Categories
Toxic Tuesdays

Nitrates

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

Nitrates

Nitrates are a class of compounds that contain nitrogen. They can occur naturally in air, water, and soil, and living things need them to survive. Nitrates are used for industrial purposes to make fertilizers, ammunition, and explosives. They are also used to preserve food, most commonly in the process of curing meat. Many vegetables we eat are naturally rich in nitrates as well.

When nitrate-containing fertilizers are used on crops or yards, the nitrates can easily migrate into surface water and groundwater. This means that people who work with these fertilizers or live near where they are applied could be exposed to nitrates in their drinking water. For most of the population, nitrate exposure happens through the food we eat. The amount of nitrates consumed in a normal diet is generally considered safe, and much of the nitrates our bodies ingest or make naturally are excreted every day. However, people may be exposed to high levels of nitrates by eating lots of foods rich in nitrates such as spinach, lettuce, cured meat, processed meat, fish, and beer.

Once consumed, the body can convert nitrates into similar compounds called nitrites. High levels of nitrites can decrease the blood’s ability to carry oxygen to our cells. This can cause dizziness, headaches, cramps, vomiting, decreased blood pressure, increased heart rate, and death. Infants seem to be more sensitive to the health effects of nitrite exposure than adults.

Once nitrates get converted into nitrites in the body, they can be further converted into compounds called nitrosamines, which are known to cause cancer. For this reason, the International Agency for Research on Cancer has determined that ingesting nitrates probably causes cancer in humans. Because nitrates occur in nature and are made naturally by our bodies, it can be hard to know our exposure risk from dietary and industrial sources. This makes it particularly important for the federal government to regulate nitrates from sources such as fertilizers and food preservation in order to keep people safe from the adverse health effects of exposure.

Learn about more toxics

Categories
Toxic Tuesdays

How the Duration of Exposure Affects Toxicity

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

How the Duration of Exposure Affects Toxicity

CHEJ has previously written about the importance of considering multiple chemical exposures when assessing the toxicity of exposure to toxic chemicals. In addition, it is also important to consider the duration of exposure. How long was a person exposed? What was the concentration of the substance(s) during this period of time are critical to truly understanding the cumulative effects that a person has suffered? Without this information, we can only partially understand the risks of exposure to toxic chemicals. 

Yet when evaluating whether exposures to toxic chemicals pose risks to human health, the government’s approach is usually very narrow: it assumes there is a single chemical from a single source at a single point in time with a single exposure pathway causing a single health effect. This approach makes risk assessment more feasible and understandable, but it does not reflect the reality of our lives.

In reality, we are exposed to multiple chemicals at a time and exposures can happen over a long period of time. This means that considering the potential effects of a single exposure to a single chemical isn’t sufficient for evaluating public health risks. We need to include cumulative risks that account for both multiple chemical exposures and exposure over time in order to begin to understand the risks to public health. But incorporating these parameters into a risk assessment poses significant new challenges that  requires more estimates and generates additional uncertainty than the traditional risk assessment approach.

In many cases, exposure assessments assume that exposure to a chemical happens in a single instant in time. In some cases – like cancer risk – EPA assumes that risk is proportional to the lifetime dose. In general, longer exposure means greater risk, but the relationship between duration of exposure and health risk is complicated. The risk depends on the effects an exposure has on the body and the body’s response to it. In some cases, the body may adapt to exposure and the threat over time may be less than additive. In other cases, the body may become more sensitive and the threat over time may be more than additive. Repeated exposure can also influence health risk: past exposure to some chemicals can make us more vulnerable to subsequent exposure. And how do you consider the effects caused by exposure to multiple chemicals that target the same organ in the body can cause more damage than exposure to any of those chemicals individually?

The effect of exposure over time is important to consider in risk assessments, but agencies like EPA and ATSDR do not have comprehensive frameworks for how to assess this cumulative risk. Part of the reason for this is a lack of data. The guideline values we use to evaluate risks are driven by data generated from exposures to a single chemical for a defined period of time. For common chemicals and chemical mixtures that people are exposed to, we need to know how different concentrations and durations of exposure affect health. There is a need for more scientific study on how exposures to chemicals over long periods of time can impact our risk for adverse health effects. Once people have been exposed to chemicals, we also need better tools to measure their past exposure so it can be accounted for in risk assessments.

