SERUM-B ESTERASES AS A NONDESTRUCTIVE BIOMARKER FOR MONITORING THE EXPOSURE OF REPTILES TO ORGANOPHOSPHORUS INSECTICIDES

A field study was conducted to validate serum B esterases as nondestru ctive biomarkers (NDBs) in lizards. Serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) activities were measured in lizards and fo ur species of birds collected in an area of 0.5 ha sprayed with 0.36 k g a.i./ha of Folidol SE5 (5% parathion). Serum B esterase activities w ere determined in a total of 213 lizards (Gallotia galloti) and 81 bir ds of four species (Sylvia melanocephala, Serinus canaria, Parus caeru leus, and Erithacus rubecula) collected for 23 days after the spraying , A control group of 39 lizards and 58 birds was sampled before the sp raying. No relationship was found between serum B esterases and sex or biometric parameters in all species. Inhibition of BChE (>40%) and Cb E (>50%) activities was recorded in lizards 23 days after spraying. BC hE activity was found to be more sensitive than CbE to inhibition by p arathion. Inhibition of serum B esterase activities was recorded in on ly two bird species (S. melanocephala and S. canaria), but the number of individuals collected was much less than the lizards. The advantage s and disadvantages of G. galloti as bioindicator of exposure to organ ophosphorus insecticides in the Canary Islands (Spain) are discussed i n relation to birds commonly used for this purpose. (C) 1997 Academic Press.