Deposition of gamma emitters from Chernobyl accident and their transfer in lichen–soil columns

Lichen–soil column samples were taken from several locations in the Southern Finland between 1986 and 2006. Columns were divided into three parts, upper lichen, lower lichen and underlying soil, and their gamma emitting radionuclides, ¹³⁴Cs, ¹³⁷Cs, ¹⁰³Ru, ⁹⁵Zr, ¹⁰⁶Ru, ^110mAg, ¹²⁵Sb and ¹⁴⁴Ce, were measured with gamma spectrometry. Deposition values were calculated as Bq/m² for each sampling site. Distribution of various radionuclides in the three compartments as a function of time was determined. Both effective and ecological half-lives of all radionuclides were calculated for upper lichen, whole lichen and whole lichen–soil column. A linear relation was derived between the physical half-lives and effective half-lives for whole lichen and for whole lichen–soil column. Reindeer meat activity concentrations of various radionuclides and ensuing radiation doses to reindeer-herding people were also estimated for a hypothetical case where a similar high radioactive pollution, as was taken place in the Southern Finland, would have occurred in the reindeer-herding areas in the Finnish Lapland.     

我国黑土地农田土壤除草剂残留特征研究及展望

粮食安全是“国之大者”.东北黑土地作为我国重要的粮仓,是保障国家粮食安全的“压舱石”.但黑土地农田除草剂的长期高强度施用,导致除草剂在土壤中积累和迁移,影响土壤质量、作物产量和品质,阻碍黑土地可持续利用和农业可持续发展.解决黑土地农田除草剂残留问题,既要从源头管控除草剂的施用,也要掌握除草剂的残留特征、时空演变和驱动因素,才能做到科学防控、精准施策.系统总结了我国黑土地农田除草剂的施用状况和存在的问题,全面梳理了除草剂的残留现状,指出了当前在黑土地农田除草剂残留特征、空间分布和污染诊断等研究上的不足,提出了我国黑土地农田除草剂残留诊断与风险管理研究思路与重点方向,为保障我国黑土地农田土壤健康、粮食安全和生态系统安全提供科技支撑.     

Subcritical water oxidation of propham by H2O2 using response surface methodology (RSM)

This study was conducted to investigate the degradation of propham, which is a compound that pollutes water and seriously threatens human health, by subcritical water oxidation and using H₂O₂ as an oxidising agent. The maximum total organic carbon removal rate of propham was obtained as 73.65% at 40 min of treatment time and 60 mM of H₂O₂ concentration and 373 K of temperature. In addition, response surface method based on the Box-Behnken design was applied to design the degradation experiments of propham for determination of the combined effects of process variables, namely temperature, concentration of oxidising agent and treatment time. The proposed quadratic model of propham degradation, which was examined with the analysis of variance, was used for navigating the design space. The R² and adjusted R² values of the model were determined as 0.9921 and 0.9819 respectively. It was shown that propham was effectively degraded, thus could be removed from the water by using an environmentally friendly method.     

PVA-SbQ固定叶绿体及其生物传感器在检测除草剂中的应用

聚乙烯－苯乙烯吡啶（PVA－SbQ）是一种新的光敏聚合物，在紫外光诱导下形成大分子网状结构，电镜照片显示PVA－SbQ固定的新鲜菠菜叶绿体－20℃贮存6mo后，内，外膜结构完整，类囊体膜排列整齐，还原DPIP的能力保留50％，将叶绿体膜固定在铂电极上，制成生物传感器，在含0．035H2O2的50mmol L^-1,pH7.4Tris-HCl缓冲液中，25℃条件下用示差脉冲伏安法检测除草剂，在0－1.0 μg/L浓度范围，百草枯，敌草隆，扑草净和阿特闰津具有较好的线性关系。图6参29     

Passive water sampling for polynuclear aromatic hydrocarbons using lipidcontaining semipermeable membrane devices (SPMDs): Application to contaminant residence times

Lipid-containing semipermeable membrane devices are applied to the quantitative determination of the persistence of polynuclear aromatic hydrocarbons (PAH) in an irrigation water canal, a representative waterway. The uniform and reproducible sampling of the USGS design of lipid-containing SPMDs is exploited to measure PAH half-lives without requiring calculation of water concentrations. The trend in calculated PAH half-lives agrees with that expected if volatilization is a significant mechanism for loss from the canal with more volatile PAHs having shorter half-lives. The higher persistence of phenanthrene compared to anthracene is consistent with the greater stability of phenanthrene and suggests, with other physicochemical evidence, that other (reactive) mechanisms may be involved. The results of this study demonstrate the feasibility of the SPMD method for the measurement of residence times in aquatic and other compartments. Such information is essential for quantifying contaminant behavior in the environment and providing insights into contaminant fate.     

