential for their bioconcentration by mushroom and evaluated for human exposure via consumption of the mushroom. The sampling sites include the Dar?lubska Wilderness, Trójmiejski Landscape Park, Sobieszewo Island, Wdzydze Landscape Park and outskirts of the K?trzyn town in Mazury from the norther part of Poland. Median values of K, Rb and P concentrations in dehydrated L. scabrum were for caps in range 27,000–44,000 mg kg^?1, 90–320 mg kg^?1 and 6,200–9,100 mg kg^?1, and followed by Mg at 880–1,000 mg kg^?1, Ca at 48–210 mg kg^?1 and Al at 15–120 mg kg^?1. The median concentrations of Cu, Fe, Mn and Zn in caps were in range 15–27 mg kg^?1 db 38–140 mg kg^?1, 5.3–27 mg kg^?1 and 130–270 mg kg^?1. For Ba and Sr, concentrations on the average were at ～1 mg kg^?1, and almost equally distributed between the caps and stipes of the fruiting bodies. L. scabrum mushrooms were low in toxic Ag, Cd, Hg and Pb, for which the median values in dried caps from five locations were, respectively, in range 0.48–0.98 mg kg^?1 (cap to stipe index, Q_C/S, was 2.5–4.1), 1.0–5.8 mg kg^?1 (Q_C/S 2.9–3.8), 0.36–0.59 mg kg^?1 (Q_C/S 1.6–2.7) and 0.20–0.91 mg kg^?1 (Q_C/S 1.2–1.9). Substantial variations in the concentrations of the “pseudo-total” fraction (extracted by aqua regia) or labile fraction (extracted by 20% solution of nitric acid) of the elements determined in forest topsoils were noted between some of the locations examined. The elements K, P, Cd, Cu, Hg, Mn, Na, Rb and Zn can be considered as those which were bioconcentrated by L. scabrum in fruiting bodies, while the rates of accumulation varied with the sampling location.     

Heavy metal accumulation by poplar in calcareous soil with various degrees of multi-metal contamination: implications for phytoextraction and phytostabilization

The object of this study was to assess the capacity of Populus alba L. var. pyramidalis Bunge for phytoremediation of heavy metals on calcareous soils contaminated with multiple metals. In a pot culture experiment, a multi-metal-contaminated calcareous soil was mixed at different ratios with an uncontaminated, but otherwise similar soil, to establish a gradient of soil metal contamination levels. In a field experiment, poplars with different stand ages (3, 5, and 7 years) were sampled randomly in a wastewater-irrigated field. The concentrations of cadmium (Cd), Cu, lead (Pb), and zinc (Zn) in the poplar tissues and soil were determined. The accumulation of Cd and Zn was greatest in the leaves of P. pyramidalis, while Cu and Pb mainly accumulated in the roots. In the pot experiment, the highest tissue concentrations of Cd (40.76 mg kg^?1), Cu (8.21 mg kg^?1), Pb (41.62 mg kg^?1), and Zn (696 mg kg^?1) were all noted in the multi-metal-contaminated soil. Although extremely high levels of Cd and Zn accumulated in the leaves, phytoextraction using P. pyramidalis may take at least 24 and 16 years for Cd and Zn, respectively. The foliar concentrations of Cu and Pb were always within the normal ranges and were never higher than 8 and 5 mg kg^?1, respectively. The field experiment also revealed that the concentrations of all four metals in the bark were significantly higher than that in the wood. In addition, the tissue metal concentrations, together with the NH₄NO₃-extractable concentrations of metals in the root zone, decreased as the stand age increased. P. pyramidalis is suitable for phytostabilization of calcareous soils contaminated with multiple metals, but collection of the litter fall would be necessary due to the relatively high foliar concentrations of Cd and Zn.     

Responses of earthworm to aluminum toxicity in latosol

Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (acidic red soil). Laboratory experiments were performed to examine the survival and avoidance of earthworms from high Al concentrations and investigate the response of earthworms upon Al toxicity at seven different Al concentrations that ranged from 0 to 300 mg kg^?1 over a 28-day period. Our study showed that the rate of the earthworm survival was 100 % within the first 7 days and decreased as time elapsed, especially for the Al concentrations at 200 and 300 mg kg^?1. A very good linear correlation existed between the earthworm avoidance and the soil Al concentration. There was no Al toxicity to earthworms with the Al concentration ≤50 mg kg^?1, and the toxicity started with the Al concentration ≥100 mg kg^?1. Low Al concentration (i.e., <50 mg kg^?1) enhanced the growth of the earthworms, while high Al concentration (>100 mg kg^?1) retarded the growth of the earthworms. The weight of earthworms and the uptake of Al by earthworms increased with the Al concentrations from 0 to 50 mg kg^?1 and decreased with the Al concentrations from 50 to 300 mg kg^?1. The protein content in the earthworms decreased with the Al concentrations from 0 to 100 mg kg^?1 and increased from 100 to 300 mg kg^?1. In contrast, the catalase (CAT) and superoxide dismutase (SOD) activities in the earthworms increased with the Al concentrations from 0 to 100 mg kg^?1 and decreased from 100 to 300 mg kg^?1. The highest CAT and SOD activities and lowest protein content were found at the Al concentration of 100 mg kg^?1. Results suggest that a high level of Al content in latosol was harmful to earthworms.     

