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1992 | Buch

Animal Biomarkers as Pollution Indicators

verfasst von: David Peakall

Verlag: Springer Netherlands

Buchreihe : Chapman & Hall Ecotoxicology Series

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Über dieses Buch

Ecotoxicology is a relatively new scientific discipline. Indeed, it might be argued that it is only during the last 5-10 years that it has come to merit being regarded as a true science, rather than a collection of procedures for protecting the environment through management and monitoring of pollutant discharges into the environment. The term 'ecotoxicology' was first coined in the late sixties by Prof. Truhaut, a toxicologist who had the vision to recognize the importance of investigating the fate and effects of chemicals in ecosystems. At that time, ecotoxicology was considered a sub-discipline of medical toxicology. Subsequently, several attempts have been made to portray ecotoxicology in a more realistic light. Notably, both F. Moriarty (1988) and F. Ramade (1987) emphasized in their books the broad basis of ecotoxicology, encompassing chemical and radiation effects on all components of ecosystems. In doing so, they and others have shifted concern from direct chemical toxicity to man, to the far more subtle effects that pollutant chemicals exert on natural biota. Such effects potentially threaten the existence of all life on Earth. Although I have identified the sixties as the era when ecotoxicology was first conceived as a coherent subject area, it is important to acknowledge that studies that would now be regarded as ecotoxicological are much older. Wherever people's ingenuity has led them to change the face of nature significantly, it has not escaped them that a number of biological con­ sequences, often unfavourable, ensue.

Inhaltsverzeichnis

Frontmatter
1. Scope and limitations of classical hazard assessment
Abstract
There is general agreement that hazard is a function of exposure and toxicity. In the simplest terms if there is no exposure there is no hazard and if there is no toxicity there is no hazard. To be accurate, there is no such thing as zero toxicity; as the 16th-century Swiss physician Bombastus von Hohenheim, better known by his boastful nickname Paracelsus, expressed it: ‘sola dosis facet veninum’. Furthermore the advances of analytical chemistry have made zero exposure rare. Nevertheless, despite these limitations and despite the disagreement of what the exact function of the relationship is, the concept that hazard = f[exposure.toxicity] is a useful one. Here I look at the two parts of the equation, first singly and then at the combination.
David Peakall
2. Biomarkers of the nervous system
Abstract
Two major classes of pesticides, the organophosphates (OPs) and carbamates, act directly on the nervous system via the inhibition of esterases. The most important of these is acetylcholinesterase (AChE) on which many studies, from detailed molecular biology to large-scale field studies, have been carried out. While the effects of OPs via Cholinesterase inhibition are transient, there are longer-term neurological effects mediated through the neurotoxic esterases (NTE). The effects of pollutants on biogenic amines, which act as neurotransmitters to the autonomic nervous system, have also been investigated, but here the focus has been on PHAHs and heavy metals.
David Peakall
3. Biomarkers of the reproductive system
Abstract
Much of the work of the effects of pollutants on the reproductive system has focused on the most sensitive life stage, for example, the OECD (Organization for Economic Cooperation and Development) early life cycle test in fish. Clearly this approach has merit in the testing of chemicals, as reproductive tests can be much more sensitive than those relying on acute mortality. A comparison of such data is given for heavy metals on fish in Table 3.1.
David Peakall
4. Studies on genetic material
Abstract
The fundamental role of DNA in the reproductive process is so well known that it is unnecessary to define it. Nevertheless, the endpoints used in assessing the damage to DNA by environmental pollutants are specific genotoxic effects, especially the increase of neoplastic disease, rather than effects on the reproductive process. For this reason effects of pollutants on genetic material are considered separately from reproductive effects.
David Peakall
5. Mixed function oxidases
Abstract
The haem-containing enzymes known as cytochromes are a major component of the defences of organisms against toxic chemicals in their environment. Originally evolved to handle naturally occurring toxic compounds, they now play an important role in the detoxification of man-made chemicals. Nebert et al. (1989) consider that the ancestral cytochrome gene is probably 2000 million years old. The major divergence occurred 800 to 1000 million years ago when animals began using plants as food, and self-defence mechanisms against toxins in plants evolved. Later, additional families of cytochromes evolved in response to the necessity to metabolize combustion products.
David Peakall
6. Thyroid function, retinols, haem and regulatory enzymes
Abstract
The specific function of the thyroid gland is to produce the thyroid hormones, thyroxine (T4) and triiodothyronine (T3), which convert plasma iodide to iodine. The overall regulatory mechanisms involved in thyroid hormone control are shown in Figure 6.1, and an outline of the metabolic pathway of the thyroid hormones is shown in Figure 6.2. In addition to providing T3 and T4, the thyroid gland is also the source of calcitonin, a polypeptide hormone involved in calcium homeostasis.
David Peakall
7. Behavioural effects: their relationship to physiological changes
Abstract
Twenty-five years ago, at a landmark symposium at the Institute for Terrestrial Ecology, the following statements on behavioural toxicology were made (Warner et al., 1966):
1.
The behaviour (or activities) of an organism represent the final integrated result of a diversity of biochemical and physiological processes. Thus, a single behavioural parameter is generally more comprehensive than a physiological or biochemical parameter.
 
2.
Behavioural patterns are known to be highly sensitive to changes in the steady state of an organism. This sensitivity is one of the key values for its use in exploring sublethal toxicity.
 
3.
Behavioural measurements can usually be made without direct physical harm to the organism. With aquatic animals especially, implantation of detectors introduces problems of considerable complexity. Behavioural measurements can avoid this difficulty.
 
David Peakall
8. Environmental immunotoxicology
Abstract
The central role played by the immune system is recognition; it recognizes self and discriminates against non-self elements. Non-self elements represent anything that is foreign and different from an individual’s own constituents. When non-self elements such as foreign cells, exogenous microorganisms (e.g. bacteria, viruses, fungi, parasites) and non-living substances (e.g. chemicals) invade the body, the immune system mounts a response in defence of the integrity of the body. The immune response can involve both humoral and cellular components.
Steve Wong, Michel Fournier, Daniel Coderre, Wanda Banska, Krzysztof Krzystyniak
9. The use of animals in wildlife toxicology
Abstract
Concerns over the use of animals in toxicological experiments are becoming an increasing force. Even non-extreme positions could, if passed into legislation, have considerable impact. It is, therefore, important to look at alternatives to animal testing and the availability of non-invasive techniques.
David Peakall
10. The role of biomarkers in environmental assessment
Abstract
Epidemiology can be defined as the study of the prevalence of disease in a community at a special time and which is produced by special causes not generally present in the affected community. Classical epidemiology has been reactive rather than proactive. The earliest examples, such as nervous disorders among makers of hats (‘mad as a hatter’) and cancer in chimney sweeps, were cases where an abnormally high incidence of disease was noted and traced back to a specific cause.
David Peakall
Backmatter
Metadaten
Titel
Animal Biomarkers as Pollution Indicators
verfasst von
David Peakall
Copyright-Jahr
1992
Verlag
Springer Netherlands
Electronic ISBN
978-94-011-2346-4
Print ISBN
978-94-010-5036-4
DOI
https://doi.org/10.1007/978-94-011-2346-4