XRF-as a tool for monitoring of biocide load in boatyards : Case study on two boatyards in Lake Mälaren

Sammanfattning: The aim of this study was to assess the suitability of a special application to a Field Portable, handheld X-Ray Fluorescence (FPXRF) analyzer for monitoring of boatyards with focus on biocide load on boat hulls. In addition, the instrument was used for investigating the spatial distribution of contaminants in soil and sediments. Field activities on two boat yards in the lake Mälaren were done from April to October 2014. Lab analysis was finished in January 2015.I have found the FPXRF analyzer to be a quick, accurate and cost efficient tool for screening of contaminated boatyards. A major usage area is the detection of boat hulls with high levels of old biocide paint. The total levels of contaminants on every boat hull can easily be determined. This information can then be used when approving boats for different types of maintenance procedures or when selecting boats for decontamination activities. The FPXRF can also be used for detection of contaminated soil and sediments. The data can then be used in a risk assessment of the area and conclusions can be drawn on the need for remediation. The investigation of the two boatyards in the Lake Mälaren has shown that high levels of heavy metals are detected in boat hulls, soil and sediments often in par with what have been detected in other boatyards on the east and west coast of Sweden. This is a threat to the Lake Mälaren as it is a source for freshwater and an inland lake system where no biocide-based paints is allowed. Paint recommendations and regulations needs to be communicated to boat owners. To reduce toxic flows to sediments and water from the boatyards, existing hulls need to be tested for contamination and the hulls with the highest risk of releasing heavy metals decontaminated. Boat washers and other cleaning equipment must be made available at a reasonable cost and distance. Surface and ground water flows from contaminated areas needs to be directed and filtered through wetlands or other bio filters.