Residential Well II
MOTOR FUELS CORPORATION
LEVELLAND, HOCKLEY COUNTY, TEXAS
This residential water well was sampled July 28, 1998; the sample was analyzed for volatile organic compounds (VOCs). All VOCs analyzed for were below their respective detection limits with the exception of 1,2-dichloroethane. The concentration which was measured was compared with concentrations at which health effects might be expected to occur.
The volatile organic compound 1,2-dichloroethane was measured at a concentration of 24.0 micrograms per liter June 30, 1998. The Maximum Contaminant Level (MCL) for 1,2-dichloroethane which is allowed in public drinking water supplies is 5 micrograms per liter. The health-based cancer-risk evaluation guide for 1,2-dichloroethane is 0.4 micrograms per liter. Although exposure to the concentration of 1,2-dichloroethane detected in this well is not likely to result in non-cancer health effects, long-term exposure to this concentration of 1,2-dichloroethane could result in a low increased risk of developing cancer over a lifetime (70 years) of exposure. The increased risk is not due to ingestion of the water by drinking or by exposure to the 1,2-dichloroethane by dermal contact during showering or bathing but it is due to inhalation of the 1,2-dichloroethane which may vaporize from the water and accumulate in the indoor air of the home.
If you are exposed to a substance such as 1,2-dichloroethane, many factors will determine whether harmful health effects will occur and what the type and severity of those health effects will be. These factors include the dose (how much you are exposed to), the duration (how long you are exposed), the route or pathway by which you are exposed (breathing, eating, drinking, or skin contact with the chemical), the other chemicals to which you are exposed, and your individual characteristics (such as age, gender, nutritional status, family traits, life-style, and overall state of health).
1,2-dichloroethane can enter the body when people drink water or breathe air containing 1,2-dichloroethane. Animals studies also show that 1,2-dichloroethane can enter the body through the skin. Experiments in animals show that 1,2-dichloroethane that is breathed in or eaten goes to many organs of the body but usually leaves in the breath within 1 or 2 days. The breakdown products of 1,2-dichloroethane in the body leave quickly in the urine.
Exposure to 1,2-dichloroethane has so far not been associated with cancer in humans. However, cancer was seen in laboratory animals who were fed large doses of the chemical. When 1,2-dichloroethane was put on the skin of laboratory animals, they developed lung tumors. Breathing 1,2-dichloroethane may also cause cancer in animals. Because of the cancer findings in animals we cannot rule out the possibility of cancer in humans.
The TDH has prepared this consult under a Cooperative Agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). TDH has included the following information in accordance with ATSDR's Child Health Initiative.
ATSDR's Child Health Initiative recognizes that the unique vulnerabilities
of infants and children demand special emphasis in communities faced with contamination
of their water, soil, air, or food. Children are at greater risk than adults
from certain kinds of exposures to hazardous substances emitted from waste sites
and emergency events. They are more likely to be exposed because they play outdoors
and they often bring food into contaminated areas. They are shorter than adults,
which means they breathe dust, soil, and heavy vapors close to the ground. Children
are also smaller, resulting in higher doses of chemical exposure per body weight.
The developing body systems of children can sustain permanent damage if toxic
exposures occur during critical growth stages. Most importantly, children depend
completely on adults for risk identification and management decisions, housing
decisions, and access to medical care. Children may be exposed to 1,2-dichloroethane
contamination from this well water both by drinking the water and inhalation
of vapor during showering.