Classification of Biocides

Application of biocides is one the industrial routines around the globe. Despite biocides and their various brand names being known to many industrialists, there are still some misunderstandings about their synergy, application mechanism, and interaction with microorganisms in a system. Some of these matters will be mentioned later in this chapter. 

Despite the decrease in the number of SRB (whether culturable or identified by methods such as qPCR, there was the same lack of information for the same reason ), this time, another problem, but for the power plant, was created. This was the main cause of the power plant s legal complaint against the mine site All of the stainless steel parts of the power plant had started to corrode at very high rates, much higher than expected. The premature failure of these parts had been a matter of 

As the reader will have noticed, there are many gaps in the story, many unknowns. In addition to all the questions mentioned above, we did not know how much and what dosage regime of the biocide had been used Was it a shock treatment or a gradual treatment  

But we were lucky in understanding the biocide used. After a careful examination of the available data, we realized that the biocide used was an SRB-specific one and not a broad-spectrum one. Even worse, the mechanism by which the biocide was acting was via creating chlorides in the environment. These chloride ions, while useful in killing the bacteria, were also detrimental to the stainless steel s protective chromium oxide film. By reacting with this film, the chloride ions dissolve the film, and thus, stainless steel loses its corrosion resistance. 

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The new Directive describes biocides as chemical preparations containing one or more active substances that are intended to control harmful organisms by either chemical or biological, but by implication, not physical means. The classification of biocides is broken down into four main groups — disinfectants and general biocides, preservatives, pest control and other biocides and these are further broken down into 23 separate categories. 

We will concentrate only on the second criterion (effects) as it is a more convenient way of classification of biocides in industry. 

Interest in (5,5)-fused ring systems developed in separate, albeit closely related, directions. In the first, chemists continue their quest for new compounds having unique biological, chemical and physical properties. In the second, emphasis is on the classification of aromaticity based upon molecular conformity with Hiickel s rule. An increasing understanding of the fundamental chemistry of heterocyclic ring systems has led to considerable advances in this field, as evidenced by the growing list of applications as biocides and in industrial processes. 

To some extent, public institutions may be involved in hazard and risk assessments and decide on risk management, such as for (harmonised) classification and labelling of chemical substances, for authorisation of biocides and of plant protection products and for specific regulatory activities like bans or restrictions on the use of certain very hazardous chemicals. 

The first section of this chapter provides a discussion of hazard assessment, classification of potentially dangerous substances, and the process of risk assessment. A summary of the mandatory and voluntary initiatives for regulating chemicals and biocides in the United States and Europe is also included together with information on the regulatory aspects of hazard communication. The second section deals with the scientific aspects of hazard identification and risk assessment of carcinogenic chemicals within the regulatory context. 

Jensen J (1999) Terrestrial Hazard Classification of Toxic Substances A Study to Evaluate Specific Terrestrial Hazard Criteria Using Pesticide and Biocide Toxicity Data, ECBI/19/99 Add. 7. National Environment Research Institute, Silkeborg, Denmark EOOTPRINT (2008) The FOOTPRINT PESTICIDE PROPERTIES DATABASE, http //www.eu-footprint.org/ppdb.html. Accessed 17 Jan 2008 Belfroid AC, Van Drunen M, Beek MA, Schrap SM, Van Gestel CAM, Van Hattum B (1998) Sci Total Environ 222 167... 

Traditionally, biocides can be classified as electrophilic or membrane active. Research over the last 20 years has improved the understanding of biocidal mechanisms to yield additional classifications ... 

A classification by chemical type is given ia Table 1. It does not attempt to be either rigorous or complete. Clearly, some materials could appear ia more than one of these classifications, eg, polyethylene waxes [9002-88 ] can be classified ia both synthetic waxes and polyolefins, and fiuorosihcones ia sihcones and fiuoropolymers. The broad classes of release materials available are given ia the chemical class column, the principal types ia the chemical subdivision column, and one or two important selections ia the specific examples column. Many commercial products are difficult to place ia any classification scheme. Some are of proprietary composition and many are mixtures. For example, metallic soaps are often used ia combination with hydrocarbon waxes to produce finely dispersed suspensions. Many products also contain formulating aids such as solvents, emulsifiers, and biocides. 

Agricultural crops, effect of acidification, 52 Agricultural productivity, biocides-net productivity relationship, 307-308 Agricultural technologies, changes, 311,313 Airborne contaminants, description, 135 Airborne pollutant, definition, 135 Air pollutants, classifications, 66 Air pollution effects, 166,167r scope, 21-22 sources, 165-166 state, 4... 

The basic idea of the CLH process is the transfer of responsibility for classification and labeling from industrial companies to authorities on a European Community level. In case of active substances in biocidal or plant protection products, all intrinsic properties including physicochemical properties, human health hazards, and environmental hazards are subject to the harmonization. By contrast, in the case of chemicals which are used in other application fields only some specific hazard classes are considered in the CLH procedure. According to Article 36 of the CLP Regulation, these are respiratory sensitization, carcinogenicity, germ cell mutagenicity, and reproductive toxicity. Consequently, these provisions have... 

The difficulty of such a classification is that some biocides act in more than one way. A more usual classification involves listing as either oxidising or nonoxidising action. Tables 14.9 and 14.10 give some examples of the wide range of common biocides but there are other chemicals available as proprietory formulations. It is not feasible in a book of this kind, to describe all biocides and their action in detail but it is useful to discuss some of the more common chemicals as this provides a background to their use. 

A further strategy to prevent this classification is to use a CIT free system. Such options could include the use of BIT/MIT. Additionally use of bronopol or FD biocides help to enhance preservation of this combination. Such products include ACTICIDE MBS, ACTICIDE MBL, ACTICIDE MBF50 respectively. See Table 1 for details. 

Additionally the Biocidal Products Directive also contains provisions on temporary authorisation of products, data protection, research and development, confidentiality, classification, packaging and labelling, advertising and poison control. 

There are several ways of classifying biocides and antibiotics. The classification in this section is based on (a) the extent to which the microbes are killed and destroyed, (b) the scope or breadth of microbial action which the agents exhibit and (c) the one or more microbial functions that are disabled or attacked by the agent to exhibit static or -cidal activity. 

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