A biocide is defined in the European legislation as a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. The US Environmental Protection Agency (EPA) uses a slightly different definition for biocides as "a diverse group of poisonous substances including preservatives, insecticides, disinfectants, and pesticides used for the control of organisms that are harmful to human or animal health or that cause damage to natural or manufactured products". When compared, the two definitions roughly imply the same, although the US EPA definition includes plant protection products and some veterinary medicines.
The terms "biocides" and "pesticides" are regularly interchanged, and often confused with "plant protection products". To clarify this, pesticides include both biocides and plant protection products, where the former refers to substances for non-food and feed purposes and the latter refers to substances for food and feed purposes. [1]
When discussing biocides a distinction should be made between the biocidal active substance and the biocidal product. The biocidal active substances are mostly chemical compounds, but can also be microorganisms (e.g. bacteria). Biocidal products contain one or more biocidal active substances and may contain other non-active co-formulants that ensure the effectiveness as well as the desired pH, viscosity, colour, odour, etc. of the final product. Biocidal products are available on the market for use by professional and/or non-professional consumers.
Although most of the biocidal active substances have a relative high toxicity, there are also examples of active substances with low toxicity, such as CO2, which exhibit their biocidal activity only under certain specific conditions such as in closed systems. In such cases, the biocidal product is the combination of the active substance and the device that ensures the intended biocidal activity, i.e. suffocation of rodents by CO2 in a closed system trap. Another example of biocidal products available to consumers are products impregnated with biocides (also called treated articles), such as clothes and wristbands impregnated with insecticides, socks impregnated with antibacterial substances etc.
Biocides are commonly used in medicine, agriculture, forestry, and industry. Biocidal substances and products are also employed as anti-fouling agents or disinfectants under other circumstances: chlorine, for example, is used as a short-life biocide in industrial water treatment but as a disinfectant in swimming pools. Many biocides are synthetic, but there are naturally occurring biocides classified as natural biocides, derived from, e.g., bacteria and plants. [2]
A biocide can be:
In Europe biocidal products are divided into different product types (PT), based on their intended use. These product types, 22 in total under the Biocidal Products Regulation (EU) 528/2012 (BPR), are grouped into four main groups, namely disinfectants, preservatives, pest control, and other biocidal products. For example, disinfectants contains products to be used for human hygiene (PT 1) and veterinary hygiene (PT 3), preservatives contains wood preservatives (PT 8), for pest control contains rodenticides (PT 14) and repellents and attractants (PT 19), while other biocidal products contains antifouling products (PT 21). It should noted that one active substance can be used in several product types, such as for example sulfuryl fluoride, which is approved for use as a wood preservative (PT 8) as well as an insecticide (PT 18).
Biocides can be added to other materials (typically liquids) to protect them against biological infestation and growth. For example, certain types of quaternary ammonium compounds (quats) are added to pool water or industrial water systems to act as an algicide, protecting the water from infestation and growth of algae. It is often impractical to store and use poisonous chlorine gas for water treatment, so alternative methods of adding chlorine are used. These include hypochlorite solutions, which gradually release chlorine into the water, and compounds like sodium dichloro-s-triazinetrione (dihydrate or anhydrous), sometimes referred to as "dichlor", and trichloro-s-triazinetrione, sometimes referred to as "trichlor". These compounds are stable while solids and may be used in powdered, granular, or tablet form. When added in small amounts to pool water or industrial water systems, the chlorine atoms hydrolyze from the rest of the molecule forming hypochlorous acid (HOCl) which acts as a general biocide killing germs, micro-organisms, algae, and so on. Halogenated hydantoin compounds are also used as biocides.
Because biocides are intended to kill living organisms, many biocidal products pose significant risk to human health and welfare. Great care is required when handling biocides and appropriate protective clothing and equipment should be used. The use of biocides can also have significant adverse effects on the natural environment. Anti-fouling paints, especially those utilising organic tin compounds such as TBT, have been shown to have severe and long-lasting impacts on marine eco-systems and such materials are now banned in many countries for commercial and recreational vessels (though sometimes still used for naval vessels). [3]
Disposal of used or unwanted biocides must be undertaken carefully to avoid serious and potentially long-lasting damage to the environment.
The classification of biocides in the BPR is broken down into 22 product types (i.e. application categories), with several comprising multiple subgroups: [4] [5]
MAIN GROUP 1: Disinfectants and general biocidal products
MAIN GROUP 2: Preservatives
MAIN GROUP 3: Pest control
MAIN GROUP 4: Other biocidal products
The EU regulatory framework for biocides has for years been defined by the Directive 98/8/EC, also known as the Biocidal Products Directive (BPD). The BPD was revoked by the Biocidal Products Regulation 528/2012 (BPR), which entered into force on 17 July 2012 with the application date of 1 September 2013. Several Technical Notes for Guidance (TNsG) have been developed to facilitate the implementation of the BPR and to assure a common understanding of its obligations. According to the EU legislation, biocidal products need authorisation to be placed or to remain on the market. Competent Authorities of the EU member states are responsible for assessing and approving the active substances contained in the biocides. The BPR follows some of the principles set previously under the REACH Regulation (Registration, Evaluation, Authorisation and Restrictions of Chemicals) and the coordination of the risk assessment process for both REACH and BPR are mandated to the European Chemicals Agency (ECHA), which assures the harmonization and integration of risk characterization methodologies between the two regulations.
