Dissipation and residue of dimethomorph in pepper and soil under field conditions

The dissipation and residual levels of dimethomorph in pepper and soil under field conditions were determined by gas chromatography with an electron capture detector (GC-ECD). The dissipation rates of dimethomorph were described using first-order kinetics and its half-life ranged from 1.7 to 3.8 days in pepper and 11.5-18.5 days in soil. At harvest time, the terminal residues of dimethomorph were below the EU's maximum residue limit (MRL, 0.5 mg kg⁻¹) in pepper when measured 7 days after the final application, which suggested that the use of this fungicide was safe for humans. The collected field samples were stable for up to two months when refrigerated at −20 °C. The residues persistence varied among three geographically separated experimental fields, suggesting that it might be affected by climatic, soil properties and local microorganisms. These results will be helpful in setting MRL guidance for dimethomorph in pepper in China.     

Phytotoxicity of PFOS and PFOA to Brassica chinensis in different Chinese soils

PFOS and PFOA are potential persistent organic pollutants that have raised many concerns in recent years. Research focusing on phytotoxicity of PFOS and PFOA to higher plants is necessary for their risk assessments. However, few toxicity data exist for PFOS or PFOA and higher plants. Here we investigated phytotoxicity of PFOS and PFOA to Brassica chinensis root growth in six different Chinese soils varying widely in soil properties using a standardized root length assay. The effective concentrations of added PFOS and PFOA causing 50% inhibition (EC₅₀) ranged from 95 to >200 mg kg⁻¹ for PFOS and from 107 to 246 mg kg⁻¹ for PFOA, respectively, representing more than 2.1- and 2.3-fold variation among the tested soils. Regressions of soil PFOS and PFOA toxicity threshold values (EC_x and NOECs) with various soil properties showed that the amount of organic matter was the most significant factor affecting their toxicity to B. chinensis.     

中日γ能谱分析土壤样品中放射性核素的比对

目的 通过开展γ能谱测量分析比对活动,检验比对样品的采集、制备、测量和分析全过程,以促进放射性核素γ能谱测量分析技术的发展。方法 由中国疾病预防控制中心辐射防护与核安全医学所采集和制备环境土壤样品,比对各方分别对两个土壤样品中的²¹⁴Pb、²¹⁴Bi、²⁰⁸Tl、²²⁸Ac、⁴⁰K和¹³⁷Cs 6个核素进行测量和分析。根据3个实验室约定测量结果的评定标准,利用各实验室上报的活度浓度和总不确定度数据计算测量结果评价变量(En)值。结果 每两个实验室间计算的En值均小于1,3个实验室的结果均为可接受的结果。结论 各比对方的测量结果在一定范围内是一致的。本次比对既检验了比对方实验室的核素分析水平,又促进了本实验室样品制备中均匀性检验能力的提高。     

重庆市人体土源性线虫感染相关因素分析

目的　探索重庆市土源性线虫感染相关因素,为土源性线虫病科学防治提供依据。方法　2011–2015年每年在重庆市设立监测点,采集监测点居民粪便采用改良加藤厚涂片法（1粪3检）检查土源性线虫虫卵;对调查对象进行问卷调查,分析影响人体土源性线虫感染的相关因素。结果　2011–2015年重庆市人体土源性线虫感染率分别为6.44%、7.30%、6.85%、6.93%和5.56%;饮用水源不干净、便后洗手频率低是蛔虫感染的危险因素,厕所经过无害化处理、肥料无害化程度高、喝生水频率低、落地食物不洗就食频率低是蛔虫感染的保护因素。结论　重庆市人体土源性线虫病已处于较低流行水平;要巩固已取得的防治成果,还要在健康教育、改水改厕和改善环境卫生的基础上,坚持分类指导、综合防治,进一步做好监测工作。     

Soil zinc deficiency and child stunting: Evidence from Nepal

We examine the negative child health impacts of soil zinc (Zn) deficiency in Nepal. Soil Zn deficiency limits both crop yields and the Zn concentration in food crops, leading many to speculate that it underlies human Zn deficiency and child stunting, globally and particularly in South Asia. We find strong evidence that soil Zn deficiency does have a causal impact on child stunting in Nepal’s Tarai region, the breadbasket of the country. Using causal bounds, we find that a 1 part per million increase in plant-available soil Zn – achievable with application of Zn-enriched fertilizer – decreases child stunting by between 1 and 7.5 percentage points. Multiple statistical sensitivity tests indicate that this relationship is unlikely to be manufactured by omitted, relevant variables.     

