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A Mackay level III distribution was calculated using the EPI Suite™ ver. 4.10 (US-EPA, 2008) for releases of methacrylic anhydride to air and water, but not soil, because there are no direct emissions to soil. The Mackay III calculations result in the following theoretical partitioning into the standard compartments.

Mackay level III Calculation (Evonik, 2013)

 

Substance

Air

(%)

Water

(%)

Soil

(%)

Sediment

(%)

Release to air

methacrylic anhydride

81.5

12.8

5.6

0.0

 

Substance

Air

(%)

Water

(%)

Soil

(%)

Sediment

(%)

Release to water

methacrylic anhydride

0.2

99.6

0.0

 0.2

If methacrylic anhydride is released to air, it preferentially stays in air and partitions to a lesser degree to water and soil. Partitioning to sediment is very low. When released to water, methacrylic anhydride tends to stay in the compartment where it was released.

Methacrylic anhydride has a low vapour pressure and a high water solubility and consequently a low Henry constant. Epiwin model calculations indicate a low volatilisation potential. In practice, volatilisation will even be lower, because in water the substance will rapidly hydrolyse and the hydrolysis product, methacrylic acid, dissociates and is not volatile.

Further studies do not need to be conducted as the substance is readily biodegradable (experimental result please see chapter 5.2.1.), With the hydrolysis product, methacrylic acid, 86 % biodegradation were obtained after 28 days. The 10-day criterion for ready biodegradability was met. (Huntingdon, 1992)