Views expressed herein are those of the authors and do not represent the views of the U.S. EPA.

Lisa Ingerman¹, Carolyn A. Tylenda², and Dennis Jones<sup>2

1</sup>Syracuse Research Corporation, Syracuse, NY and ²Agency for Toxic Substances and Disease Registry, Atlanta, GA

ATSDR has recently re-evaluated the noncancer toxicity of fluoride salts, generically referred to as fluorides, and has prepared a toxicological profile for fluorides, hydrogen fluoride, and fluorine. 

The extensive database on fluorides provides strong evidence that the skeletal system is the primary target of fluoride toxicity following chronic oral exposure. Very high daily intakes of fluoride, particularly in malnourished individuals, can result in skeletal fluorosis. At lower doses, fluoride can increase the risk of bone fractures. 

Numerous municipalities have undertaken fluoridation programs to decrease the prevalence of dental caries in children; the US Department of Health and Human Services recommends a drinking water fluoride concentration of 0.7-1.2 ppm. 

Community-based studies examining the possible association between exposure to 1 ppm fluoride (0.03 mg F/kg/day) and the risk of bone fractures, particularly hip fractures, have found increases, decreases, or no effect on hip fracture rates among older women. 

Studies involving exposure to higher doses of fluoride have consistently found significant increases in the risk of nonvertebral fractures, particularly hip fractures. 

A chronic-duration minimal risk level (MRL) is an estimate of daily exposure to a substance that is likely to be without an appreciable risk of adverse effects over a period of 1 year or more. 

A chronic-duration oral MRL of 0.05 mg F/kg/day was derived for fluorides based on a NOAEL of 0.15 mg F/kg/day and LOAEL of 0.25 mg F/kg/day identified in a study of older residents of 6 communities in China with differing levels of fluoride in the drinking water (Li et al. 2001).

P.R. McClure, D. Wohlers, Syracuse Research Corporation, Syracuse, NY. R.A. DeWoskin, U.S.EPA/ORD/NCEA, Research Triangle Park, NC. 

The U.S. EPA is updating the IRIS Assessment for Acrylamide based on new data and guidance since it was last assessed in 1988. Presented here are differences between the 1988 assessment values and rationale for the proposed revisions. The revised acrylamide assessment is currently undergoing internal review, followed by extensive external review. The numbers presented below may be further revised, based on the internal and external review comments.

M.Osier, M. Odin. Syracuse Research Corporation, Syracuse, N.Y.

Consideration of mode of action is of critical importance in the evaluation of the toxic effects of a chemical. While an emphasis on mode of action is evident in recent thinking regarding cancer risk assessment, it is also important when considering noncancer effects. Derivation of a provisional RfD for ethylene cyanohydrin provides an excellent practical example of the role that understanding of mode of action can have in noncancer risk assessment. No chronic oral studies of ethylene cyanohydrin toxicity have been reported. Of the three subchronic studies, one examined only a single endpoint and another reported only group means and failed to report statistical analysis of the data; as such, neither study provides a sufficiently detailed evaluation of ethylene cyanohydrin toxicity to allow for the derivation of an RfD. The third study evaluated a broad spectrum of endpoints in a single species. The study only reported slight, statistically significant changes in the absolute weights of the heart and brain. A lack of more clearly toxic effects would generally be of concern when attempting to derive an RfD, perhaps even resulting in no number being derived. However, consideration of a proposed mechanism of action for ethylene cyanohydrin, in situ generation of cyanide, identified the brain and the heart, both of which are very sensitive to changes in cellular energy status, as potentially sensitive targets of ethylene cyanohydrin toxicity. With this consideration in mind, subtle, statistically significant changes in organ weights of these sensitive targets were considered to be toxicologically relevant, and NOAEL and LOAEL values were identified from the study and used in the derivation of an RfD.

M. Maddaloni¹, C. Nace¹, D. Santella¹, P. Evangelista¹, S. Stephansen¹, W. Thayer², D.Griffith³, B. Allen², and G. Diamond².

¹US EPA Region 2, New York, NY; ²Syracuse Research Corporation, Syracuse, NY; ³University of Miami, Coral Gables, FL. 

The U.S. Environmental Protection Agency (EPA) supported federal, state, and New York City efforts to recover from the September 11, 2001 attack on the World Trade Center (WTC). EPA undertook the cleanup of the indoor environment in Lower Manhattan through the implementation of four projects that were funded by Federal Emergency Management Agency (FEMA) under the Stafford Act. In the primary effort EPA, along with the New York City Department of Environmental Protection (NYCDEP), provided for the monitoring and cleaning of Lower Manhattan residences through the Indoor Air Residential Assistance Program (IARP) -WTC Dust Cleanup Program. Interim final reports describing the establishment of health-based benchmarks, the Confirmation Cleaning Building study and the Background study were made available to the public in May and April of 2003 (EPA 2003a,b,c); the WTC Residential Dust Cleanup Report was made available to the public in March 2004 (EPA, 2004).  This poster summarizes the WTC Residential Dust Cleanup Report (EPA, 2004). 

Residents of Lower Manhattan below Canal Street were eligible to participate in the WTC cleanup program. Participation in the program was voluntary; residents could choose to have their residences cleaned and then tested for airborne asbestos levels, or to have them tested without cleaning. Results for the residences that were cleaned and then tested are presented here. Registration was open from June 5 through December 28, 2002. Owners and managers of residential buildings and co-op boards could request to have their building's common areas cleaned and HVAC system evaluated and cleaned, if necessary. Common areas such as the building lobby, hallways, stairways and elevator interiors were cleaned in all cases; other common areas (e.g., laundry rooms, utility rooms, compactor rooms, elevator shafts) were evaluated and cleaned as needed.