January 30, 2001
PUBLIC NOTICE Hexavalent Chromium Pollution - Northwest Berkeley
To residents, business owners, and property owners of the West Berkeley area bordered by the Interstate Highway 80, Gilman Street, Seventh Street, and the northern Berkeley boundary at Codornices Creek.
• Hexavalent chromium is present in the groundwater within this area of West Berkeley as a result of historical industrial activities.
• If you are in the referenced area (see attached map), you may have hexavalent chromium in soil or groundwater below your property, beginning at a depth of approximately three to five feet below the ground surface.
• WARNING: The State of California has determined that hexavalent chromium can cause cancer and can impact your health either through ingestion (eating, drinking, or inhalation of vapor) or prolonged physical contact with the groundwater. If you have not ingested or contacted groundwater, you do not have an exposure problem.
• If you are in the referenced area, avoid contact with the groundwater and soil at a depth of approximately three to five feet below the ground surface.
• Your municipal drinking water supply has not been affected and is safe.
• The contamination does not present a health risk for children or other users of the playing fields.
• If you are or have been in contact with the groundwater, or otherwise believe you have been exposed to this source of hexavalent chromium for any reason, please contact the Toxics Management Division at 705-8150.
The City of Berkeley is coordinating an effort with State agencies to develop an appropriate course of action to remove the contamination in the groundwater and to eliminate potential health risk. A report of the toxicity of hexavalent chromium and the evaluation of public health risk are available for review at the Toxics Management Division at 2118 Milvia Street or the West and Central Berkeley Libraries. The report referenced at the libraries as "The SOMA Report" dated December 8, 2000.
City of Berkeley Skateboard Park SOMA 00-2268
Project Evaluation Report December 8, 2000
The results of the screening-level evaluation indicate that estimates of risk for the: I) construction workers, 2) recreational users of the adjacent soccer/baseball field, 3) workers and residents of the social services shelter, and 4) people passing by the Site are not significant.
Quantitatively, the excess carcinogenic risk due to TCE for the construction worker due to inhalation exposures is a risk of 5 in 100,000,000 or five in one hundred million. Although the issue of acceptability risk is a regulatory matter, a risk of one in one million is typically used a point of departure, that is a reference point. An evaluation of occupational exposures based on methods used by Cal OSHA support the conclusion that potential occupational exposures to TCE are in compliance with Cal OSHA.
Similarly, noncarcinogenic adverse health effects would not be expected. Time constraints have limited SOMA's evaluation to potential inhalation exposures to TCE. Hexavalent chromium does not represent a source of potential adverse health effects to construction workers based on a combination of relatively low concentrations in groundwater and the absence of significant exposure pathways.
The excess carcinogenic risk due to potential inhalation of TCE to residents of the shelter was calculated to be 2 in 1,000,000 or two in one million. The exposure assumptions for this receptor are overly conservative and this estimate of risk significantly overestimates actual risks. For example, it is assumed that a resident of the shelter resides at the shelter 24-hours a day, 350 days per year for a period of 30 years. It assumes that the resident was born and raised at the shelter and never leaves the shelter. These assumptions greatly overestimate the actual use patterns of typical residents of the shelter. Although an excess risk of cancer of two in one million is greater than the commonly used point of departure of one in one million, the conservative nature of the calculations indicates that an estimate of two in one million is not significant.
