Environmental Engineering Reference
In-Depth Information
summarized in Table 3. Irgarol 1051 does not affect bacterial growth even at
a concentration of 50 mg L
-1
[14]. The 24 hLC
50
of Irgarol 1051 to crustacean
speciesisreportedtobeintherangeof5.7to12 mg L
-1
[14]. It is found to in-
hibit mobilization (48 hEC
50
)ataconcentrationof8.1 mg L
-1
[29]. The 48 h
LC
50
to oyster larvae is reported to be 3.2 mg L
-1
,whilstthe96 hLC
50
to fish
species is reported to be in a range from 0.79 mg L
-1
for rainbow trout to
4 mg L
-1
for zebra fish [31].
On the basis of the OECD ecotoxicity classification guidelines [25], these
acute toxicity values correspond to the definition of “toxic”. Furthermore, the
EC
50
determined by the inhibition of phytoplankton growth is reported to
be in the range of 0.0001 to 0.0023 mg L
-1
. Irgarol 1051 is very toxic to sea-
weed, the germination and development of spores is inhibited in the range
from 0.0006 to 0.0059 mg L
-1
[30]. The chemical structure of Irgarol 1051
resembles that of triazine herbicide; therefore, it seems reasonable that Ir-
garol 1051 is remarkably more toxic to phytoplankton and seaweed, so-called
aquatic vegetation, compared to marine animals such as crustaceans and fish
species.
On the basis of the OECD ecotoxicity classification guidelines [25], the
acute toxicity values to phytoplankton and aquatic animals (crustacean and
fish) correspond to the definition of “very toxic” and “toxic”, respectively.
As shown in Table 3, the 72 hEC
50
of M1 to phytoplankton growth is re-
ported to range between 0.0019 and 0.046 mg L
-1
.The96 hEC
50
of M1 to the
germination and development of the spores of seaweed is reported to be in the
range of 0.0017 to 0.13 mg L
-1
, whilst it exhibits acute toxicity to crustacean
(
Daphnia pulex
) species at concentrations from 5.7 to 16 mg L
-1
.Theacute
toxicity values of M1 are 10 times greater than those of the parent compound
and it is obvious that the toxicity of Irgarol 1051 decreases as the compound
is degraded. However, according to the OECD ecotoxicity classifications, the
acute toxicity of M1 is classified as “toxic”.
The chronic toxicity of Irgarol 1051 was evaluated by an early life-stage
toxicity test using rainbow trout (embryo to larval stage) (Table 4), and the
“no observed effect concentration” (NOEC) determined by the inhibition of
larval growth during the 60 days after hatching was 0.00402 mg L
-1
[31]. The
chronic toxicity and acute toxicity values reveal that the acute
chronic toxic-
ity ratio of Irgarol 1051 to rainbow trout is in the range of 3-10
2
. This ratio is
similar to that of numerous other chemical substances such as Lindane, PCP,
DDT, and Dieldrin etc.
Despite the paucity of data on the toxicity of the new biocides to aquatic or-
ganisms, it is suggested from the available published data that Irgarol 1051 is
toxic to phytoplankton and seaweed and that CuPT and ZnPT are highly toxic
to marine animals. The acute toxicity of these new biocides was found to be
in the order of
/
gL
-1
. In other words, it is equivalent to that of the TBT com-
pounds [32-34]. There is much evidence that they are highly toxic to aquatic
organisms.
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