Local Soil Exposure Pose Risk to Surrounding Residents
In a recent evaluation under the Hazard Ranking System (HRS), a small, bankrupt wood preserver site has been identified as posing a potential threat to nearby individuals, including residents, students, and day care children.
The HRS, a system used to assess the potential for environmental releases to affect human health, has highlighted the risk of vapor-forming chemicals migrating from contaminated soil or groundwater into overlying buildings, particularly relevant for residences, schools, and day care centers.
The threat to nearby individuals is quantitatively ranked to help prioritize sites for further action under the Superfund program based on their potential human health impact. The site in question has been assigned a nearby threat score of 544.5.
The nearby threat score is calculated by considering two main factors: the likelihood of exposure and the hazardous waste quantity. The likelihood of exposure is estimated from the size of the area of observed contamination and its attractiveness/accessibility for recreational use. Assuming a worst case of public recreation evidence, the likelihood of exposure value is 25 out of a possible 500 points.
The hazardous waste quantity from Table 5-2 is less than 1, but the minimum value for the soil exposure pathway is 10. At a rural site with a population density of 100 people per square mile, the estimated value for population within 1 mile is 0.21.
It's important to note that the values for toxicity and hazardous waste quantity are assigned in the same manner as for the resident population threat, but only areas with an attractiveness/accessibility factor value greater than 0 are considered. Additionally, the values assigned to nearby populations have been reduced to better reflect the relative levels of exposure.
Since there are no resident targets, a tentative value of 1 for nearby individuals has been assigned. The site is not secured from access, meaning that nearby individuals may potentially come into contact with hazardous substances.
The maximum toxicity value for wood-treating substances found in the sampling is 10,000. The site in question is a small, bankrupt wood preserver with observed contamination in the process area and drip yard, covering approximately 50,000 square feet.
The pathway score is 0.007, as the resident threat is zero. The nearby threat score is calculated by multiplying the likelihood of exposure value, the toxicity value, and the population within 1 mile.
The nearby threat score for the soil exposure pathway receives only 1/40 the value of potential targets in the drinking water threats. This reflects the lower potential for direct contact with hazardous substances through soil compared to drinking water.
The HRS will continue to monitor the site and assess the risk to nearby individuals. Further action under the Superfund program may be taken if the risk is deemed to be significant.
- The small, bankrupt wood preserver site, with contaminated soil and groundwater, poses a risk to surface water, which could lead to potential health issues for nearby individuals, including residents, students, and day care children, particularly in buildings and areas used for recreation.
- The water used in the nearby environment could potentially be contaminated with waste from the wood preserver site, posing a threat to drinking water and the health-and-wellness of the surrounding population.
- The study of environmental science is vital in understanding the potential effects of this site, as the vapor-forming chemicals could affect the quality of air and the health of nearby individuals.
- The impact of this wood preserver site on the environment, particularly in terms of contamination, should be closely monitored and addressed by the Superfund program and the relevant environmental-science authorities, to ensure the health and safety of nearby individuals.
