determination of lead and cadmium in cow’s milk and elimination by using titanium dioxide nanoparticles

background and objectives: heavy metals such as cadmium and lead are the most important toxins spreading through various ways like water, soil, and air in nature and easily enter human food chain. it is essential to determine the cumulative and harmful effects of these metals in nutrients, especially in cow milk because it is a unique source of food for all ages and it contains both essential and nonessential trace elements. materials and methods: a total of 100 milk samples were directly collected from healthy cows in zabol located on east of iran. the samples were tested to determine lead and cadmium residues. the rates of the heavy metals were determined using a rayleigh atomic absorption spectrum equipped with hollow cathode lamps (hcl) at 283.3 nm for lead (pb) and at 228.8 nm for cadmium (cd). by using the photo-catalytic titanium dioxide nanoparticles, these toxic metals were removed. results: the mean ± sd of the concentration of lead and cadmium in raw milk were 9.175± 2.5 and 4.557 ± 1.081 ppb, respectively. also, the p-values of kalmogorov– smiranov test for lead and cadmium were respectively 0.057 ppb (p>0.05) and 0.435 ppb (p>0.05). tio2 nanoparticles were used to eliminate and remove lead and cadmium in milk samples. the results showed that there was a significant difference between lead and cadmium contents before and after adding tio2 nanoparticles (p<0.05). conclusions: according to results of this study, there was a very low amount of toxic metals. so, it seems that it is not necessary to use tio2 in milk samples but these days it used frequently as an additive to some samples like milk to remove these pollutants. keywords: lead, cadmium, milk, atomic absorption spectroscopy, tio2 nanoparticles