Studies on acute and chronic toxicity of cadmium to freshwater snail Lymnaea acuminata (Lamarck) with special reference to behavioral and hematological changes

Abstract

Molluscs have long been regarded as promising bioindicator and biomonitoring subjects for heavy metals as molluscs are highly tolerant to heavy metals and exhibit high accumulation in their body. In spite of several previous studies about the impact of cadmium on molluscs, little information exists in literatures concerning the toxic effects of cadmium on Lymnaea acuminata, especially pertaining to behavioral and hematological changes as these are considered effective bioindicators and biomonitoring variables for detecting heavy metals in polluted water bodies. In the present study, the median lethal concentrations of cadmium chloride to snail, Lymnaea acuminata, were estimated to be 9.66, 7.69, 6.26, and 5.54 mg/L at 24, 48, 72, and 96 h, respectively. For behavioral studies, variable test concentrations of cadmium from 0.00 to 10 mg/L were used. The clumping tendency, crawling activity, and touch reflex in the exposed snails were gradually decreased with higher concentrations at 72 and 96 h. For measuring the hemocyte numbers in the circulating hemolymph of snail during chronic cadmium exposure, two sublethal doses of cadmium (10 and 20% 96-h LC-0.55 and 1.11 mg/L, respectively) were used. A significant variation (p < 0.05) from the control at all exposure times (7, 14, 21, and 28 days) was recorded at 1.11 mg/L concentration. The total count of circulating hemocytes was significantly reduced (p < 0.05) compared to the controls at both concentrations of cadmium exposure at all time periods except 14 and 21 days exposure at 0.55 mg/L where values were non-significantly increased. In comparison between two sublethal doses, blood cells were significantly (p < 0.05) lowered at 1.11 mg/L cadmium treatment. Considering the behavioral and hematological data, it seems possible to forecast the physiological state of snails in cadmium-contaminated water bodies and these findings can be used in determining the safe disposal level of cadmium in aquatic ecosystem.

Investigating the effects of three trace metals on the viability, embryonic development, and locomotor behavior of the Seminole ramshorn snail at environmentally relevant concentrations

“…Slight differences between the actual and nominal concentrations are likely due to solubility of the metal salts utilized, sorption of metals to treatment containers, or operator error when conducting the assay. The treatment concentrations used in this study were within or below those used in prior trace metal exposure studies with freshwater snails (Ansaldo et al, 2009; Dhara et al, 2017; Gomot, 1998; Pyatt et al, 2002; Ravera, 1977; Sawasdee & Köhler, 2010). While many of the treatments used for this study were higher than the average contamination rates observed in aquatic environments, they can be applied to circumstances dealing with acute contamination events (spills, releases, etc.…”

“…Slight differences between the actual and nominal concentrations are likely due to solubility of the metal salts utilized, sorption of metals to treatment containers, or operator error when conducting the assay. The treatment concentrations used in this study were within or below those used in prior trace metal exposure studies with freshwater snails (Ansaldo et al, 2009;Dhara et al, 2017;Gomot, 1998;Pyatt et al, 2002;Ravera, 1977;Sawasdee & Köhler, 2010).…”

The distribution and effects of microbeads on host-parasite interactions of Ontario wetland fauna: tadpoles, snails and trematodes

“…Molluscs are important environmental bioindicators because they accumulate pollutants (Dhara et al, 2017), but aquatic snails are also a key host for parasites that can affect humans, domestic animals, and wildlife, such as trematodes (flatworms) that cause the harmful disease known as schistosomiasis (Gryseels et al, 2006). The trematode life cycle is very complex with multiple intermediate hosts (Sukhdeo, 2012).…”

The allelochemical tannic acid affects the locomotion and feeding behaviour of the pond snail, Lymnaea stagnalis, by inhibiting peripheral pathways

“…The ciliary movements are modulated by serotonergic mechanisms originating from the central (pedal) neurons (Sidorov and Kazakevich 2001; Pavlova 2010), while the foot muscle contractions are under dopaminergic regulation (Pavlova 2013, 2019). The spontaneous locomotion of Lymnaea can easily be monitored and quantified (Pyatt et al 2002; Dhara et al 2017; Ford et al 2018).…”