Federal Register: January 31, 2002 (Volume 67, Number 21)
DOCID: FR Doc 02-2421
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Victims of Crime Office
ATS ID: [ATSDR-178]
NOTICE: Part IV
DOCUMENT ACTION: Notice.
Update on the Status of the Superfund Substance-Specific Applied Research Program
DATES: ATSDR provides updates on the status of its Substance-Specific Applied Research Program approximately every 3 years. ATSDR considers the voluntary research effort to be important to the continuing implementation of the SSARP. Therefore, the agency strongly encourages privatesector organizations to volunteer at any time to conduct research to fill data needs until ATSDR announces that other research mechanisms are in place to address those specific data needs.
This Notice provides the status of ATSDR's Superfund-mandated SubstanceSpecific Applied Research Program (SSARP) which was last updated in a Federal Register notice in 1999 (64 FR 2760). Authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA, also known as the Superfund statute), as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA) 42 U.S.C. 9604 (i), this research program was initiated on October 17, 1991. At that time, a list of priority data needs for 38 priority hazardous substances frequently found at waste sites was announced in the Federal Register (56 FR 52178). The list was subsequently revised based on public comments and published in final form on November 16, 1992 (57 FR 54150).
The 38 substances, each of which is found on ATSDR's Priority List
of Hazardous Substances (66 FR 54014, October 25, 2001), are aldrin/
dieldrin, arsenic, benzene, beryllium, cadmium, carbon tetrachloride,
chloroethane, chloroform, chromium, cyanide, p,p'DDT,DDE,DDD, di(2
ethylhexyl) phthalate, lead, mercury, methylene chloride, nickel,
polychlorinated biphenyl compounds (PCBs), polycyclic aromatic hydrocarbons (PAHsincludes 15 substances), selenium,
tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and zinc.
On July 30, 1997, priority data needs for 12 additional hazardous substances frequently found at waste sites were determined and announced in the Federal Register (62 FR 40820). The 12 substances, each of which is included in ATSDR's Priority List of Hazardous Substances, are chlordane, 1,2dibromo3chloropropane, dinbutyl phthalate, disulfoton, endrin (includes endrin aldehyde), endosulfan (alpha, beta, and endosulfan sulfate), heptachlor (includes heptachlor epoxide), hexachlorobutadiene, hexachlorocyclohexane (alpha , beta, delta and gamma), manganese, methoxychlor, and toxaphene.
Recently, priority data needs for 10 additional hazardous
substances frequently found at waste sites were determined and
announced in the Federal Register (66 FR 42659). The 10 substances,
each of which is included in ATSDR's Priority List of Hazardous
Substances, are asbestos, benzidine, chlorinated dibenzopdioxins, 1,2dibromoethane, 1,2dichloroethane, 1,1dichloroethane,
ethylbenzene, pentachlorophenol, 1,1,2,2tetrachloroethane, and total xylenes. ATSDR invited the public to comment on the priority data needs for these substances during a period of 90 days. ATSDR is responding to the comments, and a final list of priority data needs will be published in the Federal Register in the near future.
To date, 190 priority data needs have been identified for the first 50 hazardous substances (Table 1). ATSDR fills these data needs through U.S. Environmental Protection Agency (EPA) regulatory mechanisms (test rules), privatesector voluntarism, and the direct use of CERCLA funds. Additional data needs are being addressed through collaboration with the National Toxicology Program (NTP), by ATSDR's Great Lakes Human Health Effects Research Program, and other agency programs. Currently, 101 priority data needs associated with the first 50 substances are being addressed via these mechanisms, and 62 priority data needs have been filled. Priority data needs documents describing ATSDR's rationale for prioritizing research needs for each substance are available. See ADDRESSES section of this Notice.
This Notice also serves as a continuous call for voluntary research proposals. Privatesector organizations may volunteer to conduct research to address specific priority data needs identified in this Notice by indicating their interest through submission of a letter of intent to ATSDR (see ADDRESSES section of this Notice). A TriAgency Superfund Applied Research Committee (TASARC) composed of scientists from ATSDR, NTP, and the EPA, will review all proposed voluntary research efforts.
