Description of chemicals 2-chlorophenol and 4-chlorophenol

The solubility of chlorophenols decreases with increasing chlorine substitution and decreasing pH.Pentachlorophenol (PCP) is readily soluble at pH 8 (20°C), with a solubility.Monochlorophenols (mono-CPs) are used as antiseptics, disinfectants, pharmaceuticals, and veterinary drugs, as chemical intermediates in the manufacture of higher chlorophenols, catechols, and dyes, and as soil fungicides.4-CP is used as a denaturant for alcohol.Of the 10 isomers of dichlorophenol, only 2,4-DCP is the most widely used to make the herbicide 2,4-D.Trichlorophene is used as a fungicide, disinfectant (such as hexachlorophene), fungicide, adhesive, preservative in textiles, rubber, and other materials, and in water treatment in cooling towers and paper mills. 2,4,5-TCP is also used in the manufacture together with PCP as a wood preservative.PCP is used as a biocide, disinfectant and insecticide/herbicide and is commonly used as a wood preservative to prevent fungal attack, such as in mushroom boxes and utility poles.It is also used in the processing of paints, leather and fabrics.The use of PCP is restricted in most countries including Australia and New Zealand (Hobbs and environmental concentrations should be reduced in many places.It is registered in Australia as an insecticide for the prevention of wood rot, borers, fungus and discoloration and for the interior treatment of boats and trailers.Chlorophenols are commonly found in chlorinated wastewater, including pulp mill wastewater (CCREM 1987) and sewage treatment plants.

2-chlorophenol 

Freshwater Cladocera:The NOEC (24 days) for reproductive damage in Daphnia magna was 300 µg/L.The 95% protection level (derived from acute data) is higher than this, and the 99% protection level is recommended for slightly to moderately disturbed systems.No ACR available, a default Acute to Chronic Ratio (ACR) of 10 is used.Even the 99% level is slightly higher than the chronic NOEC.If the user is concerned with similar species, the trigger value (99%) can be divided by a factor of 1.5 to obtain a value of 230 µg/L.In the absence of other data, this lower value is recommended for high protection systems.

4-chlorophenol

Freshwater fish:The NOEC for chronic growth and mortality in one species was 249 µg/L.Freshwater Crustaceans:Chronic NOEC (mortality) of 200 to 2600 µg/L in two cladocera (10-11 days) and 630 to 1600 µg/L in reproductive impairment in the same species. The lowest number was Ceriodaphnia dubia (10-day mortality), but other endpoints for this species were 1600-6000 µg/L.Although the available ACR is 5.74, a default ACR of 10 is used to protect these species from chronic toxicity.

2,4-Dichlorophenol

Freshwater fish:Chronic 85-day NOEC for rainbow trout growth was 179 µg/L (560 µg/L at 45 days) and mortality ranged from 99 µg/L (100 days) to 179 µg/L.Freshwater Crustaceans: Chronic 21-day NOEC (reproductive impairment) on D.magna, 210 µg/L.To provide adequate protection against D.magna and O.mykiss or equivalent species, a 99% protection level (120 µg/L) should be used in lightly to moderately disturbed systems.