Internal and external spatial analysis of trace elements in local crayfish

Abstract

Pollution in urban environments is a major health concern for humans as well as the local wildlife and aquatic species. Anthropogenic waste and discharge from storm drainage accumulate nutrients and environmental contaminants in local water systems. Locating contaminated sites using water samples over the vast landscape is a daunting task. Crayfish thrive in urban environments and have been used for biomonitoring pollutants. This study aimed to use crayfish as sentinels to monitor for elements in local environments. In this study, crayfish were used to measure metals and metalloids in lotic environments using ICP-OES analysis of abdominal and exoskeletal tissue. Using cluster analysis, geographical zones of trace element accumulation were determined. Eighteen total elements were analysed providing baseline data on local genera, biometric data, and element concentrations averaging 267.3 mg/kg Mn in the exoskeleton and with Zn averaging 6.88 mg/kg being significantly higher in the abdomen. Correlations of elements with biometric data allowed for internal analyses of elements. The elements As, Cr, Hg, Ni, and Tl demonstrated equivalent concentrations in both tissues. The crayfish locations with high abundance of elements allowed for the determination of contaminated areas with higher accumulations being areas of active urban development. These analyses gave measurable results of metal and metalloid to pinpoint potential sources of pollutants. Since crayfish are consumed globally as a food source, these methods can be used to determine the risk of toxic metals being passed through the food chain to the public.

Keywords: abdomen; biomonitor; environmental factors; exoskeleton; sentinel species.