Biocide toxic pollutants

Slimicide and biocide toxic pollutants containing pentachlorophenol are used at mills in the pulp, paper, and paperboard industry. Initially, pentachlorophenol was used as a replacement for heavy metal salts, particularly mercuric types. Trichlorophenols are also used because of their availability as a byproduct from the manufacture of certain herbicides. Formulations containing organo-bromides and organo-sulfur compounds are also being used. Substitution of alternative slimicide and biocide formulations can lead to the virtual elimination of pentachlorophenol and trichlorophenol from these sources. 

Best available technology economically achievable (BAT) guidelines for the control of nonconventional and toxic pollutants (trichlorophenol and pentachlorophenol, which are chemicals used as biocides)... 

Stewart, M.E., W.J. Blogoslawski, R.Y. Hsu, and G.R. Helz. 1979. By-products of oxidative biocides toxicity to oyster larvae. Marine Pollution Bulletin 10 166-169. 

Chlorinated micropoUutants are harmful for man and environment due to their toxicity, persistence, and bioaccumulation. Persistent compounds are very stable and difficult to get metabolized and mineralized by biological and chemical processes in the environment, and as a result, they have become ubiquitous in water, sediments, and the atmosphere bioaccumulation is the result of the lipophilicity of these compounds. Polychlorinated dibenzodioxins and -furans (PCDD/F) are not produced purposely like many of other chlorinated technical products, such as chlorinated biocides DDT, lindane, and toxaphene. The production and use of persistent organic pollutants (POPs), the dirty dozen has now been banned worldwide by the Stockholm protocol. It should be mentioned that about 3000 halogenated products have now been isolated as natural products in plants, microorganisms, and animals," but the total amount of these products is much smaller compared to xenobiotics. 

The effect of pH on transformation in the subsurface aqueous environment is considered here for the case of two highly toxic biocides (methyl parathion and acrolein) and for an industrial semivolatile organic pollutant (tribromoneopentyl-alchohol, or TBNPA). The examples are based on the work of Guo and Jans (2006), Oh et al. (2006) and Ezra et al. (2005). 

Karlsson and Eklund (2004) New biocide-free anti-fouling paints are toxic. Marine Pollution Bulletin 49 456-464. 

New EU directives may limit the development and application of new biocides and for this reason, and concerns on toxicity or pollution, there is interest in alternative water treatment techniques such as ultrasound, high-pressure vortexing and electro-coagulation. These may also be used where chemical treatment is not appropriate. ATP measurements are likely to prove useful to monitor the effectiveness of these types of treatment but as with chemical biocidal treatment the nature of the ATP results may depend on the mode of action. One type of electrochemical treatment has been evaluated in our laboratory. The results indicate that as with chemical biocide treatment the use of both Total and Free ATP measurements can be of value in the interpretation of the results, monitoring the process efficacy and in optimisation of this method of water treatment. 

Various incidents of pollution have been reported from industrial waste, effluents from sewage treatment plants, food processing plants along with biocides and toxic effluents from sawmills and timber processing areas. These effects are often enhanced by disposal of hazardous wastes in municipal landfills. 

Sometimes the need to be environmentally acceptable may lead to new problems. For instance, ozone was suggested to replace biocides with no data available on the performance in the chlorination of water (60). Corrosion control techniques can have both favorable as well as ill effects and hence one has to exert balanced judgment before embarking on a corrosion prevention method. Organotin antifouling coatings on ships were effective, but they polluted the seawater and hence were banned from further use. The use of cadmium as a sacrificial anode is restricted because of its toxicity. Large amounts of zinc are used to protect steel platforms in the sheltered and shallow waters of the sea, and the effects of zinc on the contamination of waters are not known. 

Kwok, KW.H. and Leung, K.M.H. (2005) Toxicity of antifouling biocides to the intertidal harpacticoid copepod Trigriopus japonicus (Crustacea, Copepoda) effects of temperature and salinity. Mar. Pollut. Bull. 51, 830-837... 

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