Key Laboratory for Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
Key Laboratory for Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
Ecotoxicol Environ Saf. 2016 Apr;126:85-93. doi: 10.1016/j.ecoenv.2015.12.020. Epub 2015 Dec 23.
The objective of the present study was to investigate the uptake, depuration, and bioconcentration of two pharmaceuticals, roxithromycin (ROX) and propranolol (PRP), in Daphnia magna via aqueous exposure. Additionally, dietary and pH effects on the bioconcentration of two pharmaceuticals in daphnia were studied. During the 24-h uptake phase followed by the 24-h depuration phase, the uptake rate constants (k(u)) of ROX for daphnia were 9.21 and 2.77 L kg(-1) h(-1), corresponding to the exposure concentrations of 5 and 100 μg L(-1), respectively; For PRP at the nominal concentrations of 5 and 100 μg L(-1), k(u) were 2.29 and 0.99 L kg(-1) h(-1), respectively. The depuration rate constants (k(d)) of ROX in daphnia, at the exposure concentrations of 5 and 100 μg L(-1), were 0.0985 and 0.207 h(-1), respectively; while those of PRP were 0.0276 and 0.0539 h(-1) for the nominal concentrations of 5 and 100 μg L(-1), respectively. With the decreasing exposure concentrations, the bioconcentration factors (BCFs) in daphnia ranged from 13.4 to 93.5 L kg(-1) for ROX, and 18.4 to 83.0 L kg(-1) for PRP, revealing the considerable accumulation potential of these two pharmaceuticals. Moreover, after 6h exposure, the body burdens of ROX and PRP in dead daphnia were 4.98-6.14 and 7.42-12.9 times higher than those in living daphnia, respectively, implying that body surface sorption dominates the bioconcentration of the two pharmaceuticals in daphnia. In addition, the presence of algal food in the media could significantly elevate the kd values for both ROX and PRP, thereby restraining their bioconcentration in daphnia. A pH-dependent bioconcentration study revealed that the bioconcentration of the two pharmaceuticals in daphnia increased with increasing pH levels, which ranged from 7 to 9. Finally, a model was developed to estimate the relationships between pH and the BCFs of the two pharmaceuticals in zooplankton. The predicted values based on this model were highly consistent with wildlife monitoring data, implying that this model will be useful in identifying the bioaccumulation risks that pharmaceuticals pose to zooplankton.
本研究旨在通过水相暴露研究两种药物罗红霉素（ROX）和普萘洛尔（PRP）在大型溞体内的摄入、消除和生物浓缩情况。此外，还研究了膳食和 pH 值对大型溞体内两种药物生物浓缩的影响。在 24 小时的摄入阶段和随后的 24 小时消除阶段中，ROX 对大型溞的摄入速率常数（k(u)）分别为 9.21 和 2.77 L kg(-1) h(-1)，对应于 5 和 100 μg L(-1)的暴露浓度；对于 PRP，在 5 和 100 μg L(-1)的名义浓度下，k(u)分别为 2.29 和 0.99 L kg(-1) h(-1)。ROX 在大型溞体内的消除速率常数（k(d)）在 5 和 100 μg L(-1)的暴露浓度下分别为 0.0985 和 0.207 h(-1)；而 PRP 的消除速率常数（k(d)）分别为 0.0276 和 0.0539 h(-1)，对应于 5 和 100 μg L(-1)的名义浓度。随着暴露浓度的降低，大型溞体内的生物浓缩因子（BCF）范围为 ROX 的 13.4 至 93.5 L kg(-1)，PRP 的 18.4 至 83.0 L kg(-1)，表明这两种药物具有相当大的积累潜力。此外，在 6 小时暴露后，死大型溞体内 ROX 和 PRP 的体内负荷分别比活大型溞体内高 4.98-6.14 倍和 7.42-12.9 倍，表明体表面吸附主导了这两种药物在大型溞体内的生物浓缩。此外，介质中藻类食物的存在可显著提高 ROX 和 PRP 的 kd 值，从而抑制它们在大型溞体内的生物浓缩。一项 pH 依赖性生物浓缩研究表明，这两种药物在大型溞体内的生物浓缩随 pH 值的升高而增加，范围为 7 至 9。最后，建立了一个模型来估计浮游动物中两种药物的 pH 值与 BCF 之间的关系。该模型预测的值与野生动物监测数据高度一致，表明该模型将有助于识别药物对浮游动物的生物积累风险。
