NR 105.06(3)(a)1.1. For each species for which at least one chronic value is available, the species mean chronic value (SMCV) is calculated as the geometric mean of all acceptable chronic toxicity tests using the guidelines in sub.
(1) (b).
NR 105.06(3)(a)2.
2. For each genus for which one or more SMCVs are available, the genus mean chronic value (GMCV) is calculated as the geometric mean of the SMCVs available for the genus.
NR 105.06(3)(c)
(c) Ranks (R) are assigned to the GMCVs from 1 for the lowest to N for the highest. If 2 or more GMCVs are identical, successive ranks are arbitrarily assigned.
NR 105.06(3)(d)
(d) The cumulative probability (P) is calculated for each GMCVs as P=R/(N + 1).
NR 105.06(3)(e)
(e) The 4 GMCVs are selected which have P closest to 0.05. If there are less than 59 GMCVs, these will always be the lowest GMCVs.
NR 105.06(3)(f)
(f) Using the selected GMCVs and Ps, the final chronic value (FCV) is calculated using the following:
NR 105.06(3)(f)1.
1. Let EV = sum of the 4 ln GMCVs,
EW = sum of the 4 squares of the ln GMCVs,
EP = sum of the 4 P values,
EPR = sum of the 4 square roots of P, and
JR = square root of 0.05.
NR 105.06(3)(g)
(g) If, for a commercially, recreationally or ecologically important species, the geometric mean of the chronic values is lower than the calculated FCV then that geometric mean is used as the FCV instead of the calculated one.
NR 105.06(3)(h)
(h) The chronic toxicity criterion (CTC) equals the lower of the FCV and the final plant value calculated using the procedure in s.
NR 105.11.
NR 105.06(3)(i)
(i) Table 3 contains the chronic toxicity criteria for the fish and aquatic life subcategories listed in s.
NR 102.04 (3) that are calculated using the procedures described in this subsection for substances meeting the database requirements indicated in sub.
(1).
NR 105.06(4)
(4)
Chronic toxicity criteria for substances with toxicity related to water quality parameters. NR 105.06(4)(a)
(a) If data are available on a substance to show that chronic toxicity to 2 or more species is similarly related to a water quality parameter (i.e., hardness, pH, temperature, etc.), the chronic toxicity criterion (CTC) is calculated using the procedures specified in this paragraph.
NR 105.06(4)(a)1.
1. For each species for which acceptable chronic toxicity tests using the guidelines in sub.
(1) (b) are available at 2 or more different values of the water quality parameter, a least squares regression of the chronic toxicity values on the corresponding values of the water quality parameter is performed to obtain the slope of the curve that best describes the relationship. Because the most commonly documented relationship is that between hardness and the chronic toxicity of metals and a log-log relationship fits these data, geometric means and natural logarithms of both toxicity and water quality are used in the rest of this subsection to illustrate this method. For relationships based on other water quality parameters, no transformation or a different transformation might fit the data better, and appropriate changes shall be made as necessary throughout this subsection.
NR 105.06(4)(a)2.
2. For each species, the geometric mean of the available chronic values (W) is calculated and then each of the chronic values is divided by the mean for that species. This normalizes the chronic values so that the geometric mean of the normalized values for each species individually and for any combination of species is 1.0.
NR 105.06(4)(a)3.
3. For each species, the geometric mean of the available corresponding water quality parameter values (X) is calculated and then each of the water quality parameter values is divided by the mean for that species. This normalizes the water quality parameter values so that the geometric mean of the normalized values for each species individually and for any combination of species is 1.0.
NR 105.06(4)(a)4.
4. A least squares regression of all the normalized chronic values on the corresponding normalized values of the water quality parameter is performed to obtain the pooled chronic slope (V). If the coefficient of determination, or r value, calculated from that regression is found not to be significant based on a standard F-test at a 0.05 level, then the pooled chronic slope shall be set equal to zero.
NR 105.06(4)(a)5.
5. For each species the logarithmic intercept (Y) is calculated using the equation: Y = ln W - V(ln X).
NR 105.06(4)(a)6.a.a. For each species the species mean chronic intercept (SMCI) is calculated as e
Y.
NR 105.06(4)(a)6.b.
b. For each genus for which one or more SMCIs are available, the genus mean chronic intercept (GMCI) is calculated as the geometric mean of the SMCIs available for the genus.
NR 105.06(4)(a)8.
