Measurement of heavy metals in water treated salt and its comparison with rock salt

Effects of environmental pollution on food safety for human consumption is a serious global issue. Considering the serious effect of the heavy metals on public health level, measurement of concentration of toxic heavy metals in highly-consumed foodstuff such as salt, bread and water may pave the way for discovering the causes of many diseases. In this research, determination of heavy metal amounts like Fe, Pb, Cu and Cd in the samples of washed salt by water and rock salt by the flame atomic absorption spectroscopy were investigated. Mean (Mean  Standard Error) concentrations of heavy metals in salt were: Fe(3.89 ± 1.63), Pb(0.55 ± 0.47), Cu(0.29 ± 0.15) and Cd(Not detectable) (μg g-1) dry weight respectively. For rock salt, mean (Mean  Standard Error) concentrations were: Fe(8.30 ± 0.27), Pb(1.21 ± 0.08), Cu(0.89 ± 0.06) and Cd 0.17± 0.03) (μg g-1) dry weight respectively. These values were compared with each other and with allowed standard of these elements for salt as defined by the institute of industrial research and standard of Iran. Statistical analysis indicated that there is no significant difference between values of mean heavy metals Fe, Pb, Cu, Cd, in purified salt, rock salt and Iranian salt standard (P>0.05). However, with rock salt being washed out a significant change in purity from 96.98 to 98.83 mass percent was obtained (P<0.05).