Environmental fate and ecotoxicology of propanil: a review

The herbicide propanil, a synthetic anilide, was discovered in 1957 to control grasses and broad-leaf weeds in rice fields. It has been found to disrupt the electron transport chain by inhibiting the photosystem II, thus impacting plant growth. In the environment, photolysis represents a major degradation pathway, whereas volatilization is not a major route of dissipation from either water or moist soils. Propanil is rapidly degraded by microbes into the major degradation product 3,4-dichloroaniline. This degradation product has been highly detected in both groundwater and surface waters throughout the world. Propanil has been found to adversely impact many non-target organisms. It is toxic to some early life-stage aquatic organisms, in addition to being moderately toxic to the water flea (Ceriodaphnia dubia) and rainbow trout. In addition, it has been reported to pose a high acute and long-term risk to birds. In plants, growth rates are highly impacted; however, some plant species are becoming resistant to propanil.     

Analysis of the toxicity of glyphosate and Faena® using the freshwater invertebrates Daphnia magna and Lecane quadridentata

With the present contribution an evaluation of the toxicity of the pure herbicide glyphosate and its commercial formulation Faena® is reported using the cladoceran Daphnia magna Strauss and the rotifer Lecane quadridentata Ehrenberg. LC₅₀, EC₅₀, NOEC, and LOEC values for each toxicant and for both test organisms are obtained. Regarding acute toxicity, Faena was 11-fold more toxic to L. quadridentata than pure glyphosate and slightly more toxic to D. magna (1.7-fold). Inhibition of esterase activity in L. quadridentata by glyphosate was the most sensitive end-point; the EC₅₀ was 1500-fold smaller than the LC₅₀. The implications of these results and their comparison with established international and national limit values for glyphosate are discussed.     

Bioactivity,adsorption and persistence of pretilachlor in paddy field soils

The effects of environmental factors on bioactivity, adsorption and persistence of pretilachlor were studied in the laboratory and greenhouse using cucumber (Cucumis sativus L.) as the bioassay species. The three soils studied viz. Bernam, Selangor and Sabrang series were chosen for their different characteristics. The half‐life of pretilachlor decreased from 10.24 to 4.90 days as temperature increased from 25°C to 35°C in the Selangor Series soil and from 10.86 to 7.63 days in the Bernam Series soil at 60% field capacity. At the same moisture level, an increase of temperature from 25°C to 35°C also reduced the half‐life of pretilachlor in Sabrang soil from 8.87 to 2.59 days. The half‐life of pretilachlor also decreased with increasing moisture levels in Selangor and Sabrang series but not in Bernam series soils. The greatest adsorption of pretilachlor was observed in Bernam series, followed by Selangor and Sabrang series. No phytotoxic residue of pretilachlor was detected in the supernatant after 10 h incubation. Since the residue was strongly adsorbed in Bernam series, its biological activity was less than in the other soils studied.     

The effect of imazethapyr on soil microbes in soybean fields in northeast China

Large quantities of herbicides are used on agricultural soils, but the effects of herbicides on the structure of the soil microbial community have not been well investigated. In this study, soil from three soybean fields was investigated. The herbicide imazethapyr was applied in one year to soil 1 and in two sequential years to soil 2. Control soil received no imazethapyr. Microbial biomass and community structure were characterised using chloroform fumigation–extraction and phospholipid fatty acid (PLFA) determination. The imazethapyr residue was 1.62 μ g·kg^?1 in soil 1 and 1.79 μ g·kg^?1 in soil 2. The microbial biomass carbon and total PLFAs for soil 2 were much higher than for the other soils. PLFA profiles showed that fatty acids for Gram-negative and Gram-positive bacteria, as well as total bacteria and total fungi in soil 2 were higher than in other samples. Principal component analysis of the PLFAs showed that the structure of the microbial community differed substantially among the three different soybean field soils. Application of the herbicide imazethapyr to soybean fields clearly changed the soil microbial biomass and shifted the structure of the microbial community.     

2种除草剂联合胁迫下日本青鳉的逐级行为响应(The Stepwise Behavioral Responses of the Japanese Medaka under the Joint Stress of Two Herbicides)

探讨了日本青鳉在两种除草剂阿特拉津和百草枯联合暴露下的逐级行为响应,采用水质安全在线生物预警系统(BEWs)记录行为强度数据,分析不同暴露浓度、不同暴露时间日本青鳉的行为响应.10、5、1和0.1TU的暴露浓度下行为反应时间分别为:0.74、7.7、29.4和42.2h,而每个浓度不同配比之间行为反应时间差异明显.结果表明:在两种除草剂的暴露下,日本青鳉的逐级行为响应既受化合物浓度高低的影响,又受暴露时间的影响,而且每个浓度两种药物不同配比暴露下的青鳉鱼的逐级行为响应基本一致,每个浓度不同配比之间行为反应时间差异明显,即两种作用机制不同的除草剂对日本青鳉的行为毒性是协同作用.