Our water security is in danger as a result of climate change; this contribution will focus on environmental health aspects of impending water shortages and contamination. Water security is defined as “the reliable availability of an acceptable quantity and quality of water for health, livelihoods and production.”

With climate change we can expect unprecedented droughts in certain regions leading to scarce water resources. Adaptive responses to drought could include increased deep-well drilling for drinking water and irrigation. An increase in the use of agrochemicals would be necessary due to the expected increased population of invasive insects and weeds and warmer weather favoring thermophilic fungi especially those dependent on host stress. There will also be a need to house livestock in barns to protect animals from searing heat. These adaptive responses pose a threat to environmental health. These include increased contamination of drinking water by heavy metals and arsenic (prevalent in the geological formations in the mid-west) as a result of deep-well drilling, run-off of nutrients and agrochemicals into waterways used for drinking water sources, and the formation of toxic algae blooms from a combination of rising temperatures and nutrient pollution in waterways. Current wastewater and drinking water infrastructure are not configured to remove the increasing concentrations of these pollutants in water. Furthermore, increased exposure of workers to agrochemicals increases their risk for neurotoxic side effects, while the housing of livestock in close quarters will increase the prevalence of zoonotic disease.

Droughts resulting from climate change will also increase forest fires leading to the loss of lives and homes. The environmental health risks of these fires are substantial. Incomplete combustion of building materials increases particulate matter and volatile organic chemicals, affecting pulmonary function and exacerbating underlying respiratory disorders. The air plumes generated by large fires add contaminants to soil and surface water as they drift far from their place of origin. The use of flame retardants can lead to long term contamination of the soil, surface and ground water by these chemicals. Adaptive responses could include heightened enforcement of fire-codes, improved zoning of home developments, and the development of less toxic flame retardants.

With climate change, droughts in some areas will be counterbalanced by extreme flooding in others. Responses to floods can also generate environmental health challenges. Homes, if salvageable, will be contaminated by polluted water and upon drying, the infrastructure will develop mold creating environmental health hazards. Flood waters are contaminated by chemicals and microbes that they encounter, leading to the re-distribution of contaminants into drinking water sources. Adaptive responses to flooding could include improving building codes for properties in floodplains and the engineering of levees.

Many of these adaptive responses are woefully inadequate to be protective of human health. Water security needs to be more aggressively targeted by monitoring compliance with the Clean Water and Safe Drinking Water Acts. Maximum contaminant levels (MCLs) need to be enforced and new ones established for those for which MCLs do not exist (aldrin, dieldrin, endosulfans, to name but a few). Improvements in municipal waste water treatment plants could reduce contamination with toxicants so that water returned to source water is less polluted. Cost-effective desalination plants could increase the availability of water in general. Organic fertilizers could be used in place of agrochemicals to increase crop yield and reduce exposures to neurotoxicants.

Natural disasters such as large-scale drought, forest fires, or floods are to be expected and in anticipation of these events we should undertake research to better understand which preparedness and intervention strategies will be most effective in reducing disaster risk, including the subsequent environmental health impacts. This research must include planning for the emergency response as well as the recovery phase.  Interagency disaster response preparedness (DR2) programs are being led by National Institute of Environmental Health Sciences.

Trevor M. Penning, PhD is the Director of the Center of Excellence in Environmental Toxicology (CEET)

Marilyn Howarth, MD FACOEM is the Director of Community Engagement with CEET

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