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DL-LACTONE CAS N°:79-50-5 - page 14 / 113

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OECD SIDS

DL-LACTONE

Ex osure time

Guideline

LC/EC50

Reliability

Reference

code

96 hours

OECD 203

>140 mg/L

1

Bogers, 1999a

48 hours

OECD 202

>130 mg/L

1

Migchielsen, 1999

72 hours

OECD 201

>78 mg/L

1

Bogers, 1999b

concentration decreased from 105 mg/L (t=0) to 45 mg/L (t=72). The EC50 for both algal growth and growth rate is >78 mg/L (time weight average concentration) ( Bogers, 1999b).

Table 3

Or anism

Results from aquatic toxicity studies

Cyprinus carpio

Daphnia magna

Selenastrum

capricornutum

Toxicity to Micro-organisms The toxicity towards micro-organisms was investigated in a study conducted according to OECD

  • 209.

    The EC50 for D-pantolactone (one of the two isomers in DL-lactone) was > 100 mg/L (BASF,

  • 2003)

    . This finding was confirmed by the findings in the biodegradation studies, where no toxicity

toward micro-organisms was observed.

4.2

Terrestrial Effects

No data available.

4.3

Other Environmental Effects

No data available.

4.4

Initial Assessment for the Environment

DL-Lactone is soluble in water and has a logKow of -0.69. Based on its pKa (>13) DL-lactone is most likely present in the unionised form under environmental conditions. The substance is expected to disappear from the aqueous environment via biodegradation (readily) and hydrolysis (t1/2 1 day to 1 year depending on the pH).

DL-Lactone does not bioaccumulate in fish and worms. The substance has an LC50 of >140 mg/L in fish, an EC50 >130 mg/L in daphnia’s and an EC50 >78 mg/L (nominal 100 mg/L) in algae. Based on data on the toxicity towards micro-organisms of the d-isomer, the EC50 for micro-organisms is >100 mg/L.

5 RECOMMENDATIONS DL-lactone is currently of low priority for further work

Human Health: The chemical possesses properties indicating a hazard for human health (skin and eye irritation). These hazards do not warrant further work as they are related to reversible effects. They should nevertheless be noted by chemical safety professionals and users.

Environment: The chemical is currently of low priority for further work because of its low hazard profile.

14

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