A simulation model (PostPLANT-Soil) for predicting pesticide concentrations in succeeding leafy vegetables: I. Validation with experimental data in a Japanese Andosol field.

We developed a simulation model for predicting pesticide concentrations in succeeding leafy vegetables (PostPLANT-Soil), which includes the process of pesticide uptake from plant roots. To validate the model, we compared pesticide concentrations simulated by the model with values measured from field experiments in an upland Andosol. The model validation showed that pesticide concentrations in the plant shoot were correlated with the concentrations in the soil solution rather than those of the water-extracted pesticides.

A simulation model (PostPLANT-Soil) for predicting pesticide concentrations in succeeding leafy vegetables: II. Validation with experimental data on plant uptake in a growth chamber.

We validated a simulation model (PostPLANT-Soil) for predicting pesticide concentrations in succeeding leafy vegetables reported in our first paper in this series, which includes the pesticide sorption process into plant roots. As a result of the model validation with the measured data from a plant uptake study in a growth chamber, the model successfully simulated the concentration changes of pesticides in a plant shoot. However, the simulated shoot concentrations for several pesticides were overestimated compared to the measured values.

Change of clopyralid concentration in recycled beef cattle compost.

Composting of beef cattle manure using sawdust or recycled compost as a bulking agent was investigated for the management of clopyralid risk, such as changes in the clopyralid concentration and the mechanism of clopyralid accumulation caused by recycled compost. These raw materials were composted with laboratory equipment, which was controlled at 60℃ after the temperature peak by autothermal composting. Clopyralid concentration did not changed during composting in the thermophilic phase; on the contrary, it increased because clopyralid accumulated in compost when recycled compost was used repeatedly as a bulking agent.

Liquid Chromatographic Determination of Trace Bioavailable Neonicotinoids in Soil with Dispersive Liquid-Liquid Microextraction and Its Application for Experimental Monitoring.

Dispersive liquid-liquid microextraction (DLLME) was applied to extract bioavailable neonicotinoids involved in the uptake from soil through roots to plants. To quantitatively extract bioavailable neonicotinoids with the proposed DLLME, 3.5 mL of dichloromethane (extractant)/acetonitrile (dispersive solvent) (6:1, v/v) was injected into 5 mL of aqueous soil extracts in which 1 g of sodium chloride was previously dissolved.

Detection of herbicide clopyralid at nanogram per gram level in agricultural products using easy-to-use micro liquid-liquid extraction followed by analysis with ultraperformance liquid chromatography-tandem mass spectrometry.

A new sample preparation method was developed for auxin-like herbicide clopyralid residue in agricultural products. The method uses extraction with sulfuric acid - acidified acetonitrile, with cleanup of sample extracts using solid-phase extraction (diatomaceous earth) and micro liquid-liquid extraction, followed by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This sample preparation method greatly reduces the influence on ionization during determination with UPLC-MS/MS.

Effects of temperature on the dissipation of total- and water-extractable pesticides in Japanese soils.

We investigated the dissipation of 27 pesticides in five Japanese soils at three temperatures and the variability of activation energies ( ). The dissipation of total pesticides extracted sequentially using water and acetone was fitted to a single first-order (SFO) model. The values calculated from the dissipation rate constants of the SFO model showed a normal distribution with a median of 61.

Highly sensitive analytical method for herbicide clopyralid residue in cattle manure compost with ultraperformance liquid chromatography tandem mass spectrometry.

A micro liquid-liquid extraction has been applied to sample preparation in the current authorized method for clopyralid in compost. The method rendered matrix effects practically negligible during determination with ultraperformance liquid chromatography-electrospray ionization tandem mass spectrometry with an improved limit of quantification of 0.7 µg/kg dry weight.

Physiological disorder of plants depending on clopyralid concentration in the soil and plant.

The influence of clopyralid in soil on plant growth was investigated over time using three plants. The order of clopyralid sensitivity was as follows: >>, especially physiological disorder of were rapidly expressed as various serious symptoms with increasing concentration of clopyralid. In contrast, the clopyralid concentration of above-ground part was in the following order: >, , which differed from the order of sensitivity to clopyralid.

