Mercury poisoning in women and infants inhabiting the Gangetic plains of Bihar: risk assessment

Abstract

Mercury is a persistent, bio-accumulative, and hazardous contaminant. When released into the environment, it accumulates in water sediments, converting it to poisonous methylmercury that enters the food chain. The present study was carried out in habitations from the 11 districts of Bihar (India). In the study, n = 224 lactating women and their infants n = 172 infants participated. After obtaining the written informed consent, their breast milk, urine, and blood were collected for mercury estimation. The breastmilk content was measured in n = 181 subjects, in which 74% women had their breastmilk higher than the WHO permissible limit (< 1.7 μg/L), while 26% of the women had their breast milk below the permissible limit. The blood mercury content showed that 19% subjects had mercury content above the permissible limit [20 μg/L]. In urine mercury estimation, 49% women had mercury content above the permissible limit [10 μg/L], while, 51% women had the mercury content below the permissible limit. In the child's urine, 54% infants had their mercury content in urine above the permissible limit [10 μg/L] while 46% infants had content below the permissible limit. The study indicates that 20% of infants had the complete accumulation of mercury in their body which is highly toxic for them. However, the mercury content in the food (wheat) had the contamination with in the permissible limit [100 μg/kg]. There was a significant correlation found between the breastmilk and child's urine and mother's urine. The HQ study also correlates the mercury poisoning effect with 100% of the mother's and 66% of the infants exceeding the limit of non-carcinogenic risk. The Monte Carlo and multivariate study correlates the high health risk in the studied population due to mercury poisoning. The entire study concludes that population inhabitation in the Gangetic plains of Bihar are exposed to mercury poisoning which may be due to geogenic or anthropogenic sources. But, the levels of mercury contamination above the permissible limit could lead to neurogenerative changes in the lactating mothers and their infants. To control the present problem medical intervention is immediately required.

Keywords: Breastmilk; Geospatial mapping; Infants; Lactating mothers; Mercury poisoning.

Fig. 1

Showing effect of mercury contamination in human body

Fig. 2

Graph showing mercury concentration in the breastmilk samples of the lactating mothers

Fig. 3

Graph showing mercury concentration in the blood samples of the lactating mothers

Fig. 4

Graph showing mercury concentration in the urine samples of the lactating mothers

Fig. 5

Graph showing mercury concentration in the urine samples of the studied children

Fig. 6

Showing food mercury concentration in studied area of Bihar

Fig. 7

Residual plot – dependent variable—child urine mercury vs breastmilk mercury

Fig. 8

Residual plot – dependent variable – mother’s urine mercury vs breastmilk mercury

Fig. 9

Map showing mercury contamination in the mother's breastmilk samples inhabiting in the studied districts of Bihar

Fig. 10

Map showing mercury contamination in the mother's blood samples inhabiting in the studied districts of Bihar

Fig. 11

Map showing mercury contamination in the mother's urine samples inhabiting in the studied districts of Bihar

Fig. 12

Map showing mercury contamination in the child’s urine samples inhabiting in the studied districts of Bihar

Fig. 13

Map showing mercury contamination in the food samples consumed by the studied subjects of the exposed districts of Bihar

Fig. 14

A Correlation coefficient study between the mercury contamination in the breastmilk and child’s urine. B Correlation coefficient study between the mercury contamination in the breastmilk and mother’s urine

Fig. 15

A Hazard Quotient of infant. B Hazard Quotient of lactating mother