Mercury, cadmium, lead, and selenium in fish from a Norwegian fjord and off the coast, the importance of sampling locality.

Hepatic levels of mercury, cadmium, lead, and selenium and levels of mercury and selenium in muscle tissue were analysed in tusk from the Nordfjord in Norway. With the exception of selenium in the muscle tissue, the metal levels were significantly higher in the fjord fish than in fish caught off the coast. No local source is known to explain the difference in levels, and this indicates that the fjord efficiently accumulates atmospheric contaminants. The present results demonstrate the importance of sampling area when determining levels of metals in marine organisms far from point sources. The liver was increasingly used as a storage compartment for mercury and selenium with increasing exposure.

Sealworm (Pseudoterranova decipiens) infection in common seals (Phoca vitulina) and potential intermediate fish hosts from the outer Oslofjord.

Infection with Pseudoterranova decipiens in 45 common seals (Phoca vitulina) from the outer Oslofjord was investigated. Seals were collected before and during the phocine distemper virus epizootic in 1988 when the seal population in the area was reduced from about 350 to 100. In 1989, cod (Gadus morhua) and other fish species were sampled for comparison with earlier investigations on prevalence and abundance of P. decipiens infection in fishes from the outer Oslofjord. Seventy-two per cent of cod were infected with P. decipiens larvae in shallow waters between the seal skerries; the corresponding abundance was 2.2. At other fishing sites at increasing distances from the seal colony, abundance dropped to 0.05-0.20. Otoliths recovered from stomachs and scats indicated that gadids (Micromesistius poutassu, Trisopterus esmarkii and G. morhua) made up more than 80% of the seal diet. Bullrout (Myxocephalus scorpius) was also heavily infected with P. decipiens (prevalence 93% and abundance 8.4), but was not found in the seal diet. However, uninfected cod that enter shallow water from the surrounding deep waters became infected when they feed on bullrout. Recruitment to mature stock of P. decipiens occurs when highly infected cod are eaten by seals. The number of reproducing P. decipiens is very low in common seals. Only 2 seals (i.e. less than 5% of the sample) were simultaneously infected with mature worms of both sexes. The dramatic reduction of the seal stock in the outer Oslofjord by the epizootic did not seem to affect the abundance of P. decipiens in its intermediate hosts.

Mercury and selenium in arctic and coastal seals off the coast of Norway.

Mercury and selenium concentrations (wet weight) have been determined in samples of liver, kidney and brain of grey seal (Halichoerus grypus), harbour seal (Phoca vitulina), harp seal (Phoca groenlandica) and ringed seal (Phoca hispida) caught along the Norwegian coast, 114 individuals in all. Significant differences have been found in mercury contamination between the 4 species caught in the same coastal area, Jarfjord, located at the north-east of the Norwegian coast close to the Russian border. Very low hepatic mercury levels were found in the arctic species, ringed and harp seals, ranging from 0.20 to 0.67 and 0.04 to 1.0 microg g(-1), respectively, while in the coastal seal species the concentrations were 10 to 40 times higher. The corresponding ranges were 0.7 to 48.3 microg g(-1) in grey seals and 0.2 to 19.0 microg g(-1) in harbour seals. The median values were 13.5 and 0.7 microg g(-1), respectively. The highest levels were found in grey seals, indicating that particularly the stock frequenting the waters of the north-east coast of Norway and north-west coast of Russia had received a substantial mercury exposure. Fifty-five percent of these grey seals from Jarfjord had hepatic mercury levels above 10 microg g(-1) and 21% had levels above 20 microg g(-1). By a one-way analysis of covariance, sex and age were found to explain 28 and 30%, respectively, of the total variability in the mercury concentration in grey seal from Jarfjord. Significant differences in mercury concentrations were also found between stocks of harbour seals caught at different sites along the Norwegian coast, and decreasing concentration from the south to the north-east coast of Norway was revealed. The renal mercury levels in the arctic seals ranged from 0.08 to 0.45 microg g(-1), and about five times higher levels were found in grey seals and harbour seals. The mercury levels in the brain ranged from the detection level (0.01 microg g(-1)) to about 0.1 microg g(-1). The hepatic selenium levels in the arctic seal species ranged from 0.8 to 3.7 microg g(-1). The corresponding ranges in grey seals and harbour seals were 1.0 to 23.3 microg g(-1). The renal selenium levels were lower, and the levels in the brain were below the detection level (0.01 microg g(-1)). The mercury/selenium ratio was close to unity for mercury concentrations greater than 15 microg g(-1), and a nonlinear, concave relationship was found between the ratio of the hepatic mol concentrations of mercury and selenium and the hepatic mol concentrations of mercury.

Levels of environmental pollutants in male and female flounder (Platichthys flesus L.) and cod (Gadus morhua L.) caught during the year 1988 near or in the waterway of Glomma, the largest river of Norway. I. Polychlorinated biphenyls.

Levels of polychlorinated biphenyls, PCBs, in liver samples of 111 and 121 flounder (Platichthys flesus L.) and cod (Gadus morhua L.), respectively, were determined gas chromatographically by quantification of 9 individual PCB congeners. The congeners were 28, 52, 101, 118, 153, 138, 180, 170, and 209 (IUPAC numbering system, Ballschmiter and Zell 1980). The fish were caught during 1988 at 5 different stations near or in the Glomma estuary, in the Hvaler archipelago, Norway. The mean level of the sum of the congeners, 1,050 ng/g, found in cod was 3 times higher than the corresponding level found in flounder (361 ng/g). The influences on the variation in PCB levels of sex, season, and distance from the Glomma outlet and waterway were investigated using 1-, 2-, and 3-way ANOVA. The main effects of these factors as well as their possible interactions were considered. An expected decreasing PCB pollution gradient from the mouth of Glomma was found for cod, while PCB levels in flounder seemed to be less dependent on sampling site. However, the sexes in both fish species exhibited a different pattern in their PCB levels. The PCB levels in female cod were significantly affected by the season of sampling, with PCB levels in September/October significantly greater than the corresponding levels in June and November/December. No such effect was found for male cod. In flounder, a significant station effect on the PCB levels was found for females only, and a decreasing PCB pollution gradient was found to be significant. The interactions between the three factors station, season, and sex were different in the two species.(ABSTRACT TRUNCATED AT 250 WORDS)