Press release 2011-05-27 at 12:00
Finnish Environment Institute and Evira
High concentrations of organic tin compounds used in antifouling paints are still being found in perch and pike-perch in the Vanhankaupunginlahti Bay. In addition high concentrations of perfluorinated compounds (PFCs) were detected in fish included in the EU Fish II project coordinated by Finnish Food Safety Authority Evira. Since these environmental toxins can be harmful to the health, at least perch caught in this area should not be consumed.
Over a long period of time, the Vanhankaupunginlahti Bay has been affected by high levels of contamination from manufacturing industry, local communities and boat traffic. An organic tin concentration of approximately 180ng/g fresh weight (fw) has been measured in perch. This is ten times the amount found in fish in open-sea areas. Similar levels were detected in an earlier study in 2005–2007. The total concentration of organic tin compounds in a perch's liver is around three times, and for pike-perch around seven times, the concentration found in its muscle. The fact that higher levels of disintegration products of tributyltin and triphenyltin (TBT/TPT) are found in liver than muscle indicates that fish actively remove OT compounds. In the longer term, it also suggests a reduction in concentrations of the substance.
In perch liver, concentrations of PFOS, the most common PFC compound, were 70–211 ng/g fw, high in comparison to the concentrations normally found in fish, approximately 1–20 ng/g fw. Even in polluted areas, concentrations are usually less than 100 ng/g fw. In perch muscle too, the concentration of PFOS was 16–49 ng/g fw, ten times that of fish generally in other areas of the Baltic Sea. For pike-perch, PFOS concentrations in muscle were less than 10 ng/g fw. However, this can still be considered an increase compared to concentrations in fish from the other areas included in the study. Little is yet known about the occurrence and bioaccumulation of PFC compounds. It is therefore possible that relevant compounds escaped analysis in the study.
TBT, globally used until 2003 in so-called antifouling paints that prevent organisms from settling on submerged hulls, and community waste water are the main sources of OT compounds. These compounds find their way into waste water from the plastic industry and dissolve from household plastic products and water pipes. OT compounds are not air-borne. They absorb into sediments, after which they are not easily released into water.
PFC compounds have a high tendency to persist in the environment. They are used in the finishing of metals, in extinguishing foam and as a flame retardant in hydraulic oil for aircraft. In addition, they are included in several consumer products. For instance teflon pans, carpets, furniture, cleaning detergents, clothes and food packaging may contain PFC compounds, which ultimately enter the food chain.
When the use of a chemical compound is restricted, there is a delay before a reduction appears in environmental concentrations. If the compound in question is persistent, decades will elapse before it is degraded or buried under ocean sediments. Generally, when the use of one compound ends, it is replaced with an alternative chemical substance. EU chemical regulations require that more attention be paid to ensuring that alternative substances are safe for the environment and humans.
More information
Senior Researcher Jaakko Mannio, SYKE, tel +358 400 148 604
Research Professor Anja Hallikainen, Evira, tel. +358 50 386 8433