Persistent organic pollutants animals

Verboven, N., Verreault, J., et al (2009) Nest temperature and parental behaviour of Arctic-breeding glaucous gulls exposed to persistent organic pollutants. Animal Behaviour, 77(2) 411 18. 

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 toxicity associated with polychlorinated hydrocarbons, including polychlorinated naphthalenes were recognized very early due to a variety of industrial accidents.75 However, the first evidences of bioaccumulation and toxicity on animals was noted in 1966 when emaciated seabird corpses with very high PCB body burdens washed up on beaches.74 Concern over the toxicity and persistence (chemical stability) of PCBs in the environment led the United States Congress to ban their domestic production in 1977, although some use continues in closed systems such as capacitors and transformers. PCBs are persistent organic pollutants and despite the production ban in the 1970s, they still persist in the environment and remain a focus of attention.76 Their use as fire retardants was discontinued when their toxicity was discovered. 

In the following sections, the physico-chemical properties and the bioconcentration of selected super-hydrophobic persistent organic pollutants (POPs) such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD),octachlorodibenzo-p-dio-xin (OCDD), Mirex, and Toxaphene in fish and other animals will be discussed. 

Many persistent organic pollutants (POPs) and other environmental contaminants have been associated with immunotoxic effects, but, in most instances, it remains difficult to assign the effects to pure compounds. For example, immunotoxic effects of PCBs in free-ranging harbor seals have been associated with increasing blubber concentrations of PCBsJ34 yet the waters inhabited by these animals are also contaminated with other POPs, including chlorinated pesticides and chlorinated polynuclear aromatic hydrocarbons. Indeed, the PCBs themselves are mixtures of different moieties with varying immunotoxic properties. 

Fig. 7.27 Bioaccumulation (a,c) and biomagnification (b,d) of persistent organic pollutants (POPs) with increasing trophic level (i.e. position occupied by a species in the food chain). Trophic level 2 animals are primary consumers (herbivores) while higher-level animals are carnivores.

Chemicals that persist (are slow to degrade), bioaccumulate in animals (collect in animal tissue, or organs), and are toxic to humans or animals are especially problematic because their concentrations in the environment increase overtime, increasing the opportunities for exerting their toxic effects. Chemicals with these properties of persistence (P), bioaccumulation potential (B), and toxicity (T) are known as PBTs.The Stockholm Convention on Persistent Organic Pollutants (POPs)— which is designed to phase-out very persistent, very bioaccumulative, and toxic chemicals— reflects the widespread recognition of the risks posed by PBTs (POPs are synonymous with PBTs). 

POPs have been observed to persist in the environment and spread out over long distances. POPs can accumulate in human and animal tissue and become part of the human food chain. POPs have potential significant impacts on human health and the environment. Persistent organic pollutants in the marine environment attach to plastic debris, which then are consumed by marine animals, many of which are in the human food chain. The plastic pellets and fragments can transport toxic substances in the marine environment to animals and ultimately to humans (Rios et al. 2(X)7). 

Fidalgo-Used et al. [137] have recently reviewed the main extraction and clean-up procedures, published in the last 5 years, applied to the analytical determination of both conventional and emerging persistent organic pollutants (POPs), not exclusively PAHs, in environmental biota (vegetal and animal) samples. Buldini et al. [339] have also reviewed recent sample preparation methods for food analysis. 

Clostridium perfringens is a gram-positive, obligate anaerobic spore-forming rod. It is widely distributed in the environment and frequently occurs in low numbers in the intestines of humans and domestic animals. Spores of the organism persist in soil, sediments, and areas subject to human or animal fecal pollution. Any raw food may contain spores or the bacteria. 

The popularity of chlorinated pesticides was based on some important properties, in fact most of these are extremely stable, show very low solubility in water, high solubility in organic media, and high toxicity to insects but low toxicity to humans. However, some of these properties are at the base of their hazardousness. Hazards associated with these pollutants are persistence in the environment, bioaccumulation potential in the tissues of animals and humans through the food chain, and the toxic properties for humans and wildlife. 

Environmental organic chemistry is a rapidly expanding subject and one that allows many perspectives. Environmental chemistry historically grew out of analytical chemistry and the ability of analytical chemists to detect very low concentrations of pollutants, especially chlorinated organic compounds, in complex matrices such as soils, atmospheric particles, and animal tissues. The discovery that such pollutants are transported throughout the world, and that some are highly persistent in the environment, led to increasing interest in the fates of such compounds in nature. 

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