Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

For each genera, the geometric mean of the relevant SMAVs is then calculated to determine the
genus mean acute value (GMAV). The GMAVs are then ranked from high to low, and the final
acute value (FAV; the 5th percentile of the GMAVs, based on the four GMAVs surrounding the
5th percentile) is determined. Because the FAV is based on LC50/EC50 values (which represent
unacceptably high levels of effect), the FAV is divided by two to estimate a low-effect level.
This value is then termed the acute criterion, or criterion maximum concentration (CMC). Based
on the most recent AWQC document for Pb (U.S. Environmental Protection Agency, 1985),
Table AX7-2.1.2 shows the freshwater SMAVs and GMAVs for Pb, and the resulting freshwater
CMC. Note that the freshwater AWQC are normalized for the hardness of the site water, as
discussed further below in Section AX7.2.1.3.
Table AX7-2.1.2. Development of Current Acute Freshwater Criteria for Lead
(U.S. Environmental Protection Agency, 1985) 1
Rank Species
AX7-109
GMAV
(µg/L)
SMAV
(µg/L)
10 Midge (Tanytarsus dissimilis) 235,900 235,900
9 Goldfish (Carassius auratus) 101,100 101,100
8 Guppy (Poecilia reticulata) 66,140 66,140
7 Bluegill (Lepomis macrochirus) 52,310 52,310
6 Fathead minnow (Pimephales promelas) 25,440 25,440
5 Brook trout (Salvelinus fontinalis) 4,820 4,820
4 Rainbow trout (Oncorhynchus mykiss) 2,448 2,448
3 Snail (Aplexa hypnorum) 1,040 1,040
2 Cladoceran (Daphnia magna) 447.8 447.8
1 Amphipod (Gammarus pseudolimnaeus) 142.6 142.6
1 All values are normalized to a hardness of 50 mg/L (see Section AX7.2.1.3).
FAV = 67.54 µg/L
CMC = 33.77 µg/L