While more research and data is crucial, there will always be uncertainty in science and data, and we cannot let uncertainty stop us from taking action to protect health. In addition to more scientific study, we need clearer guidelines from federal agencies regarding how to consider cumulative risk – both from multiple chemical exposures and exposures over time – in evaluating if an environmental hazard is a threat to human health. We also need to acknowledge how poor the tools we have are at considering cumulative risks caused by exposures to multiple chemicals over time.

Learn about more toxics

Categories
Backyard Talk Homepage

Heat Waves Rolling In

Photo credit: Steve Marcus/Las Vegas Sun via AP

By Leila Waid.

The beginning of summer has already brought immense heat waves throughout the world. Countries in Southeast Asia, such as India and Thailand, already had extreme heat waves in April—with UNICEF stating that the extreme temperatures posed a risk to 243 million children. In the Southwest U.S., June has also seen record-breaking extreme temperatures in early June. With the summer just beginning, how many more heatwaves will the world endure this season, and how many individuals will be at risk?

Heat waves are a significant public health issue because of the variety of health issues they pose. They are a prescient environmental justice issue because, due to climate change, the temperatures will keep climbing to unbearable levels. A study using modeling techniques has found that heat waves will become more extreme and longer-lasting in the latter half of the 21st century. An alarming finding from another study forecasts that “the limit for survivability may be reached at the end of the twenty-first century in many regions of the world” because the combination of high heat and humidity levels (referred to as the wet-bulb temperature) can pose extreme danger to human health.   

One way that heat waves impact human health is by increasing the risk of cardiovascular disease. Heart disease is already the number one cause of death in the U.S. According to the American Health Association, close to 50% of the American population has some form of heart disease. This finding means that half of Americans are at an even more increased risk from heat waves. Along with impacting those who already have heart issues, heat waves are also associated with the development of heart disease – with epidemiological studies showcasing that increased temperatures can lead to the development of ischemic heart disease.

Increased temperature places undue stress on the body, and these changes can cause “imbalances in the autonomic control of the heart, increase local arterial pressures, induce systemic inflammation, and impair clotting responses.” Thus, heat waves place those with pre-existing heart disease in increased danger and also increase the risk of heart disease development in the rest of the population. One study modeled how climate change will impact cardiovascular rates in the future and found that death from heart disease could increase from 162% to 233%. Currently, extreme heat causes an estimated 1,651 deaths annually from heart disease. The study projects that this number could increase anywhere from 4,320 to 5,491 deaths by the mid-21st century.  

As with most aspects of health, the impacts are not felt equally across the populations due to societal factors. For example, those with lower socioeconomic status face worse health outcomes during heat waves. One study examined whether insurance status played a role in heat-induced heart attacks and found that it was a critical factor in individuals’ health outcomes. Based in New York, the study found that individuals without health insurance – a stand-in for socioeconomic status (SES) – had a higher risk of myocardial infarction (heart attacks) during extreme heat even than those with health insurance. Another study conducted in Hong Kong found similar results – older individuals with lower SES were more likely to be admitted to the hospital during heat waves than those with higher SES.

Climate change continues to cause record-breaking heat waves year after year, and thus, we need to be aware of all of the risks these temperatures pose to our health. At an individual level, it is essential to understand what factors can place you at risk and to avoid outside activity, if possible, during these extreme temperatures. At a community level, we must look out for one another. For example, this summer, check up on your elderly family members and neighbors and be aware of signs of heat exhaustion and heat strokes in others so that you can provide assistance in case of emergencies. And at a societal level, keep fighting for and supporting climate change policies!

