The environmental contaminants examined in this report can be classified into four groups – trace metals, chlorinated compounds, brominated flame retardants and perfluoroalkyl substances. Each of these contaminants has been examined in pike, perch and Arctic char from 32 lakes geographically spread from the north to the south of Sweden. The following summary examines overall trends, spatial and temporal, for the four groups.
Fat Content, Age and Length
Pike and perch displayed a decreasing trend in fat content at 50 % of the sites examined. An increasing trend in fat content could be seen for Arctic char from Lake Tjulträsk. The age of the perch sampled within the programme was somewhat lower in the most southern and south eastern parts of Sweden, whereas the length of the perch was homogenous in all lakes sampled.
No general temporal trend could be observed for mercury in the freshwater environment. However, in all lakes and species, except Arctic char from Abiskojaure, these concentrations are above the suggested EU-target level of 20 ng/g wet weight.
Lead is generally decreasing over the study period (in time series of sufficient length), supposedly due to the elimination of lead in gasoline. In all lakes, Pb concentration is below the suggested EU-target level of 1.0 ug/g wet weight. This result has to be interpreted carefully as the recalculation between levels of lead in whole-body and liver is based on only one study.
Cadmium concentrations show no consistent trends over the monitored period. It is worth noting that despite several measures taken to reduce discharges of cadmium, the most recent concentrations in Arctic char and pike are similar to concentrations measured 30 years ago in the longer time series. In a majority of the lakes, Cd concentration in perch is above the suggested EU target level of 0.16 ug/g wet weight. This result has to be interpreted carefully as the recalculation between levels of cadmium in whole-body and liver is based on only one study.
Nickel concentrations showed a general increasing trend in perch. Chromium concentrations showed a general decreasing trend in all matrices during the monitoring period,
but this decrease is most probably caused by the change of method for chromium analysis in 2004.
The concentrations of Zinc in perch liver are consistent in all lakes monitored. The concentrations are decreasing significantly at a majority of the perch sampling sites and in pike from Lake Storvindeln.
No general temporal trend were observed for copper, arsenic, silver, aluminium, tin, and bismuth concentrations in fish liver during the monitoring period.
Generally, a decreasing trend was observed for all compounds (DDT’s, PCB’s, HCH’s, HCB and PCDD/PCDF) in all species examined (with a few exceptions).
The chlorinated compounds generally show a somewhat higher concentration in the southern parts of Sweden than in the north.
CB-153 concentration is below the suggested target level of 1.6 ug/g lipid weight in all species and areas, while the target level for CB-118 of 0.024 ug/g lipid weight is exceeded in perch from Lake Fysingen and Lake Krankesjön. For DDE the concentration is below the suggested target level of 0.005 ug/g wet weight for all species and areas. sHCH is below the suggested target level of 0.026 ug/g wet weight for all species and areas. HCB is below the suggested target level of 0.010 ug/g wet weight for all species and areas. TCDD-eqvivalents is below the suggested target level of 3.5 pg WHO05-TEQ/g wet weight for all species and areas.
Brominated Flame Retardants
No general linear trend is observed during the whole monitoring period for the BDEs. However the concentrations of BDEs in Lake Bolmen increased from the start of the monitoring period until the late 80s to the mid 90s and appear to have decreased since then. The lower brominated flame retardants (BDE-47, BDE-99 and BDE-100) peaked earlier than the higher (BDE-153 and BDE-154).
In all areas, BDE-47 is above the suggested target level of 0.0085 ng/g wet weight for all species.
The concentration of HBCDD is under LOQ in a majority of the freshwater samples.
PFNA, PFDA, and PFUnDA all show significantly increasing concentrations in Arctic char liver from Lake Abiskojaure. PFDA, PFUnDA, PFDoDA, and PFTrDA show increasing trends in perch liver from Lake Skärgölen
. A decreasing trend in PFOS is also indicated for perch in Lake Skärgölen for the last ten years.
In about 40 % of the perch lakes, PFOS concentrations in liver are above the suggested target level for PFOS in
whole fish (9.1 ng/g wet weight). This result has to be interpreted with caution since no recalculation for the results from the liver analysis has been made, especially since liver in most cases contains higher concentrations of PFASs than muscle tissue.
Priority substances 2007 and 2010
For four of the five priority substances - DEHP, HCBD, pentachlorobenzene, and organotin compounds – all or most values were below LOQ in the years examined. The chloroalkane SCCP did have values above LOQ, however, no consistent spatial variation was seen. The highest concentrations of SCCP (approximately 30 ng/g wet weight) were found in Lake Stor-Backsjön in Jämtland County and in Lake Fiolen in Kronobergs County. No statistical difference in concentration of SCCP between year 2007 and 2010 was found.
Information about the lakes sampled within the programme can be seen in Appendix 1.
2013. , 221 p.