DDT in fish from the Bulgarian region of the Black Sea

In spite of a worldwide reduction in the utilization of organochlorine pesticides (OCPs), they are still a problem for the aquatic environment and human health. The Black Sea is still being polluted with persistent chemicals, including OCPs. Aquatic organisms (sprat, scad, bluefish, shad, belted bonito, goby, and black mussel) with different feeding behaviours were sampled on a seasonal basis from the Bulgarian region of the Black Sea, and the concentrations of 13 OCP residues were determined. Although many of the OCPs were not detected in the samples, in all samples 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) was present mainly in the form of its metabolites 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE). Only about 12% of the total DDT was present as the parent compound pp-DDT, which suggests that it was not being used recently in the region. The total DDT concentrations were generally below 150 μg kg^-1 fresh weight, but higher levels—up to 354 μg kg^-1 fresh weight—were also measured for fish species with a high fat content. Between-species differences were observed, even when the concentrations were presented on a fat-level basis. DDT concentrations did not show any significant changes over the 2-yr sampling period. Fish sampled in the northern areas of the Bulgarian Black Sea coast seemed to contain higher DDT levels than those from the southern areas, suggesting a major (historical) influence of the Danube River. For permanent monitoring purposes, the utility of Black Sea gobies and scad should be considered.     

广西近岸海水和沉积物中有机氯农药的分布及生态风险

通过对广西近岸水体和沉积物中2类有机氯农药(OCPs,包括HCHs和DDTs)的大面调查,评估了广西近岸海域OCPs的分布特征、污染状况和生态风险。结果显示:广西近岸海域的海水中所有站位都未检出HCHs和DDTs,所有站位的沉积物中也未检出HCHs,43个沉积物站位中DDTs的检出率为11.6%,沉积物中DDTs含量范围为nd~3.7 ng/g。研究表明:广西近岸水体及沉积物中OCPs的污染水平很低,沉积物中DDTs具有较为明显的空间分布规律,呈现出渔港附近含量高,以及TOC (有机碳)含量较高的河口附近含量高的特征。船舶防污漆可能是造成渔港附近DDTs含量较高的主要原因,部分河口站位主要受河流输入污染物影响,DDTs主要来源于历史残留,沉积物中TOC含量是影响DDTs残留分布的重要因素,DDTs易与悬浮物中的有机质通过吸附络合结合而沉积。生态风险评价结果显示:广西近岸海水的HCHs和DDTs生态风险极低,沉积物的HCHs生态风险也极低,沉积物中DDTs的潜在生态风险总体很低。     

粤桂水源地有机氯农药的污染特征及生态风险

利用固相萃取-气相色谱-质谱联用技术(SPE-GC-MS)检测了粤桂水源地7个采样点水样中16种有机氯农药(OCPs)的浓度,分析了研究区OCPs的污染特征;利用BurrⅢ型分布构建了8种OCPs的物种敏感度分布曲线,并计算出不同OCPs对淡水水生生物的HC5(hazardous concentration for 5%species)值,最后应用安全阈值法评价了OCPs对水生生物的生态风险.结果表明,OCPs的浓度在6.64~34.19 ng·L~(-1)之间,平均值为16.76 ng·L~(-1),HCHs和DDTs及其降解产物在污染物中的贡献比例较大.HCHs主要来自家庭杀虫剂中的林丹,DDTs主要来自三氯杀螨醇的污染或历史残留.脊椎动物对OCPs的耐受性高于无脊椎动物,α-硫丹对水生植物和微生物的影响较大,p,p'-DDT对脊椎动物和无脊椎动物的影响较大.粤桂水源地OCPs对水生生物没有显著的生态风险,但DDTs和α-硫丹对水生生物存在较高的潜在风险,应加以重视.     

