Nature itself presents hazards to human health, including disease, natural poisons, and radiation. Regulators use a process called environmental risk assessment to decide whether they need to take risk management steps in relation to a risk. In this activity, you will carry out three steps of an environmental risk assessment called release analysis, exposure analysis, and health effects analysis. This activity will require outside research in addition to the textbook and will set the stage for a larger assignment in Week 4.
Instructions
Write a 1–2 page paper using the following instructions.
Select an environmental risk that occurs in nature, and research information about its release, exposure scenarios, and health effects. The specific data in each area of the analysis will depend on the environmental risk you choose. Write at least one paragraph for each analysis:
Release Analysis: Identify the contaminant, and how it is released, measured, or detected. Include units of measurement, setting for the release, and scientific fields related to the contamination or measurement.
Exposure Analysis: Analyze the risk of exposure such as settings in which people encounter the risk or plausible scenarios in which exposure occurs.
Health Effects Analysis: Estimate the risks to human health, including short and long-term effects, demographic groups at risk, and health effects on individuals and populations.
Use 1–2 sources to support your writing. Choose sources that are credible, relevant, and appropriate. Cite each source listed on your source page at least one time within your assignment. For help with research, writing, and citation, access the library or review library guides.
Sample Answer
Environmental Risk Assessment: Naturally Occurring Radon Gas
This paper will conduct the first three steps of an environmental risk assessment—release analysis, exposure analysis, and health effects analysis—for radon gas ($\text{Rn}$), a naturally occurring environmental risk.
Release Analysis
The contaminant is radon-222 (1$\text{Rn-222}$), a colorless, odorless, radioactive noble gas.2 Radon is the progeny of the radioactive decay chain of uranium-238 (3$\text{U-238}$), which is naturally present in nearly all soils and rocks, particularly granite, shale, phosphate, and pitchblende.4 The process by which it is released is called emanation, where radon gas escapes from the solid mineral matrix of the soil or rock.5 Radon is continuously released into the atmosphere and the ground.6
The primary setting for its release that leads to human contamination is the subsurface soil. Once released, the gas migrates through the soil and enters the built environment through cracks in foundations, floor-wall joints, and utility openings.7 Since radon is ubiquitous, its release is measured by analyzing air samples.8 Detection is typically performed using specialized instruments such as charcoal canisters, alpha track detectors, or continuous radon monitors.9 Radon concentration is quantified in units of picocuries per liter (10$\text{pCi/L}$) or becquerels per cubic meter (11$\text{Bq/m}^3$).12 The scientific fields involved in its contamination and measurement include geology (understanding soil and rock composition), nuclear physics (studying radioactive decay), and environmental engineering (measuring indoor air quality and designing mitigation systems).
Exposure Analysis
The risk of exposure to radon is most significant in indoor settings, specifically homes, schools, and workplaces, especially those located on the lower levels (basements, ground floors).13 Unlike outdoor settings where radon quickly dissipates, indoor air allows the gas to accumulate to hazardous levels.14 The degree of exposure is highly dependent on the local geology and the building's characteristics.
Plausible exposure scenarios include:
Prolonged Residential Exposure: An individual living in a home built over granite bedrock with a cracked concrete slab foundation. The negative pressure created by HVAC systems or temperature differences can draw soil gas into the living spaces, leading to continuous, long-term inhalation exposure.15