The biocides legislation puts emphasis on making the Regulation compatible with the World Trade Organization (WTO) rules and requirements and with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), as well as with the OECD programme on testing methods. Exchange of information requires the use of the OECD harmonised templates implemented in IUCLID – the International Unified Chemical Information Data System (see ECHA and OECD websites). [6]
Many biocides in the US are regulated under the Federal Pesticide Law (FIFRA) and its subsequent amendments, although some fall under the Federal Food, Drugs and Cosmetic Act, which includes plant protection products (see websites below). In Europe, the plant protection products are placed on the market under another regulatory framework, managed by the European Food Safety Authority (EFSA).
Due to their intrinsic properties and patterns of use, biocides, such as rodenticides or insecticides, can cause adverse effects in humans, animals and the environment and should therefore be used with the utmost care. For example, the anticoagulants used for rodent control have caused toxicity in non-target species, such as predatory birds, due to their long half-life after ingestion by target species (i.e. rats and mice) and high toxicity to non-target species. Pyrethroids used as insecticides have been shown to cause unwanted effects in the environment, due to their unspecific toxic action, also causing toxic effects in non-target aquatic organisms.
In light of potential adverse effects, and to ensure a harmonised risk assessment and management, the EU regulatory framework for biocides has been established with the objective of ensuring a high level of protection of human and animal health and the environment. To this aim, it is required that risk assessment of biocidal products is carried out before they can be placed on the market. A central element in the risk assessment of the biocidal products are the utilization instructions that defines the dosage, application method and number of applications and thus the exposure of humans and the environment to the biocidal substance.
Humans may be exposed to biocidal products in different ways in both occupational and domestic settings. Many biocidal products are intended for industrial sectors or professional uses only, whereas other biocidal products are commonly available for private use by non-professional users. In addition, potential exposure of non-users of biocidal products (i.e. the general public) may occur indirectly via the environment, for example through drinking water, the food chain, as well as through atmospheric and residential exposure. Particular attention should be paid to the exposure of vulnerable sub-populations, such as the elderly, pregnant women, and children. Also pets and other domestic animals can be exposed indirectly following the application of biocidal products. Furthermore, exposure to biocides may vary in terms of route (inhalation, dermal contact, and ingestion) and pathway (food, drinking water, residential, occupational) of exposure, level, frequency and duration.
The environment can be exposed directly due to the outdoor use of biocides or as the result of indoor use followed by release to the sewage system after e.g. wet cleaning of a room in which a biocide is used. Upon this release a biocidal substance can pass a sewage treatment plant (STP) and, based on its physical chemical properties, partition to sewage sludge, which in turn can be used for soil amendments thereby releasing the substance into the soil compartment. Alternatively, the substance can remain in the water phase in the STP and subsequently end up in the water compartment such as surface water etc. Risk assessment for the environment focuses on protecting the environmental compartments (air, water and soil) by performing hazard assessments on key species, which represent the food chain within the specific compartment. Of special concern is a well functioning STP, which is elemental in many removal processes. The large variety in biocidal applications leads to complicated exposure scenarios that need to reflect the intended use and possible degradation pathways, in order to perform an accurate risk assessment for the environment. Further areas of concern are endocrine disruption, PBT-properties, secondary poisoning, and mixture toxicity.
Biocidal products are often composed of mixtures of one or more active substances together with co-formulants such as stabilisers, preservatives and colouring agents. Since these substances may act together to produce a combination effect, an assessment of the risk from each of these substances alone may underestimate the real risk from the product as a whole. Several concepts are available for predicting the effect of a mixture on the basis of known toxicities and concentrations of the single components. Approaches for mixture toxicity assessments for regulatory purposes typically advocate assumptions of additive effects;. [7] [8] This means that each substance in the mixture is assumed to contribute to a mixture effect in direct proportion to its concentration and potency. In a strict sense, the assumption is thereby that all substances act by the same mode or mechanism of action. Compared to other available assumptions, this concentration addition model (or dose addition model) can be used with commonly available (eco)toxicity data and effect data together with estimates of e.g. LC50, EC50, PNEC, AEL. Furthermore, assumptions of additive effects from any given mixture are generally considered as a more precautionary approach compared to other available predictive concepts.
