Matthew Nkoom,Guanghua Lu,Jianchao Liu,Haohan Yang,Huike Dong
Owing to its persistence, carbamazepine an antiepileptic drug is regularly detected in the aquatic environment. The motive for our research was to assess the bioconcentration, physiological and biochemical effects of carbamazepine in Daphnia magna . A 48 h aqueous exposure of carbamazepine yielded bioconcentration factors of 202.56 and 19.95 in Daphnia magna for the respective nominal treatments of 5 and 100 µg/L. Apparently, the inhibition of the capability of Daphnia magna to obtain food attributable to carbamazepine exposure will reduce their fitness to reproduce as well as to grow. Also, a significant alteration in the phototactic behaviour of Daphnia magna exposed to carbamazepine is maladaptive since it will increase their chance of being preyed upon in the surface water during daylight. Again, a significant decline in the acetylcholinesterase activity observed herein brings to light the neurotoxicity of carbamazepine to Daphnia magna . Moreover, significant inhibition of the superoxide dismutase, catalase and glutathione reductase activities coupled with the simultaneous induction of the malondialdehyde content imply that carbamazepine evoked a life-threatening oxidative stress that overpowered the antioxidant defence system of Daphnia magna . These observations confirm that carbamazepine can accumulate and consequently cause negative physiological and biochemical changes to wild Daphnia magna populations.
Dong Zhou,Jie Yang,Hui Li,Changzheng Cui,Yunjiang Yu,Yongdi Liu,Kuangfei Lin
To investigate biological effects of bisphenol A (BPA) over the long term, the model animal Caenorhabditis elegans was used to conduct the chronic exposure. C. elegans were exposed to BPA (0.0001–10 μM) from L4 larvae to day-10 adult in the present chronic toxicity assay system. Multiple endpoints at the physiological (growth, locomotion behaviors and lifespan), biochemical (lipofuscin accumulation), molecular (stress-related genes expressions), and population (population size) levels were examined. At the physiological level, BPA exposure induced significant negative effects on the indicators. Among the endpoints, head thrash was most sensitive and the detection limit was 0.001 μM. At the biochemical level, BPA exposure induced no significant effects on lipofuscin accumulation. At the molecular level, BPA induced strong stress responses in vivo . At the population level, the population size was significantly decreased in the treatment groups from 0.1 to 10 μM. Compared to the previous short-term toxicity evaluation, long-term exposure to BPA induced a more obvious response at the same concentration, and the phenomenon might be due to cumulative toxic effects. By the Pearson correlation analyses, cep-1 was speculated to act as an important role in BPA-induced chronic toxicity on C. elegans .