Health and Human Services Department, Agency for Toxic Substances and Disease Registry,
CERCLA as amended by SARA (42 U.S.C. 9604(i)) requires that ATSDR (1) jointly with the EPA, develop and prioritize a list of hazardous substances found at National Priorities List (NPL) sites, (2) prepare toxicological profiles for these substances, and (3) assure the initiation of a research program to address identified data needs associated with the substances. Before starting such a program, ATSDR will consider recommendations of the Interagency Testing Committee on the type of research that should be done. This committee was established under Section 4(e) of the Toxic Substances Control Act of 1976 [15 U.S.C. 2604(e)](TSCA).
The major goals of the ATSDR SSARP are (1) to address the
substancespecific information needs of the public and scientific
community, and (2) to supply information necessary to improve the
database used to conduct comprehensive public health assessments of
populations living near hazardous waste sites. We anticipate that the
information will help to establish linkages between levels of
contaminants in the environment and levels in human tissue and organs [[Page 4837]]
associated with adverse health effects. Once such links have been established, strategies to mitigate potentially harmful exposures can be developed. This program will also provide data that can be generalized to other substances or areas of science, including risk assessment of chemicals, thus creating a scientific information base for addressing a broader range of data needs.
ATSDR encourages the use of in vitro assessment methods and other innovative tools for filling priority data needs. For example, the agency believes that physiologically based pharmacokinetic (PBPK) modeling could serve as a valuable tool in predicting across route similarities (or differences) in toxicological responses to hazardous substances. Therefore, on a casebycase basis, a priority data need can be filled using existing data and modeling. In addition, ATSDR is a member of NTP's Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) and supports development, validation, and acceptance of alternative toxicological test methods that reduce, refine, and replace the use of animals, as appropriate.
CERCLA section 104(i)(5)(D) states that it is the sense of Congress that the costs for conducting this research program ``be borne by the manufacturers and processors of the hazardous substance in question,'' as required in TSCA and the Federal Insecticide, Fungicide, and Rodenticide Act of 1972 (7 U.S.C. 136 et seq.) (FIFRA), or by cost recovery from responsible parties under CERCLA. To execute this statutory intent, ATSDR developed a plan whereby parts of the SSARP are being conducted via the regulatory mechanisms referenced (TSCA/FIFRA), privatesector voluntarism, and the direct use of CERCLA funds.
The TASARC, composed of scientists from ATSDR, NTP, and EPA, has been set up to:
(1) Advise ATSDR on the assignment of priorities for mechanisms to address data needs,
(2) Coordinate knowledge of research activities to avoid duplication of research in other programs and under other authorities, (3) Advise ATSDR on issues of science related to substancespecific data needs, and
(4) Maintain a scheduled forum that provides an overall review of the ATSDR SSARP.
TASARC has met 10 times since the initiation of the SSARP. It has guided referral of data needs to EPA and the associated development of test rules through TSCA. In addition, it has endorsed the proposals of several privatesector organizations to conduct voluntary research. Furthermore, TASARC has become a forum for other federal agencies to bring forth their research agendas. For example, it has coordinated research efforts on hazardous pollutants with the Office of Air and Radiation, EPA. TASARC has developed testing guidelines for immunotoxicity; and has endorsed the use of decisionsupport methodologies such as physiologically based pharmacokinetic (PBPK) modeling and benchmarkdose modeling, where appropriate.
Additional data needs are being addressed through collaborative research efforts with NTP, by ATSDR's Great Lakes Human Health Effects Research Program, and other agency programs. To date, 101 priority data needs associated with the first 50 substances (Table 1) are being addressed via these mechanisms.
Criteria for Evaluating Status of Priority Data Needs
To update the activities covered under the SSARP, criteria for evaluating the status of the priority data needs were developed. Based on these criteria and the review of the current literature, a priority data need can be filled, or unchanged. In the event a priority data need is considered filled, it does not necessarily mean that the study has been completed and that ATSDR has accepted the data. It does, however, indicate that the agency no longer considers it a priority to initiate additional studies at this time.
The criteria for evaluating the status of the priority data needs are described below.
