Footnotes for aquatic life criteria in Table 240:

a.

A 1-hour average concentration not to be exceeded more than once every three years on the average.

b.

A 4-day average concentration not to be exceeded more than once every three years on average.

c.

An instantaneous concentration not to be exceeded at any time.

d.

A 24-hour average not to be exceeded at any time.

e.

Criteria are calculated using the Aluminum Criteria Calculator V.2.0 that is published in EPA's "Final Aquatic Water Quality Criteria for Aluminum 2018" (EPA-822-R-1-001). Default criteria values were calculated for EPA Level II ecoregions and are applicable in the absence of water body or site-specific water quality data. The freshwater default acute criterion in the Western Cordillera ecoregion is 288 µg/L, 630 µg/L is the default acute criterion in the Marine West Coast Forest ecoregion, and 1400 µg/L is the default acute criterion in the Cold Desert ecoregion. The freshwater default chronic criterion in the Western Cordillera ecoregion is 180 µg/L, 302 µg/L is the default chronic criterion in the Marine West Coast Forest ecoregion, and 720 µg/L is the default chronic criterion in the Cold Desert ecoregion. The default criterion is used in the absence of concurrently sampled pH, hardness, and dissolved organic carbon for a site-specific location or water body. Criteria calculated using concurrently sampled pH, hardness, and dissolved organic carbon for a specific water body supersede the default criteria. The aluminum criteria are based on aluminum toxicity studies where aluminum was analyzed using total recoverable analytical methods. Washington may utilize total recoverable analytical methods to implement the criteria. For characterizing ambient waters, Washington may also utilize, as scientifically appropriate and as allowable by state and federal regulations, analytical methods that measure the bioavailable fraction of aluminum (e.g., utilizing a less aggressive initial acid digestion, such as to a pH of approximately 4 or lower, that includes the measurement of amorphous aluminum hydroxide yet minimizes the measurement of mineralized forms of aluminum such as aluminum silicates associated with suspended sediment particles or clays). Washington shall use measurements of total recoverable aluminum where required by federal regulations.

f.

These ambient criteria in the table are for the dissolved fraction. The cyanide criteria are based on the weak acid dissociable method. The metals criteria may not be used to calculate total recoverable effluent limits unless the seasonal partitioning of the dissolved to total metals in the ambient water are known. When this information is absent, these metals criteria shall be applied as total recoverable values, determined by back-calculation, using the conversion factors incorporated in the criterion equations. Metals criteria may be adjusted on a site-specific basis when data are made available to the department clearly demonstrating the effective use of the water effects ratio approach established by USEPA, as generally guided by the procedures in USEPA Water Quality Standards Handbook, December 1983, as supplemented or replaced by USEPA or ecology. The adjusted site-specific criteria are not in effect until they have been incorporated into this chapter and approved by EPA. Information which is used to develop effluent limits based on applying metals partitioning studies or the water effects ratio approach shall be identified in the permit fact sheet developed pursuant to WAC 173-220-060 or 173-226-110, as appropriate, and shall be made available for the public comment period required pursuant to WAC 173-220-050 or 173-226-130(3), as appropriate. Ecology has developed supplemental guidance for conducting water effect ratio studies.

g.

Marine conversion factors (CF) which were used for calculating dissolved metals concentrations are given below. Conversion factors are applicable to both acute and chronic criteria for all metals except mercury. The CF for mercury was applied to the acute criterion only and is not applicable to the chronic criterion. Conversion factors are already incorporated into the criteria in the table. Dissolved criterion = criterion x CF

 

Metal

CF

 

Arsenic

1.000

 

Cadmium

0.994

 

Chromium (VI)

0.993

 

Copper

0.83

 

Lead

0.951

 

Mercury

0.85

 

Nickel

0.990

 

Selenium

0.998

 

Silver

0.85

 

Zinc

0.946

h.

Acute criterion = (CF)(e(0.9789[ln(hardness)]-4.189)). Conversion factor (CF) is hardness dependent. CF is calculated for other hardnesses as follows: CF = 1.136672 - [(ln hardness)(0.041838)].

i.

