Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 350 - TEXAS RISK REDUCTION PROGRAM › Subchapter D - DEVELOPMENT OF PROTECTIVE CONCENTRATION LEVELS › Section 350.77 - Ecological Risk Assessment and Development of Ecological Protective Concentration Levels

Current through Reg. 49, No. 28; July 12, 2024
(a) General. The
				  person shall evaluate the affected property by conducting an ecological risk
				  assessment in a manner appropriate and consistent with subsections (b), (c), or
				  (d) of this section. The process is discussed in the agency's ecological risk
				  assessment guidance. The purpose of the ecological risk assessment will be to
				  characterize the ecological setting of the affected property, identify complete
				  or reasonably anticipated to be completed exposure pathways and representative
				  ecological receptors, scientifically eliminate COCs that pose no unacceptable
				  risk, and develop PCLs for selected ecological receptors where warranted. The
				  POEs for the selected ecological receptors shall be established on a
				  property-specific basis. However, if the person can show that no unacceptable
				  ecological risk exists due to incomplete or insignificant exposure pathways as
				  specified in subsection (b) of this section, or if all COCs can be eliminated
				  as specified in subsection (c)(1), (6), (7), or (8) of this section, or if,
				  after incorporation of site-specific information, it can be shown that there is
				  either no ecological risk or that it is not apparent as specified in subsection
				  (d) of this section, then the ecological risk assessment process will terminate
				  at that point. Also, if after the ecological risk assessment process specified
				  in subsection (b) of this section, or if at anytime during the ecological risk
				  assessment process specified in subsections (c) or (d) of this section, the
				  person can demonstrate to the satisfaction of the executive director that the
				  implementation of a response action will eliminate the ecological exposure
				  pathway or render it insignificant, or that human health PCLs will be
				  protective of ecological receptors, then no further ecological risk assessment
				  evaluation will be required. In addition, if after the ecological risk
				  assessment process specified in subsection (b) of this section, the person can
				  demonstrate to the satisfaction of the executive director that an expedited
				  stream evaluation can determine that the completed surface water and sediment
				  pathways are insignificant, then no further ecological risk assessment
				  evaluation will be required. If no further ecological risk assessment
				  evaluation is required, then the person shall provide, as appropriate, a
				  reasoned justification and/or an expedited stream evaluation for terminating
				  the ecological risk assessment and place this information in the affected
				  property assessment report as described in §
										350.91
				  of this title (relating to Affected Property Assessment Report). Furthermore,
				  after ecological PCLs have been established, the person shall have the option,
				  where determined appropriate, of conducting an ecological services analysis as
				  a means of managing ecological risk at the affected property, in accordance
				  with subsection (f) of this section and §
										350.33(a)(3)(B)
				  of this title (relating to Remedy Standard B). Subsections (b), (c), and (d) of
				  this section describe a three-tiered approach to conducting an ecological risk
				  assessment, and although there is a logical progression from one tier to the
				  next, the person may begin the ecological evaluation of the affected property
				  at any tier.
(b) Tier 1: exclusion
				  criteria checklist. The person shall conduct a Tier 1 assessment at all
				  affected properties to which this rule is applicable as presented in §
										350.2 of
				  this title (relating to Applicability), unless the person elects to begin the
				  ecological evaluation at Tier 2 or Tier 3. The person shall use the Tier 1
				  Exclusion Criteria Checklist provided in the following figure. The person will
				  have fulfilled the ecological risk assessment requirements if the affected
				  property meets the exclusion criteria. However, the person shall re-enter the
				  ecological risk assessment process if changing circumstances result in the
				  affected property not meeting the Tier 1 exclusion criteria. The person is
				  required to continue the ecological risk assessment process as described in
				  subsection (c) or (d) of this section if the affected property fails the
				  exclusion criteria, unless the reasoned justification and/or expedited stream
				  evaluation processes described in subsection (a) of this section are used to
				  demonstrate that no unacceptable ecological risk exists.