A priority data need is filled:
A priority data need remains unchanged:
Since the 1999 SSARP update in the Federal Register, ATSDR has
developed specific criteria for two categories of data needs described below.
It should be noted that the status of the priority data needs may
change in future updates of the SSARP as new information becomes
available. Further, during the literature review, new studies may be
identified suggesting other effects of concern, such as those related
to endocrine disruptors and children's health, which have not been
included in the original list of priority data needs. In such cases,
additional priority data needs may be added to the research agenda. For
example, for both tetrachloroethylene and trichloroethylene, the
priority data need for developmental neurotoxicity study is now listed
separately from the priority data need for onespecies developmental
toxicity (see Table 1). Therefore, the total number of priority data
needs changed accordingly, i.e., from a total of 188 reported in the
Federal Register notice in 1999 (64 FR 2760) to 190 in the current
update notice. Also, research needs previously considered filled might
be reassigned as priority data needs, e.g., if a previously derived Minimal Risk Level (MRL), a
health guidance value, was withdrawn from the updated ATSDR toxicological profile. Finally, a priority data need previously associated with an implementation mechanism, may no longer be addressed via that mechanism (or any other mechanism) if the study being conducted to fill the specific priority data need is discontinued.
Based on the above criteria, 62 priority data needs have been filled.
Update of Activities in the SSARP
An update of the activities associated with the mechanisms for implementing the ATSDR SubstanceSpecific Applied Research Program (SSARP) is discussed below. Publications and reports of research completed under the various implementation mechanisms are available by writing to ATSDR (see ADDRESSES section of this Notice).
In developing and implementing the SSARP, ATSDR, NTP, and EPA have identified a subset of priority data needs for substances of mutual interest to the federal programs. These data needs are being addressed through a program of toxicologic testing under TSCA according to established procedures and guidelines. On several occasions when ATSDR identified priority data needs for oral exposure, other agencies needed inhalation data. In response, ATSDR is considering proposals to conduct inhalation studies in conjunction with physiologically based pharmacokinetic (PBPK) studies in lieu of oral studies. ATSDR expects that inhalation data derived from these studies can be used with PBPK modeling to address its oral toxicity data needs. Currently, an EPA/ ATSDR test rule, under development, includes eight ATSDR substances, i.e., benzene, chloroethane, cyanide (hydrogen cyanide and sodium cyanide), methylene chloride, tetrachloroethylene, toluene and trichloroethylene, and addresses 18 ATSDR priority data needs (Table 2). The test rule is presently undergoing ATSDR and EPA final review. We anticipate it will be available for public comment in the near future.
TASARC has established an interagency task force on metals and has conducted a survey to assess federal agencies' needs for testing metals. Currently, the task force has agreed to examine at least seven metals included in the ATSDR's SSARP (arsenic, beryllium, chromium, manganese, mercury, nickel, and selenium, associated with 22 priority data needs) (Table 2). The EPA will solicit testing proposals for these metals and pursue test rule development for these metals at a later date.
B. PrivateSector Voluntarism
On February 7, 1992, as part of the SubstanceSpecific Applied Research Program (SSARP), ATSDR announced a set of proposed procedures for conducting voluntary research (57 FR 4758). Revisions based on public comments were published on November 16, 1992 (57 FR 54160). Privatesector organizations were encouraged to volunteer to conduct research to fill specific priority data needs at no expense to ATSDR.
To date, ATSDR has established agreements with the American
Chemistry Council (ACC) [formerly the Chemical Manufacturers
Association (CMA)], the General Electric Company (GE), and the
Halogenated Solvents Industry Alliance, Inc. (HSIA) to conduct
substancespecific research (Table 2). Through the voluntary research
efforts of these organizations, at least 16 research needs for
polychlorinated biphenyl compounds [PCBs], methylene chloride,
tetrachloroethylene, trichloroethylene, and vinyl chloride are being addressed (Table 2).
American Chemistry Council (ACC) Formerly the Chemical Manufacturers Association (CMA)
In 1996, ATSDR entered into a memorandum of understanding (MOU) with ACC covering two studies, ``Vinyl chloride: Combined inhalation twogeneration reproduction and developmental toxicity study in CD rats.'' In November 2000, ATSDR accepted the final reports of the studies.
