Oregon Administrative Rules
Chapter 340 - DEPARTMENT OF ENVIRONMENTAL QUALITY
Division 41 - WATER QUALITY STANDARDS: BENEFICIAL USES, POLICIES, AND CRITERIA FOR OREGON
Section 340-041-0033 - Toxic Substances
Universal Citation: OR Admin Rules 340-041-0033
Current through Register Vol. 63, No. 3, March 1, 2024
(1) Toxic Substances Narrative. Toxic substances may not be introduced above natural background levels in waters of the state in amounts, concentrations, or combinations that may be harmful, may chemically change to harmful forms in the environment, or may accumulate in sediments or bioaccumulate in aquatic life or wildlife to levels that adversely affect public health, safety, or welfare or aquatic life, wildlife or other designated beneficial uses.
(2) Aquatic Life Numeric Criteria. Levels of toxic substances in waters of the state may not exceed the applicable aquatic life criteria as defined in Table 30 under OAR 340-041-8033.
(3) Human Health Numeric Criteria. The criteria for waters of the state listed in Table 40 under OAR 340-041-8033 are established to protect Oregonians from potential adverse health effects associated with long-term exposure to toxic substances associated with consumption of fish, shellfish and water.
(4) To establish permit or other regulatory limits for toxic substances without criteria in Table 30 under OAR 340-041-8033 or Table 40 under 340-041-8033, DEQ may use the guidance values in Table 31 under 340-041-8033, public health advisories, and published scientific literature. DEQ may also require or conduct bio-assessment studies to monitor the toxicity to aquatic life of complex effluents, other suspected discharges or chemical substances without numeric criteria.
(5) Establishing Site-Specific Background Pollutant Criteria: This provision is a performance- based water quality standard that results in site-specific human health water quality criteria under the conditions and procedures specified in this rule section. It addresses existing permitted discharges of a pollutant removed from the same body of water. For waterbodies where a discharge does not increase the pollutant's mass and does not increase the pollutant concentration by more than 3 percent, and where the water body meets a pollutant concentration associated with a risk level of 1 x 10-4, DEQ concludes that the pollutant concentration continues to protect human health.
(a)
Definitions: As used in this section:
(A)
"Background pollutant concentration" means the ambient water body concentration
immediately upstream of the discharge, regardless of whether those pollutants
are natural or result from upstream human activity.
(B) An "intake pollutant" is the amount of a
pollutant present in waters of the state (including groundwater) as provided in
subsection (C), below, at the time it is withdrawn from such waters by the
discharger or other facility supplying the discharger with intake water.
(C) "Same body of water": An
intake pollutant is considered to be from the "same body of water" as the
discharge if DEQ finds that the intake pollutant would have reached the
vicinity of the outfall point in the receiving water within a reasonable period
had the permittee not removed it. To make this finding, DEQ requires
information showing that:
(i) The background
concentration of the pollutant in the receiving water (excluding any amount of
the pollutant in the facility's discharge) is similar to that in the intake
water; and,
(ii) There is a direct
hydrological connection between the intake and discharge points.
(I) DEQ may also consider other site-specific
factors relevant to the transport and fate of the pollutant to make the finding
in a particular case that a pollutant would or would not have reached the
vicinity of the outfall point in the receiving water within a reasonable period
had the permittee not removed it.
(II) An intake pollutant from groundwater may
be considered to be from the "same body of water" if DEQ determines that the
pollutant would have reached the vicinity of the outfall point in the receiving
water within a reasonable period had the permittee not removed it. A pollutant
is not from the same body of water if the groundwater contains the pollutant
partially or entirely due to past or present human activity, such as
industrial, commercial, or municipal operations, disposal actions, or treatment
processes.
(iii) Water
quality characteristics (e.g., temperature, pH, hardness) are similar in the
intake and receiving waters.
(b) Applicability
(A) DEQ may establish site-specific criteria
under this rule section only for carcinogenic pollutants.
(B) Site-specific criteria established under
this rule section apply in the vicinity of the discharge for purposes of
establishing permit limits for the specified permittee.
(C) The underlying waterbody criteria
continue to apply for all other Clean Water Act programs.
(D) The site-specific background pollutant
criterion will be effective when DEQ issues the permit for the specified
permittee.
(E) DEQ will reevaluate
any site-specific criteria developed under this procedure upon permit renewal.
(c) DEQ may establish a
site-specific background pollutant criterion when all of the following
conditions are met:
(A) The discharger has a
currently effective NPDES permit;
(B) The mass of the pollutant discharged to
the receiving waterbody does not exceed the mass of the intake pollutant from
the same body of water, as defined in section (5)(a)(C) above, and therefore
does not increase the total mass load of the pollutant in the receiving water
body;
(C) DEQ has not assigned the
discharger a TMDL wasteload allocation for the pollutant in question;
(D) The permittee uses any
feasible pollutant reduction measures available and known to minimize the
pollutant concentration in their discharge;
(E) The pollutant discharge has not been
chemically or physically altered in a manner that causes adverse water quality
impacts that would not occur if the intake pollutants were left in-stream; and,
(F) The timing and location of the
pollutant discharge would not cause adverse water quality impacts that would
not occur if the intake pollutant were left in-stream.
