Environmental Engineering Reference
In-Depth Information
eight families represented in the data set, the California Department of Fish and
Game has derived criteria for carbaryl [1-naphthalenyl methylcarbamate] and meth-
omyl [methyl
N
-[[(methylamino)carbonyl]oxy]ethanimidothioate] using the USEPA
SSD method (1985). In so doing, professional judgment was used to determine
that species in the missing categories were relatively insensitive, and their addition
would not lower the criteria (Siepmann and Jones 1998; Monconi and Beckman
1996). An FCV may be calculated (USEPA 1985) in the same manner as is the FAV,
if chronic data are available for at least eight different families. Alternatively, an
FCV may be derived by application of an ACR to an FAV, if ACRs are available
for aquatic species in at least three families (one of which must be a fish, one an
invertebrate, and one an acutely sensitive freshwater species). The USEPA methodol-
ogy also requires data from at least one toxicity test with an alga or vascular plant,
and at least one acceptable BCF. The South African methodology (Roux et al. 1996)
has essentially the same data quantity requirements as does the USEPA, with the
exception that the data must be from species that are either indigenous to southern
Africa, or are of local commercial or recreational importance.
The state of North Carolina follows USEPA FAV derivation procedures (1985)
to determine acceptable acute toxicity levels and also provides a means for deriva-
tion of an acceptable level of acute or chronic toxicity based on the lowest available
LC
50
value, implying that a single value may be used (North Carolina Department
of Environment and Natural Resources 2003). The water quality guidance for the
Great Lakes (USEPA 2003a) allows for derivation of Tier II criteria based on
applying an AF to the lowest genus mean acute value (GMAV) in the database.
Although not explicitly stated, it appears that a Tier II criterion could be based on
a single datum, using this method.
The Canadian methodology (CCME 1999) requires studies on at least three fish
species resident in North America, including at least one cold- and one warm-water
species. A minimum of two of the fish studies must be chronic studies. The
Canadian guidelines also require two chronic studies on at least two invertebrate
species from different classes, one of which must be a planktonic species resident
in North America. A minimum of one study of a freshwater vascular plant or algal
species resident in North America is also required, unless a chemical is known to
be highly phytotoxic; in that case, at least four acute and/or chronic studies of
nontarget plants or algae are required.
For effects assessed according to the EU TGD on risk assessment (ECB 2003),
an AF method is used to derive a PNEC. To accomplish this, either one LC
50
/EC
50
(lethal or effect concentration to kill/produce effects in half of a tested population,
respectively) from each of three trophic levels (fish, crustacean, and alga), or one
or more chronic NOECs, are used. Using statistical extrapolation (SSD method),
the TGD requires at least ten chronic NOECs from eight taxonomic groups, as
follows: two families of fish, a crustacean, an insect, a family in a phylum other
than Arthropoda or Chordata, a family in any order of insect or any phylum not
already represented, and, an alga and a higher plant.
In France, data from three trophic levels (algae/plants, invertebrates, and fish)
are required for derivation of threshold values. If data from only two trophic levels
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