Water chlorinated phenol contamination

Included in the first group of general industrial contaminants are all of the aromatic hydrocarbons (no. 12-31, see Table III], most of the phenolic compounds (no. 32-42), most of the chlorinated species (no. 43-54), and some industrial solvents (no. 85,88,89,95). Almost all of these compounds have been Isolated and identified in urban watersheds (2,25,26) where they appear to arise from automobile emissions, water chlorination, and general urban activities. 

Chlorination can result in unacceptable taste intensification, where potable water is concerned. This often originates in the chlorination of phenols present in trace amounts from industrial pollution. If economics permit, use of chlorine dioxide (Section 12.2) or ozone (Section 8.3) in place of chlorine will minimize taste intensification and will also avoid formation of carcinogenic chlorocarbons, notably chloroform. These carcinogens may form from chlorination of contaminants such as acetone, a commonly used solvent that finds its way into water supplies ... 

Valo, R., Kitunen, V., Salkinoja-Salonen, M. S. Raisanen, S. (1984). Chlorinated phenols as contaminants of soil and water in the vicinity of two Finnish sawmills. Chemosphere, 13, 835-44. 

Oikari, A., Anas, E. (1985) Chlorinated phenols and their conjugates in the bile of trout Salmo gairdneri) exposed to contaminated water. Bull. Environ. Contam. Toxicol. 35, 802-809. 

Chlorination of phenol is an example of electrophilic aromatic substitution phenol is so much more reactive than, let us say, benzene that no Lewis acid catalyst is required, and the reaction takes place rapidly even in aqueous solution. The odor-causing 2-, 2,4-, and 2,6-chlorinated phenols are among the by-products because phenol is chlorinated preferentially in the ortho- and para-positions. In cases where phenols are present in the water supply, the options are to use other disinfectants than chlorine, or to remove the contaminants by the use of activated charcoal as a water filter either in water treatment plant or in home ontlets (see below). 

Non-point sources of 2,4-dichlorophenol and 2,4,5-trichlorophenol are mainly agricultural, since the phenoxy herbicides are hydrolyzed back to the phenols with a lifetime of about a week near 20°C. A minor local source of chlorophenols is chlorination of raw drinking water, which is contaminated with phenol (see Chapter 10). The most important chlorinated phenol is the pentachloro congener. 

EXPOSURE ROUTES Primarily in water and wastewater ingestion(contaminated food) pesticides soil wood leather glue preservatives occupational exposure from production sources of chlorinated phenols or waste burners. 

Chlorinated phenols enter the aquatic environment as by-products of industrial processes, such as the production of antioxidants, dyes, and drugs. In drinking water they occur as a result of the chlorination of phenols, as by-products of reactions with phenolic acids, as biocides, or as degradation products of phenoxy herbicides and chlorinated bleaching of paper. CP concentration in drinking water usually does not exceed 1 pg L, which is the US EPA s maximum allowable contaminant level (MCL) for drinking water for pentachlorophenol, the only listed CP. ... 

The breakdown of organic contaminants present in the MU water to produce ammonia (from nitrogenous contaminants), phenols and carboxylic acids (from humic and fulvic acids), and tri-halomethanes (from the by-products of chlorination)... 

Chlorinated dibenzo ip-dioxins are contaminants of phenol-based pesticides and may enter the environment where they are subject to the action of sunlight. Rate measurements showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is more rapidly photolyzed in methanol than octachlorodi-benzo-p-dioxin. Initially TCDD yields 2,3,7-trichlorodiben-zo-p-dioxin, and subsequent reductive dechlorination is accompanied by ring fission. Pure dibenzo-p-dioxin gave polymeric material and some 2,2 -dihydroxybiphenyl on irradiation. Riboflavin-sensitized photolysis of the potential precursors of dioxins, 2,4-dichlorophenol and 2,4,5-trichloro-phenol, in water gave no detectable dioxins. The products identified were chlorinated phenoxyphenols and dihydroxy-biphenyls. In contrast, aqueous alkaline solutions of purified pentachlorophenol gave traces of octachlorodibenzo-p-dioxin on irradiation. 

There is a vast range of aqueous organic pollutants with a wide toxicity profile. Some, e.g. polychlorinated biphenyls, certain herbicides, fungicides and pesticides, and organo-mercury compounds, are persistent and may bioaccumulate in the food chain. Trace contaminants such as sodium chloride, iron and phenols (especially if chlorinated) may also impart a taste to water. Typical consent levels for industrial discharges are provided in Table 13.10. 

Trace contaminants such as sodium chloride, iron and phenols (especially if chlorinated) may also impart a characteristic taste if water is subsequently used for drinking purposes. 

A case control study of 6,913 individuals living near a Korean river contaminated with 30 tons of 100% phenol found nausea, vomiting, diarrhea, and abdominal pain among 1,824 exposed subjects compared to 1,064 unexposed subjects (Kim et al. 1994). The level of phenol measured in the two reservoirs that served the community was 0.05 mg/L after the spill, while that in the chlorinated tap water was... 

Dermal Effects. Skin rash and mouth sores were reported in persons living near a site with contaminated well water resulting from an overturned tanker car carrying 37,900 L of 100% phenol (Baker et al. 1978). The level of phenol in the drinking water of this cohort was >0.1 mg/L, and while substantial oral exposure probably occurred, dermal exposure cannot be ruled out. Increases in the prevalence of skin rashes and sore throats were reported by persons drinking water from a river contaminated by an accidental spill of phenol (Kim et al. 1994). Because the water was chlorinated before use, the effect may also have been a result of exposure to chlorophenol. 

Headaches were reported six times more frequently by persons using drinking water contaminated with phenol than by controls (Kim et al. 1994). The water was used after chlorination therefore, chlorophenol may have contributed to the observed effects. 

Constructed wetlands are commercially available through a number of vendors and have been used to treat water contaminated with acid mine drainage, explosives, hydrocarbons, chlorinated solvents, phenols, agricnltnral wastes, and sewage. The RIMS2000 database discusses constructed wetlands for the treatment of acid mine drainage in summary number T0179. 

Ozone reacts slowly with many types of water contaminants such as alicyclic taste or odor compounds, e. g. geosmin or THMs and unactivated aromatics such as chlorinated benzenes. Ozone will react faster with certain types of aromatic compounds, e. g. those carrying electron supplying substituents such as the hydroxyl group in phenol. If there is no... 

---