腐殖酸作用下沉积物中纳米氧化铜对铜锈环棱螺生态毒性的影响

为了探讨不同水平腐殖酸作用下沉积物中纳米氧化铜(CuO-NPs)对底栖生物生态毒理学效应的影响,以铜锈环棱螺(Bellamya aeruginosa)为受试生物,通过腐殖酸和CuO-NPs加标沉积物的慢性(28 d)生物测试,研究了肝胰脏中Cu的生物积累、Na+K+-ATP酶(ATPase)、超氧化物歧化酶(SOD)以及过氧化氢酶(CAT)活性的变化规律.结果表明,在低浓度CuO-NPs处理组(60 μg·g1),沉积物中腐殖酸水平对Cu的生物积累以及ATPase、SOD和CAT活性均没有显著影响.在中、高浓度CuO-NPs处理组(≥180 μg·g-1),Cu的生物积累均随腐殖酸水平的增加而显著升高;肝胰脏ATPase活性随腐殖酸水平的增加而显著下降;当腐殖酸水平为0.05 g·g-1时,SOD活性显著高于未添加腐殖酸组,表现为显著诱导,当腐殖酸水平≥0.1g·g-1时,SOD活性开始下降,并具有浓度依赖性;随腐殖酸水平的增加,肝胰脏CAT活性总体上表现为浓度依赖性显著下降.由于沉积物中腐殖酸的存在,显著增加CuO-NPs在沉积物中的分散稳定性,更容易被铜锈环棱螺摄取,从而通过增加CuO-NPs的生物积累而增强对铜锈环棱螺的生态毒性.

Impacts of Humic Acid on Ecotoxicity of CuO Nanoparticle in Bellamya aeruginosa under the Sediment Scenario

The effects of with humic acid (HA) and CuO nanoparticles (CuO-NPs) in sediments on Cu accumulation, Na+K+-ATPase, SOD, and CAT activities in the hepatopancreas of Bellamya aeruginosa following a 28-d chronic bioassay were investigated to get insight into the ecotoxicological effects of CuO-NPs in sediments with various gradient of HA on benthic macroinvertebrates. The results indicated that, at low concentration of CuO-NPs (60 g·g^-1), the content of HA had no effects on the hepatopancreatic Cu accumulation, Na+K+-ATPase, SOD, and CAT activities. At CuO-NPs concentration of 180 g·g^-1 or above, Cu accumulation raised significantly with increase of HA content, however ATPase activities decreased significantly when enhancing HA content. At HA content of 0.05 g·g^-1, SOD activities were significantly higher than that in the free HA groups, indicating a marked induction. However, at HA content of 0.1 g·g^-1 or above, SOD activities showed a content-dependent decline of HA. Generally, the hepatopancreatic CAT activities increased significantly with increase of HA content. The HA in sediments could reduce the aggregation of CuO NPs and enhance its homogeneous dispersion, which facilitated ingestion of CuO-NPs by B. aeroginosa, so the increased Cu accumulation enhanced its ecotoxicity.