Spatial variability of organochlorine pesticides （DDTs and HCHs） in surface soils from the alluvial region of Beijing, China

The spatial variability in the concentrations of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane (DDT) in surface soils was studied on the basis of the analysis of 131 soil samples collected from the surface layer (0-20 cm depth) of the alluvial region of Beijing, China. The concentrations of total HCHs (including α-, β-, γ-, and δ-isomers) and total DDTs (i ncluding p,p'-DDT, p,p'-DDD, p,p'-DDE, and o,p'-DDT) in the surface soils tested were in the range from nondetectable to 31.72 μg/kg dry soil, with a mean value of 0.91, and from nondetectable to 5910.83 μg/kg dry soil, with a mean value of 32.13,respectively. It was observed that concentrations of HCHs in all soil samples and concentrations of DDTs in 112 soil samples were much lower than the first grade (50 μg/kg) permitted in "Environment quality standard for soils in China (GB15618-1995)". This suggests that the pollution due to organochlorine pesticides was generally not significant in the farmland soils in the Beijing alluvial region. In this study, the spatial distribution and trend of HCHs and DDTs were analyzed using Geostatistical Analyst and GS (513).Spatial distribution indicated how these pesticides had been applied in the past. Trend analysis showed that the concentrations of HCHs,DDTs, and their related metabolites followed an obvious distribution trend in the surface soils from the alluvial region of Beijing.     

寡糖类农药的研制

葡萄寡糖、半乳糖醛酸寡糖、几丁质寡糖是常见的、能激活植物自卫系统的激活剂,本文综述了这几类寡糖的结构、活性、制备方法、这些寡糖会为无毒、无公害的新农药。     

农作物病虫害专业化防治服务对农药施用强度的影响

农药过量施用已造成严重的负外部性。推行农作物病虫害专业化统防统治服务可以实现安全、科学、合理用药,有效缓解农业面源污染问题和提升食品的质量安全水平。为了探究病虫害专业化统防统治服务在缓解农业面源污染方面的效果,文章利用全国七省水稻病虫害专业化防治服务调查数据,基于倾向得分匹配方法(PSM),剔除样本自选择内生性问题的影响,分析农户将水稻病虫害防治环节外包给植保专业化服务组织("统防统治")与"自防自治"户相比使用农药的种类和施用次数的差异,即植保专业化防治是否取得了较好的环境效应。研究结果表明,植保专业化服务显著减少了农药施用强度,提高了无公害低毒农药的采用比例;并且其效果在小农户和规模种植大户之间存在明显差异,与采纳病虫害统防统治服务的规模种植大户相比,小规模种植户在采纳病虫害统防统治服务后在降低农药施用强度,提高无公害低毒农药的应用比例方面效果更显著。基于此,文章建议强化对植保专业化防治项目的财政扶持力度,提高病虫害专业化防治覆盖率;重点鼓励小规模种植户采纳病虫害统防统治服务;鼓励农户土地流转,促进农业生产规模化经营,加强对种植专业户的病虫害防治方面的培训和引导,并着力发挥专业大户的示范带头作用,提高统防统治的效率,从而促进食品质量安全水平的提升和农业生态环境的保护。     

Air pollution and young children's inhalation exposure to organophosphorus pesticide in an agricultural community in Japan

Assessment of airborne organophosphorus pesticides in houses of young children (1-6 years old) and childcare facilities was conducted following pesticide applications in an agricultural community in Japan. Trichlorfon and fenitrothion, applied in two separate periods, were frequently detected from outdoor and indoor air. Dichlorvos, the primary degradation product of trichlorfon, was also detected after the application of trichlorfon. Both the outdoors and indoor concentration of applied pesticide were shown to increase with decreasing distance from the pesticide-applied farm. Indoor concentration of these pesticides significantly correlated with outdoor concentration (p=0.001 for trichlorfon and p=0.001 for fenitrothion), indicating infiltration of applied pesticide inside. Ratio of indoor to outdoor concentration (I/O ratio) of fenitrothion was higher for houses with windows open during the application than those with closed windows (median value: 0.74 vs. 0.16, p=0.003). However, a similar trend was not observed for trichlorfon as well as dichlorvos in the first period. Dichlorvos was found to have a higher I/O ratio than trichlorfon during the period, and clear correlation between indoor concentrations of dichlorvos and those of trichlorfon suggested increased decomposition of trichlorfon in the indoor environment. Daily inhalation exposure estimated by using the fixed measurement data and time-activity questionnaire ranged from 0 to 35 ng/kg/day for trichlorfon, from 0 to 26 ng/kg/day for dichlorvos, and from 0 to 44 ng/kg/day for fenitrothion. Median inhalation exposure from indoor air accounted for 74%, 86.3%, and 45% of the daily inhalation exposure, respectively. For kindergarteners or nursery school children, inhalation exposure at childcare facilities was comparable with or more than that at home, indicating that pollution level at childcare facilities had potential of high impact on children's exposure. Estimated daily inhalation exposures were inversely correlated to the proximity of their activity location to the pesticide-applied farm.     

