By Maggie Wiener
Chemical and microbiological drinking water contaminants pose acute and long-term health risks to children, especially in low- and middle-income countries. Inadequate access to safe drinking water has contributed to almost half a million global diarrheal deaths a year .
Drinking water contaminated by enteropathogens, a bacteria, from human or animal feces can lead to diseases such as diarrhea, cholera, and dysentery , as well as shortfalls in physical growth and cognitive development. Drinking water contaminated by heavy metals/metalloids (HMM) and pesticides may cause children to experience reductions in immune function and cognitive development .
Despite the potential for HMMs or pesticides to alter immune responses and the likelihood or severity of infections, such toxic drinking water contaminants have typically been studied in isolation from microbiological contaminants. To address this gap, Miranda Delahoy, Ph.D., and colleagues concurrently evaluated microbiological, HMM, and pesticide contamination in drinking water across households in a low-income setting in Piura, Peru.
Data used in this NIEHS-funded study were collected from participants enrolled in a previous birth cohort. The study authors collected drinking water samples, administered health and exposure questionnaires, and collected infant stool samples over two visits when infants were approximately six months old. All infants had been breastfed. Nearly all infants, except for 11, were regularly given drinking water either alone or in formula in addition to getting breastfed. The majority of households used piped water as their primary source for drinking water, and households commonly stored drinking water in containers.
Researchers found a high prevalence of chemical and microbiological contaminants in water samples in this area. Arsenic was detected in 50% of samples from all types of household primary drinking water sources, with a quarter of samples exceeding WHO safe drinking water standards; at least one pesticide was detected in 65% of samples; and E. coli was detected in 37% of samples. Using containers to store drinking water was associated with higher odds of pesticide and E. coli detection. Most infants had at least one enteropathogen detected in their stool. The most prevalent pathogens in stool samples were Salmonella spp., Campylobacter spp., and Clostridium difficile toxin A or B. The 11 infants not given drinking water in the past week had significantly lower odds of infection with an enteropathogen in the following week.
"We are still trying to learn more about the linkages between these exposures and outcomes, but the high prevalence of these contaminants and of these infections is alarming in such young children," Delahoy explained.
Although Piura has high access to piped drinking water, the study shows that chemical and biological contamination is still prevalent. Safer storage of drinking water could help to reduce health risks.
As several infants in the study experienced enteropathogen infection and were potentially exposed to different types of drinking water contaminants, there is concern for cognitive development and other health outcomes, as well as immune system disruption or gut inflammation. Caretakers of young children should be made aware of the risks of these concurrent contaminations of drinking water and associated health impacts in children.
Water Contamination on Tribal Lands
NIEHS and NTP have conducted studies on per- and polyfluoroalkyl substances (PFAS), lead, and arsenic exposure relating to drinking water. Such studies have included collaboration with the Sipayik Environmental Department (SED) in Maine and with the Navajo Nation.
In Maine, student researchers from the Massachusetts Institute of Technology and researchers from SED launched a participatory science project in which residents of three remote Maine communities, including the Sipayik reservation, collected drinking water samples from their homes for arsenic and lead analysis.
In a webinar series funded partly by the NIEHS Superfund Research Program, NIEHS-funded researchers explored the ways exposure to arsenic, uranium, and other substances in unregulated wells in the Navajo Nation can affect health and well-being. Additionally, the COVID-19 pandemic intensified the effects of environmental health problems in the Navajo Nation. A lack of both clean water and indoor plumbing, and the abandoned uranium mines and waste sites across the Navajo Nation further lead to ongoing health risks and increased disease vulnerability.
Delahoy suggested that "as we continue to learn more about where contamination is occurring in the water distribution system or in the household, there are some measures that people can take to protect young children from being exposed to contaminants in drinking water, and these include following established guidelines on safe drinking water storage as well as encourage infant breast feeding."
Advancing Additional NIEHS Research on Water
NIEHS has a robust portfolio of research on the potential health effects of contaminants in water and on the ways to protect the public from contact with unsafe water. NIEHS offers time-sensitive grants that allow researchers to launch studies quickly in response to natural disasters or industrial accidents that could affect water quality.
The National Toxicology Program (NTP), an interagency partnership within the U.S. Department of Health and Human Services that is administered by NIEHS, reviews available toxicology evidence and conducts studies to build knowledge and promote public health. Such reviews may include chemicals found in drinking water.
NIEHS-Funded Technologies and Interventions
NIEHS also funds researchers and businesses to develop technologies and interventions to combat contaminant exposure. Researchers at the Texas A&M University (TAMU) SRP Center have developed a therapeutic sorbent technology that can bind to hazardous chemicals in the body after exposure, reducing their uptake and bioavailability. These enterosorbent materials can be added to food or water and ingested by humans and animals to reduce harmful contaminant exposures, especially following disasters and other emergencies. Funded through the NIEHS Small Business and Innovation Research and Small Business Technology Transfer grants, several businesses have worked on new technologies and products ranging from portable devices to detect lead in tap water in real time to in-home PFAS filtration media. Such innovations can have important implications for preventing adverse health outcomes associated with contaminated water.
Citation:
Delahoy MJ, Hubbard S, Mattioli M, Culquichicon C, Knee J, Brown J, Cabrera L, Barr DB, Ryan PB, Lescano AG, Gilman RH, Levy K. 2022. High Prevalence of Chemical and Microbiological Drinking Water Contaminants in Households with Infants Enrolled in a Birth Cohort-Piura, Peru, 2016. Am J Trop Med Hyg 107(4):881-892. [ Abstract ]
