Miljöriskbedömning av Braån - med avseende på den BT Kemi-typiska fenoxisyran MCPP

Sammanfattning: As things stand there are almost 24,500 risk classified contaminated sites in Sweden. One of the most well-known is the BT Kemi area in Scania. BT Kemi was an herbicide producing factory that in the 1970s buried a total of 1000 barrels containing toxic waste on their factory grounds. A few years later the toxins started to leach into soil and water. Today, 50 years later, the area is still polluted and toxic substances have spread to the adjacent river Braån. One of the BT Kemi toxins suggested to pose the biggest threat to Braån is the phenoxy acid MCPP. The present study presents an environmental risk assessment with the aim to closer account for which risks MCPP possess to Braån. Also, possible effects caused by MCPP on aquatic organisms are described. The study shows that current concentrations of MCPP in Braån are not high enough to pose any risk to aquatic organisms (RQ = 0,016). It is also shown that aquatic plants are the group of organisms that are most sensitive to MCPP. There is a possibility that the toxicity of MCPP increases in mixture with other impurities in the river. A lack of previous studies describing these kinds of effects motivates further investigations. Except from direct toxic effects consideration must be taken to that long-term exposure to pollutants can result in new characteristics of the organisms. Such adjustments may have led to that the organisms in Braån are not as successful as they were 50 years ago when it comes to characteristics such as reproduction and growth. Finally, accounting for the risks associated to a contaminated site can be a helpful tool. Since restoring of a contaminated area requires a lot of time and money an environmental risk assessment is helpful when deciding which area should be prioritized.