摘要
水蚯蚓污泥减量技术是一种可持续发展的新技术,已成功应用于城镇生活污水处理系统.但污水处理厂的剩余污泥尤其是工业废水处理系统的剩余污泥中往往含有各种重金属污染物.为了将水蚯蚓的应用范围拓宽至含重金属污染的城镇污水或工业废水处理系统中,本文选取典型重金属铬作为研究污染物,以呼吸速率和LC50为指标,考察在Cr胁迫下水蚯蚓的响应机制.96 h急性毒性试验结果表明,随着曝露时间的增加,半致死浓度LC50降低,24 h LC50和96 h LC50分别为7.94 mg·L-1和0.49 mg·L-1,Cr(Ⅵ)对水蚯蚓的安全浓度为0.09 mg·L-1.正交试验结果表明,当Cr(Ⅵ)浓度为2.50 mg·L-1、温度26℃、pH=6.0、DO为6.0 mg·L-1时,水蚯蚓呼吸速率最高.对水蚯蚓呼吸速率影响的因素从主到次为Cr(Ⅵ)浓度、温度、DO浓度、pH值.在本试验中,当六价铬浓度低于2.50 mg·L-1时,铬对水蚯蚓的呼吸速率有促进作用,反之,当六价铬浓度高于8.00mg·L-1时,则对水蚯蚓的呼吸速率起到明显抑制作用.
Tubificidae is now used in the wastewater treatment systems to successfully minimize the sludge production,which has been proved an effective,economical and sustainable technology. But the excess sludge inevitably contains a variety of heavy metals,especially the sludge from industrial wastewater treatment plant. In order to apply tubificidae to these systems,Chromium was selected as pollutant object and the physiological responses of tubificidae to Chromium were studied in this paper. Acute toxicity was analyzed and Median lethal concentrations(LC50) were determined over 96 h periods for Cr. Results indicated that24 h LC50 and 96 h LC50were7. 94 mg·L- 1and 0. 49 mg·L- 1,respectively. The duration of tubificidae in Cr solution decreased with increasing Cr concentration.Under the Cr stress,a highest respiration rate was obtained when the concentration of Cr(Ⅵ),temperature,pH and DO was 2. 50mg·L- 1,26℃,6.0 and 6.0 mg·L- 1,respectively. The order of these factors was the concerntration of Cr(Ⅵ),temperature,DO and pH. The respiration experiments demonstrated that low concentration( < 2. 50 mg·L- 1) of Cr could promote the respiration rate of tubificidaes. On the other hand,when the concentration of Cr was 8. 00 mg·L- 1,it could remarkably inhibit the respiratory rates of tubificidae.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2014年第11期4205-4211,共7页
Environmental Science
基金
浙江省自然科学基金项目(Y12E080076)
浙江省高等学校创新团队支持计划项目(T200912)
关键词
六价铬
水蚯蚓
急性毒性
呼吸速率
正交
Cr(Ⅵ)
tubificidae
acute toxicity
respiration rate
orthogonal
