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Survey, emission and health assessment of chemical substances in baby products 4 Environment assessment
4.1.1 Hexabromocyclododecane (HBCD)Hexabromocyclododecane, CAS no. 25637-99-4, is not classified regarding to the environment. The proposed classification for the environment is N;R50/53 (EC Draft RAR 2003). This means that the substance is Dangerous to the environment, very toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment. Due to the use of HBCD and occurrence in products the environment will still be exposed through different productions and products. Hexabromocyclododecane (HBCD) is a brominated flame retardant that is extensively used especially in Europe. Additive flame retardants as HBCD, contrary to reactive flame retardants, are not chemically incorporated in the material. This implies that they rather easily can leak out of the material during the entire lifetime of the product, causing a diffuse contamination to the environment (Hutzinger and Thoma, 1987, Alaee and Wenning 2002; Remberger et al. 2004). HBCD has been found in environmental samples from different parts of the world, e.g. Japan (water, sediment and fish samples collected in 1987; Watanabe and Sakai, 2003), UK and the Netherlands (river sediment and sewage sludge; EC Draft RAR 2003) and Norway (cod; EC Draft RAR 2003). In Sweden, high levels of HBCD was found in river sediment and fish (pike) collected in 1995 (Sellström et al., 1998). HBCD has also been detected in Swedish air (Bergander et al., 1995), municipal sewage sludge (Nylund et al., 2002), and recently also in eggs collected in 1987-1999 from the wild populations of peregrine falcon (Falco peregrinus) breeding in Sweden (Lindberg et al., 2004). Furthermore, the substance was found in a variety of samples, including air, water, sediment and fish collected both close to point sources and in remote regions in the Swedish environment (Remberger et al., 2004). As is the case for many other persistent organic pollutants, the organisms in the Baltic Sea seem to be particularly at risk for HBCD exposure. The substance has been found in guillemot (Uria aalge) eggs collected at Stora Karlsö in the Baltic Sea proper from year 1969 to 2001, with concentrations approximately doubled during the study period (Sellström et al., 2003). More so, HBCD was the most abundant BRF in Baltic Sea herring (Clupea harengus), salmon (Salmo salar) and guillemot sampled in year 2000, while the levels in grey seal (Halichoerus grypu) muscle were at least as high as those of the major PBDE congener (BDE-47) (EC Draft RAR 2003). HBCD is a prioritised substance within the Programme of Existing Substances in the EU and the EU risk assessment draft is currently being prepared by the Swedish Chemical Inspectorate (EC Draft RAR 2003). HBCD is lipophilic, with a water solubility of 3.4 µg/l and log Kow 5.6 (EC Draft RAR 2003). Since HBCD is not readily biodegradable and has a high affinity to accumulate in biota (the bioconcentration factor for fish is determined to 18 100) (EC Draft RAR 2003) it is potentially harmful in the environment. Ecotoxicity data is available for a few species of phyto- and zooplankton in single-species tests (EC Draft RAR 2003). The concentration resulting in a 50% population growth reduction (EC50) in three marine microalgae was 9.3 µg/l for Skeletonema costatum, 50 µg/l for Thalassiosira pseudonana, while Chlorella sp. was not inhibited to 50% by as much as 1.5 mg/l of HBCD (Walsh et al., 1987). In an acute toxicity test for Daphnia magna the no observed effect concentration (NOEC) was determined to1 mg/l (EC Draft RAR 2003). However, in a life-cycle toxicity test with D. magna (21d), the toxicity of the substance was much higher, with LOEC (lowest observed effect concentration) determined to 5.6 µg/l (Drottar and Krueger, 1998). This kind of single species toxicity tests on plankton can give an idea of the range of concentrations where direct toxic effect may occur for specific aquatic organisms. A further step in the risk assessment, and in the understanding of the mechanisms behind change in the whole ecosystem, can be taken with model ecosystem experiments. In enclosures, often referred to as micro- or mesocosms, assemblages of organism groups (plankton communities in the present study) coexist and interact at conditions similar to those in natural ecosystems. There are many strong arguments in favour of model ecosystem studies, the most obvious being that they more closely represent the real world than single species laboratory tests do. The direct toxic effect can be determined on several species simultaneously, which is of great importance since even closely related species can differ significantly in toxic response towards a specific substance (see e.g. the algal toxicity data for HBCD presented above). In addition, secondary effects, i.e. the effect that direct toxicity on one species can have on connected species, can be assessed. Theoretically, secondary indirect effects could be detected at lower concentrations than primary toxic effects. A decrease in grazing capability by zooplankton due to direct toxic effect could, for instance, be detected as an increase in phytoplankton abundance at lower concentrations than what causes mortality (i.e. visible change) to the grazers. 4.1.1.1 Concluding remarksA quite recent founding has concluded that HBCD has the potential to induce profound changes in the composition of natural plankton communities at low (ppb) concentrations (Pirzadeh, P. Gustafsson, K and Woin P. 2004). Depending on the inherent properties, showing PBT risks, in combination with indications from recent independent research results (EC Draft RAR 2003, Gustafsson 2004), a general warning flag has to be hoist up. There seems to be high risks for both the environment and human health on the long term scale, and therefore, in agreement with the precautionary principle the substance could be considered undesirable. 