利用隆线溞趋光行为检测水体中五氯酚钠和镉的研究

采用自主选育的隆线溞单克隆体作为试验生物,研究了五氯酚钠(PCP-Na)和镉对隆线溞趋光指数的影响,并与急性毒性试验方法进行了比较.结果表明,在试验浓度范围内,水溞的趋光指数分别随五氯酚钠和镉浓度的升高而降低,呈极显著线性关系,说明隆线溞趋光指数的变化可以指示水体中这2种毒物的生物有效浓度.PCP-Na使隆线溞趋光指数(3h)发生显著改变的下限浓度为0.18 mg·L～,远低于LC50(96 h)(0.59 mg·L-1),上限浓度大于3.20 mg·L-1,也远高于LC50(24h)(0.73 mg·L-1),表明隆线溞趋光指数法比急性毒性试验法的灵敏度高,检测范围大,耗时短.在试验溶液范围内,五氯酚钠和镉之间不存在明确的相互作用关系.

Monitoring sodium pentachlorophenate and cadmium in aquatic solutions by phototactic behavior of Daphnia carinata clone

Daphnia carinata clone was used to study the phototactic behavior in response to sodium pentachlorophenate (PCP-Na) and cadmium. Phototactic index of Daphnia carinata was decreased with the concentrations of PCP-Na and Cd increased. A linear regression equation (p<0.01) was established between the phototactic index and the concentrations of the toxicants, indicating the detection of bioavailable concentrations of the two toxicants in aquatic solutions by the changes in phototactic behavior of Daphnia carinata. The detection limit for changes in phototactic behavior of Daphnia carinata was 0.18 mg·L^-1 for PCP-Na present at 3 hours, quite lower than LC₅₀(96h) (0.59 mg·L^-1), the half lethal concentration,while the maximum detection concentration was higher than LC₅₀(24h)(0.73 mg·L^-1). The results showed the more sensitive and quicker changes in the phototactic behavior of Daphnia carinata in response to PCP-Na and wider ranges of PCP-Na concentrations monitored by the phototactic index than acute lethal method. There was no interaction effect of PCP-Na×Cd²⁺ on phototactic behavior.