Assessment of the dietary transfer of pesticides to dairy milk and its effect on human health

Abstract

The transfer of organophosphate and pyrethroid pesticides in dairy cattle’s milk when fed on agroindustrial by-product diet was assessed in this study. The transfer and accumulation of such pesticide in cattle fat tissue and milk was also assessed and the adverse effect on cattle’s and human health was also studied. For that purpose, about 80 milk and 30 diet samples were collected from various dairy farms. All samples were extracted with acids using "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method and analyzed through gas chromatography-mass spectrometry (GC-MS). The results show that about 40 and 20% of milk samples had greater content of cypermethrin+chloropyrifos and porfenofos than their maximum residue limits as suggested by World Health Organisation (WHO). Cypermethrin, chloropyrifos and profenofos were present at concentration greater than their maximum residue limits in mixed diet whereas profenofos was completely absent in sugarcane khal and was present in traces in cotton khal but remained within the maximum residue limit. Nonetheless, transfer of residue of parent cypermethrin, chloropyrifos and profenofos to milk was not consistent with diet in all dairy milk samples. This revealed the contention that some other sources such as drinking or inhaling contaminated water or dust are also contributing to pesticide contamination in milk. Cancer potency factor for cypermethrine in children and adults remained within the recommended value. Generally, although pesticides residue in milk was not high enough to cause cancer risk in human, they might cause adverse health effect and delayed toxicity due to their long term accumulation and persistence within cattle’s body. Therefore, there was an urgent need to estimate their contents in dairy cattle milk in order to provide a baseline for the health ministry to make safety regulations.

Keywords: Pesticides, contamination, milk, cattle diet, risk assessment

African Journal of Biotechnology, Vol. 13(3), pp. 476-485, 15 January, 2014