General Electric Company (GE)
In 1995, ATSDR entered into an MOU with SSARP covering two studies
on PCBs: (1) ``An assessment of the chronic toxicity and oncogenicity
of Aroclors 1016, 1242, 1254, and 1260 administered in diet to rats,''
including ``PCB congener analyses,'' and (2) ``Metabolite detection as a tool for determining naturally occurring aerobic PCB
biodegradation.'' While the above studies do not address ATSDR's priority data needs for PCBs, they do address other agency research needs for these substances.
The agency accepted the final report for the chronic toxicity and oncogenicity of the four aroclors in October 1997,and the final report for the aerobic biodegradation study in July 1999.
Halogenated Solvents Industry Alliance (HSIA)
In 1995, ATSDR entered into an MOU with HSIA covering studies to address three priority data needs for methylene chloride. The studies, ``Addressing priority data needs for methylene chloride with physiologically based pharmacokinetic modeling,'' evaluated acute and subchronicduration toxicity and developmental toxicity via oral exposure. The data were obtained using physiologically based pharmacokinetic modeling. The final report for these studies was accepted by the agency in February 1997.
In September 1999, HSIA entered into a second MOU with ATSDR to conduct a study, ``Methylene chloride: 28 day inhalation toxicity study in the rat to assess potential immunotoxicity.'' The agency accepted the final report for the study in November 2000. HSIA is in the process of obtaining oral data from the inhalation study using PBPK modeling. This is because ATSDR has determined ingestion of contaminated environmental media to be the primary exposure route at hazardous waste sites. HSIA intends to conduct similar immunotoxicity studies for tetrachloroethylene and trichloroethylene.
In February 2000, ATSDR signed a third MOU with HSIA, which conducted a study, ``Trichloroethylene: Inhalation Developmental Toxicity Study in CD Rats.'' The agency accepted the final report of the study in September 2001. As in the case of the methylene chloride immunotoxicity study described above, HSIA intends to obtain developmental toxicity data for oral exposure using PBPK modeling. Also, HSIA plans to perform similar developmental toxicity studies for tetrachloroethylene. Finally, ATSDR and HSIA are continuing discussion to address additional priority data needs for trichloroethylene and tetrachloroethylene in conjunction with EPA's pilot studies for its Voluntary Children's Chemical Evaluation Program.
In addition to the substancespecific MOUs described above, in
March 2001, ATSDR also signed an MOU with the Electric Power Research
Institute, Inc. (EPRI) on ``Verification of Techniques for Assessing
the Effects of Neurotoxicants on Neurodevelopment in Children.'' The
objective of the study is to validate a battery of neurodevelopmental
tests for use in assessing the effects of prenatal or postnatal
exposure to developmental neurotoxicants. The study includes an evaluation of a broad spectrum of
functions; therefore, the validation of these tests will be useful for further assessing the developmental neurotoxicity of some of the ATSDR priority substances such as the PCBs, methylmercury, and lead. In addition to the private sector support (EPRI), ATSDR is coordinating a federal effort (via interagency agreements with EPA, Food and Drug Administration [FDA] and NIEHS) to support the study.
C. CERCLAFunded Research (Minority Health Professions Foundation Research Program)
During FY 1992, ATSDR announced a $4 million cooperative agreement program with the Minority Health Professions Foundation (MHPF) to support substancespecific investigations. A notforprofit Internal Revenue Code 501(c)(3) organization, the MHPF comprises 11 minority health professions schools. Its primary mission is to research health problems that disproportionately affect poor and minority citizens. The purpose of this cooperative agreement is to address substancespecific data needs for priority hazardous substances identified by ATSDR. In addition, this agreement strengthens the environmental health research opportunities for scientists and students at MHPF member institutions and enhances existing disciplinary capacities to conduct research in toxicology and environmental health.
In the first 5year project period that concluded during FY 1997, nine priority data needs for 21 priority hazardous substances and 22 other research needs for these and other substances were addressed. The MHPF has developed a report, ``Environmental Health and Toxicology Research Program: Meeting Environmental Health Challenges Through Research, Education, and Service,'' that describes the research findings and other successes from the first 5 years of the program. New research initiated in the second 5year project period includes studies to address 10 additional priority data needs for chlordane, 1,2 dibromo3chloropropane, dinbutyl phthalate, lead, manganese, the polycyclic aromatic hydrocarbons (PAHs), zinc, and eight other research needs.
