THE INFLUENCE OF PLACE OF CAPTURE, SEX, AND SEASON ON THE ORGANOCHLORINE PESTICIDE CONTENT IN BARBEL (BARBUS-GRAELLSI) FROM NORTHEASTERN SPAIN

Residue levels of the alpha, beta, gamma, and delta isomers of hexachl orocyclohexane (HCH), p,p'-DDT and p,p'-DDD in flesh samples of 68 bar bels, Barbus graellsi, collected in the Gallego and Cinca Rivers, nort heastern Spain, were determined. A significant positive correlation wa s found between fish length and organochlorine concentration only for DDT homologs. Significantly higher levels of HCH isomers were found in barbels from the Gallego River, as compared to the corresponding mean levels in barbels from the Cinca River. However, residues of DDT homo logs were significantly higher in barbels from the Cinca River. In bar bels from the Gallego River all organochlorines analyzed were higher i n females, but only alpha and beta HCH isomers, p,p'-DDT and Sigma DDT were statistically significantly. In barbels from the Cinca River, ho wever, organochlorine concentrations did not seem to be dependent on s ex. There were strong evidences for seasonal variation regarding the l evels of HCH isomers and DDT homologs in barbels, with higher levels d uring summer than during spring. (C) 1997 Elsevier Science Ltd.