Seasonal variations on the levels of some pesticide residues in dairy farms

Abstract

The present work was carried out to study the effect of seasonal variations on the levels of pesticideresidues in water, feeds and milk. Our results illustrated that the significantly highest concentrations ofOCs in water and feed were detected during summer [(1.05±0.35, 0.72±0.24, 0.77±0.25, 2.5±0.70 and0.81±0.27 μg/L, for p.p.DDT, aldrin, β-BHC, lindane and γ.chlordane respectively in water samples)and (30.0±10.20, 45.00±13.02, 65.33±21.90, 35.33±13.20, 43.67±13.30, 22.00±7.33 and 19.13±8.6 μg/kg, for p.p.DDD, p.p.DDE, p.p.DDT, aldrin, lindane, γ.chlordane and methoxychlor, respectively infeed samples) ], while the lowest were detected during spring, on the other hand, none of pesticidesdetected in winter which may be attributed to environmental factors. The significantly highestconcentration of diazinon in water and feed was recorded during autumn (78.75±26.30 μg/L and140.00±64.60 μg/kg, respectively), while the lowest levels were detected during spring. Also, thehighest concentrations of deltamethrin was detected during spring in water (55.30±18.50 μg/L) andduring summer in feed samples (78.40±26.70 μg/kg), while the lowest levels were detected duringautumn in water and during spring in feed samples. The significantly highest concentrations of residuesin milk were detected during summer (p.p.DDD, p.p. DDE, p.p.DDT, heptachlor, heptachlor epoxide,γ.chlordane, methoxychlor, diazinon and deltamethrin were 20.10±6.01, 52.30±17.20, 33.20±20.06,1.16±0.38, 6.72±0.90, 2.570±2.23, 0.70±0.20, 58.50±19.20 and 45.13±15.10 μg/kg, respectively) andthe lowest were detected in winter. Our results concluded that the seasonal variations greatly influencethe levels of all examined pesticide residues with variable degree specially diazinon and deltamethrin.