8. Ranks (R) are assigned to the GMCIs from 1 for the lowest to N for the highest. If 2 or more GMCIs are identical, successive ranks are arbitrarily assigned.
NR 105.06(4)(a)9.
9. The cumulative probability (P) is calculated for each GMCI as P=R/(N + 1).
NR 105.06(4)(a)10.
10. The 4 GMCIs are selected which have P closest to 0.05. If there are less than 59 GMCIs, these will always be the lowest GMCIs.
NR 105.06(4)(a)11.
11. Using the selected GMCIs and Ps, the final chronic value (FCV) is calculated using the following:
NR 105.06(4)(a)11.a.
a. Let EV = sum of the 4 ln GMCIs,
EW = sum of the 4 squares of the ln GMCIs,
EP = sum of the 4 P values,
EPR = sum of the 4 square roots of P, and
JR = square root of 0.05.
FCV = e(V ln(water quality parameter) + ln FCI).
The FCE shall be applicable only over the range of water quality parameters equivalent to the mean ± 2 standard deviations using the entire freshwater chronic toxicity data base and the water quality parameter transformation employed in subd. 1. If the value at a specific location is outside of that range, the endpoint of the range nearest to that value shall be used to determine the criterion. Additional information may be used to modify those ranges.
NR 105.06(4)(a)13.
13. If, for a commercially, recreationally or ecologically important species, the SMCI is lower than the calculated FCI, then that SMCI is used as the FCI instead of the calculated one.
NR 105.06(4)(b)
(b) At a value of the water quality parameter, the chronic toxicity criterion (CTC) equals the lower of the FCV and the final plant value calculated using the procedure in s.
NR 105.11.
NR 105.06(4)(c)
(c) Table 4 contains the chronic toxicity criteria for the fish and aquatic life subcategories listed in s.
NR 102.04 (3) that are calculated using the procedures described in this subsection for substances meeting the database requirements indicated in sub.
(1). Table 4A contains the water quality parameter ranges calculated in par.
(a) 1. NR 105.06(5)(a)(a) The acute-chronic ratio is used to estimate the chronic toxicity of a substance to fish or other aquatic species when the database of sub.
(1) (a) is not satisfied.
NR 105.06(5)(b)
(b) The acute-chronic ratio for a species equals the acute concentration from data considered under s.
NR 105.05 (1) divided by the chronic concentration from data calculated under sub.
(1), subject to the following conditions:
NR 105.06(5)(b)1.
1. If the acute toxicity of a substance is related to any water quality parameter, the acute-chronic ratio shall be based on acute and chronic toxicity data obtained from organisms exposed to test water with similar, if not identical, values of those water quality parameters. Preference under this paragraph shall be given to data from acute and chronic tests done by the same author or reference in order to increase the likelihood of comparable test conditions.
NR 105.06(5)(b)2.
2. If the acute and chronic toxicity data indicate that the acute-chronic ratio varies with changes in the values of the water quality parameters, the acute-chronic ratio used at specified values of the water quality parameters shall be based on the ratios at values closest to that specified.
NR 105.06(5)(b)3.
3. If the acute toxicity of a substance is unrelated to water quality parameters, the acute-chronic ratio may be derived from any acute and chronic test on a species regardless of the similarity in values of those parameters. Preference under this paragraph shall be given to data from acute and chronic tests done by the same author or reference to increase the likelihood of comparable test conditions.
NR 105.06(5)(c)
(c) A final chronic value shall be calculated for a substance under this subsection only if at least one acute-chronic ratio is available for at least one species of aquatic animal in at least 3 different families, provided that of the 3 species, one is a fish, one is an invertebrate, and the third is a relatively sensitive freshwater species on an acute toxicity basis. The other 2 may be saltwater species.
NR 105.06(5)(d)
(d) The geometric mean acute-chronic ratio is calculated for each species using the available acute-chronic ratios for that species. That mean ratio shall be called the species mean acute-chronic ratio (SMACR).
NR 105.06(5)(e)
(e) For a given substance, if the SMACR appears to increase or decrease as the species or genus mean acute values (SMAVs or GMAVs) calculated for that substance using the procedure described in s.
NR 105.05 increase, the final acute-chronic ratio (FACR) shall be equal to the geometric mean of the SMACRs for species with SMAVs closest to the final acute value.
NR 105.06(5)(f)
(f) For a given substance, if no trend is apparent regarding changes in SMACRs and GMAVs, the FACR shall be equal to the geometric mean of all SMACRs available for that substance.
