Arsenic is the chemical listed as number 1 on the ATSDR Substance Priority List, recognized for posing the most significant potential risk to human health.
Understanding the ATSDR Substance Priority List
The Agency for Toxic Substances and Disease Registry (ATSDR), a federal public health agency of the U.S. Department of Health and Human Services, compiles a Substance Priority List (SPL). This list identifies hazardous substances found at National Priorities List (NPL) sites, also known as Superfund sites, that pose the most significant potential threat to human health. The ATSDR evaluates substances based on a combination of their toxicity, the frequency with which they are found at NPL sites, and their potential for human exposure. This prioritization helps guide public health activities and research efforts.
Arsenic: The Top-Ranked Chemical
Arsenic holds the top position on the ATSDR Substance Priority List due to its widespread presence in the environment and its severe toxic effects on human health. It is a naturally occurring element found in the earth's crust and can be released into the environment through both natural processes and human activities.
Health Impacts of Arsenic Exposure
Exposure to arsenic can lead to a range of serious health problems, varying depending on the dose, duration, and individual susceptibility. Both acute (short-term) and chronic (long-term) exposure can have devastating effects:
- Cancer: Long-term exposure to arsenic is strongly linked to an increased risk of various cancers, including skin, bladder, lung, kidney, and liver cancer.
- Skin Lesions: Characteristic skin changes, such as hyperpigmentation (darkening of the skin) and hyperkeratosis (thickening of the skin on palms and soles), are common indicators of chronic arsenic exposure.
- Cardiovascular Disease: Exposure can contribute to heart disease, including hypertension and peripheral vascular disease.
- Neurological Effects: Symptoms like neuropathy, weakness, and numbness in the hands and feet can occur.
- Developmental Effects: In children, arsenic exposure has been associated with developmental delays and cognitive impairments.
Common Sources of Arsenic Exposure
People can be exposed to arsenic through various pathways:
- Contaminated Drinking Water: This is a primary source of exposure globally, especially in areas where groundwater naturally contains high levels of arsenic or near industrial sites.
- Food: Arsenic can accumulate in certain foods, particularly rice, rice-based products, and some seafood.
- Industrial Exposure: Workers in industries like mining, smelting, and pesticide manufacturing may face higher exposure risks.
- Soil and Dust: Living near sites with contaminated soil or consuming vegetables grown in arsenic-rich soil can also lead to exposure.
Top Substances on the ATSDR Priority List
The ATSDR periodically updates its Substance Priority List. As of the 2022 list, the top four substances identified as posing the most significant risk to human health are:
| Rank | Substance Name | CAS RN |
|---|---|---|
| 1 | ARSENIC | 7440-38-2 |
| 2 | LEAD | 7439-92-1 |
| 3 | MERCURY | 7439-97-6 |
| 4 | VINYL CHLORIDE | 75-01-4 |
For a comprehensive understanding of all prioritized substances and their profiles, the full ATSDR Substance Priority List can be accessed on the CDC website.
Significance for Public Health
The ATSDR Substance Priority List plays a critical role in public health by identifying the most hazardous chemicals that require immediate attention. This prioritization helps:
- Direct Research: Focus scientific research on the health effects and remediation strategies for these high-priority substances.
- Inform Policy: Guide regulatory bodies in developing policies and guidelines to protect communities from exposure.
- Public Awareness: Raise awareness among the public about potential environmental health risks.
Understanding the ATSDR's prioritization helps individuals, communities, and public health agencies take informed actions to minimize exposure and safeguard human health.