To date, the MHPF activities have resulted in the publication of 50 manuscripts in peerreviewed journals. The institutions receiving awards and their current respective research projects that fill identified research needs are listed in Table 2.
D. National Toxicology Program (NTP)
Section 104(i)(5) of CERCLA directs the administrator of ATSDR (in consultation with the administrator of EPA and agencies and programs of the Public Health Service) to assess whether adequate information on the health effects of priority hazardous substances found at NPL sites is available. Where adequate information is not available, ATSDR, in cooperation with the National Toxicology Program (NTP), is required to assure the initiation of a program of research designed to determine these health effects (and techniques for developing methods to determine such health effects).
ATSDR has been collaborating with NTP to address priority data needs of mutual interest, including (1) dinbutyl phthalate: dose response data in animals for acuteduration exposure via oral exposure route, (2) carbon tetrachloride: immunotoxicology study via oral exposure, and (3) heptachlor: reproductive toxicity study via oral exposure (Table 2).
E. Great Lakes Human Health Effects Research Program
Some of the priority data needs identified in the SSARP have been independently identified as research needs through the ATSDR Great Lakes Human Health Effects Research Program, a separate research program.
In support of the Great Lakes Critical Programs Act of 1990, ATSDR announced in FY 1992 the availability of $2 million for a grant program to conduct research on the potential for short and longterm adverse health effects from consumption of contaminated fish from the Great Lakes basin. Research undertaken through this program is intended to build on and amplify the results of past and ongoing fish consumption research in the Great Lakes basin. The ATSDRsupported research projects focus on known highrisk populations to define further the human health consequences of exposure to persistent toxic substances (PTSs) identified in the Great Lakes basin. These atrisk populations include sport anglers; African Americans, Asians and other nonEnglish speaking populations; pregnant women; fetuses, nursing infants, and children of mothers who consume contaminated Great Lakes sport fish; the elderly, and the urban poor. To date, the research activities of the ATSDR Great Lakes research program have resulted in 55 publications in peerreviewed journals.
Currently, 14 priority data needs for 24 priority hazardous substances (including 15 PAHs) identified in the SSARP are being addressed through this program. The institutions receiving awards and their respective studies are listed in Table 2.
F. Other ATSDR Programs
In its role as a public health agency addressing environmental health, ATSDR may collect human data to validate substancespecific exposure and toxicity findings. The need for additional information on levels of contaminants in humans has been identified, and remains as a priority data need for 49 of the first 50 priority substances (Table 1). ATSDR will obtain this information through exposure and health effects studies, and through establishing and using substancespecific subregistries of people within the agency's National Exposure Registry who have potentially been exposed to these substances.
The list of the 50 priority hazardous substances in the SSARP was forwarded to ATSDR's Exposure and Disease Registry Branch (EDRB), Division of Health Studies, for consideration as potential candidates for subregistries of exposed persons, based on criteria described in its 1994 document, ``National Exposure Registry: Policies and Procedures Manual (Revised),'' Agency for Toxic Substances and Disease Registry, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia, NTIS Publication No. PB95154571. To date, of the first 50 priority substances in the SSARP, ATSDR has established subregistries for benzene, chromium, and trichloroethylene. Arsenic, cadmium, and lead are not considered to be in the pool of candidate substances for an exposure registry at this time, and, therefore, are not considered priority data needs. This decision will be reevaluated as more information on the chemicals and exposure sites become available. All other substances in the SSARP (Table 1) remain in the candidate pool and therefore continue to be classified as priority data needs. They will be considered for selection as primary contaminants during each selection process.
The results of the research conducted via the SSARP are expected to
provide information necessary to improve the database used to conduct
comprehensive public health assessments of populations living near
hazardous waste sites. The information will enable the agency to
establish linkages between levels of contaminants in the environment
and levels in human tissue and organs associated with adverse health
effects, ultimately helping to determine methods for interdicting
exposure and mitigating toxicity. This program will also provide [[Page 4840]]
data that can be generalized to other substances or areas of science, including risk assessment of chemicals, thus creating a scientific information base for addressing a broader range of data needs. The agency plans to provide an update on the status of this research program approximately every 3 years.
