Mineral contents of tissues and body fluids and heavy metal contaminants of four predominant snail species in the Niger Delta.

摘要

Mineral contents and heavy metal contaminants of 4 predominant snail species in the Niger Delta, African giant land snail (Archachatina marginata), African land snail (Achatina fulica), water snail (Pila ovata) and garden snail (Limicolaria aurora), were evaluated. Snail tissues and body fluids were harvested having cracked the tail-end of the shell. Triplicate samples of macerated snail tissues and body fluids were separately digested and extracts evaluated for contents of K, Na, Ca, Mg, Zn, Fe and P. Contributions of mineral elements in snail tissues to daily RDA for adult males and females were assessed and the results discussed. Contents of Cu, Pb, Cd, Hg and Cr in the tissues as heavy metal contaminants were analysed and compared with Federal EPA (FEPA) specifications for metals in foods. Ranges of K, Na and Ca contents of snail tissues were 40.4-61.7, 19.3-93.2 and 44.6-530.9 mug/g, respectively. Similarly Mg, Zn and Fe ranges in snail tissues were 45.6-87.5, 0.7-6.6 and 3.5-34.9 mug/g, respectively. Significant (P < 0.05) species differences were observed in mineral contents of snail tissues and body fluids. Higher concn. of K were recorded in tissues of P. ovata, A. fulica and L. aurora than in A. marginata. L. aurora tissues had significantly (P <= 0.05) higher Ca, Mg and Zn than other snail tissues. Mineral contents of body fluids followed the trends of distribution in snail tissues. L. aurora had the highest contribution of Ca (13.3/13.3%), Mg (5.46/7.10%) and Zn (15.0/20.6%) to the RDA for adult males and females, respectively. A. fulica, P. ovata and L. aurora had mean contributions of K (0.3%), while P. ovata had the highest contribution of Fe (109.1%) and Na (4.7%) to the RDA for adult males and females. Generally, Cu, Pb, Cd, Hg and Cr were accumulated at levels lower than the WHO and FEPA, Nigeria, specifications for metals in foods.