Toxicity and accumulation of lead and cadmium in the land snail, Archachatina papyracea, in a tropical Alfisol from Southwestern Nigeria.

Olugbenga John Owojori,Olukayode Oluwole Jegede,Oluwadunsin Esther Ayanda,Michael Awodiran

doi:10.1007/s11356-022-18947-z

Olugbenga John Owojori, Olukayode Oluwole Jegede + Show 2 more

Open Access

https://doi.org/10.1007/s11356-022-18947-z

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Abstract

Snails are an important link in the transfer of contaminants, especially metals in the food chain. Yet, few studies have examined the toxicity and accumulation of metals in snails in the tropics. This study assessed the toxicity and accumulation of two non-essential metals (cadmium and lead) to the tropical snail Archachatina papyracea. Specimens of the snail A. papyracea were exposed in a loamy soil collected from Ile-Ife, Nigeria and spiked with varying concentrations of Cd and Pb over 28days. Survival and weight change of snails were monitored weekly, while tissue accumulation was assessed at the end of the 28-day period. Survival was a more sensitive endpoint than the weight change of snails. The Cd median lethal concentration (LC50) value was 93 ± 4.4mg/kg, while the median effect concentration (EC50) for snail weight change was 131 ± 41mg/kg. For Pb, LC50 value was 1121 ± 457mg/kg, while the EC50 value for weight change was higher at 4541 ± 1180mg/kg. Therefore, Cd was a factor of about 10 to 30 × more toxic than Pb, consistent with findings on the relative toxicity of Cd and Pb to other soil organisms, including earthworms, springtails, and mites. Although not included initially as an endpoint, egg production in the snails decreased with increasing Cd and Pb concentrations in the substrate. Metal analysis of the foot and visceral mass of surviving snails showed progressive accumulation of Cd and Pb as concentration increased, showing the tendency to use body residue of A. papyracea as an indicator of metal pollution. It further suggests the role of this snail species in above-ground metal transfer in the food chain and highlights the potential danger for human consumption.

Highlights

Heavy metal pollution has become a great source of concern, especially through contamination of soil and groundwater via point and non-point sources (Edwards, 2002)
The soil was oven-dried for seven days to defaunate it, and the physicochemical properties of the soils such as soil texture, water holding capacity (WHC), pH, and organic matter (OM) were subsequently determined using methods described by Jaabiri Kamoun et al (2018)
This study demonstrated that Pb and Cd, two contrasting metals, are toxic to the tropical snail A. papyracea exposed to concentrations likely to be found in the environment

Summary

Introduction

Heavy metal pollution has become a great source of concern, especially through contamination of soil and groundwater via point and non-point sources (Edwards, 2002). Soil contamination with metals results in accumulation and subsequent toxicity to plants (Zayed et al 1998; Gimmler et al 2002), microbes and invertebrates (Owojori et al 2009a). In metal-contaminated industrial soils, reports of loss of invertebrate species diversity are commonly reported (Spurgeon et al 1994; Jones 1991). Heavy metals can cause spermatozoa damage thereby reducing the earthworm sperm count (Cikutovic et al 1993; Reinecke and Reinecke 1997), which negatively affects reproduction (Spurgeon et al 1994). Abnormal environmental metal concentrations have been reported to adversely affect the feeding, growth, reproduction, and general physiology of molluscs (Bonally De Calventi 1965; Calabrese et al 1977)

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