Levels of heavy metals in urine samples of school children from selected industrial and non-industrial areas in Dar es Salaam, Tanzania

Abstract

ObjectivesThe levels of lead, zinc, iron, copper and cadmium metals in the urine samples of selected school children in industrial and non-industrial areas in Dar es Salaam were investigated.MethodsUrine samples were collected from 120 children in industrial areas and 120 children in non-industrial areas then digested in concentrated acids and analysed using atomic absorption spectrophotometry (AAS).ResultsThe concentrations of the heavy metals in the urine samples ranged from below detection limit/non-detectable (ND) to 1.92 mg/L for lead, ND to 2.55 mg/L for zinc, ND to 8.98 mg/L for iron and ND to 0.05 mg/L for copper. Cadmium was not detected. Significant differences were found between the concentrations of heavy metals in urine of pupils from the industrial areas and those from non-industrial areas. The mean concentrations of lead and copper in samples from industrial areas were significantly higher than those found in non-industrial areas (p < 0.002), while the mean concentrations of zinc and iron found in samples from non-industrial areas were significantly higher than those found in industrial areas (p < 0.0001).ConclusionThe contamination levels were generally high in samples from both areas indicating exposure from various sources. The findings indicate public health risks.

Toward revising dietary zinc recommendations for children aged 0 to 3 years: a systematic review and meta-analysis of zinc absorption, excretion, and requirements for growth

“…A total of 26 studies measured urinary zinc in infants and children aged 0 to 9 years. [48][49][50][51]54,57,60,[62][63][64][67][68][69][70][71]74,[76][77][78][79][82][83][84][85][86][87] Of these, 14 provided data from children aged 0 to 3 years [48][49][50]54,57,60,67,71,73,74,77,84,86,87 and 13 provided data from children aged 4.5 to 9 years. 48,51,[62][63][64][68][69][70]76,79,82,…”

“…Tables S1 and S3 in the Supporting Information provide descriptions of these studies, with Table S1 detailing studies excluded from the metaanalyses and Table S3 detailing studies included in the meta-analyses. Urinary zinc was measured by atomic absorption spectrometry, 48,49,51,54,60,[62][63][64]68,69,71,74,[76][77][78][79]82,84,86,87 a colorimetric method, 50,67 inductively coupled plasma-atomic emission spectrophotometry, 85 inductively coupled plasma mass spectrometry, 70 and liquid chromatography. 83 Three studies assessed zinc excretion from spot urine samples.…”

Method for Determining Regional Reference Values of Metal Content in Biological Substrates and Their Intake into the Body via Drinking Water

“…The most informative or diagnostic biosubstrates are those that are involved in the processes of transport, excretion, and accumulation of metals [ 1 , 3 , 8 ]. In population-based studies, human hair (nails), blood (whole or serum), and urine (morning or daily) are usually used as such diagnostic biosubstrates.…”

Determination of Heavy Metals in Urine of Patients and Tissue of Corpses by Atomic Absorption Spectroscopy

“…Workers such as Mahugija et al have reported high contamination levels of heavy metals in urine samples of school children from selected industrial and non-industrial areas in Tanzania [10]. Similarly, Sá et al investigated the presence and distribution of heavy metals in samples of renal cell carcinoma, as well as adjacent renal tissue (control samples) in patients submitted to radical or partial nephrectomy for renal cell carcinoma [11].…”