Aquatic Ecology and Water Environment Safety

CLC number: X592

Efficacy and Mechanism of Common Chemical Agents on Limnoperna fortunei in Hydraulic Engineering

常见化学药剂对水利工程中淡水壳菜的防治效果及作用机理

¹ Ecology and Environment Monitoring and Scientific Research Center, Changjiang Basin Ecology and Environment Administration, Ministry of Ecology and Environment, Wuhan 430010, Hubei, China (生态环境部长江流域生态环境监督管理局　生态环境监测与科学研究中心，　湖北　武汉　430010)
² Key Laboratory of Aquatic Organisms Monitoring and Assessment of the Changjiang Basin, Ministry of Ecology and Environment (under construction), Wuhan 430010, Hubei, China (生态环境部长江流域水生生物监测与评估重点实验室(筹)，　湖北　武汉　430010)
³ China Yangtze Power Co., Ltd., Yichang 430014, Hubei, China (中国长江电力股份有限公司，　湖北　宜昌　430014)

^† Corresponding author. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 15 July 2025

Abstract

Limnoperna fortunei (L. fortunei) is a major fouling organism in hydraulic systems, where chemical control remains a common practice. This study evaluated the molluscicidal efficacy and mechanisms of eight chemical agents including copper sulfate (CuSO₄), chloramine, sodium hypochlorite (NaClO), salicylic acid, glyphosate, chitosan-based flocculant, nicotinoyl aniline sulfate (C₁₂H₁₀N₂O·H₂SO₄, abbreviated as NS) and polyquaternium. The results show that the order of toxicity from high to low was NS > CuSO₄ > NaClO > polyquaternium > salicylic acid > glyphosate > chloramine > chitosan-based flocculant. Notably, NS (2 mg/L), CuSO₄ (1 mg/L), and NaClO (3 mg/L) each achieved over 73% mortality of L. fortunei. Enzymatic activity analysis revealed distinct response patterns. NS caused sustained increases in superoxide dismutase (SOD) and glutathione-S-transferase (GST), malondialdehyde (MDA) increased significantly at 70% mortality, succinate dehydrogenase (SDH) were all below the control group, while acetylcholinesterase (AChE) slightly increased and then decreased. CuSO₄ induced continuous SOD increase, fluctuated MDA and GST levels, similar inhibition of SDH to NS, elevated AChE at 50% mortality. NaClO resulted in moderate SOD increase, severe MDA accumulation, an initially GST increase and then decrease, elevated SDH at 70% mortality, and higher AChE at 50% mortality. These results suggest that NS and CuSO₄ suppress the physiological activity of L. fortunei primarily through oxidative stress and mitochondrial inhibition, whereas NaClO acts directly via membrane damage and oxidative injury at late stage. Histological examination of gills and gonads at 50% and 70% mortality revealed that NS triggered gill structural abnormalities and gonad atroph, CuSO₄ caused gill atrophy and gonad cavitation, NaClO induced only minor changes at 50% mortality but major gill cell loss and gonad nuclear disappearance at 70% mortality. The results of HE showed that all three chemical agents caused structural disorder of the gill filaments, gonadal atrophy and cavitation, and even disappearance of nuclei in L.fortunei, leading to significant tissue damage. These findings provide theoretical basis for selecting effective chemical controls including NS, CuSO₄ and NaClO against L. fortunei in hydraulic and enclosed infrastructure.

摘要

淡水壳菜(Limnoperna fortunei)是水利工程中常见的污损生物，化学药剂灭杀是去除淡水壳菜的常用方法。本文研究了CuSO₄、氯胺、NaClO、水杨酸、草甘膦、壳聚糖基絮凝剂、硫酸烟酰苯胺盐(以下简称NS)和聚季铵盐八种化学药剂对淡水壳菜的灭杀效果和机理。结果表明，毒性效果由高到低依次为：NS > CuSO₄＞NaClO>聚季铵盐＞水杨酸＞草甘膦＞氯胺＞壳聚糖基絮凝剂。其中，NS(2 mg/L)、CuSO₄(1 mg/L)、NaClO(3 mg/L)这三种药剂对淡水壳菜的灭杀效果较好，死亡率达73%以上。测定了三种药剂作用后不同死亡率下淡水壳菜酶活含量，结果发现，NS、CuSO₄、NaClO对淡水壳菜生理生化指标的影响存在显著差异。NS作用淡水壳菜时，超氧化物歧化酶(SOD)和谷胱甘肽S-转移酶(GST)随死亡率升高持续增强，丙二醛(MDA)在死亡率70%时明显升高，琥珀酸脱氢酶(SDH)均显著低于对照组，乙酰胆碱酯酶(AChE)略有升高后降低。CuSO₄作用淡水壳菜时，不同死亡率下SOD持续升高，MDA、GST剧烈波动，SDH抑制趋势与NS类似，AChE在50%死亡率时升高。NaClO处理淡水壳菜时，SOD轻度升高，MDA剧增，GST先升高后降低，SDH在死亡率为70%时升高，AChE在死亡率50%时升高。这说明NS和CuSO₄可能是由氧化应激和线粒体抑制来抑制淡水壳菜机体活性，而NaClO直接通过膜损伤与晚期氧化损伤作用来胁迫机体。死亡率达到50%、70%时对淡水壳菜的鳃丝及性腺进行染色切片观察。NS作用后鳃丝形态异常、细胞分布紊乱，性腺萎缩空化；CuSO₄作用后鳃丝萎缩、性腺破损严重，结缔组织空化明显；NaClO在死亡率为50%时对腮丝和性腺影响较小，但在死亡率为70%时鳃丝细胞减少、顶端空洞，性腺空化明显，核消失。组织病理学观察显示，三种化学药剂作用会导致淡水壳菜鳃丝结构紊乱、性腺萎缩空化，甚至细胞核消失，造成明显的组织损伤。本研究为水利工程管道和封闭结构中化学药剂灭杀淡水壳菜(如NS、CuSO₄和NaClO等)的选择提供了理论依据。