Draft document with asbestos data tables, DEP Box 09

NYC 9/11 Public Portal Document

-S I ' DRAFT Sy X H95 95% UCL = exp [Ybar + 0.5 x S/ +--------- ] n-1 Where: 95% UCL = the 95% UCL on the arithmetic mean for a log normally distributed dataset Ybar the average of the natural logarithms of all concentrations Sy the standard deviation of the logarithms of the concentrations n the number of samples H95 a statistical parameter which depends on n and Sy, obtained as a table value (Gilbert, 1987).

Estimation of Average Daily Exposure Since the Commuter’s daily exposure is for only short durations and the service life of the recovered vehicles is expected to be less than the receptor’s lifetime, the asbestos concentration in air, as represented by the EPC, was adjusted to represent a continuous lifetime average daily exposure using the following standard equation:

LADE EPC X EF X ED X EP X UC AT Where:

LADE = Lifetime average daily exposure via inhalation (fibers/mL) EPC = Exposure point concentration (fibers/mL) EF Exposure Frequency (events/day) ED Exposure Duration (hours/event) EP Exposure Period (years) UC = Unit Conversion (days/hour) AT = Averaging Time (years)

Toxicity Assessment

The Environmental Protection Agency’s Integrated Risk Information System (IRIS) lists asbestos as a Class-A human carcinogen based on “increased mortality and incidence of lung cancer, mesotheliomas and gastrointestinal cancer in occupationally exposed workers that are consistent across investigators and study populations”. A unit risk factor of 0.23 (fibers/mL) ' is provided in IRIS and is based on data from a number of occupational studies. This unit risk value was adjusted to continuous exposure by

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