Pesticide Residues in Fish - Pesticides: Evaluation of Environmental Pollution - page 377

River (390.80 and 340.29 ng/g of gross mass). The maximum total content of DDT (270.70
ng/g of gross mass) was recorded in the brain of the dark plaice Pleuronectes obscurus
from Zapadnaya Bay and in the liver of the far eastern smooth flounder Pleuronectes
pinnifasciatus caught in Amursky Bay to the west of Skrebtsov Island (212.80 ng/g of
gross mass). The level of HCHs and DDT in mollusks and flounders from Zapadnaya
Bay was higher than that in the same species from Sivuchya Bay. The concentration of
OCPs in P. pinnifasciatus from the inner part of Amursky Bay at Skrebtsov Island was
higher than in individuals of that species from the open part of the Bay at Peschany
Pen. The DDT/DDE and DDT/∑DDT ratios evidenced the recent entry of DDT into
the ecosystem of Peter the Great Bay. The southwest part of Peter the Great Bay, from
the mouth of the Tumen River up to Furugelm Island, was contaminated by HCHs to
a greater extent than Amursky Bay. OCPs accumulated in appreciable quantities in the
organs of fish and mollusks of Peter the Great Bay, though their present content does
not exceed sanitary and hygienic standards, a subsequent monitoring of their concen-
trations in biota is necessary (Syasina 2003).
Many research activities have been carried out in China to investigate the OCPs in marine
organisms. The results showed that the fish and shellfish species in the Chinese coastal
zone are contaminated by OCPs. DDTs were at the top level. A recent report released in
Asian countries revealed that the contents of DDTs in the marine benthos along the coastal
areas of China were at the top level (Monirith et al. 2003). Results also showed that South
China is the most contaminated coastal sea among the major seas in China (Monirith et al.
2003; Chen et al. 1996, 2000, 2002; Fang et al. 2001; Phillips 1985; Tanabe et al. 1987). There
are possible reasons behind this observation. The coastal area of Guangdong province in
South China has 60,000 fishing ships, which is above 1/5 of the total number in China. It
can be estimated that about 30-60 tons of DDT may be introduced to the coastal environ-
ment of Guangdong, including the Pearl River Delta. According to Fu et al. (2003), the Pearl
River is believed to carry a considerable load of chlorinated pesticides, up to 863 tons per
annum, which is the highest among China's rivers. A high ratio of DDT/(DDD+DDE) in
sediment (Hong et al. 1995; Zhang 2001; Mai et al. 2002) as well as water (Zhou et al. 2001;
Luo et al. 2004) samples indicated the relatively recent releases of DDT (Zhang et al. 2002;
Luo et al. 2004; Zhou and Wong 2004; Chen et al. 2006). However, comparatively lower
levels of DDTs were found in marine organisms collected from the East coast. But the
survey of the National Bureau of Coastal Zone Protection during 1980-1987 showed that
the organochlorine flux just carried by Yangtze River (the longest river in China) was 239.3
tons per year, which accounted for 19.8% of the total flux by Chinese river catchments into
the marine coastal sites. Bohai Sea, Northern China, collects pollutants from major rivers,
namely Yalu, Daliao, Luan, and Yellow, and it showed comparatively intermediate levels
of DDT among the recent researches. Wu et al. (1999) noted high concentrations of DDTs
in the river sediments from Northern China where a factory with a high manufacturing
capacity of DDT is located.
Fish tissues from different fishery types (freshwater farmed, seawater farmed, and sea-
water wild) collected from the Pearl River Delta, China, showed significantly higher ∑OCP
levels in seawater-farmed fish than others, and among three freshwater-farmed species,
the lowest levels occurred in filter-feeding fish (bighead carp). Liver contained the highest
∑OCP levels, while no significant differences were found among other tissues. Among
DDT components, p,p′ - DDT was abundant in seawater fish, while for freshwater fish, p,p′ -
DDE was the predominant congener, except for northern snakehead (34% for p,p′-DDE and
30% for p,p′ - DDT). The new source of DDTs to freshwater fish ponds was partly attributed
to dicofol, whereas sewage discharged from the Pearl River Delta and antifouling paint