鄂东鸭儿湖地区大气中有机氯农药特征及土-气交换

采用聚氨酯泡沫-被动采样法（PUF-PAS）采集鸭儿湖地区大气样,研究典型污染源地区大气中有机氯农药（OCPs）组成、来源及土-气交换现状。鸭儿湖地区大气中OCPs主要组成为艾氏剂（Aldrin）、滴滴涕（DDTs）、六六六（HCHs）、六氯苯（HCB）、甲氧滴滴涕（Methoxychlor）和a-硫丹（α-Endosulfan）,约占OCPs总量的84%。较高浓度Aldrin（平均浓度为161.25 pg/m³）广泛存在应引起高度重视。HCHs（平均浓度为89.64 pg/m³）和DDTs（平均浓度为92.29 pg/m³）普遍存在且含量高,污染程度比较明显。HCHs异构体中β-HCH高于α-HCH,远远高于γ-HCH和δ-HCH,说明HCHs经过长期降解已逐渐稳定下来;来源分析推测存在工业HCHs的使用或者受大气长距离传输影响。DDTs在各点位分布明显不同于HCHs,且各点位DDTs的六种组成均存在很大差别,可能由于点位地理位置以及农药使用情况导致;来源分析推测大气中DDTs主要来自历史残留。鸭儿湖地区OCPs土气交换研究表明,HCHs主要表现为从大气向土壤中沉降;DDTs在大多数点位源于土壤中历史残留的挥发,部分点位受到大气长距离传输影响。     

高温制备土霉素菌渣生物炭对铀尾矿库渗排水中铀的吸附效果与机理

以土霉素菌渣（oxytetracycline fermentation residue,OFR）为原料,在300~900 ℃（间隔100 ℃）条件下制备生物炭,研究高温（800~900 ℃）制备OFR生物炭对废水中铀的吸附效果与机理。结果表明：对于不同温度下制备的生物炭,随着温度的升高,OFR生物炭表面功能基团逐渐减少,Ca晶体形态由CaC₂O₄（300~400 ℃）转变为CaCO₃（500~700 ℃）、CaO（800~900 ℃）,而这也导致了吸附效果的变化。当制备温度升至800~900 ℃时,OFR生物炭10 min吸附即可对南方某铀尾矿库渗排水中的铀达到98%以上去除率,且高温制备的OFR生物炭在较宽的pH范围（4.0~9.0）与铀初始浓度（0.8~3.0 mg/L）下,均能稳定达到大于98%的去除率,处理后上清液中铀浓度远低于铀矿冶辐射防护和辐射环境保护规定的排放标准。因此,高温制备OFR生物炭在铀尾矿库渗排水原位处理方面,展示了较好的应用前景。

     

呋喃丹在模拟水稻-鱼和水稻-萍-鱼生态系统中行为归趋的比较研究

用~(14)C标记法研究呋喃丹在水稻-鱼和水稻-萍-鱼两种模拟生态系统中的分布、消失和残留行为。结果表明,由于萍的引入,使在水稻-萍-鱼系统中,田表水中的残留较低,而鱼体中残留较高。结合态残留物是土壤、鱼和植株体中呋喃丹的主要残留形态。