Chlorine acute toxicity

Wastewater. Phenol is a toxic poUutant to the waterways and has an acute toxicity (- 5 m g/L) to fish. Chlorination of water gives chlorophenols, which impart objectionable odor and taste at 0.01 mg/L. Biochemical degradation is most frequently used to treat wastewater containing phenol. Primary activated sludge, along with secondary biological treatment, reduces phenol content to below 0.1 mg/L (69). 

Toxicity. The acute toxicity of chlotinated paraffins has been tested ia a range of animals and was found to be very low (4). A comprehensive study (5) demonstrated that the toxicity of chlotinated paraffins was related to carbon chain length and to a lesser degree chlorine content. The shorter chain-length chlotinated paraffins were more toxic than the longer chain chlotinated paraffins. 

The acute toxicity of chlorinated paraffins to mammals, binds, and fish is very low (8), but over longer periods of exposure certain chlorinated paraffins have proved to be toxic to some aquatic species. However, the very low water solubility of chlorinated paraffins has made studies on aquatic species complicated. Laboratory experiments in which the chlorinated paraffins had been artificially solubilized showed only the short-chain grades to be toxic at low concentration other longer-chain grades showed no adverse effects on the majority of aquatic species tested. The degree of solubilization achieved in the laboratory is unlikely ever to be experienced in the environment and is of doubtful environmental relevance (9). 

Pesticides include the broad categories of insecticides, fungicides, rodenticides, and herbicides. Insecticides in common use fall into three categories. The chloroinsec-ticides have chlorine in their structure. They are less soluble than the other insecticide forms and much less biodegradable (i.e., more persistent). While they are less acutely toxic, several have been identified as potential carcinogens. Carbamatea are a relatively new form of pesticide. They are less persistent and less... 

Data on the bioavailability of PCDDs are limited. It is known that PCDDs incorporated into wood as a result of chlorophenol (preservative) treatment are bioavailable. Swine and poultry using chlorophenol-treated wooden pens or litter have been found to be contaminated with PCDDs (NRCC 1981). Toxicities of individual PCDD isomers can vary by a factor of 1000 to 10,000 for isomers as closely related as 2,3,7,8-TCDD and 1,2,3,8-TCDD, or 1,2,3,7,8-penta-CDD and 1,2,4,7,8-penta-CDD (Rappe 1984). Isomers with the highest biological activity and acute toxicity have four to six chlorine atoms, and all lateral (i.e., 2,3,7, and 8) positions substituted with chlorine. On this basis, the most toxic PCDD isomers are 2,3,7,8-TCDD, 1,2,3,7,8-penta-CDD, 1,2,3,6,7,8-hexa-CDD, 1,2,3,7,8,9-hexa-CDD, and 1,2,3,4,7,8-hexa-CDD (Rappe 1984). Ishizuka et al. (1998) have assigned toxic equivalencies for various PCDDs, with 2,3,7,8-TCDD given a value of 1 (highest biological activity), followed by a value of 0.5 for 1,2,3,7,8-penta-CDD a value of 0.1 for three PCDD isomers (1,2,3,4,7,8-hexa-CDD, 1,2,3,4,7,8-hexa-CDD, 1,2,3,7,8,9-hexa-CDD), a value of 0.01 for 1,2,3,4,6,7,8-hepta-CDD and a value of 0.001 for 1,2,3,4,6,7,8,9-octa-CDD. 

The halogenated hydrocarbons are generally of low acute toxicity, but several are associated with anesthetic effects and cardiac sensitization. Cardiac sensitization to halogenated alkanes appears related to the number of chlorine or fluorine substitutions. Halogenated alkanes in which >75% of the... 

McCarty LP, Flarmagan DC, Randall SA, et al. 1992. Acute toxicity in rats of chlorinated hydrocarbons given via the intratracheal route. Human Exper Toxicol 11 173-177. 

Bobra, A., Shiu, W. Y.. and Mackay. D. A predictive correlation for the acute toxicity of hydrocarbons and chlorinated hydrocarbons to the water flea. Chemosphere, 12(9-10) 1121-1129, 1983. 

Hattula, M.L., Wasenius, V.-M., Reunanen. H., and Arstila, A.U. Acute toxicity of some chlorinated phenols, catechols and cresols in trout, Bull. Environ. Contam. Toxicol, 26(3) 295-298, 1981. 

Palau-Casellas, A. and Hutchinson, T.H. Acute toxicity of chlorinated organic compounds to the embryos and larvae of the marine worm Fiatynersis rfumen/ii (Polychaete Nereidae), Environ. Toxicol Water Qual, 13(2) 149-155, 1998. 

Shi L, Xie C. 1999. Experimental observation on acute toxicity and irritative effect of stable chlorine dioxide. Zhongguo Xiaoduxue Zazhi 16(l) 39-40. 

