Renal bioaccumulation of trace elements in urban and rural Sri Lankan populations: A preliminary study based on post mortem tissue analysis

The effectiveness of an intervention to reduce exposure to trace metals during or prior to pregnancy: A prospective study in urban and rural locations

Background

Prenatal exposure to trace metals can have adverse effects on health and increase the risk of developing certain diseases. This study aimed to determine the effectiveness of giving women advice to reduce their exposure to trace metals during pregnancy or prior to conception. The study also examined differences in exposure between rural and urban environments in southern France.

Methods

In this prospective study, pregnant women or those intending to conceive were recruited from two medical centers for gynecology/obstetrics (rural location: Saint-Rémy-de-Provence; urban location: Marseille). Hair samples were collected and analyzed to determine the levels of exposure to trace metals. Participants with 'risky' levels were given corresponding advice sheets on how to reduce their exposure or, for certain metals, they were encouraged to find out about potential sources of exposure. A second hair sample was collected and analyzed 3 months later.

Results

It was found that 109 women had 'risky' levels of exposure to trace metals, out of a total of 184 women (59.2 %). Cerium was the most frequently identified metal (N = 26), followed by nickel (N = 23), and titanium (N = 19). There were more women at the urban center with 'risky' levels (56/86; 65.1 %) than at the rural center (53/98; 54.1 %), but this difference was not statistically significant (p = 0.13). Advice sheets were given to 64 of the 109 participants with 'risky' levels (58.7 %), but only 21 returned for the second hair analysis. Of these, 14 were found to have reduced their exposure, which corresponds to just 12.8 % (14/109) of the participants with 'risky' levels.

Conclusions

These results indicate that it would be helpful to develop new interventions to reduce trace metal exposure during or prior to pregnancy.

Analysis of Threshold Effect of Urinary Heavy Metal Elements on the High Prevalence of Nephrolithiasis in Men

Exposure to heavy metals in the environment exerts serious effects on kidney health. However, the effects of joint exposure on the kidneys have been rarely studied, particularly in non-occupational exposure high-risk populations. This study provided a reference threshold range of heavy metals in urine and explored the effect of joint exposure on nephrolithiasis in men. The data were obtained from the China Multi-Ethnic Cohort database, and 1502 men were included in the study. A two-piece-wise regression model was used to assess the dose-response relationship between heavy metal exposure and nephrolithiasis. The least absolute shrinkage and selection operator regression model was used to calculate the score of joint exposure to heavy metals. The threshold effect analysis revealed a linear relationship between the concentration of arsenic (As) in the urine and the prevalence of nephrolithiasis, whereas a nonlinear relationship was observed with cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb). In addition, As, Cd, Cr, Hg, and Pb may significantly affect the joint exposure effect. Moreover, the final risk of nephrolithiasis increased by 123% (P for trend < 0.001). This study found a threshold relationship between heavy metals (Cd, Cr, Hg, Pb) in male urine and the occurrence of nephrolithiasis. Joint exposure to heavy metals in urine caused a high-risk effect on nephrolithiasis. The study provided a reference threshold value of related studies and indicated that environmental pollution caused by heavy metals should be reduced.

Kidney Cadmium Concentrations in an Urban Sri Lankan Population: an Autopsy Study

Contamination and bioaccumulation of toxic heavy metals in our geo-environment is a growing public health concern. Human biomonitoring is an essential step in assessing the population risk of chronic exposure to environmental contaminants. Whole kidneys collected from a cohort of 92 deceased individuals undergoing forensic autopsies in Colombo, Sri Lanka, were analysed for cadmium (Cd) bioaccumulation using ICP-MS. Mean age of the population was 55.4 ± 15.4 years. Mean and median renal Cd concentrations of the total population were 4.38 and 2.60 μg g^-1 w/w, respectively, which were below estimated toxic ranges. Males accumulated higher levels of Cd than females (p = 0.377). Cd concentrations were higher in the < 60 age group than the > 60 age group (p = 0.92), while the highest levels were reported in 51-60 age group. However, no significant correlation was found between renal Cd concentration and age (Ʈ_b = - 0.005, p = 0.94). Individuals who smoked, chewed betel or consumed alcohol were found to have elevated renal Cd concentrations in comparison to those who did not use these substances. This is the largest autopsy study on renal Cd bioaccumulation in Sri Lanka, and the findings do not indicate a high exposure risk to environmental Cd contamination at present.

Groundwater as a potential cause of Chronic Kidney Disease of unknown etiology (CKDu) in Sri Lanka: a review

The cause of Chronic Kidney Disease of unknown etiology (CKDu) in the rural dry zone of Sri Lanka remains unidentified, despite vast research efforts that brought about an extensive list of potential risk factors. Among these, the long-term exposure to various nephrotoxic elements through drinking groundwater was widely suspected owing to the unique geographical distribution of the disease. This review focuses on such well-known hypotheses suspecting the relations with fluoride, hardness, major ions, heavy metals, metalloids, organic matter, agrochemical residues, pathogens, and bacterial toxins in the groundwaters of the CKDu-endemic region. It was comprehensively discussed why each of these constituents was considered a risk factor of CKDu, how could they possibly trigger the pathogenesis of the disease, what was the evidence that supported or failed each hypothesis, and whether providing safe drinking water had been effective at mitigating the progression of the disease. Although plenty of circumstantial evidence supported an etiology related to groundwater for CKDu, it was impossible to elucidate the cause-effect relationships between drinking impaired groundwater and the occurrence of the disease. Future research should be effectively designed to clarify the role of groundwater in the onset of CKDu by taking into account the gaps in past research.