The potential occurrence of synergistic effects presents a special case, and may occur for example when one substance increases the toxicity of another, e.g. if substance A inhibits the detoxification of substance B. Currently, predictive approaches cannot account for this phenomenon. Gaps in our knowledge of the modes of action of substances as well as circumstances under which such effects may occur (e.g. mixture composition, exposure concentrations, species and endpoints) often hamper predictive approaches. Indications that synergistic effects might occur in a product will warrant either a more precautionary approach, or product testing.chemical
As indicated above, the risk assessment of biocides in EU hinges for a large part by the development of specific emission scenario documents (ESDs) for each product type, which is essential for assessing its exposure of man and the environment. Such ESDs provide detailed scenarios to be used for an initial worse case exposure assessment and for subsequent refinements. ESDs are developed in close collaboration with the OECD Task Force on Biocides and the OECD Exposure Assessment Task Force and are publicly available from websites managed by the Joint Research Centre and OECD (see below). Once ESDs become available they are introduced in the European Union System for the Evaluation of Substances (EUSES), [9] an IT tool supporting the implementation of the risk assessment principles set in the Technical Guidance Document for the Risk Assessment of Biocides (TGD). [10] EUSES enables government authorities, research institutes and chemical companies to carry out rapid and efficient assessments of the general risks posed by substances to man and the environment.
Once a biocidal active substance is allowed onto the list of approved active substances, its specifications become a reference source of that active substance (so called 'reference active substance'). Thus, when an alternative source of that active substance appears (e.g. from a company that have not participated in the Review Programme of active substances) or when a change appears in the manufacturing location and/or manufacturing process of a reference active substance, then a technical equivalence between these different sources needs to be established with regard to the chemical composition and hazard profile. This is to check if the level of hazard posed to health and environment by the active substance from the secondary source is comparable to the initial assessed active substance.
It goes without saying that biocidal products must be used in an appropriate and controlled way. The amount utilized of an active substance should be minimized to that necessary to reach the desired effects thereby reducing the load on the environment and the linked potential adverse effects. In order to define the conditions of use and to ensure that the product fulfils its intended uses, efficacy assessments are carried out as an essential part of the risk assessment. Within the efficacy assessment the target organisms, the effective concentrations, including any thresholds or dependence of the effects on concentrations, the likely concentrations of the active substance used in the products, the mode of action, and the possible occurrence of resistance, cross resistance or tolerance is evaluated. [11] A product cannot be authorized if the desired effect cannot be reached at a dose without posing unacceptable risks to human health or the environment. Appropriate management strategies needs to be taken to avoid the buildup of (cross)resistance. Last but not least, other fundamental elements are the instructions of use, the risk management measures and the risk communication, which is under responsibility of the EU member states.
While biocides can have severe effects on human health and/or the environment, their benefits should not be overlooked. To provide some examples, without the above-mentioned rodenticides, crops and food stocks might be seriously affected by rodent activity, or diseases like Leptospirosis might be spread more easily, since rodents can be a vector for diseases. It is difficult to imagine hospitals, food industry premises without using disinfectants or using untreated wood for telephone poles. Another example of benefit is the fuel saving of antifouling substances applied to ships to prevent the buildup of biofilm and subsequent fouling organisms on the hulls which increase the drag during navigation.
Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others. The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. Most pesticides are used as plant protection products, which in general protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors. Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species.
Piperonyl butoxide (PBO) is a pale yellow to light brown liquid organic compound used as an adjuvant component of pesticide formulations for synergy. That is, despite having no pesticidal activity of its own, it enhances the potency of certain pesticides such as carbamates, pyrethrins, pyrethroids, and rotenone. It is a semisynthetic derivative of safrole and is produced from the condensation of the sodium salt of 2-(2-butoxyethoxy) ethanol and the chloromethyl derivative of hydrogenated safrole (dihydrosafrole). Although this route of synthesis has faced a lot of criticism in recent times. The new route of synthesis is through 1,2-Methylenedioxybenzene, developed by The Anthea Group and patented in 2019.
Bifenthrin is a pyrethroid insecticide. It is widely used against ant infestations.
Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. Specifically, it causes a blockage of the nicotinergic neuronal pathway. By blocking nicotinic acetylcholine receptors, imidacloprid prevents acetylcholine from transmitting impulses between nerves, resulting in the insect's paralysis and eventual death. It is effective on contact and via stomach action. Because imidacloprid binds much more strongly to insect neuron receptors than to mammal neuron receptors, this insecticide is more toxic to insects than to mammals.
Pentachlorophenol (PCP) is an organochlorine compound used as a pesticide and a disinfectant. First produced in the 1930s, it is marketed under many trade names. It can be found as pure PCP, or as the sodium salt of PCP, the latter of which dissolves easily in water. It can be biodegraded by some bacteria, including Sphingobium chlorophenolicum.
