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.
A Wed, study studied this question.