Molecular Cloning of CYP1A1 in the Rockfish (Sebastes schlegeli) and Effects of PCB on Its Gene Expression

Most studies on the interaction of environmental pollutants with fish hepatic cytochrome P450 have been focused on the induction of this enzyme system. There have been attempt to use the P450 level and ethoxyresorufin-O-deethylase (EROD) activity in fish as a biochemical markers to determine the extent of exposure to enzyme inducing chemicals (e.g. dioxins). However, It is suggest that CYP1A1 can be induced or inhibited by some xenobiotics such as polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs). Furthermore, relationship between chemicals structure or dosages and gene expression remains unclear. A cDNA library and cloned a partial CYP1A1 mRNA of rockfish, which is a commercially important marine species in Korea, was constructed to use them for monitoring studies. The deduced amino acid sequence of CYP1A1 mRNA showed a high homology to those of other fishes (81%). CYP1A1 mRNA transcript from hepatic tissue has been extracted for the northern blot analysis. Effects of PCB 153 and Aroclor 1260 on CYP 1A1 mRNA expression in vivo with juvenile rockfish were examined using the northern blot analysis. CYP 1A1 mRNA in the juvenile rockfish injected with 0.16 mM/kg of PCB 153 increased at 24 hrs and decreased at 72 hrs after injection. However, Aroclor 1260 showed difference in effects of gene expression. The expression level of CYP 1A1 mRNA decreased at all the time after injection in both dosages of Aroclor 1260. These results indicate that the expression of CYP 1A1 mRNA is different between single PCB species and PCB mixtures.1

황해의 지속성 유기오염물질과 중금속 오염

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Induction of imposex in rock shell, Thais clavigera, exposed to tributyltin and other antagonistic chemicals

Many endocrine disruptors (e.g. nonylphenol) are known as feminizing chemicals, while TBT as a masculinizing agent for gastropod. Actually, other feminizing chemicals as well as TBT exist together in the marine environment. In this study, interactions of both feminizing and masculinizing chemicals in inducing imposex in gastropod was investigated with a long term exposure experiment. Imposex-free rock shell (Thais clavigera) were exposed to TBT and other antagonistic chemicals (nonylphenol and DDT), P450 inducer (phenobarbital) and natural sex hormone (estrogen) mixtures for 60 days. None of imposexed-female were found in control, sham (ethanol) and testosterone exposure groups, on the other hand imposex was induced in the TBT exposure group and all the TBT + antagonist mixture groups. After 60-day exposure, frequency of imposex female ranged from 31 - 68%, and relative penis length index was 7.2 - 21.2%. Female mean penis length (FMPL) of imposexed-female ranged from 0.87 - 2.58 mm. However, the degree of imposex induction was different among the exposure groups. The FMPLs of three exposure groups (TBT + estrogen, TBT + DDT and TBT + nonylphenol) were less than that of TBT exposure group, while TBT + phenobarbital exposure group was higher. Ethoxyresorufin-O-deethylase (EROD) activities in gastropod decreased in the TBT and all the TBT + antagonist exposure groups compared to the contro groupl. A negative correlation was obtained between TBT body residue and EROD activity as well as degree of imposex in gastropod except for the TBT + DDT exposure group. Although TBT concentration was relatively high in the TBT + DDT exposure group, the TBT + DDT exposure group demonstrated low EROD activity and low degree of imposex. These results indicate that a certain antagonistic effect of DDT occurred in induction of imposex.1

TBT pollution and its impact on marine life in Korea

TBT-based antifouling paints were banned since March 2000 in Korea, though Korea needs large quantities of them for its shipping industry that is one of the largest in the world. Organotins were studied in the coast of Korea, in order to assess the exposure of marine organisms to butyl- and phenyltin compounds and to understand the toxic effects of these compounds to marine organisms. Butyltin compounds (BTs) were detected from the mussel and oyster samples collected from 67 sites on the coast of Korea, where phenyltin compounds (PTs) were below detection limits at 26 out of 67 sites. Overall range of tributyltin (TBT) and triphenyltin (TPT) concentrations were 48 to 2800 ng/g and <3 to 1820 ng/g, respectively. The mean TBT concentration in bivalves was 3.5 times higher than that of TPT.1

Towards better understanding of the effects of oil spill accident in Korea: Fingerprinting approach

Every year more than two million tons of petroleum hydrocarbons are introduced into the marine environment. The pollution of the marine, coastal and harbor environments by these products continues to be an issue around the globe. Since 1995 when super tanker Sea Prince spilled 5000 tons of crude oil into the south coast of Korea, full-scale environmental risk assessment of the oil spill accident has been initiated. Fingerprinting of spilled oil covering source identification and allocation has become essential research area. During developmental stages, only 16 or 24 kinds of PAHs were measured. Strict fingerprinting approaches comprised of several steps and requires a lot of chemical parameters. Recently full step fingerprint method were set up and applied to small scale spill accident. It revealed lots of case specific fingerprint and concluded that spilled and source oil were in probable match. Government has also given a lot of attention to oil pollution via enactment of legislation and supporting research projects. Ministry of Maritime and Fisheries (MOMAF) supports 10-year project which will set baseline for scientific risk assessment of oil spill accident. Now database for alkane and PAHs contents in crude and some of refined oil were made and baseline contamination status of area of concern were also integrated into database. Marine pollution act has compulsory articles which enforce survey of marine pollution impact caused by oil spill accident exceeding 50 kl spillage. Recently first survey according to that law was launched for T/V Jung Yang spill accident. This survey will cover natural environment, living environment and socio-economic fields, but the main focus will be on the fingerprint study.1

