Arsenic and Fluoride Exposure in Drinking Water: Children’s IQ and Growth in Shanyin County, Shanxi Province, China

Abstract

BackgroundRecently, in a cross-sectional study of 201 children in Araihazar, Bangladesh, exposure to arsenic (As) in drinking water has been shown to lower the scores on tests that measure children’s intellectual function before and after adjustment for sociodemographic features.ObjectivesWe investigated the effects of As and fluoride exposure on children’s intelligence and growth.MethodsWe report the results of a study of 720 children between 8 and 12 years of age in rural villages in Shanyin county, Shanxi province, China. The children were exposed to As at concentrations of 142 ± 106 μg/L (medium-As group) and 190 ± 183 μg/L (high-As group) in drinking water compared with the control group that was exposed to low concentrations of As (2 ± 3 μg/L) and low concentrations of fluoride (0.5 ± 0.2 mg/L). A study group of children exposed to high concentrations of fluoride (8.3 ± 1.9 mg/L) but low concentrations of As (3 ± 3 μg/L) was also included because of the common occurrence of elevated concentrations of fluoride in groundwater in our study area. A standardized IQ (intelligence quotient) test was modified for children in rural China and was based on the classic Raven’s test used to determine the effects of these exposures on children’s intelligence. A standardized measurement procedure for weight, height, chest circumference, and lung capacity was used to determine the effects of these exposures on children’s growth.ResultsThe mean IQ scores decreased from 105 ± 15 for the control group, to 101 ± 16 for the medium-As group (p < 0.05), and to 95 ± 17 for the high-As group (p < 0.01). The mean IQ score for the high-fluoride group was 101 ± 16 and significantly different from that of the control group (p < 0.05). Children in the control group were taller than those in the high-fluoride group (p < 0.05); weighed more than the those in the high-As group (p < 0.05); and had higher lung capacity than those in the medium-As group (p < 0.05).ConclusionsChildren’s intelligence and growth can be affected by high concentrations of As or fluoride. The IQ scores of the children in the high-As group were the lowest among the four groups we investigated. It is more significant that high concentrations of As affect children’s intelligence. It indicates that arsenic exposure can affect children’s intelligence and growth.

Fluoridation and hypothyroidism – a commentary on Peckham et al.

“…Furthermore the majority of these studies did not account for major confounders, a problem that cannot be solved in a summary. Wang et al (2007) carried out a study on the intelligence and fluoride exposure in 720 children between 8 and 12 years of age from a homogenous rural population in the Shanxi province, China. Subjects were drawn from control (fluoride concentration in drinking water 0.5 mg/L, n=196) and high fluoride (8.3 mg/L) areas.…”

Zebrafish as a Model for Developmental Neurotoxicity Assessment: The Application of the Zebrafish in Defining the Effects of Arsenic, Methylmercury, or Lead on Early Neurodevelopment

“…Global epidemiological studies report a close relationship between early-life arsenic exposure and intellectual/cognitive ability of school-aged children [109][110][111][112]. For example, in a recent study conducted in the United States (US), Wasserman et al [112] investigated the association of arsenic exposure through drinking water at home and the IQ levels of 272 school-aged children (mean age of 9.67-years) with the mean residence time in the current dwelling place (~7.34 years).…”

Inorganic Arsenic Exposure and Children’s Neurodevelopment: A Review of the Evidence

“…In two studies conducted in Bangladesh, water arsenic level accounted for approximately 4% of the variance in the IQ scores of 10 year olds [31] and approximately 1% of the variance in the IQ scores of 6 year olds [33]. In a study conducted in China, the frequency of IQ scores ≤ 70, the cut-off generally used to identify children with mild intellectual disability, was 8.3% in the group with "high" water arsenic levels (mean of 192 µg /L), 3.3% in the group with "medium" water arsenic levels (mean 142 µg /L), and 0% in the group with "low" water arsenic levels [35].…”