Chronic criterion = (CF)(e(0.7977[ln(hardness)]-4.446)). Conversion factor (CF) is hardness dependent. CF is calculated for other hardnesses as follows: CF = 1.101672 - [(ln hardness)(0.041838)].

j.

Where methods to measure trivalent chromium are unavailable, these criteria are to be represented by total-recoverable chromium.

k.

Acute criterion = (0.316)(e(0.8190[ln(hardness)] + 3.533))

l.

Chronic criterion = (0.860)(e(0.8190[ln(hardness)] + 0.4921))

m.

The conversion factor used to calculate the dissolved metal concentration is 0.982.

n.

The conversion factor used to calculate the dissolved metal concentration is 0.962.

o.

The acute criterion is represented by the higher criteria value of the two equations: 1) Acute criterion = e(0.700*ln(DOC) + 0.579*ln(hardness) + 0.778*pH – 6.738) and 2) Acute criterion = e(0.855*ln(DOC) + 0.221*ln(hardness) + 0.216*pH – 1.183). Default criteria values were calculated for EPA Level II ecoregions and are applicable in the absence of water body or site-specific water quality data. The freshwater default acute criterion in the Western Cordillera ecoregion is 1.4 µg/L, 2.4 µg/L is the default acute criterion in the Marine West Coast Forest ecoregion, and 4.8 µg/L is the default acute criterion in the Cold Desert ecoregion. The default criterion is used in the absence of concurrently sampled pH, hardness, and dissolved organic carbon for a site-specific location or water body. Criteria calculated using concurrently sampled pH, hardness, and dissolved organic carbon for a specific water body supersede the default criteria.

p.

Chronic criterion = e(0.855*ln(DOC) + 0.221*ln(hardness) + 0.216*pH – 1.402) . Default criteria values were calculated for EPA Level II ecoregions and are applicable in the absence of water body or site-specific water quality data. The freshwater default chronic criterion in the Western Cordillera ecoregion is 1.2 µg/L, 1.8 µg/L is the default chronic criterion in the Marine West Coast Forest ecoregion, and 3.2 µg/L is the default chronic criterion in the Cold Desert ecoregion. 1.6 µg/L is applicable in western Washington and 1.8 µg/L is the applicable default chronic criterion in eastern Washington. The default criterion is used in the absence of concurrently sampled pH, hardness, and dissolved organic carbon for a site-specific location or water body. Criteria calculated using concurrently sampled pH, hardness, and dissolved organic carbon for a specific water body supersede the default criteria.

q.

Acute criterion = (CF)(e(1.273[ln(hardness)] - 1.460)). Conversion factor (CF) is hardness dependent. CF is calculated for other hardnesses as follows:

CF = 1.46203 - [(ln hardness)(0.145712)].

r.

Chronic criterion = (CF)(e(1.273[ln(hardness)] - 4.705)). Conversion factor (CF) is hardness dependent. CF is calculated for other hardnesses as follows: CF = 1.46203 - [(ln hardness)(0.145712)].

s.

The conversion factor used to calculate the dissolved metal concentration is 0.85.

t.

These criteria are based on the total-recoverable fraction of the metal.

u.

If the four-day average chronic concentration is exceeded more than once in a three-year period, the edible portion of the consumed species should be analyzed. Said edible tissue concentrations shall not be allowed to exceed 1.0 mg/kg of methylmercury.

v.

Acute criterion = (0.998)(e(0.8460[ln(hardness)] + 0.1667))

w.

Chronic criterion = (0.997)(e(0.8460[ln(hardness)] – 1.466))

x.

There is no freshwater acute criterion for aquatic life for selenium. The freshwater chronic criterion is expected to adequately protect against acute effects.

y.

