Variation in Persistent Organochlorine Pesticide Residues among Various Tissues of House Sparrow, Passer domesticus, from Tamil Nadu, India, during 2001–2006

Abstract

ABSTRACT
The present study focuses on persistent organochlorine pesticides (OCPs) on various tissues of house sparrow, Passer domesticus, from Tamil Nadu, India, between 2001 and 2006. The major compounds quantified in eggs, liver, brain and muscle tissues are hexachlorocyclohexane (HCH), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p’-DDE), dichloro-diphenyl-trichloroethane (ΣDDT), dieldrin, and heptachlor epoxide. The mean concentrations of ΣPCBs, ΣHCH and ΣDDT in eggs are 0.94 ± 0.66 μg/g and 0.35 ± 0.26 μg/g respectively on wet wt. basis. Concentrations of p,p’-DDE, a metabolite of p,p’-DDT, contributed 77% to the total DDT. Variations in residue levels of ΣHCH, ΣDDT and heptachlor epoxide were not significant (p > 0.05) among different tissues analyzed except eggs (p < 0.05). Twenty-eight percent of egg samples exceeded the p,p’-DDE concentration which was proposed as critical levels for birds. Although the residue levels among various years show a decrease (from 2001 to 2005) and increase in (2005 onwards), the trend of concentration, continuous presence of HCH and DDE indicate the input of chemicals to the environment. Given the scarcity of information on toxicity threshold levels for OCPs in avian species, coupled with the trend toward continuing concentrations in house sparrow, continued monitoring and further toxicological studies of these compounds are warranted.
Keywords: OCPs, house sparrow, egg shell thickness, tissues