Relationship between growth stage of var. and the abilities for uptake and translocation of pesticides in soil.

The relationships between plant growth stage and pesticide-uptake ability were investigated cultivation of L. var. in soil to which was added four pesticides of relatively high log : fenobucarb, procymidone, flutolanil, and tolclofos-methyl.

Comparison of soil sorption parameters of pesticides measured by batch and centrifugation methods using an andosol.

We compared the soil sorption coefficient ( ) measured by batch and centrifugation methods using a Japanese andosol and ten pesticides. Although the values measured by both methods increased with time, those obtained the batch method tended to be higher during the test period. The difference in values between the two methods affected pesticide concentrations estimated in the soil solution, and the results estimated using values obtained the batch method underestimated the observed trends.

The influence of var. growth conditions on the uptake and translocation of pesticides.

We cultivated var. in soil mixed with four pesticides (fenobucarb, procymidone, flutolanil, and tolclofos-methyl) at different temperatures, day lengths, and soil water contents. We compared plants' uptake and translocation abilities of the pesticides as affected by growth conditions.

Differential uptake and translocation of organic chemicals by several plant species from soil.

We performed uptake experiments with 12 different organic chemicals using 16 plant species and determined differences in the ability of plant species to take up and translocate these chemicals. There were differences among the plant species in the shoot and root concentrations of each organic chemical. The root concentration factor values increased with an increasing log of the -octanol-water partition coefficient (log ) of organic chemicals.

Source characterization and risk of exposure to atmospheric polychlorinated biphenyls (PCBs) in Ghana.

With recent evidence that persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) are emerging in environmental media in some developing countries that otherwise have sparing production and usage history, it has become important to identify such contemporary source factors of PCBs and the risks this may pose, in line with the global consensus on POP management and elimination. The present study investigated contaminations from atmospheric PCBs in Ghana, deciphered source factors, and accessed risk of exposure to dioxin-like PCBs (DL-PCBs). Atmospheric PCBs were monitored by deployment of PUF-disk passive air samplers (PAS) at several sites across Ghana for 56 days.

Atmospheric monitoring of organochlorine pesticides across some West African countries.

Most African countries have ratified the Stockholm Convention on persistent organic pollutants (POPs) and are expected to reduce emissions of POPs such as organochlorine pesticides (OCPs) to the atmosphere. Emerging evidence, however, suggests that there are contemporary sources of OCPs in African countries despite the global ban on these products. This study investigated the atmospheric contamination from OCPs in four West African countries-Togo, Benin, Nigeria, and Cameroon-to ascertain the emission levels of OCPs and the characteristic signatures of contamination.

Potential application of immunoassays for simple, rapid and quantitative detections of phytoavailable neonicotinoid insecticides in cropland soils.

This study evaluated the applicability of commercially available kit-based enzyme-linked immunosorbent assay (ELISA) to simple, quick, and quantitative detection for three water-extractable (phytoavailable) neonicotinoid insecticides: dinotefuran, clothianidin, and imidacloprid in soils. ELISA showed excellent analytical sensitivity for determination, but with cross-reaction to structurally related neonicotinoid analogues, which might produce false positives. To analyze insecticides in soil samples of diverse physicochemical properties, they were extracted with water.

Biodegradation of γ-hexachlorocyclohexane by transgenic hairy root cultures of Cucurbita moschata that accumulate recombinant bacterial LinA.

γ-HCH was successfully degraded using LinA-expressed transgenic hairy root cultures of Cucurbita moschata . Fusing an endoplasmic reticulum-targeting signal peptide to LinA was essential for stable accumulation in the hairy roots. The pesticide γ-hexachlorocyclohexane (γ-HCH) is a persistent organic pollutant (POP) that raises public health and environmental pollution concerns worldwide.

Effect of Time-Dependent Sorption on the Dissipation of Water-Extractable Pesticides in Soils.

The dissipation behavior of water-extractable pesticides in soils is important when assessing the phytoavailability of pesticides in soils. This process is less understood than pesticide extraction with organic solvents. To elucidate the dissipation behavior of water-extractable pesticides in soils, we conducted an incubation study using 27 pesticides and five Japanese soils.