Dated: January 25, 2002.
Director, Office of Policy and External Affairs, Agency for Toxic Substances and Disease Registry.
Table 1.ATSDR's SubstanceSpecific Priority Data Needs for 50 Priority Hazardous Substances Status change Substances PDN ID \1\ PDN description Program \2\ \3\ Comments \4\ Aldrin/Dieldrin............... 1A Doseresponse .............. Filled....... An MRL was data in animals derived in the for intermediate 2000 updated duration oral toxicological exposure. profile. 1B Bioavailability from soil.
1C Exposure levels .............. ............. This priority in humans living data need, near hazardous previously waste sites and addressed in a other study in the populations, Great Lakes such as exposed research workers. program, is no longer investigated in that study. 1D Potential ATSDR......... candidate for subregistry of exposed persons. Arsenic....................... 2A Comparative EPA. ................ toxicokinetic studies to
determine if an appropriate
animal species can be
2B Halflives in EPA........... surface water, groundwater. 2C Bioavailability EPA........... from soil.
2D Exposure levels G. Lakes...... Filled....... Background level in humans living data are near hazardous available in waste sites and ATSDR's 1993 other toxicological populations, profile, and at such as exposed least seven workers. ATSDR studies that evaluated urine arsenic levels and potential adverse health effects are available. Also, additional studies are available in ATSDR's 2000 updated toxicological profile. Benzene....................... 3A Doseresponse EPA........... data in animals for acute and intermediate duration oral exposure. The subchronic study should include an extended
histopathology. 3B Twospecies EPA........... ............. Previously developmental planned study toxicity study in the MHPF via oral research exposure. program to address this priority data need was canceled. 3C Neurotoxicology EPA........... battery of tests via oral
3D Epidemiologic .............. Filled....... Based on an studies on the evaluation of health effects the data in of benzene ATSDR's 1997 (Special updated emphasis end toxicological points include profile. ATSDR immunotoxicity). will continue to evaluate new data as they become available to determine if additional studies are needed. 3E Exposure levels .............. Filled....... Reference range in humans living concentrations near hazardous are available waste sites and (Ashley et al. other 1992, 1994; populations, Needham et al. such as exposed 1995), and at workers. least one ATSDR study that evaluated blood benzene levels and potential adverse health effects is available. ATSDR acknowledges that reference concentration data can support exposure and health assessments at waste sites, but the agency also continues to recognize the importance of collecting additional data on uniquely exposed populations at waste sites. [[Page 4841]]
Beryllium..................... 4A Doseresponse EPA........... data in animals for acute and intermediate duration
exposures. The subchronic study should include extended
histopathology. 4B Twospecies EPA........... developmental toxicity study via inhalation exposure.
4C Environmental EPA........... fate in air; factors
bioavailability in air.
4D Analytical .............. Filled....... Based on an methods to evaluation of determine the data in environmental ATSDR's 2000 speciation. updated toxicological profile. 4E Immunotoxicology EPA........... battery of tests following oral exposure.
