Modeling the Relationship of Groundwater Salinity to Neonatal and Infant Mortality From the Bangladesh Demographic Health Survey 2000 to 2014

Abstract

We evaluated the relationship of drinking water salinity to neonatal and infant mortality using Bangladesh Demographic Health Surveys of 2000, 2004, 2007, 2011, and 2014. Point data of groundwater electrical conductivity (EC)— a measure of salinity—were collated from the Bangladesh Water Development Board and digitizing salinity contour map. Data for groundwater dissolved elements (sodium, calcium, magnesium, and potassium) data came from a national hydrochemistry survey in Bangladesh. Point EC and dissolved minerals data were then interpolated over entire Bangladesh and extracted to each cluster location, the primary sampling unit of Bangladesh Demographic Health Surveys. We used restricted cubic splines and survey design‐specific logistic regression models to determine the relationship of water salinity to neonatal and infant mortality. A U‐shaped association between drinking water salinity and neonatal and infant mortality was found, suggesting higher mortality when salinity was very low and high. Compared to mildly saline (EC ≥0.7 and < 2 mS/cm) water drinkers, freshwater (EC < 0.7 mS/cm) drinkers had 1.37 (95% CI: 1.01, 1.84) times higher neonatal mortality and 1.43 (95% CI: 1.08, 1.89) times higher infant mortality. Compared to mildly saline water drinkers, severe‐saline (EC ≥10 mS/cm) water drinkers had 1.77 (95% CI: 1.17, 2.68) times higher neonatal mortality and 1.93 (95% CI: 1.35, 2.76) times higher infant mortality. We found that mild‐salinity water had a high concentration of calcium and magnesium, whereas severe‐salinity water had a high concentration of sodium. Freshwater had the least concentrations of salubrious calcium and magnesium.

Quality Unknown: The Invisible Water Crisis

“…Much of the evidence comes from Bangladesh, where salinity is endemic in the coastal areas and where at least one-third of the population drink saline water. A rise in drinking water salinity is linked to high levels of infant and neonatal death (Dasgupta, Huq, and Wheeler 2016;Naser et al 2018). Recent evidence shows that around 3 percent of infant deaths in the coastal subdivisions of Bangladesh can be attributed to increased drinking water salinity and that in some divisions, such as Barisal, this rate rises to 20 percent (Naser et al 2018).…”

“…A rise in drinking water salinity is linked to high levels of infant and neonatal death (Dasgupta, Huq, and Wheeler 2016;Naser et al 2018). Recent evidence shows that around 3 percent of infant deaths in the coastal subdivisions of Bangladesh can be attributed to increased drinking water salinity and that in some divisions, such as Barisal, this rate rises to 20 percent (Naser et al 2018). 10 Similarly, women living within 20 kilometers of the coastline are 1.3 times more likely to miscarry than those who live inland (Savage 2018).…”

Impact of Salinity on Infant and Neonatal Mortality in Bangladesh

“…This is consistent with the results of categorical exposure version which showed harmful effects for infants and neonates exposed to freshwater and severely saline water as well as the protecting effects of mild salinity exposure. Calcium and magnesium peak around 1 mS/cm EC, but their concentrations do not change afterward with increasing level of EC, which explains why there was lower neonatal or infant mortality among the mild-salinity water drinkers (Naser et al, 2019b). In contrast, the relationship between groundwater sodium and EC followed an almost linear upward trend, suggesting severe-saline water drinkers have very high sodium intake.…”

“…During the intrauterine and first six months of life, fetuses and infants depend on their mother for these essential macro-minerals. Babies born to mothers who drink mildly-saline water during pregnancy have lower neonatal or infant mortality rates (Naser et al, 2019b).…”

“…fresh drinking water (<0.7 mS/cm), the marginal effect of salinity on infant death is always negative, which can be calculated by the first derivate of outcome with respect to GWEC shown in the Appendix. Drinking slightly saline water can help to reduce infant mortality because slightly saline water has mostly healthy mineral concentration and limited sodium concentration relative to freshwater with low concentrations of salubrious calcium and magnesium (Naser et al, 2019b) As drinking water becomes mildly saline (0.7 -2 mS/cm) and moderately saline but below 4.11 mS/cm (calculated in Appendix), the negative marginal effect is decreasing, suggesting that the protective role of drinking saline water is attenuating. As drinking water becomes moderately saline (above 4.11 mS/cm), the marginal effect becomes positive and increasing, with associated high infant mortality and high-level EC contributed by high concentration of sodium but limited concentrations of salubrious calcium and magnesium.…”