Absorption and bioaccumulation of heavy metals in giant African land snails (Archachatina marginata)

Abstract

Interest in the production of micro-livestock to supply the required protein has resulted in the intensive production of Snails. Wild and domesticated snails fed on contaminated feed may accumulate heavy metals which may be injurious to the consumers. Although toxicity and the resulting threat to human health of any contaminant are, of course, a function of concentration, it is well-known that chronic
exposure to heavy metals and metalloids at relatively low levels can cause adverse effects. This study aimed at investigating the ability and effects (if any) of heavy metal accumulation in Giant African Land Snails (Archachatina marginata). 120 A. marginata growers were randomly allotted to 2 feed treatments (T1: Heavy metal contaminated pawpaw fruits and leaves; and T2: Heavy metal free pawpaw fruits and leaves) in a Completely Randomized Design. Each treatment has 4 replicates containing 15 snails per replicate. The experimental diets were fed ad libitum for the period of 12 weeks during which recommended management practices were strictly adhered to. Data were collected on shell length, shell width, and live weight. Results
obtained revealed that giant land snails possess the ability to bio-accumulate heavy metals in their tissues and this accumulation could have a reducing effect on all studied parameters, caused pathological lesions of the edible foot and mortality. It was thus recommended that feeds given to caged snails, and even other animals, should be ascertained heavy metals free before offered.

Keywords: Heavy metals, Bioaccumulation, Giant Land Snails, Contamination, Food safety.