Environmental Engineering Reference
In-Depth Information
Table 7.5
Rating of selection criteria for estuarine or marine amphipod sediment toxicity testing (ASTM 2008c).
Species
Eohaustorius
estuarius
Leptocheirus
plumulosus
Rhepoxynius
abronius
Criterion
Ampelisca abdita
a
Relative sensitivity toxicity database
+/
−
+
+
+
Round-robin studies conducted
+
+
+
+
Contact with sediment
+
+
+
+
Laboratory culture
+/
−
−
+
−
Taxonomic identifi cation
+
+
+
+
Ecological importance
+
+
+
+
Geographical distribution
Atlantic coast, Pacifi c coast,
and Gulf of Mexico
Pacifi c coast
Atlantic coast
Pacifi c coast
Sediment physico-chemical tolerance
+
+
+
+
Response confi rmed with benthos
+
−
−
+
Populations peer reviewed
+
+
+
+
Endpoints monitored
Survival
Survival, reburial
Survival
Survival, reburial
+, postive attribute;
−
, negative attribute.
a
Ampelisca abdita
is a tube-dwelling species, which could reduce exposure to sediment-
associated COPCs.
conducting sediment toxicity tests with these addi-
tional organisms because they did not meet all the
required selection criteria listed in Table 7.4. For
both of the selected species (
H. azteca
and
C. dilutus
),
survival is the principal endpoint measured in 10- to
14-day acute toxicity tests (although growth is also
commonly measured), whereas survival, growth,
emergence (midges only) and/or reproduction are
the principal endpoints measured in longer-term
exposures.
The USEPA (2000b) evaluated relative endpoint
and organism sensitivity in a database developed
from 92 published reports that included a total of
1657 fi eld-collected samples with high-quality
matching sediment toxicity and chemistry data. The
database comprised primarily 10- to 14-day or 28- to
42-day toxicity tests with the amphipod
H. azteca
(designated as the HA10 or HA28 tests) and 10- to
14-day toxicity tests with the midges
C. dilutus
or
C. riparius
(designated as the CS10 test). Endpoints
reported in these tests were primarily survival or
growth. For each test and endpoint, the incidence of
effects above and below various mean probable
effects concentration (PEC) quotients (mean quo-
tients of 0.1, 0.5, 1.0, and 5.0) was determined. In
general, the incidence of sediment toxicity increased
consistently and markedly with increasing levels of
sediment contamination. See MacDonald
et al.
(2000b) for additional information on the calcula-
tion of mean PEC quotients.
A higher incidence of toxicity with increasing mean
PEC quotients was observed in the HA28 test com-
pared with the short-term HA10 or CS10 tests and
may be due to the duration of the exposure or the
sensitivity of the growth endpoint in the longer HA28
test. A 50% incidence of toxicity in the HA28 test
corresponds to a mean PEC quotient of 0.63 when
survival or growth were used to classify a sample as
toxic (Fig. 7.2) (USEPA 2000b). By comparison, a
50% incidence of toxicity is expected at a mean PEC
quotient of 3.2 when survival alone was used to clas-
sify a sample as toxic in the HA28 test. In the CS10
test, a 50% incidence of toxicity is expected at a mean
PEC quotient of 9.0 when survival alone was used to
classify a sample as toxic, or at a mean PEC quotient
of 3.5 when survival or growth were used to classify
a sample as toxic (Fig. 7.2). In contrast, similar mean
PEC quotients resulted in a 50% incidence of toxicity
in the HA10 test when survival alone (mean PEC
quotient of 4.5) or when survival or growth (mean
PEC quotient of 3.4) were used to classify a sample
as toxic. The results of these analyses indicate that
both the duration of the exposure and the endpoints
measured can infl uence whether a sample is found to
be toxic or not. The longer-term tests in which growth
and survival are measured tended to be more sensitive
