多相催化-臭氧氧化法处理模拟有机磷农药废水

实验通过臭氧氧化法来降解模拟废水中的有机磷农药,将其转化为无害物质,并试验研究了在废水中加入2种自制的催化剂对降解结果的影响。采用气相色谱法测定水中有机磷农药的量。结果表明,只用臭氧处理的情况下1周后有机磷的去除率为78.03%;在催化剂A存在下,去除率可达93.85%;在催化剂B存在下,去除率可达为88.35%。结果表明,臭氧氧化法对此类污水具有较好的降解作用,尤其在有催化剂存在的情况下处理效果更好,在室温和中性介质中均属于一级反应。     

12种常见农药对海胆胚胎发育的毒性影响

为了研究低浓度下农药对海胆胚胎的毒性影响,以及正辛醇/水分配系数(LogP)与致死率的关系,实验研究了12种常见农药(阿维菌素、硫丹、除虫脲、甲氰菊酯、三环唑、使它隆、抑霉唑、戊唑醇、磺胺吡啶、磺胺甲噁唑、磺胺二甲嘧啶和磺胺嘧啶)在低浓度(0.01mg.L-1)下对光棘球海胆(Strongylocentrotus nudus)胚胎发育的急性毒性影响.结果显示:1)实验浓度下,磺胺吡啶、三环唑、磺胺嘧啶和抑霉唑分别对受精膜举起期、2细胞期、上浮囊胚期和棱柱幼体期相对致死率最高,分别达到3.70%、6.19%、5.84%和6.07%.2)农药对海胆胚胎发育存在低剂量有毒物质的刺激作用(Hormesis现象).3)在海胆胚胎各发育期,LogP与相对致死率呈现一定的负相关性,即随着LogP的增加,各农药对海胆胚胎的相对致死率逐渐下降.     

农药阿维菌素在水中的光解动态及机理

为了科学评价农药阿维菌素的环境安全性,采用室内模拟方法研究了其在水环境中的光解动态,考察了波长、光强和添加物质等对阿维菌素光降解的影响,进而利用LC/MS鉴定了其主要降解产物,并对降解机理进行了初步探讨.结果表明:紫外灯辐射波长对阿维菌素的光解速率影响较大,波长越短,越有利于阿维菌素的光降解;模拟太阳光强度越大,阿维菌素的光解速率越快;1%H_2O_2、0.1%TiO_2和10%丙酮作为添加物质都能加快阿维菌素的光解进程;通过分析阿维菌素光解产物的TIC图和质谱图,可能主要有两种代谢产物,分析了其降解途径及机理.     

Reduction of recruitment of Acartia pacifica nauplii from benthic resting eggs due to organochlorine pesticides

Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment ofnauplii to the water column population. The potential effects of two organochlorine pesticides, hexchloriobinzene （HCH） and dichlorodiphenyltrichloroethane （DDT）, on the recruitment of A ccu＇tla pacifica nauplii from benthic resting eggs in the seabed of Xiamen Bay were experimentally investigated. The abundance of A. pacifica nauplii hatched from the sediment significantly decreased with the increase of pesticide concentration. Trimmed Spearman-Karber analysis gave sediment 96-h LC50 values were 84.81 ng/g for HCH, and 157.94 ng/g for DDT. The median AI （Al50） was -0.77, which suggested that the combined effect of riCH and DDT showed a weak effect than individual effects. There was a positive relationship between mortality and exposure time in DDT treatment, while the relationship was not significant in HCH treatment. The results suggest that organochlorine pesticides can reduce recruitment of A. pacifica nauplii from benthic resting eggs to planktonic population.     

Feasibility of using salivary biomarkers to assess human exposure to chlorpyrifos

The objective of this study was to determine the feasibility of using salivary biomarkers to assess chlorpyrifos exposure using data collected from laboratory controlled animal study, as well as from farmers in Thailand and Nicaragua who applied chlorpyrifos in the field. Time-matched saliva and arterial blood samples were collected from rats and adult agricultural workers, while spot saliva samples were collected from children. Specimen samples were analyzed for chlorpyrifos using a commercially available enzyme-linked immunosorbent assay. The results from both animal and farmer studies show that chlorpyrifos is excreted into saliva. Nevertheless, salivary excretion of chlorpyrifos seems to differ from other pesticides, as evidenced by the lack of correspondence of chlorpyrifos levels between saliva and plasma samples. The lower chlorpyrifos concentrations in saliva collected from rats, and from farmers and their children, may have resulted from the rapid hydrolysis of chlorpyrifos during the intracellular passive diffusion in the salivary gland. In conclusion, chlorpyrifos is excreted into saliva; however, the majority of chlorpyrifos that is excreted in saliva may have been metabolized due to base-dependent hydrolysis. Because of this finding, it was hypothesized that it would be ideal to measure its metabolite, 3,5,6-trichloropyridinol, in saliva as the biomarker for chlorpyrifos exposure.     

