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Environmental fate & pathways

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C4 acrylate is an intermediate used as a monomer which is further polymerized into various polymer matrices in the manufacture of a variety of materials. It is a very reactive monomer and is rapidly polymerized in its uses. The facility that manufactures and uses unreacted C4 acrylate monomer contains ventilation to control worker exposure to vapors. All 3M manufacture and polymerisation of C4 acrylate in the EU will be at a location where multiple treatment technologies are applied in series to process wastewater. The final treatment stage incorporates granular activated carbon (GAC) filtration. Reduction of C4 acrylate to <2 ppb (the limit of quantification) in the effluent water after treatment has been shown. No direct release to surface water is expected. Solid waste from the manufacturing process and sewage sludge is incinerated. Indirect release to soil by application of sewage sludge will not occur. None of the uses of C4 acrylate result in direct release to soil.

C4 acrylate is semivolatile (vapor pressure of 0.25 Pa at 25 °C) and slightly soluble ( 2.02 mg/L at 22 °C). Solubility of C4 acrylate decreases with increased ionic content of the medium. A Henry's Law constant of 50 Pa*m³/mol at 25 °C, calculated within EUSES v.2.1.2, indicates a tendency to volatilize from aquatic systems or moist environments mitigated by a tendency to partition to suspended solids and dissolved organic matter (see Koc, below). A limited quantity of C4 acrylate is expected to be released directly to the atmosphere during manufacture and polymerization. The physical/chemical properties indicate that C4 acrylate released to the atmospheric compartment will be removed by dry deposition or wet deposition by means of wash out. The acrylate functionality of the C4 acrylate molecule will be subject to indirect phototransformation in the atmosphere, however the degradation products of photochemical reactions have not been assessed. Vapor-phase C4 acrylate is expected to degrade quickly in the atmospheric compartment, with a modeled half-life of 16.7 hours. Based on the limited quantity of C4 acrylate released directly to the atmosphere and rapid degradation, predicted environmental concentrations (PECs) in aquatic compartments are expected to remain well below the best-attainable limit of quantitation. PECs in soil and sediment compartments were below the predicted no-effect concentrations.

No biodegradation of C4 acrylate was observed in an OECD 301 B assay, indicating that biological transformation in the environment is expected to be slow or nonexistent. A measured abiotic hydrolysis half-life of 0.6049 years (221 days) at pH 7 and 25°C indicate that abiotic hydrolysis will not contribute significantly to fate in wastewater treatment systems. As noted above, no direct releases of C4 acrylate are expected to aquatic systems due to process controls.

C4 acrylate has an experimentally determined log Kow of 4.19 by a shake-flask method. It is therefore not bioaccumulative according to screening criteria in Technical Guidance Chapter R.11 on PBT Analysis. Further, little or no release of C4 acrylate as such to aquatic systems is expected, and direct and indirect exposure of the aquatic compartment is not expected. Therefore by column 2 of Annex IX bioconcentration need not be tested.

The log adsorption coefficient (log Koc) was estimated by an HPLC method, providing a value of log Koc = 4.03. This indicates that C4 acrylate would have a low mobility in soil and a tendency to bind to organic materials in soils, soils and sediments. However, as noted above, concentrations in the terrestrial compartment are expected to be less than predicted no-effect concentrations.

Summary: C4 acrylate will be polymerized in industrial applications. Operational conditions and risk management measures result in low expected release to the environment.