Polychlorinated biphenyls (PCBs) residues in milk from an agroindustrial zone of Tuxpan, Veracruz, Mexico

► There a contamination of cow milk by biphenyls polychlorinated in a tropical system. The presence of organic contaminants is due by punctual source. It is the first research for this agroindustrial about organochlorine compounds. Production principal of milk is considered as organic product. The presence of high values of PCBs in milk will be a serious risk for population health. The coasts of the Gulf of Mexico are zones exposed to the exploration and exploitation of petroleum sources, and the products generated in agricultural zones may become contaminated by persistent organic pollutants (POPs). The objective of the present study was to evaluate the presence of polychlorinated biphenyl compounds (PCBs) in milk from dairy production units near sources of environmental pollutants. It was confirmed that the seven congeners of nondioxin-like PCBs (NDL-PCBs) are present in milk where compounds PCB101, PCB118, PCB153 and PCB180 appear in 100% of the samples analyzed, the rank of concentration for the sum of the seven congeners fluctuating between 2.6 and 26ngg−1 with a median of 6ngg−1. None of the samples surpassed the provisional value established by the EU of 40ngg−1 of milk fat for the sum of the seven congeners, indicator that was not affected by the season of the year (p