Categories
Toxic Tuesdays

1,2-dichloroethane (1,2-D)

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

1,2-dichloroethane (1,2-D)

1,2-dichloroethane (1,2-D) – also called ethylene dichloride – is a clear, oily liquid with a sweet smell that is man-made and not found in nature. It is used in the production of plastic and vinyl products like polyvinyl chloride (PVC) pipes, upholstery, automobile parts, and housewares. It is also added to the leaded gasoline used in airplanes and racecars. 1,2-D was previously used in some household products like carpet cleaners, but most of these products are discontinued. 1,2-D can enter the environment during its production, disposal, or use. It can enter the water and soil, but because it is volatile (meaning it readily evaporates), most 1,2-D ends up in the air. Once in the air, it can persist for many months and travel long distances.

Because most 1,2-D in the environment ends up in the air, people are most likely to be exposed to it by breathing contaminated air. Exposure can cause damage to many organ systems: brain dysfunction such as nausea and blurred vision; gastrointestinal dysfunction such as vomiting, gastritis, and colitis; respiratory dysfunction such as difficulty breathing and bronchitis; immune system dysfunction such as decreased ability to fight infection and decreased blood clotting; liver damage; and kidney damage. In extreme cases, exposure can cause heart attack and death. In studies of laboratory animals, exposure also caused lung, liver, brain, and reproductive cancers. Based on this research, the US Environmental Protection Agency has determined that 1,2-D probably causes cancer in humans.

1,2-D is known to be a very dangerous chemical with multiple harmful effects on human health. It is a positive development that household products with 1,2-D are largely discontinued. However, its continued use in products like PVC pipes and leaded gasoline mean that 1,2-D and its threats to human health remain pervasive in both household and industrial environments.

Learn about more toxics

Categories
Toxic Tuesdays

Lead in Public Housing

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

Lead in Public Housing

Lead is a naturally occurring metal that has been used in many household products like paint and plumbing materials. This makes people most likely to be exposed to lead in their own homes, through ingesting or inhaling contaminated paint, dust, or water. Lead exposure affects all organs but is particularly damaging to the brain, causing defects in learning and memory. Children are especially vulnerable to lead exposure because of their growing brains, and exposure can cause defects in brain development, behavioral problems, and irreversible learning disabilities. Even though it’s been known for over two hundred years that lead is toxic, it is estimated that 800 million children worldwide are exposed to lead today. (CHEJ has previously written about the health effects of lead exposure here.)

A new study has found that access to federal housing assistance is associated with lower blood lead levels (BLLs), demonstrating how housing access influences health. The US Department of Housing and Urban Development (HUD) has three main housing assistance programs that help 5 million low-income households access affordable, high-quality housing:

  1. The public housing program provides subsidized housing units at a specific site that is owned by the local public housing authority.
  2. The multifamily income-restricted housing program provides subsidized housing units at a specific site that is owned by a private entity.
  3. Tenant-based housing choice vouchers (HCVs) provides subsidies for tenants to use towards finding housing in the private market.

The study authors linked HUD administrative records to data from an existing survey that measured people’s health including their BLLs. This allowed the authors to connect people’s BLLs to whether or not they were enrolled in a HUD housing program. To determine if access to HUD housing programs was associated with lower BLLs, the authors compared those who were enrolled in a HUD program to those who were not enrolled but would become enrolled within the next 2 years. This ensured that the groups being compared were similar in their socio-economic status and eligibility for HUD housing assistance. Overall, the study sample included over four thousand people.

The authors found that when controlling for demographic factors like race, ethnicity, sex, age, partnership status, and households size, average BLL was 11.4% lower for people enrolled in HUD housing programs compared to people who were not enrolled at the time. The effect was biggest for people enrolled in public housing programs. The effect was smallest for people enrolled in the HCV program. The authors hypothesize that this protective effect of HUD housing assistance is because HUD has stricter compliance and enforcement of federal lead-paint laws – such as the Lead-Paint Poisoning Prevention Act, the Residential Lead-Based Paint Hazard Reduction Act, and the Lead-Safe Housing Rule – in their public-owned housing units compared to housing units that are privately owned. Because the HCV program has recipients find housing on the private market, this may explain why there was little effect on BLLs for people enrolled in HCV. The authors also note that as housing construction has slowed in the past few decades, affordable housing options on the private market tend to be older construction that are more likely to contain lead-based paint and pipes. HUD’s required inspections, maintenance, abatement, and clearance activities seem to be effective at decreasing people’s exposure to lead. This is consistent with previous studies that have found other positive health outcomes associated with public housing.

