Levels of toxic and essential metals in maternal and umbilical cord blood from selected areas of South Africa—results of a pilot study

Abstract

This pilot study uses concentrations of metals in maternal and cord blood at delivery, in seven selected geographical areas of South Africa, to determine prenatal environmental exposure to toxic metals. Samples of maternal and cord whole blood were analysed for levels of cadmium, mercury, lead, manganese, cobalt, copper, zinc, arsenic and selenium. Levels of some measured metals differed by site, indicating different environmental pollution levels in the regions selected for the study. Mercury levels were elevated in two coastal populations studied (Atlantic and Indian Ocean sites) with mothers from the Atlantic site having the highest median concentration of 1.78 mg/L ranging from 0.44 to 8.82 mg/L, which was found to be highly significant (p < 0.001) when compared to other sites, except the Indian Ocean site. The highest concentration of cadmium was measured in maternal blood from the Atlantic site with a median value of 0.25 mg/L (range 0.05-0.89 mg/L), and statistical significance of p < 0.032, when compared to all other sites studied, and p < 0.001 and p < 0.004 when compared to rural and industrial sites respectively, confounding factor for elevated cadmium levels was found to be cigarette smoking. Levels of lead were highest in the urban site, with a median value of 32.9 mg/L (range 16-81.5 mg/L), and statistically significant when compared with other sites (p < 0.003). Levels of selenium were highest in the Atlantic site reaching statistical significance (p < 0.001). All analysed metals were detected in umbilical cord blood samples and differed between sites, with mercury being highest in the Atlantic site (p < 0.001), lead being highest in the urban site (p < 0.004) and selenium in the Atlantic site (p < 0.001). To the best of our knowledge this pilot investigation is the first study performed in South Africa that measured multiple metals in delivering mothers and umbilical cord blood samples. These results will inform the selection of the geographical sites requiring further investigation in the main study.

Prenatal exposure to manganese in South African coastal communities

“…In the rural study cohort, Mn was also measured in the respective umbilical cord blood samples, and the Mn levels in cord bloods were found to be double those found in the respective maternal samples. These findings are in agreement with the outcomes of the pilot of this study and other investigations, except that no significant correlation was found between maternal and the respective cord blood Mn levels, as has been reported in other studies 12,30 . Some studies have found some correlation between maternal MnB levels and birth outcomes such as birth weight and head circumference; however, these correlations were not evident in the current study cohort 15.31 .…”

“…It has been shown that due to the active transport of Mn across the placenta, levels of Mn in cord blood are higher than those in the maternal blood at delivery [10][11][12][13] . Su et al…”

The Argentinian mother-and-child contaminant study: a cross-sectional study among delivering women in the cities of Ushuaia and Salta

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“…The Arctic Monitoring and Assessment Programme (AMAP) started in 1991 and currently all Arctic countries are members, namely: Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden and USA [9–12]. Countries located in tropical and southern areas have joined more recently, including South Africa [8,13], Brazil [6,14], Vietnam [15] and Australia [16,17]. The extent of human exposure, as measured by biological contaminant concentrations, has not been adequately investigated in South America.…”

Heavy Metal Pollution in Sub-Saharan Africa and Possible Implications in Cancer Epidemiology

“…The sampled population who are non-miners demonstrated the prevalence heavy metal pollutions in Nigeria among ordinary people. In a similar study in South Africa, the extent of heavy metal pollution was demonstrated by determining the concentrations of heavy metals in maternal and umbilical cord blood from residents of selected areas (Rollin et al, 2009). Although levels of some measured metals differ by site indicating different environmental pollution levels, unacceptably high levels of mercury, cadmium, lead and selenium were found.…”