Persistent exposure to arsenic via drinking water in rural Bangladesh despite major mitigation efforts

Abstract

Objectives: Elevated arsenic levels in tube-well water in Bangladesh have prompted extensive mitigation projects. We evaluated the effectiveness of long-term mitigation efforts by longitudinally measuring arsenic exposure in pregnant women and their children, the most susceptible population groups.

Methods: The study was nested in a population-based nutrition intervention in Matlab, Bangladesh. Mother-child pairs (n = 1951) were followed from 2001 to 2003, beginning in early gestation and continuing to 5 years postpartum. We measured arsenic concentrations in urine (U-As) of the 5-year-old children by using high-performance liquid chromatography online with hydride generation and inductively coupled plasma mass spectrometry and compared them with earlier childhood U-As and maternal U-As during pregnancy.

Results: Children had elevated U-As at 5 years old (median = 51 μg/L, 5th-95th percentiles = 16-355 μg/L), and U-As distribution was similar to that observed in the mothers during gestation. Children's U-As at 5 years old significantly correlated with their U-As at 1.5 years old and to maternal U-As during early and late gestation.

Conclusions: Despite major mitigation efforts, arsenic exposure remains highly elevated in rural Bangladesh. Further mitigation strategies are required and must be rigorously evaluated for long-term efficacy.

FIGURE 1

Range of urinary arsenic concentrations in maternal urine at gestational week 30, and children's urine at 1.5 and 5 years old. Note. GW = gestational week. The dashed line represents the median urinary arsenic value reported by Schulz et al. in German children with no fish consumption in the previous 48 hours, which is similar to values reported for children in the United States and Taiwan. Urinary arsenic concentrations are shown on the log scale.

FIGURE 2

Association of urinary arsenic concentrations between (a) children at 5 years old and their mothers at GW 8 (P < .001 in a linear regression model), (b) children at 5 years and 1.5 years old (P < .001), and (c) children at 1.5 years old and their mothers at GW 8 (P < .001). Note. GW = gestational weight; U-As = urinary arsenic concentrations.