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is a United States federal law that set up the basic U.S. system of pesticide regulation to protect applicators, consumers, and the environment. It is administered and regulated by the United States Environmental Protection Agency (EPA) and the appropriate environmental agencies of the respective states. FIFRA has undergone several important amendments since its inception. A significant revision in 1972 by the Federal Environmental Pesticide Control Act (FEPCA) and several others have expanded EPA's present authority to oversee the sales and use of pesticides with emphasis on the preservation of human health and protection of the environment by "(1) strengthening the registration process by shifting the burden of proof to the chemical manufacturer, (2) enforcing compliance against banned and unregistered products, and (3) promulgating the regulatory framework missing from the original law".
The Principles of Good Laboratory Practice (GLP) establish rules and criteria for a quality system that oversees the organizational processes and conditions in which non-clinical health and environmental safety studies are planned, conducted, monitored, recorded, reported, and archived. These principles apply to the non-clinical safety testing of substances found in various products to ensure the quality and integrity of the safety data submitted to regulatory authorities globally.
The European Chemicals Agency is an agency of the European Union working for the safe use of chemicals. It manages the technical and administrative aspects of the implementation of the European Union regulation called Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). ECHA is the driving force among regulatory authorities in implementing the EU's chemicals legislation. ECHA has to ascertain that companies comply with the legislation, advances the safe use of chemicals, provides information on chemicals and addresses chemicals of concern. It is located in Helsinki, Finland. ECHA is an independent and mature regulatory agency established by REACH. It is not a subsidiary entity of the European Commission.
Icaridin, also known as picaridin, is an insect repellent which can be used directly on skin or clothing. It has broad efficacy against various arthropods such as mosquitos, ticks, gnats, flies and fleas, and is almost colorless and odorless. A study performed in 2010 showed that picaridin spray and cream at the 20% concentration provided 12 hours of protection against ticks. Unlike DEET, icaridin does not dissolve plastics, synthetics or sealants, is odorless and non-greasy and presents a lower risk of toxicity when used with sunscreen, as it may reduce skin absorption of both compounds.
The European Chemicals Bureau (ECB) was the focal point for the data and assessment procedure on dangerous chemicals within the European Union (EU). The ECB was located in Ispra, Italy, within the Joint Research Centre (JRC) of the European Commission. In 2008 the ECB completed its mandate. Some of its activities were taken over by the European Chemicals Agency (ECHA); others remained within the Joint Research Centre. The history of the ECB has been published as a JRC technical report.
Indoxacarb is an oxadiazine pesticide developed by DuPont that acts against lepidopteran larvae. It is marketed under the names Indoxacarb Technical Insecticide, Steward Insecticide and Avaunt Insecticide. It is also used as the active ingredient in the Syngenta line of commercial pesticides: Advion and Arilon.
Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has been used as a pesticide since the late 1700s. Clothianidin and other neonicotinoids act on the central nervous system of insects as an agonist of nAChR, the same receptor as acetylcholine, the neurotransmitter that stimulates and activating post-synaptic acetylcholine receptors but not inhibiting AChE. Clothianidin and other neonicotinoids were developed to last longer than nicotine, which is more toxic and which breaks down too quickly in the environment.
The Biocidal Products Directive (BPD) also known as the Biocides Directive is European Union Directive, (98/8/EC), which concerns biocides. It is officially known as Directive 98/8/EC of the European Parliament and of the Council of 16 February 1998 concerning the placing of biocidal products on the market. In 2013 the Biocidal Products Directive was superseded by The Biocidal Products Regulation.
Thiamethoxam is the ISO common name for a mixture of cis-trans isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing.
Chlormequat is an organic compound with the formula ClCH
2CH
2N(CH
3)+
3 that is used as a plant growth regulator. It is typically sold as the chloride salt, chlormequat chloride (C5H13Cl2N), a colorless hygroscopic crystalline substance that is soluble in water and ethanol. It is an alkylating agent and a quaternary ammonium salt. Chlormequat is one of the onium-type growth regulators.
Azamethiphos is an organothiophosphate insecticide. It is a veterinary drug used in Atlantic salmon fish farming along with other fish in the Salmonid family to control parasites, specifically sea lice. It is also used as an insecticide in biocidal products in Europe.
Powdered corn cob (PCC) is a rodenticide, marketed as a natural and environmentally-friendly alternative to anticoagulant types. The preparation was approved in July 2013 under the European Biocide Directive Program. It works by causing acute and ultimately lethal dehydration.
A pesticide, also called Plant Protection Product (PPP), which is a term used in regulatory documents, consists of several different components. The active ingredient in a pesticide is called “active substance” and these active substances either consist of chemicals or micro-organisms. The aims of these active substances are to specifically take action against organisms that are harmful to plants. In other words, active substances are the active components against pests and plant diseases.