4.1.2 Toluene 2,4-diisocyanate (TDI)Toluene 2,4-diisocyanate, CAS no. 584-84-9, is classified "R52/53" for the environment. This means that the substance is harmful to aquatic organisms and may cause long-term adverse effects in the aquatic environment. Due to the use of Toluene 2,4-diisocyanate and occurrence in products the environment will still be exposed through different productions and use of products. 4.1.3 2-Ethylhexanoic acid (2-EHA)2-Ethylhexanoic acid, CAS no. 149-57-5, is not classified regarding to the environment. 2-ethylhexanoic acid is marked in the N-CLASS database as N.C. (not classified as dangerous to the aquatic environment) assessed in 1995-96 but with the remark “no data found” (N-CLASS, 2005). 2-Ethylhexanoic acid is marked as WGK=1 (Weakly water polluting) in Germany (Iuclid, 2005). As Log Kow is 2.64-2.81 and the substance is more soluble in organic solvents than in water it would be relevant to consider BCF values if they were available. The available data on biodegradation is very limited and does not refer to the Standard OECD methods for ready biodegradability (Iuclid, 2005). The test result show that the lowest L/EC50 is about 40 mg/l (Iuclid, 2005 and US EPA, 2005). If 2-ethylhexanoic acid is not readily biodegradable, the substance would be in the range for R52/53. Due to the use of 2-ethylhexanoic acid as a stabiliser for PVC products and occurrence as a rest product from the PU production the environment will still be exposed through different productions and uses. 4.1.4 AcetophenoneAcetophenone, CAS no. 98-86-2, is not classified regarding to the environment. Log Kow is 1.58 and L/EC50 is above 100 mg/l (US EPA, 2005). Acetophenone is marked in the N-CLASS database as N.C. (not classified as dangerous to the aquatic environment) (N-CLASS, 2005). 4.1.5 FormaldehydeFormaldehyde, CAS no. 50-00-0 is not classified regarding to the environment. Formaldehyde is marked in the N-CLASS database as N.C. (not classified as dangerous to the aquatic environment) (N-CLASS, 2005). 4.1.6 1,1,2,2-Tetrachloroethane1,1,2,2-Tetrachloroethane, CAS no. 79-34-5, is classified "N;R51/53" for the environment. This means that the substance is toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment. The use of tetrachloroethane is decreasing, but due to its wide use and occurrence in products the environment will still be exposed through different productions and products. 4.1.7 StyreneStyrene, CAS no. 100-42-5, is currently not classified for the environment. Data on the acute toxicity values for fish, daphnia and algae all lie between 1 and 10 mg/l, which is the range for R51. Styrene is readily biodegradable but has a log Kow value of approximately 3, so it may accumulate in organisms. The available data leave styrene on the borderline for classification, but it is concluded that styrene will not accumulate in aquatic organisms and that R53 is therefore not appropriate. The proposal is that styrene is not classified as dangerous to the environment (EU Risk Assessment Report, 2000. Styrene). 4.1.8 2-Bromo-4,6-dinitro-benzenamine (BDNA)2-Bromo-4,6-dinitro-benzenamine, CAS no. 1817-73-8, is not classified regarding to the environment. Log Kow is 2.73. No data regarding environmental effects has been found for the substance. BDNA is used as a chemical intermediate for azo dyestuff production. The environment will be exposed through productions and use of mainly textile products. In a sediment-water system the reduction of BDNA and formation of 3-bromo-5-nitro-1,2-diaminobenzene among others was reported (Weber, E.J., Rebecca, L.A., 1995). The reduction of BDNA in natural sediments can result in subsequent release of potentially hazardous aromatic amines to the water column, which may affect the environment as well. 4.1.9 Hexaethylene glycol dimethyl etherHexaethylene glycol dimethyl ether, CAS no. 1072-40-8, is not classified regarding to the environment. No data regarding environmental effects has been found for the substance. 4.1.10 Tetrapropylene glycol monomethyl etherTetrapropylene glycol monomethyl ether, CAS no. 20324-34-9, is not classified regarding to the environment No data regarding environmental effects has been found for the substance. 4.2 Overall AssessmentThe classification of the substances regarding the environmental part is given in the Table 4.1 below. Table 4.1 Overview for environmental classification
N.C.: Not classified as dangerous to the aquatic environment (N-CLASS 2005). The three substances hexabromocyclododecane (HBCD), 1,1,2,2-tetrachloroethane and toluene 2,4-diisocyanate (TDI) are very toxic, toxic or harmful to aquatic organisms, respectively and may all cause long-term adverse effects in the aquatic environment. The discharge and exposure of these substances to the aquatic environment should therefore be reduced or prevented. Furthermore the possible environmental effects of the substances 2-ethylhexanoic acid (2-EHA), 2-bromo-4,6-dinitroaniline (BDNA), hexaethylene glycol dimethyl ether and tetrapropylene glycol monomethyl ether is not known due to lack of data. The discharge and exposure of these substances to the aquatic environment should therefore be minimized until the possible environmental effects are known. It may be assumed in general, that the direct waste water discharge of substances from the daily use and washing of these types of products, except for the washing cloths, is minor compared to other kinds of e.g. textiles, which are washed more regularly. The washing cloths contain 2-EHA among other substances, which may be discharged to the waste water system through continued use of new cloths (see table 2.5). As HBCD and the phthalates are substances with low vapour pressure and a high log Kow value, it is most likely that the majority of the content will remain in the products during the use time of their lifecycle unless the products come in contact with organic solvents or are heated to higher temperatures for longer periods. Nevertheless, the distribution of these substances to the environment will most likely proceed in small amounts as long as products contain these substances.
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