The authors found that the association between HUD housing program enrollment and lower BLLs was strongest for non-Hispanic white people. The association was much lower for Black and Mexican American people. While the study cannot explain why this is, the authors offer several explanations rooted in historical and ongoing racism:

“Black households continue to face significant barriers to high-quality housing and high-opportunity neighborhoods that may have fewer lead hazards because of legacies of racist housing policies and urban planning practices in the United States. These practices include redlining, zoning and land use restrictions, gerrymandering of school and census boundaries, predatory lending, and urban renewal initiatives in Black and Brown neighborhoods that displaced families and built highways, airports, and other large pollution-emitting sources in their neighborhoods through eminent domain.”

Overall, this study indicates that housing through HUD programs protects against lead exposure. This is likely a success story of regulations that require inspection, abatement, and removal of lead in public housing; it suggests that requiring units on the private housing market to adhere to these same regulations could have a significant impact on lead exposure in the United States. Because lead is one of the worst toxic chemicals with the potential to do lifelong damage to children, public policy efforts that reduce lead exposure should be a priority. The fact that the lead protective effect of HUD programs is less substantial for nonwhite people demonstrates how systemic racism impacts housing and health. This study shows that housing justice and environmental justice are deeply intertwined: access to high-quality housing is crucial for health and safety. The study also shows that neither housing justice nor environmental justice can be achieved without racial justice.

Learn about more toxics

Categories
Toxic Tuesdays

Dealing with Uncertainty When Evaluating Toxicity​

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

Dealing with Uncertainty When Evaluating Toxicity

In a recent issue, we discussed the many challenges in evaluating the adverse health effects that result from exposure to a mixture of toxic chemicals. Despite this, scientists still estimate and assess risks by attempting to compensate for these uncertainties.

This is done by assigning an uncertainty factor (UF) to the different uncertainties. How well these uncertainty factors fill in the gap in what we do not know is a matter of controversy and opinion. Especially when you acknowledge that we only have good toxicity information on about 1% of the more than 80,000 chemicals that are in use.

Consider just a few of the uncertainties. The first step in assessing risks is to determine what substances a person was exposed to, at what concentration and for how long. Rarely is this information ever available, so assumptions need to be made to estimate this critical information. Sometimes, there is limited air, soil or water data. This data is often collected for a different purpose, such as to evaluate the need for remediation as opposed to evaluating public health risks. There are also uncertainties in how the samples were collected, the accuracies of and precision of the analytical measurements and the thoroughness of the sampling (were the samples taken at the right places, analyzed for the right substances and at relevant concentrations). At times, modeling is used to estimate how much of a chemical a person was exposed to (usually after making assumptions about even what kind of chemicals a person was exposed to), how long they were exposed and at what concentration.

The next step is to evaluate the toxicity information available on the chemical in question. This would include information from animal studies, clinical trials and epidemiological studies involving people. Since most of the data that exists is from animal studies, this step already creates enormous uncertainties. These uncertainties include extrapolating results in animals to people; the variability in response among people; the sensitivity in response among people; estimating acute or short-term responses in people when the only data you have is from chronic or long-term exposure, and vice versa. These examples just touch the surface of the many uncertainties in our understanding of how chemicals affect a person’s health. 

Another factor that comes into play is the health status of the individual who was exposed. People who are generally healthy and without pre-existing conditions respond differently to toxic chemicals than people with prior exposures, poor immune or nutritional status, or pre-existing health problems.

To address these many uncertainties, scientists have developed what were originally called safety factors, but now are referred to simply as uncertainty factors (UF). These uncertainty factors can range from 1 to 10 and often are multiplied together to yield a composite uncertainty factor that can be as high as 100 (10 x 10). These UFs are included in the estimate of the risks a person or group of people face.