Organochlorine pesticide residues in fodder from rural areas of Haryana,India

Residues of organochlorine pesticides (OCPs) namely 1,2,3,4,5,6-hexachlorocyclohexane isomers (HCH-isomers), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) and its metabolites, and endosulfan stereoisomers were analyzed in dry and green fodder samples from rural areas of Ambala, Gurgaon, and Hisar districts of Haryana, India during winter, summer, and post-monsoon seasons. The HCH isomers γ-HCH and β-HCH, and DDT and its metabolites p,p′-DDD, p,p′-DDE, and p,p′-DDT had more traceability in test samples as compared to other isomers and metabolites studied. Total OCPs (ΣOCPs), i.e., ΣHCH, ΣDDT, and Σendosulfan were found to be the highest in wheat straw (1.1–1.2?mg?kg^?1) from Ambala and Gurgaon, followed by that in sorghum straw (0.46?mg?kg^?1) from Hisar. Dry fodder samples were found to have relatively higher residue levels than green fodders. In case of green fodder samples, maximum ΣOCP residues of 0.44?mg?kg^?1 were found in whole plant samples of sorghum from Gurgaon district followed by that in pearl millet (0.40?mg?kg^?1) from Ambala. The findings indicate highly significant differences (p?>?0.0001) in ΣOCPs and ΣDDT in wheat straw between different districts and reveal the persistence of OCP residues in both dry and green fodder samples in the study area.     

Subacute chlorpyrifos-induced alterations in serum lipids and some oxidative stress biomarkers in male Wistar rats: beneficial effect of acetyl-L-carnitine

The present study evaluated the beneficial effect of acetyl-L-carnitine (ALC) on subacute chlorpyrifos (CPF)-induced alterations in serum lipid profiles and some biomarkers of oxidative stress in Wistar rats. Twenty-eight adult male rats divided into four groups of seven animals each (group I–IV) were used: I (S/oil) received soya oil (2 ml kg^?1), II (ALC) received ALC (300 mg kg^?1); III (CPF) received CPF (8.5 mg kg^?1 ～ 1/10th LD₅₀); IV (ALC+CPF) was pretreated with ALC (300 mg kg^?1) and then exposed to CPF (8.5 mg kg^?1), 30 min later. The treatment was orally for 28 days duration. Sera obtained from blood samples were evaluated for the levels of triglyceride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-c), malondialdehyde (MDA), and the activities of superoxide dismutase (SOD) and catalase (CAT). The levels of low density lipoprotein-cholesterol (LDL-c), very low density lipoprotein-cholesterol (VLDL-c), and atherogenic index (AI) were calculated. The result showed that elevated levels of TG, TC, LDL-c, VLDL-c, AI, and MDA, and the decreased levels of HDL-c, CAT, and SOD induced by CPF were modulated by ALC. It was concluded that ALC ameliorated the alterations in serum lipid and oxidative stress induced by CPF exposure in the rats, partly through its antioxidant properties.     

Influence of a botanical pesticide,azadirachtin, on ultimobranchial gland of the freshwater catfish Heteropneustes fossilis

Freshwater catfish, Heteropneustes fossilis, were subjected to 42 mg L^?1 of azadirachtin for short-term exposure (96 h) and to 10.5 mg L^?1 for long-term exposure (28 days). Six fishes were sacrificed on each time interval from control and experimental groups after 24, 48, 72, and 96 h in the short-term exposure and after 7, 14, 21, and 28 days in the long-term experiment. The calcium regulating endocrine gland, viz. the ultimobranchial gland, was fixed for histological studies. Up to 72 h of azadirachtin treatment, there was no histological alteration in the UBG (ultimobranchial gland) of H. fossilis. After 96 h exposure, the ultimobranchial cells stain feebly and the nuclear volume of these cells were slightly decreased. No histological alterations have been observed in the UBG cells up to 14 days following azadirachtin exposure. After 21 days, the cytoplasm of ultimobranchial cells was feebly stained and the nuclear volume exhibits a decrease. The nuclear volume of these cells was further decreased and the gland shows vacuolization and degeneration at certain places after 28 days azadirachtin treatment. Hence, it can be concluded that azadirachtin severely affects the physiology of calcium homeostasis in H. fossilis. Therefore, the botanical pesticides should be used carefully near aquatic reservoirs.     

贵州百花湖水体中有机氯农药的残留及健康风险评价

为了研究贵州百花湖水体中有机氯农药(OCPs)对人体的潜在健康风险,在百花湖及其周边布设8个采样点分别采集水样,采用液液萃取-毛细管气相色谱法对OCPs的残留状况进行测定.结果显示,水样中11种有机氯的总含量范围为15.5～43.8ng·L-1,其中,BHCs和DDTs含量范围分别为3.2～14.6和1.2～7.8 ng·L-1.采用美国国家环境保护局(EPA)推荐的健康风险评价方法的评价结果表明,百花湖水体中OCPs的致癌风险和非致癌风险均低于国际辐射防护委员会(ICRP)推荐的最大可接受风险水平,表明百花湖水体中11种OCPs对人体健康风险处于较低水平.     

蔬菜主要污染问题

根据国内外有关资料及杭州市菜区调查结果，讨论了重金属、硝酸盐、农药、氟化物、苯并（ａ）芘在及塑料薄膜等对蔬菜污染的途径和危害，阐述了目前我国蔬菜所面临的主要污染问题。