| 1. |
- Lagerström, Maria, 1986-
(författare)
-
Occurrence and environmental risk assessment of antifouling paint biocides from leisure boats
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of biocidal antifouling (AF) paints is the most common way to prevent fouling on leisure boat hulls. The main aim of this thesis was to investigate the pathways through which AF biocides, past and present, may reach the environment through their use on leisure boats and to improve the risk assessment of biocidal AF paints intended for amateur use. The work presented focuses mainly on the Baltic Sea, with emphasis on regulation and risk assessment procedures in Sweden. A new method was developed for the quantification of nowadays banned organotin compounds (OTCs) such as tributyltin (TBT) in paint flakes (paper I). OTCs were detected in hull paint scrapings from three countries around the Baltic Sea. Thus, historic layers of organotin paint on leisure boats may constitute as sources of TBT to the marine environment. Total tin was identified as an indicator for the presence of OTCs on boat hulls, allowing for quicker identification of vessels in need of remediation. Nowadays, most AF paints tend to contain high amounts of copper (Cu) and zinc (Zn). The use of AF paints was shown to cause exceedance of guideline values for these two metals in soil, sediment and water in various investigated marinas (papers II and IV). The pollution of boatyard soil was linked to hull maintenance activities carried out over unprotected ground (paper II). AF paints were also found to impact both the concentration and speciation of dissolved Cu and Zn in two Baltic Sea marinas, with increased concentrations as well as an increased proportion of bioavailable species as a function of an increased number of moored boats (paper IV). A new method utilizing X-Ray Fluorescence (XRF) was used to derive the release rates of Cu and Zn in the field for five commercially available AF paints for amateur use (paper III). Salinity and paint properties were found to be important parameters affecting the release. The in situ release rates were also found to exceed those derived with current standardized release rate methods. Given the high release rates, none of the studied paints should have been approved for the Swedish market. This finding likely explains the exceedance of guideline values for dissolved Cu and Zn in investigated Baltic Sea marinas (paper IV). In conclusion, there is a need for caution when authorizing new biocides as the phasing out of banned substances can be a lengthy process due to their continued presence in historic paint layers. Additionally, paint-specific release rates determined under conditions reflecting the intended use of the product should be used for a more realistic environmental risk assessment of AF paints.
|
|
| 2. |
- Andrén, Cecilia M., 1964-
(författare)
-
Toxicity of Inorganic Aluminium in Humic Streams
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aluminium (Al) has been recognised as a main toxic factor alongside pH in acidified water ecosystems. The toxic effect of Al has been attributed to inorganic Al (Ali), though there are few in situ studies in ambient humic waters which are the focus of this thesis.The aim was to estimate Ali toxicity and thus also Ali concentrations in Swedish humic streams. Subsequently it is necessary to analyse Ali correctly, which was studied by modelling and method intercalibrations. The hypothesis was that the effect of Ali could be followed via physiological effects and Al accumulation, as well as by mortality. Toxicity was studied by in stream exposures of brown trout (Salmo trutta L.) and two salmonid prey organisms (Gammarus pulex and Baetis rhodani) during spring flood.The modelling of the Ali fraction was performed using monitoring data covering all of Sweden with satisfactory results. The essential variables for Ali modelling were determined; Al, DOC, pH and F, while Fe, Ca and Mg had less effect. The automated analytical procedure for Ali (with cation exchange followed by complexation with pyrocatechol violet) was modified and validated and showed to be the preferred method for laboratory analyses.To avoid detrimental effects for brown trout Ali should be <20 µg/L and pH >5.0; mortality was high when the Ali was above 50 µg/L. The invertebrates were more sensitive, as mortalities occurred at pH <6.0 and Ali >15 µg/L for G. pulex, and at pH <5.7 and Ali >20 µg/L for B. rhodani. It is prudent to use a wide view and let the most sensitive species set the tolerance limits; a pH above 5.7-6.0 and Ali below 15-20 µg/L allows the stream ecosystems to thrive.Today, as waters are recovering from acidification, the aim of mitigating liming is to carefully adjust dosage to avoid suboptimal water quality. The thresholds found in this thesis can be used to efficiently but carefully decrease liming, as both Ali and pH levels have to be balanced to sustain the recovering aquatic biota.
|
|
| 3. |
- Bighiu, Maria Alexandra, 1989-
(författare)
-
Use and environmental impact of antifouling paints in the Baltic Sea
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biocide-based antifouling (AF) paints are the most common method for preventing biofouling, i.e. the growth of algae, barnacles and other organisms on boat hulls. AF paints for leisure boats are predominantly based on copper (Cu) as the main biocide, with zinc (Zn) present as a pigment and stabilizer. Both metals are released from the paint matrix into the water column, leading to contamination of marinas which typically have only limited water exchange. Thus, the aim of this PhD thesis was to describe the use of AF paints in different regions in Sweden, as well as the associated environmental consequences with regard to contamination of the environment and toxicity to non-target aquatic snails. Using a recently developed X-ray fluorescence application, high levels of Cu were detected on boats moored in freshwaters, despite a more than 20-year-old ban, as well as high levels of tin (Sn) on 10 % of the boats, indicating the presence of (old) tributyltin paints (TBT), which might pose an environmental risk and a health hazard for people performing the paint scraping (paper 1). In addition, very high levels of Cu and Zn were measured in the biofouling material collected from the boat hulls, and this is problematic because the biofouling is commonly disposed of on the soil in boatyards at the end of each season. No difference was found in the amount of biofouling on boats coated with Cu or biocide-free paints, which implies that Cu might be currently overused in areas of low salinity and low barnacle density (paper 2). This work also introduces the use of a new species for ecotoxicological field experiments, the snail Theodoxus fluviatilis. Chronic field experiments (paper 3) revealed 6-fold increases in snail mortality, negative growth and up to 67-fold decreased reproduction in marinas, compared to areas not impacted by boating (‘reference areas’). Moreover, a higher prevalence of snails with histopathological alterations (e.g. necrosis of gills, gonads, midgut gland and parasite infestation, among others) was observed in the marinas, compared to the reference areas (paper 4). Statistical modelling indicated that the majority of the toxic effects were best predicted by the metals, most likely originating from AF paints. The results presented in this thesis depict some important aspects of AF paint use in brackish water and highlight the necessity of implementing a suitable management practice for the heavily contaminated biofouling waste in order to minimize the risk to soils. In addition, the evidence of toxicity to snails in marinas can be used as a basis to increase the public understanding of the impact of recreational boating and encourage people to choose less toxic alternatives to AF paints.
|
|
