Reference intervals for Cd, Hg, Mn and Pb in the general children of Kinshasa (DR Congo)

Abstract

Abstract The RIs (reference intervals), proposed by the IFCC (International Federation of Clinical Chemistry and Laboratory Medicine) and the IUPAC (International Union of Pure and Applied Chemistry), were derived for Cd, Hg, Mn and Pb in the blood and urine of the children population living Kinshasa (n = 200, aged 3–14 years with 97 girls). Metals were measured using coupled plasma mass (ICP-MS). In blood, the proposed RIs [P5-P95 (GM)] were 0.022–1.112 µg/L (0.074), 35.69–144.50 µg/L (71.43), 0.060 to 1.161 µg/L (0.208) and 6.597–15.740 µg/L (9.882) for Cd, Pb, Hg and Mn, respectively. Urinary levels [(P5-P95 (GM)] were 0.082–1.530 µg/L(0.366) for Cd, 1.827–18.500 µg/L (5.458) for Pb, 0.323–1.953 µg/L (0.709) for Hg and 0.070 to 1.703 µg/L (0.186) for Mn. As compared to the CDC updated blood Pb reference value (3.5 µg/dL), Pb levels remain higher of public health concern. Cd and Mn levels were similar to those found in the same city in 2015 and databases involving non-occupationally exposed populations from other countries. Hg levels significantly lower than those found in the same city in 2015, probably due to exclusion criteria of metal exposure applying in the present survey (occupationally exposed to the studied metals, smoking habits, amalgam tooth fillings, fish consumption habit more than one time per week, etc.). These background metal exposures will be useful for future occupational and/or environmental surveys as well as undertaking a reliable regulation of chemical exposure in Kinshasa via a national HBM program.