(d) The site-specific background pollutant
criterion must be the most conservative of the following four values. Section
(5)(e) of this rule describes the procedures for deriving these values.
(A) The projected in-stream pollutant
concentration resulting from the current discharge concentration and any
feasible pollutant reduction measures under (c)(D) above, after mixing with the
receiving stream.
(B) The
projected in-stream pollutant concentration resulting from the portion of the
current discharge concentration associated with the intake pollutant mass after
mixing with the receiving stream. This analysis ensures that there will be no
increase in the mass of the intake pollutant in the receiving water body as
required by condition (c)(B) above.
(C) The projected in-stream pollutant
concentration associated with a 3 percent increase above the background
pollutant concentration as calculated:
(i)
For the main stem Willamette and Columbia Rivers, using 25 percent of the
harmonic mean flow of the waterbody.
(ii) For all other waters, using 100 percent
of the harmonic mean flow or similar critical flow value of the waterbody.
(D) A criterion
concentration value representing a human health risk level of 1 x 10-4. DEQ
calculates this value using EPA's human health criteria derivation equation for
carcinogens (EPA 2000), a risk level of 1 x 10-4, and the same values for the
remaining calculation variables that were used to derive the underlying human
health criterion.
(e)
Procedure to derive a site-specific human health water quality criterion to
address a background pollutant:
(A) DEQ will
develop a flow-weighted characterization of the relevant flows and pollutant
concentrations of the receiving waterbody, effluent and all facility intake
pollutant sources to determine the fate and transport of the pollutant mass.
(i) The pollutant mass in the effluent
discharged to a receiving waterbody may not exceed the mass of the intake
pollutant from the same body of water.
(ii) Where a facility discharges intake
pollutants from multiple sources that originate from the receiving waterbody
and from other waterbodies, DEQ will calculate the flow-weighted amount of each
source of the pollutant in the characterization.
(iii) Where a municipal water supply system
provides intake water for a facility and the supplier provides treatment of the
raw water that removes an intake water pollutant, the concentration and mass of
the intake water pollutant must be determined at the point where the water
enters the water supplier's distribution system.
(B) Using the flow weighted characterization
developed in section (5)(e)(A), DEQ will calculate the in-stream pollutant
concentration following mixing of the discharge into the receiving water. DEQ
will use the resultant concentration to determine the conditions in section
(5)(d)(A) and (B).
(C) Using the
flow-weighted characterization, DEQ will calculate the in-stream pollutant
concentration based on an increase of 3 percent above background pollutant
concentration. DEQ will use the resultant concentration to determine the
condition in Section (5)(d)(C).
(i) For the
main stem Willamette and Columbia Rivers, DEQ will use 25 percent of the
harmonic mean flow of the waterbody.
(ii) For all other waters, DEQ will use 100
percent of the harmonic mean flow or similar critical flow value of the
waterbody.
(D) DEQ will
select the most conservative of the following values as the site-specific water
quality criterion.
(i) The projected
in-stream pollutant concentration described in section (5)(e)(B);
(ii) The in-stream pollutant concentration
based on an increase of 3 percent above background described in section
(5)(e)(C); or
(iii) A water
quality criterion based on a risk level of 1 x 10-4.
(f) Calculation of water quality
based effluent limits based on a site-specific background pollutant criterion:
(A) For discharges to receiving waters with a
site-specific background pollutant criterion, DEQ will use the site-specific
criterion in the calculation of a numeric water quality based effluent limit.
(B) DEQ will compare the
calculated water quality based effluent limits to any applicable aquatic
toxicity or technology based effluent limits and select the most conservative
for inclusion in the permit conditions.
(g) In addition to the water quality based
effluent limits described in section (5)(f), DEQ will calculate a mass-based
limit where necessary to ensure that the condition described in section
(5)(c)(B) is met. Where mass-based limits are included, the permit will specify
how DEQ will assess compliance with mass-based effluent limitations.
(h) The permit shall include a provision
requiring DEQ to consider the re-opening of the permit and re-evaluation of the
site-specific background pollutant criterion if new information shows the
discharger no longer meets the conditions described in subsections (5)(c) and
(e).
(i) Public Notification
Requirements.
(A) If DEQ proposes to grant a
site-specific background pollutant criterion, it must provide public notice of
the proposal and hold a public hearing. The public notice may be included in
the public notification of a draft NPDES permit or other draft regulatory
decision that would rely on the criterion and will also be published on DEQ's
water quality standards website;
(B) DEQ will publish a list of all
site-specific background pollutant criteria approved according to this rule.
DEQ will add the criterion to this list within 30 days of its effective date.
The list will identify the:
(i) Permittee;
(ii) Site-specific background
pollutant criterion and the associated risk level;
(iii) Waterbody to which the criterion
applies;
(iv) Allowable pollutant
effluent limit; and,
(v) How to
obtain additional information about the criterion.
