Chlorinated alkenes in freshwater and marine water
Toxicant default guideline values for protecting aquatic ecosystems
Extracted from Section 8.3.7 ‘Detailed descriptions of chemicals’ of the ANZECC & ARMCANZ (2000) guidelines.
The default guideline values (previously known as ‘trigger values’) and associated information in this technical brief should be used in accordance with the detailed guidance provided in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality.
Description of chemical
Chlorinated ethylenes and propenes are low boiling volatile solvents. Chloroethylene (vinyl chloride) is used to manufacture PVC plastics, as a refrigerant, as an intermediate in organic synthesis in adhesives and previously as an aerosol propellant. It has a molecular weight of 62.5, low log Kow (0.6) and is soluble in water at 2700 mg/L (HSDB 1996).
Dichloroethylenes are soluble in water between 2.5 and 6.0 g/L, and their log Kow is around 1.5–2.5. The various isomers are used as solvents, especially for rubber, as copolymers for PVC, in synthetic fibres, lacquers, perfumes, and dyes. Trichloroethylene is used for degreasing, dry cleaning, wool scouring, gas purification, and as a refrigerant and a PVC chain terminator (HSDB 1996). It has a log Kow of 2.3 and is only slightly soluble in water (1.1 mg/L).
Dichloropropenes are used as soil fumigants and solvents. Their log Kow values are low (≤ 1.4) and water solubilities are 360 mg/L for 3-chloropropene and 2700-2800 mg/L for 1,3-dichloropropene.
Chloroethylenes are readily volatilised from water with T½ of 1-6 days (HSDB 1996). They are not hydrolysed readily, do not bioaccumulate and are not adsorbed to sediments. Photodegradation decreases with increasing chlorine substitution. Biodegradation is slow.
The toxicity data used for guideline derivation for chlorinated alkenes is detailed in Table 8.3.13 of the ANZECC & ARMCANZ (2000) guidelines. There were no chronic data available for chlorinated alkenes.
|CAS No.||Chloroethylene 75-01-4||Dichloroethylene (1,1) 75-35-4*||Trichloroethylene (1,1,2) 79-01-6||Tetrachloroethylene 127-18-4||3-chloropropene 107-05-1||1,3-dichloropropene
|Fish||–||–||–||5-18.5 (n=3)||20-51 (n=4)||0.24-6.8 (n=4)|
|Crustaceans||–||–||–||7.5-18 (n=1)||–||0.09-6.2 (n=1)|
|Other invertebrates||–||–||–||30.8 (n=1)||–||–|
|Algae/ciliates||520 (n=1)||–||–||–||3.2-4.1 (n=2)||–|
|TV Fresh Low reliability µg/L||100 (Q; SD)||700 (Q; SD)||330 (Q; SD)||70 (Q; SD)||3 (AF)||0.1 (AF)|
|Fish||–||250 (n=2)||3.1-58 (n=2)||3.5-5.5 (n=2)||–||1.8-3.3 (n=1)|
|Crustacean||–||224 (n=1)||–||–||–||0.79 (n=1)|
|TV Marine Low reliability µg/L||100 (f)||700 (f)||330 (f)||70 (f)||3 (f)||0.8 (AF)|
* different CAS Nos for different isomers, this refers to 1,1-isomer; Low = low reliability TV; Q=QSAR data used; AF = assessment factor used; SD = statistical distribution with 95% protection (recommended for slightly to moderately disturbed systems); f/m = fresh/marine TV adopted; 48-96-h LC50 data reported. Alternative protection levels (99%, 90% and 80% respectively) were: chloroethylene 70, 140 and 200 µg/L; dichloroethylene 500, 900 and 1300 µg/L; 1,1,2-TCE 220, 400 and 600 µg/L; TeCE 40, 100 and 150 µg/L.
Australian and New Zealand—toxicity data
No data were available.
Factors that modify toxicity
No data were available. Rapid loss by volatilisation and biodegradation is expected. See chlorinated ethenes.
Low reliability trigger values for the chloroethylenes were derived using the QSAR approach for chronic figures using either the statistical distribution method or applying an assessment factor (AF) of 10. These are listed in Table 8.3.13 of the ANZECC & ARMCANZ (2000) guidelines. They should only be used as indicative interim working levels. The quantitative structure activity relationship (QSAR) calculations for chloropropenes using the statistical distribution method gave chronic values near to or greater than measured acute LC50s and it was necessary to adopt a more protective value using the AF method.
ANZECC & ARMCANZ 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra.
HSDB (Hazardous Substances Data Bank) 1996. Micromedex Inc. 31 July 1996.