Characterize the risk for a chronic daily exposure by the water pathway (oral) of 1.34 x 10^-4 mg/kg/day of tetrachloroethylene, 1.43 x 10^-3 mg/kg/day of arsenic, and 2.34 x 10^-4
mg/kg/day of dichloromethane (methylene chloride).
To characterize the risk for chronic daily exposure through the water pathway (oral) of hazardous substances like tetrachloroethylene, arsenic, and dichloromethane, we need to determine their respective risk factors.
1. Tetrachloroethylene:
The risk factor for tetrachloroethylene can be found by comparing the daily exposure level (1.34 x 10^-4 mg/kg/day) with its reference dose or acceptable daily intake (ADI). The ADI for tetrachloroethylene is typically provided by regulatory agencies such as the Environmental Protection Agency (EPA) or World Health Organization (WHO). By dividing the exposure level by the ADI, we can assess the risk factor.
2. Arsenic:
Similar to tetrachloroethylene, we need to compare the daily exposure level (1.43 x 10^-3 mg/kg/day) with the ADI for arsenic. Arsenic has different ADIs based on inorganic and organic forms, which are determined by using toxicity assessments. Again, dividing the exposure level by the corresponding ADI allows us to determine the risk factor.
3. Dichloromethane (methylene chloride):
Like the previous substances, we need to compare the daily exposure level (2.34 x 10^-4 mg/kg/day) with the ADI for dichloromethane. Dichloromethane also has regulatory guidelines for safe exposure levels, typically expressed as a maximum allowable concentration in drinking water or air. By calculating the exposure level to ADI ratio, we can determine the risk factor.
By obtaining the relevant ADIs for each substance and performing the calculations, we can characterize the risk associated with chronic daily exposure through the oral water pathway for tetrachloroethylene, arsenic, and dichloromethane.
To characterize the risk for a chronic daily exposure by the water pathway (oral) of tetrachloroethylene, arsenic, and dichloromethane, we can use the concept of acceptable daily intake (ADI) and compare the exposure levels with the corresponding reference values.
1. Tetrachloroethylene:
- ADI: The World Health Organization (WHO) has established an ADI of 0.05 mg/kg/day for tetrachloroethylene.
- Exposure Level: The given exposure level is 1.34 x 10^-4 mg/kg/day, which is significantly lower than the ADI. Therefore, the risk for chronic daily exposure to tetrachloroethylene through the water pathway is low.
2. Arsenic:
- ADI: The WHO has established an ADI of 0.0003 mg/kg/day for inorganic arsenic.
- Exposure Level: The given exposure level is 1.43 x 10^-3 mg/kg/day, which is higher than the ADI. Therefore, the risk for chronic daily exposure to arsenic through the water pathway is moderate to high.
3. Dichloromethane (Methylene chloride):
- ADI: The WHO has not established a specific ADI for dichloromethane. However, the United States Environmental Protection Agency (EPA) has set a reference dose (RfD) of 0.02 mg/kg/day for inhalation exposure.
- Exposure Level: The given exposure level is 2.34 x 10^-4 mg/kg/day, which is lower than the RfD. Although this value is based on inhalation exposure, it can still be used as a reference for assessing risk via the oral route. Therefore, the risk for chronic daily exposure to dichloromethane through the water pathway is low.
In summary, the risk for chronic daily exposure to tetrachloroethylene and dichloromethane through the water pathway is low, while the risk for arsenic exposure is moderate to high.