Differential uptake and translocation of β-HCH and dieldrin by several plant species from hydroponic medium.

To compare the uptake and translocation of hydrophobic organic chemicals by plant species, the authors performed uptake experiments with β-1,2,3,4,5,6-hexachlorocyclohexane (β-HCH) and 1,2,3,4,10,10-Hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-endo-1,4-exo-5,8-dimethanonaphthalene (dieldrin) using 5 species: Hordeum vulgare, Glycine max, Solanum lycopersicum, Brassica oleracea, and Cucurbita pepo. The present study evaluated uptake ability using root concentration factor (RCF) and translocation ability by transpiration stream concentration factor (TSCF). The RCFs of β-HCH and dieldrin did not differ remarkably among species, except that the RCF of β-HCH in B.

Contamination of indoor dust and air by polychlorinated biphenyls and brominated flame retardants and relevance of non-dietary exposure in Vietnamese informal e-waste recycling sites.

This study investigated the occurrence of polychlorinated biphenyls (PCBs), and several additive brominated flame retardants (BFRs) in indoor dust and air from two Vietnamese informal e-waste recycling sites (EWRSs) and an urban site in order to assess the relevance of these media for human exposure. The levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) in settled house dust from the EWRSs (130-12,000, 5.4-400, 5.

Atmospheric polychlorinated naphthalenes in Ghana.

A nationwide monitoring of atmospheric POPs (persistent organic pollutants) was conducted in Ghana between May and July 2010, applying polyurethane foam (PUF) disk passive air samplers (PAS). Reported here are preliminary findings on PCNs, an industrial organic contaminant currently under review for possible listing under the global chemical treaty. The present results constitute the first set of nationwide data on air PCNs from a West African country.

Passive air monitoring of PCBs and PCNs across East Asia: a comprehensive congener evaluation for source characterization.

A comprehensive congener specific evaluation of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in the atmosphere was conducted across East Asia in spring 2008, applying polyurethane foam (PUF) disk passive air sampler (PAS) as monitoring device. Mean concentrations derived for Japan, China and Korea were 184 ± 24, 1100 ± 118, and 156 ± 20 pg m(-3) for ∑(202) PCBs, and 9.5 ± 1.

Dieldrin-dissolving abilities of the xylem saps of several plant families, particularly Cucurbita pepo L.

The uptake ability of hydrophobic organic chemicals by plants and the nature of xylem sap of the plants were studied. The plants were grown in soil contaminated with dieldrin. High amounts of dieldrin were detected in the shoots of Cucurbita pepo and Cucumis sativus, but little was seen in the shoots of Brassica oleracea var.

Dieldrin uptake and translocation in plants growing in hydroponic medium.

It has been known that the Cucurbitaceae family takes up a large amount of persistent organic pollutants from soils and that the translocation of those compounds in cucurbits is higher than those in non-cucurbits. To understand the persistent organic pollutant uptake mechanisms of plant species, we compared the dieldrin absorption and transportation potentials of several plants in hydroponic medium. Sorghum (Sorghum vulgare Moench), sunflower (Helianthus annuus L.

Relationship between dieldrin uptake in cucumber and solvent-extractable residue in soil.

To prevent the distribution of cucumbers with dieldrin contamination exceeding the limit set by the Japanese Food Sanitation Law, the extraction solvent for dieldrin-contaminated soil was selected prior to cultivation so that the dieldrin residue level in cucumber could be predicted. The exhaustive extraction from soil could not explain the dieldrin uptake by cucumber plants. However, significant correlation (R(2) = 0.

Mass balance and long-term fate of PCDD/Fs in a lagoon sediment and paddy soil, Niigata, Japan.

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in a sediment core and in samples of surface sediment and paddy soil collected from the Toyano lagoon and Kameda basin in Niigata, Japan, were analyzed to elucidate the temporal trends of their concentrations in the lagoon sediment and the relationship between the sediment and the paddy soil. The mass balance of these pollutants was also estimated to determine their long-term fate in surface waters. An analysis by chemical mass balance identified the agrochemicals pentachlorophenol and 2,4,6-trichlorophenyl 4-nitrophenyl ether as the major sources of PCDD/Fs.