Image Credit: Unsplash, Kevin Turcious

Pollution of air, soil, food, and water resources has a variety of causes, including rapid consumerism, rising energy demands, unplanned urbanization, and the discharge of industrial pollutants into the environment. Such pollutants include heavy metals and metalloids, which are not biodegradable—meaning they collect in water, soil, and plants—posing a serious threat to human and environmental health.

Indeed, the contamination of water and air by toxic metals impacts hundreds of millions of people around the world, but it has not affected all people equally. In the US, significant health issues—including cancer, lung disease, and heart attacks—are far more common in communities of color as a result of such communities’ exposure to heavy metal pollution, indicating that this is not solely an environmental health issue but a problem of environmental racism. Environmental racism is a form of systemic racism characterized by the disproportionate exposure of people of color to environmental hazards, such as when communities of color are forced to live near harmful waste sources like sewage works, mines, landfills, power plants, major roadways, and sources of airborne particulate matter. While it’s difficult to separate the consequences of poverty and race, the evidence has mounted: race often corresponds with proximity to pollution more than income alone.


How Heavy Metals Contaminate the Environment

Pollutants are released into the environment by industries, agriculture, wastewater, mining and metallurgical operations, and runoffs. Most metals carried in wind-blown dust come from industrial locations. Other sources of heavy metal contamination include auto emissions, which emit lead, smelting, which emits arsenic, copper, and zinc, insecticides, which also emit arsenic, and the combustion of fossil fuels, which emits nickel, vanadium, mercury, selenium, and tin.

Because most heavy metals are nondegradable, they persist in the environment for a long period after they are released, accumulating in food chains, damaging entire ecosystems, and posing a real health threat to humans and other animals. For example, motor vehicle operations increase metal levels in our ecosystem, particularly lead and nickel, as a result of the combustion of fossil fuels and the wear and tear on vehicle components such as brakes, vehicle bodies, tires, and vehicle fluids. Unsurprisingly, in industrial regions, lead is the most common heavy metal contaminant identified in surrounding soils and aquatic ecosystems.

Although there are numerous sources of water pollution, industrialization and urbanization are two of the primary causes of increased heavy metal water contamination. Carried away by runoff from industries, businesses, and residences, heavy metals can be highly poisonous in very small amounts, especially when they are found in water, posing significant health risks to humans and other organisms. Indeed, heavy metal poisoning of water affects all creatures. Humans are increasingly vulnerable to health problems when heavy metal concentrations rise in the food chain.


The US’s Coal Ash Problem

Out of all the heavy metal pollutants in the US, coal ash seems to be the most prevalent. According to the EPA, 140 million tons of coal ash are generated each year, making coal ash the second most prevalent industrial waste stream in the US, trailing only mine wastes. Coal ash is disposed of at almost 1,000 locations around the country, in every state except Rhode Island, Vermont, and Idaho. More than a third is disposed of in dry landfills, typically at the coal-burning power station. Coal ash may also be combined with water and disposed of behind earthen barriers in so-called “ponds.” Around a fifth of coal ash disposal occurs in these moist “surface impoundments.”

Coal-burning has been an essential energy source in the US since the early 1900s, resulting in the accumulation of almost a century of coal ash. While coal is not a particularly toxic substance in and of itself, when burned, it generates lead, mercury, cadmium, chromium, arsenic, and selenium at amounts that may be harmful to human health. The most recent data on ash stockpiles date to 2014, when the US produced 130 million tons of coal ash in a single year. To put that number in context, it is slightly less than half the weight of the whole human population on the planet.

Over 1,000 active coal ash storage sites exist throughout the US, and there are currently no regulatory requirements for container liners or leak detection devices. According to a 2007 EPA investigation, coal ash leaks affected groundwater in 67 municipalities across 26 states in the early 2000s. That figure is almost certainly an underestimation as utilities that own coal ash storage facilities are frequently exempt from groundwater monitoring requirements. Because monitoring is not necessary, it is difficult to determine the true scope of this problem.

Indeed, the US EPA and public interest groups have documented at least 24 sites where private wells have been affected by coal ash. Yet, neither electricity companies nor state regulators frequently conduct tests on private drinking water wells. Most state regulations and the EPA’s CCR Rule require power plant owners to conduct groundwater testing solely on-site. As a result, contamination in private wells may go unnoticed for years, as most coal ash contaminants have no detectable flavor or color.


Vulnerable Communities are Disproportionately Affected

According to mounting data, low-income and minority communities are disproportionately exposed to environmental contamination. A number of studies analyzed the spatial distribution of environmentally hazardous facilities and discovered that these facilities were concentrated in or near communities of color and poor communities. Researchers have found a statistically significant connection between environmental exposure and socioeconomic class as well as racial compositions in recent years. Although there is a vast amount of environmental justice literature, there are still numerous knowledge gaps.