There is a pronounced difference in biological and toxicological effects between different PCDD and PCDF isomers which is contradictory to the chemical and physical properties of these compounds discussed above. The isomers with the highest acute toxicity are 2,3,7,8-tetra-CDD, 1,2,3,7,8-penta-CDD, 1,2,3,, 7 8-, 1,2,3,6,7,8- and 1,2,3,7,8,9-hexa-CDD, 2,3,7,8-tetra-CDF, 1,2,3,7 8 and 2,3,, 7 8-penta-CDF and 2,3,U,6,7,8-hexa-CDF, see Figure 2. All these isomers have their four lateral positions substituted for chlorine, and they all have LD,-0 values in the range 1-100 yg/kg for the most sensitive animal species (15-17) The same isomers have been reported to have the highest biological potency (l8). 

The acute and/or chronic nature of the toxicity of a chemical should be part of any decision-making process about its use or subsequent release. The focus cannot be solely on reduction of acute hazards, which tends to be easily achievable. The majority of cases in which chemicals have been released into the environment, only to cause serious ecological impacts over large spatial scales, were usually identified after many years, and at chronic low-dose exposures, with low acute toxicity to nontarget organisms. The classic examples of DDT and other chlorinated pesticides such as dieldrin and toxaphene, along with PCBs, exemplify the flaws in an approach that focuses on acute hazards, with more recent examples being the perfluorinated... 

Other chlorinated dibenzodioxins show markedly varied toxicological properties. Thus 2,7-dichloro and octachloro derivatives have low acute toxicity whereas hexachloro derivatives are much more toxic. However, none are as toxic as TCDD itself (77MI22602). 

The acute toxic properties of the chlorinated hydrocarbon insecticides in humans are qualitatively similar. These agents interfere with inactivation of the sodium channel in excitable membranes and cause rapid repetitive firing in most neurons. Calcium ion transport is also inhibited. These events affect repolarization and enhance the excitability of neurons. The major effect is central nervous stimulation. With DDT, tremor may be the first manifestation, possibly continuing on to convulsions, whereas with the other compounds convulsions often appear as the first sign of intoxication. There is no specific treatment for the acute intoxicated state, management being symptomatic. 

In their acute toxic effects on the skin and liver PCBs resemble the chlorinated naphthalenes. Acute yellow atrophy is produced in the liver and enhanced in the presence of CHClj (synergism). Toxicity increases with increase in chlorine content of the PCB, and with oxide formation. Skin lesions (chloracne) consist of small pimples and dark pigmentation of exposed areas. Later comedones and pustules develop. With systemic intoxication, progressive symptoms are nausea, vomiting, weight loss, jaundice, edema, abdominal pain, and, where liver damage is severe, it is followed by coma and death (Sax, 3d ed., p. 551). 

Oxidizing agents TBA assessment of the acute toxicity of ozone, an alternative to chlorination to control biofouling in cooling water systems of power plants, to fish larvae of three species and to D. magna. F,F,F,I (Leynen et al., 1998)... 

Stahl BU, Kettrup A, Rozman K. 1992. Comparative toxicity of four chlorinated dibenzo-p-dioxins (CDDs) and their mixture. Part I Acute toxicity and toxic equivalency factors (TEFs). Arch Toxicol 66(7) 471-7. 

Weber LWD, Stahl BU, Rozman K. 1992c. Are serotonergic mechanisms involved in the acute toxicity of chlorinated dibenzo-p-dioxins (CDDs) Chemosphere 25 161-164. 

Gehring, P.J., Torkelson, T.R., Oyen, F. (1967) A comparison of the lethality of chlorinated pyridines and a study of the acute toxicity of 2-chloropyridine. Toxicol. Appl. Pharmacol. 11, 361-371. 

The long range or indirect effects have been most disturbing. The most widely used pesticides, the chlorinated hydrocarbons, are concentrated by living matter in the aquatic environment. An increasing buildup of the pesticide may occur in each link of the food chain. These effects may not be discovered for some time after initial contact, particularly if acute toxicity of the pesticide is low. Multiple contacts may increase the amount of the chemical accumulating in the animal tissues over the years. The amounts tolerated before noticeable effects vary with the particular animal species and the pesticide. Some species can tolerate larger amounts, but sooner or later are affected by decreased fertility, interference with normal food sources, and eventually death (29). The oyster is particularly efficient in its ability to concentrate chlorinated hydrocarbon pesticides. After seven days in water at 10 p.p.b. of DDT, eastern oysters were analyzed and found to contain 151 p.p.m. (parts per million) DDT (52). 

The PCBs have low acute toxicity, as shown by studies in experimental animals, but chronic exposure does seem to cause a number of toxic effects. The PCBs used commercially are often mixtures of compounds with various levels of chlorination. The greater the number of chlorines, the greater the toxicity. They are also often contaminated with other substances such as dibenzofurans, which are similar to dioxins and are... 

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