Thanks to TOSC, we have received some information about these HBVCs to help explain and interpret the information in the EPA's Fact Sheet #3.
Usually at a contaminated site the concentration of each chemical in the soil, water, and air will be measured, and based on that measurement, the potential risk that the chemical poses on the surrounding residents will be measured. The risk is based on the toxicity of the chemical, its concentration and characteristics, the exposure duration, etc. The risk is defined as being acceptable if it amounts to less than one person in a million developing cancer from exposure to this chemical. The HBCVs, on the other hand, use this acceptable risk of one in a million and using the characteristics of a given chemical, calculate acceptable concentrations in soil, air, and water. They are simply risk assessments in reverse.
HBCVs are another name for Preliminary Remediation Goals (PRGs) which are the acceptable contamination levels (in residential soil, industrial soil, air, and residential water) of toxic chemicals used for planning purposes by the EPA.
PRGs are the acceptable levels of chemical in the air, water, or soil, as based on a chemical's toxicity and its effect on human health (chemical risk assessment). The EPA bases risk assessments on the probability that only one person in a million will develop cancer after being exposed to a chemical. Therefore, if a million people are exposed to a chemical, only one person will develop cancer due to this exposure.
The EPA uses an equation to calculate the acceptable concentration of a noncarcinogen in soil. This equation combines all risks (from ingestion, inhalation, and dermal [skin] contact) when computing the permissible concentration. The values used are those of a child since they are usually more sensitive to a chemical than is an adult. The following chart is the list of chemicals found at the South Phoenix site which were in excess of those found in the control homes. As can be seen, the ambient air HBCVs are a lot lower than the soil HBCVs so hopefully we can get better results after Phase II testing by the EPA. Key:
mg/kg/day is milligrams per kilogram per day ppm is parts per million ug/m3 is micrograms per cubic meter.
| CHEMICAL | Oral RfD (mg/kg/day) | Soil HBCV (PRG) (ppm) | Ambient Air PRG (ug/m3) |
|---|---|---|---|
| Boron | .09 | 5900 | 21 |
| Copper | .037 | 2800 | NA |
| Tin | .6 | 46,000 | NA |
| Lead | NA | 400 | NA |
| Nickel | .02 | 1500 | NA |
| Fluoride | .06 | 3900 | 220 |
| Nitrate | 1.6 | 97,000 | NA |
| Nitrate | . 3 | 23,000 | NA |
| PAHs | NA | .06-60 | .00092-1100 |
During South Phoenix community meetings about the QPC fire, ATSDR has been requested to ask people to provide their name, address, and phone number if they wanted ATSDR to contact their physician to ensure that everyone in the South Phoenix area had an opportunity to respond to the ATSDR offer of physician consultation.
To do this, you really don't need a special form. You need to provide certain information in a clearly written, legible manner. Please provide your name and the names of any family members that are provided health care services by the physician. Provide the name, address, and phone number of the physician who provides you and/or your family with health care services if you would like for ATSDR to contact your physician and offer medical consultations. Even if you already provided this information previously, you may want to again provide this information to ensure that ATSDR has the correct name, address, and telephone number of you and your physician. If you DO NOT want ATSDR to contact your physician, DO NOT provide this information to ATSDR.
Mail this information to: AGENCY FOR TOXIC SUBSTANCES DISEASE
REGISTRY ATTENTION: DAN C. STRAUSBAUGH REGIONAL
REPRESENTATIVE ATSDR REGION IX 75 HAWTHORNE STREET SUITE 100;
MS:HHS-1 SAN FRANSICSO, CA 94105
SEE PAGE 7 FOR SPECIAL ATSDR
PUBLIC SERVICE ANNOUNCEMENT