DEQ-CFW_00082001

The updated level of 140ng/L is lower than the level in NC DHHS's preliminary assessment for several
reasons, including the following:
0 After consultation with EPA, a different set of animal studies was identified as an appropriate
starting point for the assessment. This change lowered the health goal by10-fo|d.
* Since the new starting point was based on intermediate (sub -chronic) rather than long-term
(chronic) animal studies, an additional uncertainty factor was added, which lowered the level by
* While the preliminary assessment assumed that drinking water was the only source of exposure,
the updated value includes an assumption that only 20% of a person's GenX exposure comes
from drinking water, lowering the level anotherS4o|d. EPA's practice is to use this 2UY6default
factor as a generic assumption when information is lacking about other sources of exposure in
the environment as is currently the case with GenX. NC DHHS's use of the 20% factor was
A list of scientific studies and reports used and details on the preliminary assessment and the revised
health goal are inthe attached document, which is also posted on-line athttps://deqoc8ov/nexvs/hot-
It is important to note that 140ng/L is not a boundary line between a "safe" and "dangerous" level of
GenX.Rather, it represents the concentration of GenX at which no adverse non -cancer health effects
would be anticipated in the most sensitive population over an entire lifetime of exposure.
As with the preliminary assessment, it is also important to note that this updated health goal is not final
and is likely to be updated as new information becomes available or when standards are made available
by the EPA.
The Department of Health and Human Services had two doctoral -level toxicologists working in the
Occupational and Environmental Epidemiology Branch until one position was eliminated in 2008.
SinceJOOQ one toxicologist has had primary responsibility for a wide range of tasks, including providing
expert consultation to local health departments and private citizens onwell water results as required by
15A NCAC 18A.3800 (Private Drinking Water Well Sampling Rule).
Emergent water issues such as hexavalent chromium/coal ash and GenX/perfluorinated compounds
require a high level of specialized technical knowledge and an intensive focus from the toxicologist in
order to rapidly review all available data and provide usable health information. During recent years,
these prolonged responses have diverted considerable time and attention from important routine
responsibilities, resulting in a delay in services to local health departments and NC citizens. As testing
capabilities improve, it is likely that this trend will continue. Part of the toxicologist's time during these
OEQ-CFVV_00082001

emergent responses is spent translating scientific information for partners and for the public, which is
why a health educator would also be a valuable asset to the Department and the state.