Environmental Engineering Reference
In-Depth Information
No literature has been found concerning toxicities of Dichlofluanid, Di-
uron, TCMTB, and Zineb. Furthermore, very little is known about the chronic
toxicities of these new biocides. In order to estimate the exact PNEC value,
ecotoxicological information such as acute chronic ratios should be eluci-
dated by performing detailed experiments on the ecotoxicity of these new
biocides.
3
Preliminary Risk Assessment
The predicted “no effect concentration” (PNEC) was tentatively estimated
from the lowest acute toxicity value by the OECD method. According to
OECD, the uncertainty factor of 100 was used to calculate PNEC. The values
of PNEC for several alternative biocides are shown in Table 5. The highest
seawater concentrations determined by individual survey are also shown in
Tab l e 5 .
As shown in Table 5, the PNEC of Irgarol 1051, M1, Sea Nine 211, ZnPT,
CuPT, and PK was 690 ng L
-1
, 16 ng L
-1
, 190 ng L
-1
, 27 ng L
-1
, 26 ng L
-1
,
22 ng L
-1
,and22 ng L
-1
, respectively. The PNEC of Chlorothalonil was two
orders of magnitude higher than the highest concentration found in natu-
ral waters. Although the available data on the Chlorothalonil concentration
in natural waters is very limited, these results suggest that its hazardous im-
pact on the aquatic environment is considered small. The PNECs of Irgarol
1051, M1, and Sea Nine 211 were one order magnitude lower than the con-
centrations of these biocides in the seawater of marinas. We are concerned
with these findings which suggest that Irgarol 1051, M1, and Sea Nine 211
are hazardous to the aquatic ecosystem especially in marinas and fishery har-
bors. The concentrations of Irgarol 1051, M1, and Sea Nine 211 in seawater
collected in coastal areas such as beaches were significantly lower when com-
pared to the PNEC values. The hazardous impact of these new biocides seems
to be restricted to particular areas such as marinas and fishery harbors where
many pleasure boats and
or fishing boats are moored.
Harino et al. [7] did not detect pyrithion compounds (ZnPT and CuPT)
in the seawater of the port of Osaka, Japan. Because of the results from the
port of Osaka it is assumed that any hazardous impacts from the pyrithion
compounds can be ignored at present. The toxicity of pyridine sulfonic acid,
which is a degradation product of ZnPT and CuPT was lower than that of the
parent compounds. These results suggest that the toxicity of ZnPT and CuPT
decreases during the degradation process.
Published data on the concentrations of PK have not been found. There-
fore, any potential hazardous impacts on the marine ecosystem from PK
cannot be evaluated at present and further studies are needed.
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