Environmental racism refers essentially to a type of systematic racism in which industrial facilities have been—and are still—often placed in low-income neighborhoods, particularly communities of color, where land is cheap and opposition weak. The ensuing creation of contaminated environments frequently results in health concerns such as asthma, the most prevalent chronic disease in the US, affecting more than six million children each year. Black children are disproportionately affected in comparison to white children because, according to research, they are 79 percent more likely to live in regions where industrial pollution is regarded to pose the greatest health risk.

Even though distinguishing between the consequences of poverty and race may be difficult, the rising corpus of data indicates that poverty and race are linked when it comes to environmental contamination. When compared to economic status alone, race is a more reliable indicator of the presence of pollution in a specific area. Individuals of color suffer a 28 percent larger health burden than the general population as a result of living in close proximity to enterprises that emit particle pollution, according to EPA specialists’ research published in 2018.

Of course, when it comes to environmental policy, the wealth of a community is frequently a decisive factor, particularly when it comes to land use and zoning regulations, building permits, and regulatory enforcement. Therefore, low-income families of all races are exposed to far higher levels of pollution than their more prosperous counterparts. Various studies have discovered a statistically significant positive connection between poverty and cadmium contamination, consistent with previous research that found higher soil-metal contamination in poverty-stricken areas. Further investigation revealed that those living in poverty were more likely to be directly exposed to chromium, selenium, and silver. They were also more likely to be indirectly exposed to other metals due to their proximity to emission sources.

Findings demonstrated a statistically significant higher probability of exposure to arsenic, cadmium, and lead among communities of color. These findings are consistent with previous research that has found that minorities are more vulnerable to soil-metal pollution. Following further investigation, it was discovered that minority individuals are directly harmed by arsenic and lead. Furthermore, depending on the closeness of minorities to pollutants, there is a higher risk of barium exposure as well. Further compounding the problem, cosmetic and personal care products marketed to minorities often include more toxic chemicals than those marketed to White people.


Health Effects Associated with Long Term Exposure

Metals such as lead and cadmium enter the human body through the digestive tract, the skin, or by inhalation. Toxic metals have been shown to be a significant concern to human health, mostly due to their propensity to cause membrane and DNA damage and to disrupt protein function and enzyme activity, among other things. Sodium, potassium, magnesium, zinc, and calcium are vital metabolic nutrients, while others—such as cadmium, arsenic, mercury, and chromium—can be harmful even at extremely low amounts. Excessive exposure to these heavy metals has been shown to cause gastrointestinal, respiratory, cardiovascular, reproductive, renal, hemopoietic, and neurological diseases. Some heavy metals, through a variety of pathogenetic pathways, promote the growth of cancer and impair its susceptibility to treatment. A substantial amount of exposure to mercury has been linked to neurological disorders as well as kidney dysfunction. Additionally, a link has been established between infertility and elevated mercury levels in the blood.

Exposure to lead is particularly hazardous for children under the age of six because it interferes with the development, growth, and differentiation of nerve cells and with the formation and maintenance of bone tissue. Because of the dangers of cadmium, which can cause significant health problems even after a brief period of exposure, it is highly suggested that you avoid it entirely. Chronic exposure to cadmium ions has been linked to a variety of health problems, including anemia, sleeplessness, kidney damage, bladder and prostate cancer, and osteoporosis. Consumption of cadmium has a deleterious impact on fertility and is linked to cardiovascular disease.


What Can Be Done to Mitigate Contamination Risks 

The Environmental Protection Agency’s Toxic Substances Control Program (TRI) now recognizes 770 chemicals. The TRI classifies as “toxic” chemicals those that are known to cause cancer or other adverse health effects, as well as those that have a negative impact on the environment and human health. The agency receives annual reports from facilities detailing the amount of chemicals released into the environment, including the air, water, and ground.

Measures must be implemented to mitigate or remove harmful community exposure in areas where the problem has gone uncontrolled for an extended period of time. To counteract this problem, stronger laws, increased and more consistent enforcement, and larger fines are only a few of the policy improvements that are required.

Hundreds of coal ash ponds must be closed over the next several years. Some of the hazardous material may be beneficially repurposed—rather than dumping it in a landfill or simply storing it near power plants, we can use it in concrete or as a filler for roads and embankments. By incorporating ash into concrete, for example, the heavy metals are retained, and the concrete is strengthened. This particular use has prevented the Environmental Protection Agency (EPA) from classifying it as hazardous waste.

Negative health impacts of heavy metals disproportionately affect communities of color, making this a problem of systemic environmental racism that must be addressed. In order to prevent these negative outcomes, both preventative and corrective actions should be implemented. Reducing heavy metal concentrations in the environment will require: legal regulations, monitoring studies, the use of soluble and non-toxic compounds in environmental compartments (air, water, soil, and plants) in industrial processes, heavy metal-free pesticides, appropriate wastewater treatment plants, and the use of renewable energy sources in place of fossil fuels. It is important to remember that  processes, laws, and norms do not impact all communities equally. We must therefore address—within all of these causes and their proposed solutions—how racism permeates life circumstances and health outcomes in this country. In the fight for health justice, confronting the issue of heavy metals contamination in the US is inextricable from confronting environmental racism.