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Human Health and Ecological Risk Assessments - DEIS Oregon/Washington BLM



Human Health and Ecological Risk Assessments - DEIS

Appendix 8 of the Vegetation Treatments Using Herbicides on BLM Lands in Oregon -- Final Environmental Impact Statement: July 2010 Human Health and Ecological Risk Assessments

Risk Assessments (See links below)

One of the Purposes identified in Chapter 1 of the Final EIS is: 6. Prevent herbicide control treatments from having unacceptable adverse effects to applicators and the public, to desirable flora and fauna, and to soil, air, and water. To help address this Purpose, the EIS relies on BLM and/or Forest Service-prepared Human Health and Ecological Risk Assessments for the 18 herbicides analyzed in this EIS. The Risk Assessments are used to quantitatively evaluate the probability (i.e. risk) that herbicide use in wildland settings might pose harm to humans or other species in the environment. As such, they address many of the risks that would be faced by humans, plants, and animals, including special status species, from the use of the herbicides. The level of detail in the Risk Assessments for wildland use exceeds that normally found in EPA's registration examination.

Risk is defined as the likelihood that an effect (injury, disease, death, or environmental damage) may result from a specific set of circumstances. It can be expressed in quantitative or qualitative terms. While all human activities carry some degree of risk, some risks are known with a relatively high degree of accuracy because data have been collected on the historical occurrence of related problems (e.g. lung cancer caused by smoking, auto accidents caused by alcohol impairment, and fatalities resulting from airplane travel). For several reasons, risks associated with exposure to herbicides cannot be so readily determined. The Risk Assessments help evaluate the risks resulting from these situations.

Risks to non-target species associated with herbicide use are often approximated via the use of surrogate species, as toxicological data does not exist for most native non-target species. Survival, growth, reproduction, and other important sub-lethal processes of both terrestrial and aquatic non-target species were considered. Assessments considered acute and chronic toxicity data. Exposures of receptors1 to direct spray, surface runoff, wind erosion, and accidental spills were analyzed.

Most of the Human Health and Ecological Risk Assessments were developed by the BLM for the 2007 PEIS, or by the Forest Service for the 2005 Pacific Northwest Region Invasive Plant Program EIS (see Table A8-1). Three Human Health Risk Assessments used in this EIS (bromacil, diuron, and tebuthiuron) were used in BLM's 1991 Vegetation Treatment on BLM Lands in Thirteen Western States EIS and more recent literature has been examined to ensure these Risk Assessments remain current. The Risk Assessments, for herbicides analyzed, total over 6,000 pages. The various sections of each Risk Assessment can be accessed on the web as described below, or obtained on compact disk by calling, emailing, or writing to the BLM at the contact points listed on the title page of this EIS.

The Risk Assessments, related separate analyses, and the EIS include analysis of inerts and degradates for which information is available and not constrained by confidential business information (CBI) restrictions. Preparing a risk assessment for every conceivable combination of herbicide, tank mix, surfactant, adjuvant, and other possible mixture is not feasible, as the BLM cannot prepare hundreds of risk assessments, and the cost would be exorbitant. To the degree a toxic substance is known to pose a significant human or ecological risk, the BLM has undertaken analysis to assess its impacts through risk assessments. Additional information about uncertainty in risk assessments is included in Appendix 13.

When evaluating risks from the use of herbicides proposed in a NEPA planning document, reliance on EPA's pesticide registration process as the sole demonstration of safety is insufficient. The U.S. Forest Service and Bureau of Land Management were involved in court cases in the early 1980's that specifically addressed this question (principally Save Our Ecosystems v. Clark, 747 F.2d 1240, 1248 (9th Cir. 1984) and Southern Oregon Citizens v. Clark, 720 F. 2d 1475, 1480 (9th Cir. 1983)). These court decisions and others affirmed that although the BLM can use EPA toxicology data, it is still required to do an independent assessment of the safety of pesticides rather than relying on Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) registration alone. This Court also found that FIFRA does not require the same examination of impacts that the BLM is required to undertake under NEPA. Further, risk assessments consider data collected from both published scientific literature and data submitted to EPA to support FIFRA product registration, whereas EPA utilizes the latter data only. The EPA also considers many wildland pesticide uses to be minor. Thus, the project-specific application rates, spectrum of target and non-target organisms, and specialized exposure scenarios evaluated by the BLM are frequently not evaluated by EPA in its generalized registration assessments.