Residues of carbosulfan and its metabolites carbofuran and 3-hydroxy carbofuran in rice field ecosystem in China

The fate of carbosulfan (seed treatment dry powder) was studied in rice field ecosystem, and a simple and reliable analytical method was developed for determination of carbosulfan, carbofuran, and 3-hydroxyl carbofuran in brown rice, rice straw, paddy water, and soil. The target compounds were extracted using acetonitrile or dichloromethane, cleaned up on acidic alumina or florisil solid phase extraction (SPE) cartridge, and analyzed by gas chromatography. The average recoveries of carbosulfan, carbofuran and 3-hydroxy carbofuran in brown rice, rice straw, paddy water, and soil ranged from 72.71% to 105.07%, with relative standard deviations of 2.00–8.80%. The limits of quantitation (LOQs) of carbosulfan, carbofuran and 3-hydroxy carbofuran in the samples (brown rice, rice straw, paddy water and soil) were 0.011, 0.0091, 0.014, 0.010 mg kg^?1, 0.016, 0.019, 0.025, 0.013 mg kg^?1, and 0.031, 0.039, 0.035, 0.036 mg kg^?1, respectively. The trials results showed that the half-lives of carbosulfan, carbofuran and 3-hydroxy carbofuran in rice straw were 4.0, 2.6 days, 3.9, 6.0 days, and 5.8, 7.0 days in Zhejiang and Hunan, respectively. Carbosulfan, carbofuran and 3-hydroxy carbofuran were detected in soils. Carbosulfan and 3-hydroxy carbofuran were almost undetectable in paddy water. Carbofuran was detected in paddy water. The final residues of carbosulfan, carbofuran and 3-hydroxy carbofuran in brown rice were lower than 0.05 mg kg^?1, which were lower than 0.5 mg kg^?1 (MRL of carbosulfan) or 0.1 mg kg^?1 (MRL of carbofuran). Therefore, a dosage of 420 g active ingredient per 100 kg seed was recommended, which could be considered as safe to human beings and animals. These would contribute to provide the scientific basis of using this insecticide.     

Distribution of potentially toxic elements (PTEs) in tailings,soils, and plants around Gol-E-Gohar iron mine,a case study in Iran

This study investigated the concentration of potentially toxic elements (PTEs) including Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, V, and Zn in 102 soils (in the Near and Far areas of the mine), 7 tailings, and 60 plant samples (shoots and roots of Artemisia sieberi and Zygophylum species) collected at the Gol-E-Gohar iron ore mine in Iran. The elemental concentrations in tailings and soil samples (in Near and Far areas) varied between 7.4 and 35.8 mg kg^?1 for As (with a mean of 25.39 mg kg^?1 for tailings), 7.9 and 261.5 mg kg^?1 (mean 189.83 mg kg^?1 for tailings) for Co, 17.7 and 885.03 mg kg^?1 (mean 472.77 mg kg^?1 for tailings) for Cu, 12,500 and 400,000 mg kg^?1 (mean 120,642.86 mg kg^?1 for tailings) for Fe, and 28.1 and 278.1 mg kg^?1 (mean 150.29 mg kg^?1 for tailings) for Ni. A number of physicochemical parameters and pollution index for soils were determined around the mine. Sequential extractions of tailings and soil samples indicated that Fe, Cr, and Co were the least mobile and that Mn, Zn, Cu, and As were potentially available for plants uptake. Similar to soil, the concentration of Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, and Zn in plant samples decreased with the distance from the mining/processing areas. Data on plants showed that metal concentrations in shoots usually exceeded those in roots and varied significantly between the two investigated species (Artemisia sieberi > Zygophylum). All the reported results suggest that the soil and plants near the iron ore mine are contaminated with PTEs and that they can be potentially dispersed in the environment via aerosol transport and deposition.     

Aminocyclopyrachlor sorption-desorption and leaching from three Brazilian soils

This study aimed to evaluate the sorption-desorption and leaching of aminocyclopyrachlor from three Brazilian soils. The sorption-desorption of ¹⁴C-aminocyclopyrachlor was evaluated using the batch method and leaching was assessed in glass columns. The Freundlich model showed an adequate fit for the sorption-desorption of aminocyclopyrachlor. The Freundlich sorption coefficient [K_{f (sorption)}] ranged from 0.37 to 1.34 µmol ^(1–1/n) L^1/n kg^?1 and showed a significant positive correlation with the clay content of the soil, while the K_{f (desorption)} ranged from 3.62 to 5.36 µmol ^(1–1/n) L^1/n kg^?1. The K_{f (desorption)} values were higher than their respective K_{f (sorption)}, indicating that aminocyclopyrachlor sorption is reversible, and the fate of this herbicide in the environment can be affected by leaching. Aminocyclopyrachlor was detected at all depths (0?30 cm) in all the studied soils, where leaching was influenced by soil texture. The total herbicide leaching from the sandy clay and clay soils was <0.06%, whereas, ～3% leached from the loamy sand soil. The results suggest that aminocyclopyrachlor has a high potential of leaching, based on its low sorption and high desorption capacities. Therefore, this herbicide can easily contaminate underground water resources.