(6) Arsenic Reduction Policy: The inorganic arsenic criterion for the protection of human health from the combined consumption of organisms and drinking water is 2.1 micrograms per liter. While this criterion is protective of human health and more stringent than the federal maximum contaminant level (MCL) for arsenic in drinking water, which is 10 micrograms per liter, it is based on a higher risk level than EQC used to establish other human health criteria. This higher risk level recognizes that much of the risk is due to naturally high levels of inorganic arsenic in Oregon's waterbodies. In order to maintain the lowest human health risk from inorganic arsenic in drinking water, EQC determined that it is appropriate to adopt the following policy to limit the human contribution to that risk.
(a) It is EQC policy to reduce the
addition of inorganic arsenic from new or existing anthropogenic sources to
waters of the state within a surface water drinking water protection area to
the maximum amount feasible. The requirements of this rule section (OAR
340-041-0033(6)) apply to sources that discharge to surface waters of the state
with an ambient inorganic arsenic concentration equal to or lower than the
applicable numeric inorganic arsenic criteria for the protection of human
health.
(b) Definitions. As used
in this section:
(A) "Add inorganic arsenic"
means to discharge a net mass of inorganic arsenic from a point source (the
mass of inorganic arsenic discharged minus the mass of inorganic arsenic taken
into the facility from a surface water source).
(B) A "surface water drinking water
protection area," means an area delineated as such by DEQ under the source
water assessment program of the federal Safe Drinking Water Act, 42 U.S.C.
§ 300j 13. DEQ delineates these areas to protect public or community
drinking water supplies that use surface water sources. These delineations are
on DEQ's drinking water program Web page.
(C) "Potential to significantly increase
inorganic arsenic concentrations in the public drinking water supply source
water" means:
(i) A discharge will increase
the concentration of inorganic arsenic in the receiving water by 10 percent or
more after mixing with the harmonic mean flow of the receiving water; or
(ii) As an alternative, if
sufficient data are available, the discharge will increase the concentration of
inorganic arsenic in the surface water intake water of a public water system by
0.021 micrograms per liter or more based on a mass balance calculation.
(c)
Following the effective date of this rule, applications for an individual NPDES
permit or permit renewal received from industrial dischargers located in a
surface water drinking water protection area and identified by DEQ as likely to
add inorganic arsenic to the receiving water must include sufficient data to
enable DEQ to determine whether:
(A) The
discharge adds inorganic arsenic; and,
(B) The discharge has the potential to
significantly increase inorganic arsenic concentrations in the public drinking
water supply source water.
(d) Where DEQ determines that both conditions
in subsection (c) of this section (6) are true, the industrial discharger must
develop an inorganic arsenic reduction plan and propose all feasible measures
to reduce its inorganic arsenic loading to the receiving water. The proposed
plan, including proposed measures, monitoring and reporting requirements, and a
schedule for those actions, will be described in the fact sheet and
incorporated into the source's NPDES permit after public comment and DEQ review
and approval. In developing the plan, the source must:
(A) Identify how much it can minimize its
inorganic arsenic discharge through pollution prevention measures, process
changes, wastewater treatment, alternative water supply for groundwater users,
or other possible pollution prevention and control measures;
(B) Evaluate the costs, feasibility and
environmental impacts of the potential inorganic arsenic reduction and control
measures;
(C) Estimate the
predicted reduction in inorganic arsenic and the reduced human health risk
expected to result from the control measures;
(D) Propose specific inorganic arsenic
reduction or control measures, if feasible, and an implementation schedule;
and,
(E) Propose monitoring and
reporting requirements to document progress in plan implementation and the
inorganic arsenic load reductions.
(e) In order to implement this section, DEQ
will develop the following information and guidance within 120 days of the
effective date of this rule and periodically update it as warranted by new
information:
(A) A list of industrial sources
or source categories, including industrial stormwater and sources covered by
general permits likely to add inorganic arsenic to surface waters of the state.
For industrial sources or source categories permitted under a general permit
that have been identified by DEQ as likely sources of inorganic arsenic, DEQ
will evaluate options for reducing inorganic arsenic during permit renewal or
evaluation of Stormwater Pollution Control Plans.
(B) Quantitation limits for monitoring
inorganic arsenic concentrations.
(C) Information and guidance to assist
sources in estimating, according to subsection (d)(C) of this section, the
reduced human health risk expected to result from inorganic arsenic control
measures based on the most current EPA risk assessment.
(f) It is the policy of EQC that landowners
engaged in agricultural or development practices on land where pesticides,
fertilizers, or soil amendments containing arsenic are currently being or have
previously been applied, implement conservation practices to minimize the
erosion and runoff of inorganic arsenic to waters of the state or to a location
where such material could readily migrate into waters of the state.
NOTE: Tables 30, 31 and 40 are found under OAR 340-041-8033.
Tables referenced are not included in rule text. Click here for PDF copy of table(s)
Stat. Auth.: ORS 468.020, 468B.030, 468B.035 & 468B.048
Stats. Implemented: ORS 468B.030, 468B.035 & 468B.048
Disclaimer: These regulations may not be the most recent version. Oregon may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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