Environmental Engineering Reference
In-Depth Information
Thomas [1] listed eight of these new biocides as shown in Fig. 1,
namely 2,4,5,6-tetrachloro-isophthalonitrile (Chlorothalonil),
N
-dimethyl-
N
-phenylsulphamide (Dichlofluanid), 1-(3,4-dichlorophenyl)-3,3-dimethylu-
rea (Diuron), 2-methylthio-4-
t
-butylamino-6-cyclopropylamino-
s
-triazine
(Irgarol 1051), 4,5-dichloro-2-(n-octyl)-4-isothiazoline (Sea Nine 211),
2-(thiocyanomethylthio)benzothiazole (TCMTB), bis-(1-hydroxy-2(1H)-
pyridinethionate-O,S) zinc, (Zinc pyrithion, ZnPT), and zinc ethylene bis-
(dithiocarbamate) (Zineb). Pyridinetriphenylboron (PK) and bis-(1-hydroxy-
2(1H)-pyridinethionate-O,S) copper (Copper pyrithion, CuPT) are used in
Japan as new biocides [2].
Concentrations of Chlorothalonil [3, 4], Dichlofluanid [5], Diuron [6,
7], Irgarol 1051, [8-16] and Sea Nine 211 [5, 7, 17] were determined in
coastal waters including marinas and fishery harbors. The concentrations
of Chlorothalonil were very low. However, Dichlofluanid, Diuron, Irgarol
1051, and Sea Nine 211 were detected in seawater, and the concentrations
were higher in marinas and fishery harbors than in the coastal zones such
as the beach. Liu et al. [18] demonstrated that Irgarol 1051 is degraded
by the biological activities of white rot fungus,
Phanerachaete crysospo-
rium
,to2-methylthio-4-
t
-butylamino-6-amino-
s
-triazine (M1). Irgarol 1051
is also transferred to M1 by photolysis [19]. M1 is not degraded further by
P. c r y s o s p o r i u m
, and appeared to be accumulated as an end degradation prod-
uctintheaquaticenvironment.TheconcentrationofM1inseawaterwas
determined by Okamura et al. [14] and Liu et al. [15] in the Seto Inland Sea.
They reported that the M1 concentration tends to be higher than that of Ir-
garol 1051. These results suggest that M1 remains in the aquatic environment
much longer than Irgarol 1051.
Therefore, this paper summarizes details on ecotoxicity available in pub-
lished literature in order to estimate the harmful effects of the new biocides
and their degradation products on aquatic organisms. Furthermore, the risks
to the aquatic environment posed by these new biocides are also discussed.
2
Harmful Effects of the New Biocides on Aquatic Organisms
2.1
Chlorothalonil
Acute toxicity to
Daphnia magna
,
Onchorhynchus mykiss
,and
Gasterosteus
aculeatus
are summarized in Table 1. The 48 hEC
50
to
Daphnia magna
is in
the range of 0.097 to 0.129 mg L
-1
,andthe96 hLC
50
to fish species is in the
range of 0.069 to 0.076 mg L
-1
. Acute toxicities to crustacean and fish species
are significant, and are classified as “very toxic” by the OECD ecotoxicity clas-
sification guidelines [25].