4F Exposure levels .............. Filled....... Reference range in humans living concentrations near hazardous in urine are waste sites and available other (Paschal et al. populations, 1998). ATSDR such as exposed acknowledges workers. that reference concentration data can support exposure and health assessments at waste sites, but the agency also continues to recognize the importance of collecting additional data on uniquely exposed populations at waste sites. 4G Potential ATSDR......... candidate for subregistry of exposed persons. Cadmium....................... 5A Analytical .............. Filled....... Based on an methods for evaluation of biological the data in tissues and ATSDR's 1999 fluids and updated environmental toxicological media. profile. 5B Exposure levels G. Lakes...... Filled....... Referent in humans living population near hazardous urine cadmium waste sites and levels are other available populations, (NHANES III), such as exposed and at least workers. nine ATSDR studies that evaluated blood and urine cadmium levels and potential adverse health effects are available. Carbon tetrachloride.......... 6A Doseresponse
data in animals for chronic oral exposure. The study should include extended reproductive organ and
nervous tissue histopathology. 6B Immunotoxicology NTP........... Filled....... NTP dosefinding battery of tests study and one via oral new study in exposure. ATSDR's 1994 updated toxicological profile addressed the priority data need. 6C Halflife in soil .............. Filled....... One new study in ATSDR's 1994 updated toxicological profile provided information on halflife in soil. 6D Exposure levels .............. Filled....... Reference range in humans living concentrations near hazardous in blood are waste sites and available other (Ashley et al. populations, 1992, 1994; such as exposed Needham et al. workers. 1995). ATSDR acknowledges that reference concentration data can support exposure and health assessments at waste sites, but the agency also continues to recognize the importance of collecting additional data on uniquely exposed populations at waste sites. [[Page 4842]]
6E Potential ATSDR......... candidate for subregistry of exposed persons. Chlordane..................... 7A Oral MHPF.......... Filled....... Availability of multigenerationa NTP........... ongoing study l studies to in the MHPF evaluate research reproductive program and toxicity. anticipated initiation of an NTP study in 2002. 7B Bioavailability studies
ingestion of contaminated media.
7C Exposure levels in humans living near hazardous waste sites and other
7D Potential ATSDR......... candidate for subregistry of exposed persons. Chloroethane.................. 8A Doseresponse EPA........... data in animals for acute and intermediate duration oral exposures. The subchronic study should include an evaluation of immune and
nervous system tissues, and extended
histopathology. 8B Doseresponse EPA........... data in animals for chronic
exposures. The study should include an
evaluation of nervous system tissues.
8C Potential ATSDR......... candidate for subregistry of exposed persons. Chloroform.................... 9A Doseresponse .............. Filled....... An MRL was data in animals derived in for intermediate ATSDR's 1997 duration oral updated exposure. toxicological profile. 9B Epidemiologic .............. Filled....... Based on an studies on the evaluation of health effects the data in of chloroform ATSDR's 1997 (Special updated emphasis end toxicological points include profile. ATSDR cancer, will continue neurotoxicity, to evaluate new reproductive and data as they developmental become toxicity, available to hepatotoxicity, determine if and renal additional toxicity). studies are needed. 9C Exposure levels .............. Filled....... Reference range in humans living concentrations near hazardous in blood are waste sites and available other (Ashley et al. populations, 1992, 1994; and such as exposed Needham et al. workers. 1995). ATSDR acknowledges that reference concentration data can support exposure and health assessments at waste sites, but the agency also continues to recognize the importance of collecting additional data on uniquely exposed populations at waste sites. [[Page 4843]]
9D Potential ATSDR......... candidate for subregistry of exposed persons. Chromium...................... 10A Doseresponse EPA........... data in animals for acute
chromium (VI) and (III) via oral exposure and for
chromium (VI) via oral
10B Multigeneration EPA........... reproductive toxicity study via oral
chromium (III) and (VI).
10C Immunotoxicology EPA........... battery of tests following oral exposure to
chromium (III) and (VI).
10D Twospecies EPA........... developmental toxicity study via oral
chromium (III) and (VI).
10E Exposure levels G. Lakes...... Filled....... Reference range in humans living concentrations near hazardous in urine are waste sites and available other (Paschal et al. populations, 1998). Also, at such as exposed least two ATSDR workers. studies that evaluated urine chromium levels and potential adverse health effects are available. In addition, this PDN is being addressed in a study in the Great Lakes research program. Cyanide....................... 11A Doseresponse EPA........... data in animals for acute and intermediate duration
exposures via inhalation. The subchronic study should include extended
histopathology and evaluation
FOR FURTHER INFORMATION CONTACT
Dr. William Cibulas, Chief, Research
Implementation Branch, Division of Toxicology, ATSDR, 1600 Clifton
Road, NE., Mailstop E29, Atlanta, Georgia 30333, telephone: (404) 498
0715, fax: (404) 4980092. This notice will also be available on ATSDR's website at
http://www.atsdr.cdc.gov or you may call the ATSDR Information Center at 18884228737.