Freshwater chronic selenium criteria:

 

15.1 mg/kg dry weight (egg-ovary tissue)1

 

8.5 mg/kg dry weight (whole-body tissue)2

 

11.3 mg/kg dry weight (muscle tissue)2

 

1.5 µg/L (water lentic)3

 

3.1 µg/L (water lotic)3

 

WQCint = WQC – Cbkgrnd (1 – fint) / fint (water lentic or lotic)3,4

 

1 Egg-ovary supersedes any whole-body, muscle, or water column element when fish egg-ovary concentrations are measured, except as noted in footnote 4. Tissue criterion is not to be exceeded.

 

2 Fish whole-body or muscle tissue supersedes the water column element when both fish tissue and water concentrations are measured, except as noted in footnote 4. Tissue criterion is not to be exceeded.

 

3 Water column values are based on dissolved total selenium in water and are derived from fish tissue values via bioaccumulation modeling. When selenium inputs are increasing, water column values are the applicable criterion element in the absence of steady-state condition fish tissue data. Water column criteria are based on a 30-day average concentrations, except for WQCint (see footnote 4). Water column criteria are not to be exceeded more than once every three years on average.

 

4 Where WQCint is the intermittent exposure concentration in µg/L; WQC is the applicable water column element, for either lentic or lotic waters; Cbkgrnd is the average daily background concentration occurring during the remaining time, integrated over 30 days; fint is the fraction of any 30-day period during which elevated selenium concentrations occur, with fint assigned a value ≥ 0.033 (corresponding to one day). Intermittent exposure criteria averaging period is the number of days per month with an elevated concentration.

z.

Acute criterion = (0.85)(e(1.72[ln(hardness)] – 8.590))

aa.

Chronic criterion = (0.85)(e(1.72[ln(hardness)] – 9.511))

bb.

Acute criterion = (0.978)(e(0.8473[ln(hardness)] + 0.3313))

cc.

Chronic criterion = (0.986)(e(0.8473[ln(hardness)] – 0.6900))

dd.

Aldrin is metabolically converted to Dieldrin. Therefore, the sum of the Aldrin and Dieldrin concentrations are compared with the Dieldrin criteria.

ee.

This value was derived from data for endosulfan. Where concentrations for both alpha-endosulfan and beta-endosulfan are available, the sum of alpha-endosulfan and beta-endosulfan concentrations shall be compared to the criteria.

ff.

Shall not exceed the numerical value in total ammonia nitrogen (mg N/L) given by:

gg.

Shall not exceed the numerical concentration calculated as follows:

 

Unionized ammonia concentration for waters where salmonid habitat is an existing or designated use:

 

Applied as a 30-day average concentration of total ammonia nitrogen (in mg N/L) not to be exceeded more than once every three years on the average. The highest four-day average within the 30-day period should not exceed 2.5 times the chronic criterion.

hh.

Measured in milligrams per liter rather than micrograms per liter.

ii.

The listed freshwater criteria are based on un-ionized or total ammonia concentrations, while those for marine water are based on un-ionized ammonia concentrations. Tables for the conversion of total ammonia to un-ionized ammonia for freshwater can be found in the USEPA's Quality Criteria for Water, 1986. Criteria concentrations based on total ammonia for marine water can be found in USEPA Ambient Water Quality Criteria for Ammonia (Saltwater)-1989, EPA440/ 5-88-004, April 1989.

jj.

Criterion based on dissolved chloride in association with sodium. This criterion probably will not be adequately protective when the chloride is associated with potassium, calcium, or magnesium, rather than sodium.

kk.

The criteria for cyanide is based on the weak acid dissociable method in the 19th Ed. Standard Methods for the Examination of Water and Wastewater, 4500-CN I, and as revised (see footnote f, above).

ll.

The cyanide criteria are: 2.8 µg/L chronic and 9.1 µg/L acute and are applicable only to waters which are east of a line from Point Roberts to Lawrence Point, to Green Point to Deception Pass; and south from Deception Pass and of a line from Partridge Point to Point Wilson. The chronic criterion applicable to the remainder of the marine waters is l µg/L.

mm.

Acute criterion = e[1.005(pH) – 5.450]

nn.

