Trace Metal Concentrations in Mesopodopsis orientalis (Crustacea: Mysidae) with Regard to Its Life Stages and Sex in the Cochin Estuary, India

Abstract

Trace metal concentrations with regard to certain life stages and sex of mysid species, <i>Mesopodopsis orientalis</i>, from the Cochin estuary were studied during monsoon and pre-monsoon seasons. Spatially varying heterogeneous patterns of trace metal loads were apparent within the mature males, immature males, spent females, brooding females, immature females and juveniles of <i>M. orientalis</i> for the region. The concentration ranges of trace metals like Fe, Mn, Zn, Pb, Cu, Cd, Ni, Cr and Co in <i>M. orientalis</i> were: 590.5 to 1554.9 mg/kg, 4.1 to 15.1 mg/kg, 42.0 to 126.5 mg/kg, 2.5 to 17.0 mg/kg, 12.8 to 61.9 mg/kg, 0.2 to 2.3 mg/kg, 7.6 to 25.5 mg/kg, 8.8 to 33.4 mg/kg and 0.2 to 2.2 mg/kg, respectively. Higher metal concentrations were noted for the life stages of <i>M. orientalis</i> during the monsoon season than in the pre-monsoon season. Mature males, immature males, spent females, brooding females, immature females and juveniles of <i>M. orientalis</i> showed large variability in bioaccumulation for specific metals probably associated with distinct physiological processes. Juveniles and immature stages of <i>M. orientalis</i> showed higher metal concentrations than adult organisms. High metal bioaccumulation and its spatial and seasonal variability with regard to animal life stages and sex suggest the importance of <i>M. orientalis</i> as a biomonitor for tracing metal contamination in estuarine environments.