NR 105.06(5)(g)
(g) For a given substance, the final chronic value (FCV) shall be equal to the final acute value (FAV) divided by the final acute-chronic ratio (FACR). The chronic toxicity criterion shall be equal to the lower of the FCV and the final plant value as calculated using the procedure in s.
NR 105.11, if available.
NR 105.06(5)(h)
(h) Chronic toxicity criteria for the fish and aquatic life subcategories listed in s.
NR 102.04 (3) that are calculated using acute-chronic ratios are listed in Table 5 for substances with acute toxicity unrelated to water quality parameters and in Table 6 for substances with acute toxicity related to water quality parameters. Equations listed in Table 6 are applicable over the range of water quality parameters as contained in Table 4A. Table 2A should be used where no range is listed in Table 4A.
NR 105.06(6)
(6)
Secondary chronic values. If all 8 minimum data requirements for calculating FCVs in sub.
(1) (a) are not met for a substance, secondary chronic values (SCVs) shall be calculated for that substance using the procedure in this subsection.
NR 105.06(6)(a)
(a) If any one of the combinations of information in subds.
1. to
3. is available, a SCV may be calculated. To calculate a SCV for a substance, the acute value from subds.
1. to
3. is divided by the applicable acute-chronic ratio in the same subdivision.
NR 105.06(6)(a)1.
1. Calculate a FAV using the procedure in s.
NR 105.05 (2) and divide it by a secondary acute-chronic ratio (SACR) using the procedure in sub.
(7).
NR 105.06(6)(b)
(b) If appropriate, the SCV shall be made a function of a water quality characteristic in a manner similar to that described in sub.
(4) (a).
NR 105.06(6)(c)
(c) If, for a commercially, recreationally or ecologically important species, the SMCV is lower than the calculated SCV, that SMCV shall be used as the SCV instead of the calculated SCV.
NR 105.06(6)(d)
(d) If there is an FPV available using the procedure in s.
NR 105.11 which is lower than the calculated SCV, that FPV shall be used as the SCV instead of the calculated SCV.
NR 105.06(7)(a)
(a) If a FACR cannot be calculated using the procedure in sub.
(5) because SMACRs are not available for a fish, an invertebrate or an acutely sensitive freshwater species, a secondary acute-chronic ratio (SACR) may be calculated using the procedure in this subsection.
NR 105.06(7)(b)
(b) The SACR shall be equal to the geometric mean of 3 acute-chronic ratios. Those ratios consist of the SMACRs available for the species in sub.
(5) (c). When SMACRs are not available for the species in par.
(a), the default acute-chronic ratio to be used is 18. Use of a SACR will result in the calculation of a secondary chronic value.
NR 105.06(8)
(8)
Chronic toxicity criteria expressed in the dissolved form. Chronic water quality criteria may be expressed as a dissolved concentration. The conversion of a chronic water quality criterion expressed as a total recoverable concentration to a chronic water quality criterion expressed as a dissolved concentration, the portion of the substance which will pass through a 0.45 um filter, shall be done using the equations in pars.
(a) and
(b). Substances which may have criteria expressed as a dissolved concentration are listed in par.
(a) with corresponding conversion factors.
NR 105.06(8)(a)
(a) The conversion of the water quality criterion expressed as total recoverable (WQC
Total R.) to the water quality criterion expressed as dissolved (WQC
D) shall be performed as follows:
WQCD = (CF)(WQCTotal R.)
Where: WQCTotal R. = Criteria from NR 105, Table 5 or 6.
CF = Conversion factor for total recover-
able to dissolved.
Conversion factors are as follows:
Arsenic 1.000
Cadmium 0.850
Chromium (III) 0.860
Chromium (VI) 0.962
Copper 0.960
Lead 0.792
Mercury 0.85
Nickel 0.997
Selenium 0.922
Zinc 0.986
NR 105.06(8)(b)
(b) The translation of the WQC
D into the water quality criterion which accounts for site-specific conditions (WQC
TRAN) shall be performed as follows:
WQCTRAN = (Translator)(WQCD)
Where: Translator (unitless) = ((MP)(TSS) + MD)/MD
MP = Particle-bound concentration of the pollutant (ug/g) in receiving water.
MD = Dissolved concentration of the pollutant in receiving water (ug/L).
TSS = Total Suspended Solids (g/L) concentration in receiving water.
