Concentrations of organochlorine pesticides in fish (Mugil cephalus) from a coastal ecosystem in the southwestern Gulf of California

Concentrations of organochlorine pesticides (OCPs) were determined in the muscle tissue of the fish commonly known as mullet (Mugil cephalus; in Mexico, lisa). Muscle tissues were collected during bimonthly samplings from March 2010 to February 2011 in the Navachiste Bay (southwestern area of the Gulf of California). The pesticides δ-HCH and dieldrin were the substances most frequently detected throughout the collection period, while endosulfan 1, endosulfan 2, endrin, heptachlor epoxide, γ-HCH and methoxychlor were identified in 80% of the samples analysed. Other pesticides were found in 20%-60% of samples. No correlation was found among water physicochemical parameters and OCPs concentration. The one-way variance analysis between OCP concentrations and collection months revealed no significant differences. The correlation between OCP concentrations and the weight or size of the fish was not significant, although between size and weight there was a significant correlation. During the study period, as a whole, the pesticides that showed the highest concentrations above 0.3ppm per sample were α-HCH (MAY-JUN-2010), dieldrin (ENE-FEB-2011), dieldrin (JULAGO- 2010), methoxychlor (two samples in MAR-ABR-2010) (0.568, 0.533, 0.533, 0.503 and 0.330ppm, respectively). The pesticides aldrin, dieldrin, endosulfan (1 and 2), heptachlor epoxide, DDT and γ-HCH, are listed in Appendix III of theRotterdam Convention, which means that their use is illegal in most signatory countries. According to results, the higher OCP concentrations detected make frequent consumption of M. cephalus a human health risk for the low-income population in the Navachiste area.