WTC environmental investigation report, Sep 2002

NYC 9/11 Public Portal Document

Final Technical Report of the Public Health Investigation Page 35 of 56 were samples taken which showed fibers by PCM, which were not re-analyzed. Any of these air samples, especially those taken in areas with asbestos or SVF in the dust, may have some of these fibers as part of the PCM fiber count. Generally, the levels of dust and air did not indicate a consistent pattern at different locations. It was not possible to conduct a more accurate correlation analysis between asbestos and SVF material in settled surface dust and fibers in air because the majority of air samples were not analyzed specifically for asbestos or SVF (i.e., TEM or SEM analysis). The limited data gathered during this investigation does not support nor refute the assumption that all the fibers in the air samples will be asbestos or SVF even when asbestos was found in dust.

B. Public Health Evaluation

The potential for health effects is possible after exposures to certain materials. An exposure to a material occurs when it comes into contact with or is taken into our bodies. The route of exposure is the method by which a material comes into contact with the body (e.g., dermal contact, inhalation, or ingestion). The nature of the health effect will depend on the material involved, how it comes into contact with the body, the amount of material (exposure level), the duration of the exposure, resultant dose, and the susceptibility of the individual (e.g., pre-existing health conditions may make an individual more sensitive to a contaminant).

Initially, screening values were established and listed in the project-sampling plan. These screening values were established to provide a guideline for evaluating the data as it was collected for any indication of a hazard requiring immediate attention, and to ensure the proper analytical detection limit to support a chronic health evaluation. These screening values were not used in this report because this public health evaluation is specific to the levels of materials found in the study area.

Because levels of asbestos, SVF, and some crystalline minerals are elevated in the settledsurface dust of some buildings in lower Manhattan, individuals may be exposed to those materials in their homes, out of doors, or at work either by direct contact or by inhalation when the dust is disturbed and suspended in the air. Depending on the environment, one or all of these materials may be present in the dust of an area.

1. Sensitive Populations

Sensitive populations are individuals who may experience greater responses when exposed to a material than normally predicted. This sensitivity may be due to life stage, pre-existing medical or exposure conditions, or genetic susceptibility.

Children are considered a sensitive population for several reasons. The first consideration is the potential for greater exposure than adults. With a lower body weight, and higher relative ventilation rate, children have higher doses than adults given exposure to the same levels of materials in air, food, or drinking water. For biopersistent materials, such as some of the minerals discussed

http://www.atsdr.cdc.gOv/asbestos/lowennaiihattan/ResSamp_Sep2002_Text.html 07/18/2003 NYC-WTC_000178422