Acute and chronic health risk assessment for inhalation and ingestion exposure in acrylic acid leak accidents.

We established a hypothetical acrylic acid leak accident scenario, conducted a health risk assessment of local residents, and compared an actual accident case to the hypothetical scenario. The exposed subjects were divided into four age groups, and a noncarcinogenic health risk assessment was conducted for inhalation and soil ingestion. In the hypothetical scenario, 40 tons of acrylic acid was leaked in Ulsan for 1 h from midnight on January 1, 2017. In the actual accident case, 3 L of acrylic acid was leaked in Hwaseong, Gyeonggi Province, for 1 h from 11:00 am on March 5, 2020. The environmental concentration of acrylic acid was calculated using the dynamic multimedia environmental model. Noncarcinogenic assessment of the hypothetical scenario showed the hazard quotient exceeded 1 across all age groups, suggesting that a health risk is likely to occur due to inhalation exposure to acrylic acid resulting from a chemical accident. In addition, Hazardacute exceeded 1 until 2 h after the accident under the hypothetical scenario, indicating the likelihood of a health risk. Thus, we propose a methodology that can assess changing concentrations in a hazardous chemical leak from a chemical accident based on the time, place, the chemical's behaviors in different environmental media, and the health risk posed by the exposure of the chemical to local residents in the area affected by the accident.

Health risk assessment for multimedia exposure of formaldehyde emitted by chemical accident.

This study was conducted to provide basic data for chemical accident response by assessing the health risks of residents living near a chemical accident site due to long-term exposure. The study considered the temporal concentration changes of the leaked chemical (i.e., its behavior in the environment and dilution) until its extinction. A virtual chemical accident was assumed, in which 40 t of formaldehyde was accidentally discharged for 1 h in Ulsan Metropolitan City, Korea. Formaldehyde concentrations over time in each environmental medium after the accident were calculated using a multimedia environmental dynamics model. Exposure subjects divided into four age groups were considered. Carcinogenic risks due to respiration and non-carcinogenic risks due to soil intake were assessed. For all the age groups, the excess cancer risk did not exceed 1.0 × 10-6, indicating that no harmful health impact was caused by inhalation exposure to formaldehyde. The hazard index exceeded 1 for all the age groups, confirming that harmful health impacts were caused by exposure to soil containing the formaldehyde. This study is the first to assess chronic health risks by reflecting long-term residual and temporal concentration changes of a pollutant released in a chemical accident in each environmental medium until its extinction. This work is also significant in that it reflects the exposure characteristics of the toxic chemical.

Development on Health Risk Assessment Method for Multi-Media Exposure of Hazardous Chemical by Chemical Accident.

In this study, a long-term health risk assessment was conducted for complex, multimedia exposure where the exposure duration was set for the leak of a hazardous chemical spilled after an accident. The study designed a virtual chemical accident scenario where 40 tons of benzyl chloride leaked in a factory inside the Ulsan Petrochemical Industrial Complex for one hour on 1 January 2017. Using a multimedia environmental dynamics model, benzyl chloride concentrations in air and soil were estimated. The time when the atmospheric concentration was less than or equal to the background concentration was recorded as the end point. An assessment of the cancer risk via soil ingestion was carried out after dividing the subjects into four age groups (0-9 years; 10-18 years; 19-65 years; >65 years). All age groups showed an increased cancer risk where the values exceeded 1.0 × 10-6. The 0-9 years age group showed the largest distribution (4.27% of the total area) with the highest maximum and mean values. The distribution maps for all age groups exhibited a trend towards the southeast of the accident site.

Distribution and Influencing Factors of Airborne Bacteria in Public Facilities Used by Pollution-Sensitive Population: A Meta-Analysis.

The aim of this study was to support management of airborne bacteria in facilities used by pollution-sensitive individuals (in daycares, medical facilities, elder care facilities, and postnatal care centers). A field survey was conducted on 11 facilities from October 2017 to April 2018. Elder care facilities in industrial, urban, and forested areas were excluded. Two indoor, and one outdoor, measuring points were selected per facility. These points were located in areas most often used by the residents. Measurements were taken at random time-points before February 2018 and at specific times in the morning and afternoon thereafter. The relationships among bacterial counts, carbon dioxide concentrations, dust levels, temperature, relative humidity, and ventilation were examined. The pooled average bacterial counts at the daycares, medical facilities, elder care facilities, and postnatal care centers were 540.25 CFU m-3, 245.49 CFU m-3, 149.63 CFU m-3, and 169.65 CFU m-3, respectively. Considering the upper 95% confidence interval, the bacterial counts in many daycares may in fact be >800 CFU m-3, which is the threshold set by the Korean Ministry of the Environment. The pooled average indoor: outdoor bacterial count ratio was 1.13. Indoor airborne bacterial counts were influenced mainly by their sources. This study found no significant correlations among indoor temperature, relative humidity, carbon dioxide concentration, dust levels, and airborne bacterial counts, unlike previous studies. Airborne bacteria management at daycares should be a top priority. The sources of airborne bacteria must also be identified, and a management plan must be developed to control them.