Scientists give an UF to each specific uncertainty trying to compensate for the uncertainty. Doing this requires making many assumptions about areas of knowledge that very little is known about. These assumptions are made by “scientific experts” who very quickly become convinced that they “know” the health risks that a person or a group of people face. Of course, they do not really know. Instead, what they have is an opinion based on multiple assumptions, typically for a single substance.

What compounds this process is that the people who make these risk assessment estimates are scientific experts, and do not include the people who have to bear the risks of the chemical exposures. That’s not right! The people who bear the risks need to be involved in the risk assessment and health evaluation process because of the many uncertainties that exist in estimating exposures and in extrapolating what little data exist to evaluate adverse health effects resulting from exposures to low level mixtures of toxic chemicals.

For more about uncertainties when evaluating the adverse effects from chemical exposures, see Environmental Decisions in the Face of Uncertainty, by the Institute of Medicine of the National Academies, 2013.

Learn about more toxics

Categories
Backyard Talk Homepage

Tennessee EJ Groups are Suing FERC

Photo credit: John Partipilo

By Franklin Sharon.

On May 1, 2024, Anita Wadhwani of Tennessee Lookout reported that Tennessee environmental groups have filed a suit against the Federal Energy Regulatory Commission (FERC) over its approval of a pipeline that will wind through mostly poor and Black Middle Tennessee communities. This pipeline will supply methane gas to a new Tennessee Valley Authority (TVA) powerplant near Clarksville.

What Are the Groups Asking For?  The Sierra Club and Appalachian Voices are asking the United States Court of Appeals for the District of Columbia Circuit to set aside a January order approving the 32-mile pipeline through Dickson, Houston and Stewart Counties. Below is a proposed system map of the Kinder Morgan pipeline that runs through these three Tennessee counties.

Represented by the Southern Environmental Law Center (SELC), these environmental groups say the construction and ultimate operations of the pipeline poses a host of avoidable risks to the communities and natural resources that lie in its path. These groups have criticized federal regulators for caving to pressure from the Tennessee Valley Authority and the company building the pipeline, Tennessee Gas Pipeline.

According to an analysis by FERC, The proposed pipeline’s route goes through eleven (11) communities, seven (7) of which are disproportionately in poor or Black communities and three (3) of which have minority populations of 50% or more. Additionally, the pipeline would cut through dozens of streams that feed into the popular Harpeth River.

Other concerns raised by environmental groups centers on the danger of pipes leaking methane into the atmosphere. Methane is a key contributor to climate warming. The groups also issued a warning, that the costs which TVA is incurring to complete this project will ultimately be borne by consumers in the form of higher energy costs. 

Why is This Pipeline So Controversial?  The pipeline project is intended to supply natural gas to a new TVA plant in Cumberland City, which is approximately 20 miles southwest of Clarksville.  This plant is one of eight gas-powered plants that TVA has announced and is drawing criticism from environmental groups for its continued reliance on climate-damaging fossil fuels instead of investments in renewable energy.

Why Is This Important?  Spencer Gall, SELC attorney, said “FERC’s decision to greenlight this project ignored the harm the pipeline and gas plant would inflict on Middle Tennessee and beyond,”

“FERC is supposed to safeguard the public interest, not rubberstamp unnecessary pipeline projects that will harm our communities, hurt the climate, and contribute to higher power bills”.

Categories
Toxic Tuesdays

1,4-dichlorobenzene (1,4-DCB)

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

1,4-dichlorobenzene (1,4-DCB)

1,4-dichlorobenzene (1,4-DCB) – also known as p-dichlorobenzene (p-DCB) – is a colorless solid chemical that readily evaporates into the air. 1,4-DCB does not occur in nature, and it is often produced for use in deodorants or disinfectants because it has a strong odor that humans can smell at very low concentrations. It is commonly used in household products like mothballs and deodorizing sprays. It also has industrial uses as a pesticide ingredient and a precursor to commercial dyes. 1,4-DCB can enter the environment through its household uses, pesticides, and industrial waste disposal. 1,4-DCB mostly enters the environment as a vapor, and people are likely to inhale it in homes and buildings where it is used. Solid 1,4-DCB can also bind to soil and remain there for long periods of time, but people are less likely to be exposed to it in this way.

