环境内分泌干扰物质的健康影响与作用机制

本文综述了环境内分泌干扰物质与人或动物生殖发育、行为智力、免疫功能、肥胖、糖尿病、癌症等异常或疾病的相关性及相关作用机制,讨论了其"低剂量效应"和"复合效应",对本领域今后发展的方向进行了探讨.     

中国四种土壤跳虫对重金属汞的响应

为了研究汞(Hg)对不同种类跳虫的毒性效应,将曲毛裸长()(Sinella curviseta)、四刺泡角()(Ceratophysella duplicispinosa)、小原等节()(Proisotoma minuta)、茉莉花长角()(Entomobrya sp.)4种中国优势跳虫物种分别暴露于Hg的6个浓度组中进行24 h,72 h-LC50急性毒性实验,利用Bliss法测得其4种跳虫的24h LC50分别为92.42、36.85、34.93、47.56 mg·L-1,其95%置信区间分别为68.57~168.6、29.61~43.53、25.57~44.94、34.33~65.11 mg·L-1;72 h的LC50为21.92、20.17、18.44、15.99 mg·L-1,其95%置信区间分别为16.18~29.82、6.64~29.81、13.87~26.45、10.03~21.37 mg·L-1。将小原等节()和茉莉花长角()分别暴露于Hg的6个相对较低浓度组中进行28 d生存繁殖实验,得到成虫存活数量和幼虫繁殖及生存数量。结果表明,4种跳虫中茉莉花长角()和曲毛裸长()对汞有较强的耐受性,小原等节()次之,四刺泡角()较弱。此外,小原等节()在Hg2+浓度为0.05 mg·L-1范围左右条件下有低剂量刺激效应。     

E. coli and bacteriophage MS2 disinfection by UV,ozone and the combined UV and ozone processes

The combination of low-dose ozone with ultraviolet （UV） irradiation should be an option to give benefit to disinfection and reduce drawbacks of UV and ozone disinfection. However, less is known about the disinfection performance of UV and ozone （UV/ozone） coexposure and sequential UV-followed-by-ozone （UV- ozone） and ozone-followed-by-UV （ozone-UV） expo- sures. In this study, inactivation of E. coli and bacterioph- age MS2 by UV, ozone, UV/ozone coexposure, and sequential UV-ozone and ozone-UV exposures was investigated and compared. Synergistic effects of 0.5-0.9 log kill on E. coli inactivation, including increases in the rate and efficiency, were observed after the UV/ozone coexposure at ozone concentrations as low as 0.05 mg-L-1 in ultrapure water. The coexposure with 0.02-mg.L-1 ozone did not enhance the inactivation but repressed E. coli photoreactivation. Little enhancement on E. coli inactivation was found after the sequential UV-ozone or ozone-UV exposures. The synergistic effect on MS2 inactivation was less significant after the UV/ozone coexposure, and more significant after the sequential ozone-UV and UV-ozone exposures, which was 0.2 log kill for the former and 0.8 log kill for the latter two processes, at ozone dose of 0.1 mg. t-1 and UV dose of 8.55 mJ. cm 2 in ultrapure water. The synergistic effects on disinfection were also observed in tap water. These results show that the combination of UV and low-dose ozone is a promising technology for securing microbiological quality of water.