Fate of Alkylphenols, Chlorophenols and Bisphenol A in the Lake Shihwa, Korea

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Accumulation characteristics of organochlorines in marine species of Gwangyang Bay.

Gwangyang Bay is one of the highly industrialized bays of Korea. To assess the contamination and accumulation characteristics of organochlorine residues in Gwangyang Bay, benthic species were collected and analysed. Target species were clam, prawn, crab, sea-cumber, starfish, and flatfish. The overall concentrations of PCBs, DDTs, HCHs and CHLs in species were in the range of 74.7 - 345 ng/g lipid, 31.7-118 ng/g lipid, ND-32 ng/g lipid, and 8.59-20.9 ng/g lipid, respectively. Flatfish showed the highest concentrations of PCBs and organochlorine pesticides among target species. Other species showed similar concentration level each other. Organochlorine residues significantly correlated with lipid content (r2=0.52 ~ 0.71), indicating lipid content is the major factor for accumulation of organochlorines. Tri-, hexa- and hepta-CBs were the major PCBs ranging form 55% to 76% (68±8%). The homologue pattern in benthic biota was relatively highly chlorinated than those in sediment. DDE, β-HCH and γ-chlordane accounted for the large portion of DDTs, HCHs and CHLs, respectively.2

Application of pressurized liquid extraction in the GC-MS determination of sterols from sediment samples

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Seasonal and Spatial Distribution of Nonylpheol and IBP in Saemangeum Bay, Korea

In order to investigate spatial and temporal distribution of organic pollutants in the Saemangeum Bay, organophosphorus pesticides (10), alkylphenols (7), chlorophenols (2), bisphenol A were analyzed from the surface seawater taken in 2002-2003. Most of the analytes were not detected in all stations except nonylphenol and S-benzyl O,O-di-isopropyl phosphorothioate (IBP). Concentrations of nonylphenol and IBP ranged from ND to 298 ng/l and from ND to 1841 ng/l, respectively. The high levels of nonylphenol and IBP were found in the estuary areas of Mangyeong and Dongjin River. The levels of nonylphenol and IBP in surface seawater varied through seasons and the high levels of nonylphenol and IBP were in summer season (August). Based on real time monitoring of IBP and on correlation between concentrations of target compounds and contents of salinity in seawater, physical mixing and diffusion of seawater were found to be the major factors that affect the spatial distribution of IBP and nonylphenol in the Saemangeum Bay environment.1

Groundwater contamination by underground oil stockpiling facility

Underground oil storage cavern uses groundwater as a barrier for oil and oil-derived vapor leakage. And there exists concern for groundwater contamination. This study investigated status of polycyclic aromatic hydrocarbons (PAHs) contamination and tried to find out possible input sources of PAHs into the underground environment. Groundwater samples were taken from groundwater level monitoring wells and 16 EPA priority PAHs and alkylated PAHs were analyzed. Sum of 16 PAHs concentration ranged 0.04 ~ 7.29 ug/L with a mean of 0.63 ug/L, 0.05 ~ 0.37 ng/L with a mean of 0.16 ug/L, 0.01 ~ 1.75 ug/L with a mean of 0.68 ug/L in the groundwater samples from monitoring wells in the first, second and third cavern system, respectively. Though the third cavern is being built and does not contain any crude oil, PAHs levels in the third cavern are comparable with the results of the first cavern. Sum of alkylated PAHs (C1 ~ C4 naphthalene, C1 ~ C4 phenanthrene, C1 ~ C3 dibenzothiophene) ranged 0.04 ~ 10.6 ug/L with a mean of 1.21 ug/L, 0.03 ~ 2.9 ug/L with a mean of 0.76 ug/L, 1.26 ~ 99.8 ug/L with a mean of 20.1 ug/L in the first, second and third cavern system, respectively. Profiles of 24 PAHs provide first clue for the input sources. The first cavern was dominated by low molecular weight PAHs, while the third cavern by middle and high molecular weight PAHs and the second cavern showed mixed pattern of the first and the third. The difference between the first and other caverns were more distinct in alkyl homologue series pattern. PAHs chromatogram pattern of groundwater in the first storage cavern was compared with those of Dubai crude, major stockpiling oil, and untreated wastewater which contact crude oils. Due to the cracks and other structural defects, small amounts of water soluble fractions were supposed to be diffused into the surrounding underground environment. In case of the second and third cavern, drilling process unintentionally introduced cutting oils to groundwat1