Abstract

This study determined the levels of specific trace elements in the urine of children aged 9 – 15 years old in zinc-contaminated areas and studied the simultaneous presence of certain elements influenced the bioavailability of lead and cadmium. Urine samples of 736 children living in three sub-districts of Tak province, including Prathadpadeang, Mae Tao, and Mae Ku, were investigated with inductively coupled plasma mass spectrometry to determine levels of zinc (Zn), copper (Cu), iron (Fe), lead (Pb), and cadmium (Cd). The results showed that 43.0% of children lived in Mae Tao sub-district. The body weight of the subjects at birth was < 3,000 grams, and they were underweight as per body mass index. The difference in Cd level in urine (UCd) between 13-15 years old and 9-12 years old was statistically significant. Furthermore, statistically significant differences were observed in levels of Cu level in urine (UCu) and Pb level in urine (UPb) based on the gender of the subjects. UCd and UPb levels were higher compared to other trace elements in older children and female/ male (SRM 2670:NIST). In contrast, UCu and UZn levels were low. Stepwise regression analyses indicated that Cu concentration was a dominant factor influencing the availability of Pb (r²= 0.25) and Cd (r²= 0.16) in human body as follows: Lead availability = 0.295 + 0.304 Cu + 0.256 Fe + 152Zn, Cadmiumavailability=0.050-0.079Cu+0.057Fe+0.395Zn.Our study concluded that Cu levels were lowin children aged9-15years old, which couldhave led to accumulationofCd andPb in their bodies.