The Risk Assessments are the source for much of the individual herbicide information presented in each of the effects sections in the EIS, including the high-moderate-low risk ratings shown in tables at the end of Chapter 3 and referenced in Chapter 4. Individual Risk Assessment Tools (IRATs) are being, developed for each herbicide to assist field managers in translating risks to project design parameters. The use of these tools is explained in Chapter 3, Use of Individual Risk Assessment Tools During Implementation.

The component parts of the various Risk Assessments, and their origins, are shown on Table A8-1. Each part is available on the web via http://www.blm.gov/or/plans/vegtreatmentseis/riskassessments/index.php. At this address, each of the Xs in the table are clickable links that access the respective section.

Table A8-1: Risk Assessments
Ecological Risk Assessments (ERA) Human Health Risk Assessments (HHRA)
2007 BLM PEIS1 2005 FS EIS2 (Ecological & Human Health (and worksheet) 2007 BLM PEIS1 1991 BLM EIS3
Risk Assessment Appendices4 Risk Assessment Appendices5
Herbicide A B C D E A B C D E
  1. 2007 PEIS: Risk Assessments adopted for 2007 Vegetation Treatments Using Herbicides on Bureau of Land Management Lands in 17 Western States Programmatic Environmental Impact Statement.
  2. 2005 FS EIS: Risk Assessments adopted for 2005 Pacific Northwest Region Invasive Plant Program Final Environmental Impact Statement. These risk assessments are both human health and ecological; however, if the BLM has a more current ERA or HHRA, the FS risk assessment is only used for the remaining risk assessment.
  3. 1991 BLM EIS: Human Health Risk Assessments adopted with the 1991 Vegetation Treatments on BLM Lands Record of Decision, and originally adopted for the Forest Service's 1988 Managing Competing and Unwanted Vegetation Final Environmental Impact Statement. This document discusses the three herbicides below, included within a HHRA that covers 16 herbicides.
  4. 2007 BLM PEIS Ecological Risk Assessment Appendices are as follows:
    1. Relevant Data
    2. ERA Worksheets
    3. Listed Species
    4. CBI Information
    5. Tank Mix Risk Quotients
  5. 2007 BLM PEIS Human Health Risk Assessment Appendices are as follows:
    1. Herbicide Labels
    2. Spreadsheets
    3. AgDrift Modeling
    4. Gleams Modeling
    5. Public Uncertainty Analysis
  6. Updated in 2006.
2,4-D x6 (x)
Bromacil x x x x x x x
Chlorsulfuron x x x x x x x
Clopyralid x (x)
Dicamba x (x) x x x x x x  
Diquat x x x x x x x x x x x
Diuron x x x x x x x
Fluridone x x x x x x x x x x x
Glyphosate x (x)
Hexazinone x (x)
Imazapic x x x x x x x x x x x x
Imazapyr x (x)
Metsulfuron methyl x (x)
Overdrive x x x x x
Diflufenzopyr x x x x x x x x x x x x
Picloram x (x)
Sulfometuron methyl x x x x x x x x x x x x
Tebuthiuron x x x x x x
Triclopyr x (x)
Table A8-2: Additional Risk Assessment Information
Ecological Risk Assessment Protocol Preparation of Environmental Documentation and Risk Assessments Appendix B Spreadsheets
Appendix A: AgDrift Modeling Occupational All
Appendix B: Gleams Modeling Nonylphenol Polyethoxylate-based (NPE) Surfactants Public General