DETERMINATION OF HEAVY METALS IN RAW MILK SAMPLES FROM DIFFERENT AREAS OF LAHORE

Study was conducted to analyze the concentration of different heavy metals including lead (Pb), Chromium (Cr), Zinc (Zn), Nickel (Ni), Manganese (Mn), Copper (Cu) and Iron (Fe) in raw milk samples from four towns of Lahore (Ravi Town, Data Gang Baksh Town, Iqbal Town and Town ship). 5ml of each sample was digested by using 14 ml HNO3 and after 30 minutes by adding 10 ml HCL04 for almost 2 hours at the temperature of 250° C until vine green or color less solution is formed. The concentration of heavy metals were determined by using Atomic Absorption Spectrophotometer. The mean concentration of all the heavy metals in all these towns except Zn and Fe were above the permissible limit set by WHO. The concentration of Mn and Ni was slightly high. Heavy metals having highest toxicity have higher contamination and lowest toxicity has lowest contamination. Highest toxic metal Pb (WHO standard is 0.02 ppm) contamination ranges between 3.3 ppm to 6.3 ppm among these towns. The lowest toxic heavy metal Zn (WHO standard is 60 ppm) having highest nutritious value, the contamination ranges lie between 1.41 ppm to 3.6 ppm. The results shows that milk in Lahore has little to low nutritious value with high contamination. According to analysis it was found that the contamination of Township milk samples in heavy metals (Cr, Fe and Zn) was comparatively high as compared to other towns. The contamination of all the selected heavy metals in milk samples of Data Gang Baksh Town were comparatively low.