Attached
					 Graphic
(c) Tier
				  2: screening-level ecological risk assessment. The person shall conduct a
				  screening-level ecological risk assessment to scientifically eliminate COCs
				  that do not pose an ecological risk and to develop PCLs for those COCs that do
				  pose an unacceptable risk to selected ecological receptors. Effect levels and
				  exposure factors from the literature are used as early input, but Tier 2 PCLs
				  are not developed without consideration of realistic assumptions and available
				  site-specific information. The screening-level ecological risk assessment
				  should contain the three following widely-acknowledged phases of an ecological
				  risk assessment: problem formulation, which establishes the goals, breadth, and
				  focus of the assessment; analysis, which consists of the technical evaluation
				  of data on both the exposure of the ecological receptor to a chemical stressor
				  and the potential adverse effects; and risk characterization, where the
				  likelihood of adverse effects occurring as a result of exposure to a chemical
				  stressor is evaluated. In order to develop a screening-level ecological risk
				  assessment which appropriately evaluates ecological risk, the person shall meet
				  the minimum requirements listed in paragraphs (1) - (10) of this subsection.
				  Additional information on these requirements, as well as case examples, are
				  provided in the agency's ecological assessment guidance. The person shall:
(1) use affected property concentrations of
				  non-bioaccumulative COCs to compare to established ecological benchmarks and/or
				  use approved methodologies to develop benchmarks to determine potential effects
				  and to eliminate COCs that do not pose unacceptable ecological risk (if all
				  COCs are eliminated at this point, the ecological risk assessment process ends
				  and the items listed in paragraphs (2) - (9) of this subsection are not
				  required);
(2) identify communities
				  (e.g., soil invertebrates, benthic invertebrates) and major feeding guilds
				  (e.g., omnivorous mammals, piscivorous birds) and their representative species
				  which are supported by habitats on the affected property for each complete or
				  reasonably anticipated to be completed exposure pathway;
(3) develop a conceptual model which
				  graphically depicts the movement of COCs through media to communities and the
				  feeding guilds;
(4) discuss COC
				  fate and transport and toxicological profiles;
(5) prepare a list of input data which
				  includes values from the literature (e.g., exposure factors, intake equations
				  that account for total exposure, no observed adverse effect level (NOAEL) and
				  lowest observed adverse effect level (LOAEL) values, references), any available
				  site-specific data, and reasonably conservative exposure assumptions, and then
				  calculate the total exposure to selected ecological receptors from each COC not
				  eliminated according to paragraph (1) of this subsection and present these
				  calculations in tables or spreadsheets;
(6) utilize an ecological hazard quotient
				  methodology to compare exposures to the NOAELs in order to eliminate COCs that
				  pose no unacceptable risk (i.e., NOAEL hazard quotient less than or equal to
				  1); however, when multiple members of a class of COCs are present which exert
				  additive effects, it is also appropriate to utilize an ecological hazard index
				  methodology (if all COCs are eliminated at this point, the ecological risk
				  assessment process ends and the items listed in paragraphs (7) - (9) of this
				  subsection are not required);
(7)
				  justify the use of less conservative assumptions (e.g., a larger home range) to
				  adjust the exposure and repeat the hazard quotient exercise in paragraph (6) of
				  this subsection, once again eliminating COCs that pose no unacceptable risk
				  based on comparisons to the NOAELs and adding another set of comparisons, this
				  time to the LOAELs, for those COCs indicating a potential risk (i.e., NOAEL
				  hazard quotient >1); however, when multiple members of a class of COCs are
				  present which exert additive effects, it is also appropriate to utilize an
				  ecological hazard index methodology (if all COCs are eliminated at this point,
				  the ecological risk assessment process ends and the items listed in paragraphs
				  (8) and (9) of this subsection are not required);
(8) develop an "uncertainty analysis" which
				  discusses the major areas of uncertainty associated with the screening-level
				  ecological risk assessment, including a justification for not developing PCLs
				  for particular COCs/pathways, if appropriate (e.g., NOAEL hazard quotient >
				  1 > LOAEL hazard quotient, an evaluation of the likelihood of ecological
				  risk, a discussion of the half-life of the COCs, etc.); however, when multiple
				  members of a class of COCs are present which exert additive effects, it is also
				  appropriate to utilize an ecological hazard index methodology (if all COCs are
				  eliminated at this point, the ecological risk assessment process ends and the
				  item listed in paragraph (9) of this subsection is not required);
(9) calculate medium-specific PCLs bounded by
				  the NOAEL and the LOAEL used in paragraph (7) of this subsection for those COCs
				  that are not eliminated as a result of the hazard quotient exercises or the
				  uncertainty analysis; and
(10) make
				  a recommendation for managing ecological risk at the affected property based on
				  the final ecological PCLs, unless proceeding under Tier 3 (may be included as
				  part of the affected property assessment report, self-implementation notice, or
				  the response action plan).