Chronic criterion = e[1.005(pH) – 6.155]

oo.

Freshwater chronic PFOS criteria:

 

8.4 µg/L (water)1,2

 

0.937 mg/kg ww (invertebrate whole-body)1,3,4

 

6.75 mg/kg ww (fish whole-body)1,3,4

 

2.91 mg/kg ww (fish muscle)1,3,4

 

1 All water column and tissue criteria are intended to be independently applicable for compliance determinations and no one criterion takes primacy.

 

2 Water column criteria are based on a four-day average concentration not to be exceeded more than once every three years on average.

 

3 Tissue criteria derived from the chronic water column concentration with the use of bioaccumulation factors and are expressed as wet weight (ww) concentrations.

 

4 Tissue data is an instantaneous point measurement that reflect integrative accumulation of PFOS over time and space. Criteria are not to be exceeded more than once every 10 years on average.

pp.

Freshwater chronic PFOA criteria:

 

94 µg/L (water)1,2

 

1.11 mg/kg ww (invertebrate whole-body)1,3,4

 

6.10 mg/kg ww (fish whole-body)1,3,4

 

0.125 mg/kg ww (fish muscle)1,3,4

 

1 All water column and tissue criteria are intended to be independently applicable for compliance determinations and no one criterion takes primacy.

 

2 Water column criteria are based on a four-day average concentration not to be exceeded more than once every three years on average.

 

3 Tissue criteria derived from the chronic water column concentration with the use of bioaccumulation factors and are expressed as wet weight (ww) concentrations.

 

4 Tissue data is an instantaneous point measurement that reflect integrative accumulation of PFOS over time and space. Criteria are not to be exceeded more than once every 10 years on average.

Footnotes for human health criteria in Table 240:

A.

This criterion for total arsenic is the maximum contaminant level (MCL) developed under the Safe Drinking Water Act. The MCL for total arsenic is applied to surface waters where consumption of organisms-only and where consumption of water + organisms reflect the designated uses. When the department determines that a direct or indirect industrial discharge to surface waters designated for domestic water supply may be adding arsenic to its wastewater, the department will require the discharger to develop and implement a pollution prevention plan to reduce arsenic through the use of AKART. Industrial wastewater discharges to a privately or publicly owned wastewater treatment facility are considered indirect discharges.

B.

This criterion was calculated based on an additional lifetime cancer risk of one-in-one-million (1 x 10-6 risk level).

C.

This criterion is based on a regulatory level developed under the Safe Drinking Water Act.

D.

This recommended water quality criterion is expressed as total cyanide, even though the integrated risk information system RfD used to derive the criterion is based on free cyanide. The multiple forms of cyanide that are present in ambient water have significant differences in toxicity due to their differing abilities to liberate the CN-moiety. Some complex cyanides require even more extreme conditions than refluxing with sulfuric acid to liberate the CN-moiety. Thus, these complex cyanides are expected to have little or no "bioavailability" to humans. If a substantial fraction of the cyanide present in a water body is present in a complexed form (e.g., Fe4[Fe(CN)6]3), this criterion may be overly conservative.

E.

This criterion applies to total PCBs, (e.g., the sum of all congener or all isomer or homolog or Aroclor analyses). The PCBs criteria were calculated using a chemical-specific risk level of 4 x 10-5. Because that calculation resulted in a higher (less protective) concentration than the current criterion concentration (40 C.F.R. 131.36) the state made a chemical-specific decision to stay at the current criterion concentration.

F.

This criterion was derived using the cancer slope factor of 1.4 (linearized multistage model with a twofold increase to 1.4 per mg/kg-day to account for continuous lifetime exposure from birth).

G.

EPA has removed Washington from the National Toxics Rule at 40 C.F.R. 131.36 for mercury and promulgated new human health criteria for methylmercury in the EPA's final federal rule at 40 C.F.R. 131.45.

H.

Human health criteria applicable for Clean Water Act purposes in the state of Washington are contained in 40 C.F.R. 131.45 and effective as of December 19, 2022 (87 FR 69183).