Inhaling high concentrations of 1,4-DCB can cause irritation or burning sensations in the eyes and nose. It can also cause coughing, nausea, difficulty breathing, dizziness, headaches, and liver dysfunction. Touching products that contain 1,4-DCB can also cause burning sensations on the skin. In studies of laboratory animals, 1,4-DCB exposure caused liver, kidney, and blood defects as well as liver cancer. The US Department of Health and Human Services and the International Agency for Research on Cancer both classify it as being reasonably anticipated to cause cancer.

Because of the danger to human health, the Environmental Protection Agency has set a maximum 1,4-DCB concentration that can be present in drinking water without observing adverse health effects. The European Union has gone even further, banning use of 1,4-DCB in mothballs and air fresheners because of its potential to cause cancer. Similar regulation in the US could protect more people from the health risks of 1,4-DCB exposure.

Learn about more toxics

Categories
Toxic Tuesdays

Barium

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

Barium

Barium is a silver-colored metal which is found in the earth in compounds with other elements. Many barium compounds have industrial uses: barium sulfate is used as a drilling lubricant by the oil and gas industries to facilitate drilling through rock; barium carbonate is a rat poison; and barium oxide is used in the production of electronics and glass. Barium can enter the air through the production of barium-containing compounds and the improper disposal of barium-containing waste. It can then enter the soil and water. Barium compounds that do not dissolve in water can persist in the soil and water for a long time.

People are most likely to be exposed to barium by drinking contaminated water. Barium compounds that do not dissolve in water – like barium sulfate and barium carbonate – are not known to be harmful to human health. However, barium compounds that do dissolve in water – like barium chloride and barium hydroxide – can harm human health because they release barium ions into the body. Barium ions interfere with the normal electrical impulses generated in the brain, muscles, and heart. Exposure can cause gastrointestinal dysfunction such as vomiting, diarrhea, and abdominal cramps. It can also cause anxiety, disorientation, difficulty breathing, decreased blood pressure, numbness, muscle weakness, and paralysis. The eyes, immune system, respiratory system, and skin can also be damaged by barium exposure. The Environmental Protection Agency (EPA) has set a limit on how much barium can safely be in drinking water, but almost 800 Superfund sites are known to have barium contamination, suggesting that there may be potential for barium exposure in some communities.

Learn about more toxics

Categories
Toxic Tuesdays

Carbon Monoxide

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

Carbon Monoxide

Carbon monoxide is a toxic gas that is difficult to detect because it has no smell, taste, or color. It can be produced from both natural and human-made sources when carbon fuel – such as gasoline, wood, coal, charcoal, propane, natural gas, or trash – is incompletely burned. The most common source of carbon monoxide in outdoor air is exhaust from gas-powered vehicles. It can also be produced in indoor air through house fires or use of gas-powered appliances such as portable generators, furnaces, water heaters, stoves, and fireplaces. Carbon monoxide is also produced in industrial chemical manufacturing to create a group of plastics called polycarbonates.

When carbon monoxide enters the air it can remain there for several months. Inhaling air contaminated with carbon monoxide interferes with red blood cells’ ability to carry oxygen throughout the body. This can cause difficulty with breathing, headache, nausea, dizziness, vomiting, vision impairment, confusion, and chest pain. In high doses it can cause seizures, coma, and death. Exposure to high doses while pregnant can also cause miscarriage. People with heart or lung diseases are particularly vulnerable to the effects of carbon monoxide exposure. Even once exposure to carbon monoxide has ended, there can be long-term effects on heart and brain function.

Because of the extreme toxicity of carbon monoxide, the Environmental Protection Agency (EPA) sets standards for safe levels of carbon monoxide in the air. Despite these standards, studies estimate that 50,000 people in the United States need emergency medical treatment for carbon monoxide exposure each year, and that about 1,000 die from carbon monoxide exposure each year. Carbon monoxide has also been found in many Superfund sites identified by the EPA. These realities indicate that more stringent standards, testing, and regulations may be necessary to keep people safe from carbon monoxide.

Learn about more toxics