Effects of Chemical Contaminants in Domestic Water Sources in Buuri-East Sub-County, Meru County, Kenya

Abstract

Domestic water supplies can contain chemical contaminants and heavy metals that may have subtle and not readily apparent health implications. This study aimed to determine the levels of chemicals and heavy metals detected in domestic water sources in Buuri-East Sub-County, Meru County, Kenya, and household awareness of chemical water testing in the sub-county. A cross-sectional design was used. Concentrations of fluoride, chloride, alkalinity, nitrates, phosphates, and six heavy metals (lead, mercury, copper, arsenic, chromium, and cadmium) at 15 water sampling points in three wards (Ruiri/Rwarera, Kibirichia, and Kiirua/Naari) were compared with World Health Organization (WHO) and Kenya Bureau of Standards (KEBS) limits. Household awareness and testing behaviour were assessed in a survey (n = 340). The concentrations of fluoride and nitrate at all tested sites were within WHO/KEBS limits. Chloride concentrations exceeded the limit of 250 mg/l at around 40% of sites; alkalinity concentrations exceeded the limit of 500 mg/l (as CaCO₃) at 40% of sites; and phosphate exceeded the limit of 0.5 mg/l, with the highest prevalence in Ruiri/Rwarera ward. Lead was the only metal found to exceed the WHO limit of 0.01 mg/l, with approximately 40% of sites recording concentrations above this limit; the highest concentration was recorded at Mugwuku-A (0.0402 mg/l), more than four times the WHO limit. Mercury, copper, arsenic, chromium, and cadmium were below the relevant limits in all samples. More than half of the households (63.8%) reported that their water had never been tested for chemicals, and 74.1% did not know whether any community water quality monitoring system existed. The results show a chemical contamination profile skewed towards lead that is not reflected in community awareness or in the ability of local institutions to test for chemical contamination; boiling, the most common household treatment practice, provides no protection against dissolved chemicals.