A comparative study on different multiple cropping patterns of Bupleurum chinense

Bupleurum chinense is a genuine medicinal material in Shanxi Province, and planting B. chinense is one of the main sources for local farmers to increase their income. In B. chinense cultivation, wheat-B. chinense, maize-B. chinense and soybean-B. chinense are commonly used as multiple cropping patterns. In the present study, we studied the effects of three different multiple cropping patterns on N, P and K levels of soil, photosynthetic parameters, agronomic characteristics, saikosaponin A, C and D contents, yield and economic benefits of B. chinense. The results showed that the soybean-B. chinense multiple cropping pattern was beneficial to the enrichment of N in the soil, thus promoting photosynthetic parameters, growth, saikosaponin accumulation, yield and economic benefits of B. chinense. It is suggested that soybean-B. chinense multiple cropping was an appropriate multiple cropping pattern for local cultivation of B. chinense.     

Effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil

An enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (LAS) (10 and 500 microg ml(-1)). Nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by PCR-amplification and partial sequencing of the 16S rRNA gene. Amongst the isolates, strains LAS05 (Pseudomonas syringae), LAS06 (Staphylococcus epidermidis), LAS07 (Delftia tsuruhatensis), LAS08 (Staphylococcus epidermidis) and LAS09 (Enterobacter aerogenes), were able to grow in pure culture in dialysed soil media amended with LAS (50 microg ml(-1)). The three Gram-negative strains grew to higher cell numbers in the presence of 50 microg ml(-1) of LAS, compared to LAS-unamended dialysed soil medium, and were selected for further testing of their ability to use LAS as carbon source. However, HPLC analysis of culture supernatants showed that the three strains can tolerate but not degrade LAS when grown in pure cultures. A higher concentration of soluble phosphates was recorded in dialysed soil media amended with LAS (50 microg ml(-1)) compared to unamended control media, suggesting an effect of the surfactant that enhanced the bioavailability of P from soil. The presence of LAS at a concentration of 50 microg ml(-1) had an important impact on growth of selected aerobic heterotrophic soil bacteria, a deleterious effect which may be relevant for the normal function and evolution of agricultural soil.     

The response of Ty1 test to genotoxins

The Ty1 assay is a short-term test for detection of genotoxins based on induction of the transposition of a gene-engineered Ty1 retrotransposon in Saccharomyces cerevisiae cells. Here, we provide evidence that the Ty1 test responds positively in concentration-dependent manner to the carcinogenic genotoxins benz(a)anthracene, benzo(a)pyrene, chenodeoxycholic and taurodeoxycholic free bile acids and to environmental soil samples polluted with carcinogenic substances. The Ty1 test gives negative results with the noncarcinogenic mutagens benz(b)anthracene, benzo(e)pyrene, lithocholic and taurodeoxycholic conjugated bile acids and to soil samples not polluted with carcinogens. Presence or absence of genotoxins in soil samples was evidenced by chemical analysis. Several explanations for the sensitive differential test’s response to genotoxins are proposed and discussed. It is concluded that the Ty1 test can complement existing assays in laboratory and environmental studies showing high sensitivity to a wider spectrum of carcinogenic genotoxins.     

焦炭生产对空气及土壤的污染调查

了解焦炭生产对环境的影响。「方法」对山西省焦炭生产地区空气质量状况和土壤样品芳烃类物质含量分别进行了监测和分析。「结果」总悬浮微粒,二氧化硫和苯并（ａ）芘日均值超过ＧＢ３０９５－１９９６二级标准值。