壬基酚对浮游生物的毒性效应及其食物链传递

以蛋白核小球藻及5种枝角类（微型裸腹溞、多刺裸腹溞、盔型溞、蚤状溞、大型溞）浮游动物为研究对象，开展壬基酚（NP）对浮游生物的毒性效应，及NP在“水-蛋白核小球藻-大型溞”食物链的生物富集和生物传递能效研究.结果表明：NP对微藻的半抑制效应浓度为3.33mg/L；对5种枝角类浮游动物的48h半致死效应浓度范围介于8.67~131.79μg/L，裸腹溞属耐受性显著高于溞属.1和5μg/LNP连续暴露下，大型溞存活率显著降低，且首次繁殖时间延迟，前者仅在第8d有子代产出，而后者未观察到子代个体.微藻对培养液中0.1mg/LNP的生物富集系数（BCF）在3h时达到最大值7393.投喂NP暴露后的微藻，大型溞摄食率呈显著降低的趋势，且第3d天出现死亡现象.大型溞体内NP含量最大值为0.07mg/g，NP经蛋白核小球藻传递到大型溞的生物富集系数仅为0.097.NP的低食物链传递可能与大型溞对NP的转化、大型溞生长过程中的蜕壳以及摄食后的消化和排泄过程有关.

Toxic effects of nonylphenol on plankton and its bioconcentration through algae-cladoceran food chain

Nonylphenol (NP) transformed from detergents was detected in water, sediment and biota all over the world. Acute toxicity of nonylphenol to Chlorella pyrenoidosa, five species of cladocerans (Monia micrura, Monia macrocopa, Daphnia geleata, Daphnia pulex, Daphnia magna) and chronic toxicity of NP to Daphnia magna were measured. In addition, the bioconcentration effect of NP through the trophic chain (water-C. pyrenoidosa-D. magna) was studied. The half inhibitory effect concentrations (EC₅₀) of NP on algae was 3.33mg/L after cultured for 96h, while the lethal concentrations 50(LC₅₀) on five species of cladocerans were ranged from 8.67 to 131.79μg/L. The LC₅₀ values suggested that the tolerance of Monia was higher than Daphnia. The survival rate and reproductivity of D. magna were significantly inhibited under 1and 5μg/L NP exposure during chronic toxicity test. The offspring production was observed only in the 8th day exposed to 1μg/L NP, while no offspring production was observed treated with 5μg/L NP. The bioconcentration factor of NP in C. pyrenoidosa was 7393 at 3h exposed to 0.1mg/L NP. The grazing rate of D. magna was decreased significantly when fed with NP-rich algae and the survival rate was declined after 3days culture. However, almost all NP ingested by D. magna was metabolized, therefore, only traces of NP (0.7mg/g) was found in D. magna. The bioconcentration factor of NP through C. pyrenoidosa to D. magna was 0.097. The results indicated that microalgae acted as the first level of trophic chain are able to bioconcentrate the endocrine disruptor NP significantly. The NP-rich algae affected the growth characters of crustacean, however, the metabolism of NP in crustacean eliminating the further effects of NP through food chain. Moreover, the low efficiency of the bioconcentration factor in D. magna was also due to the physiological processes, such as, transformation, exuviation, digestion and excretion.