Assessment, environmental protection fundamentals

The sufficient supply of pure water is of fundamental importance for achieving the goals of socio-economic development and environmental protection. Enhancing anthropogenic impacts on the environment are of concern here. For instance, the area of freshwater wetlands, which play an important role in natural water purification and in formation of the water cycle, have almost halved in the last 20 years. At the same time, economic assessment puts a value on their losses equivalent to 20,000/ha/yr. About 2% of 10,000 species of freshwater fish are either on the brink of extermination or are extinct. The number of large dams in the world increased front 5,000 in 1950 to more than 45,000 today, the negative ecological consequences of which need no comment. 

REACH aims to protect both the environment and human health from the industrial chemicals used in Europe, which refer to tens of thousands of substances. In this case, the ideal systems to be evaluated are human health and environment. However, the legislation defines a series of models, which can be used to assess the effects on these two major systems. Animal models are quite often mentioned, in case of toxicity studies and bioaccumulation. Examples of such models are models using rat and fish. Rat and mouse, typically, are used as models for human health, and fish is useful for environmental endpoints. However, it is well recognized that humans are different from rodents for a series of biochemical processes. To study carcinogenicity, for instance, a battery of tests is common, using rat and mouse, both male and female animals. Differences are often found in the different rodent experiments, and this highlights the problems in extrapolating results to humans. Still, in vivo experiments are a fundamental way to study toxicity. 

Accurate and precise identifications and measurements of specific chemical substances are fundamental to environmental studies and protection programs. Determinations are required to understand natural background concentrations of chemicals in the environment, the nature and extent of environmental pollution by anthropogenic chemicals, trends in concentrations of these substances, the transport and fate of chemical substances, and the causes of variations of concentrations intime and space. Accurate and precise determinations are also required to assess human health and ecological risks caused by exposure to natural and anthropogenic substances, establish air and water quality standards, develop pollution control strategies, evaluate the effectiveness of pollution prevention and treatment technologies, and monitor compliance with and the effectiveness... 

Currently, there are a limited number of chemicals classified as male reproductive toxicants. As scientific, public, and regulatory interest in this field increases, the result will most certainly be an increased knowledge base of the type and number of chemicals that can adversely affect the male reproductive tract. Once a chemical is considered a potential reproductive toxicant, there are measures in place to protect humans from occupational and environmental exposure. For example, when the results from a risk assessment indicate that the potential exists for adverse reproductive effects in humans, a regulatory agency such as the US EPA may impose restrictions on the availability or uses of certain compounds. Reproductive toxicity testing is fundamental to this type of risk-based decision-making, and will hopefully lead to the development of safer chemicals and drugs. 

While risk assessment in the context of protecting public health has been performed for many years, it is the 1983 U.S. National Academy of Sciences Report (Committee on the Institutional Means for Assessment of Risks to Public Health Commission on Life Sciences National Research Council 1983) that has served as the tenet for practicing risk assessors (see Chapter 1). Risk assessment was defined as the characterization of the potential adverse health effects of human exposures to environmental hazards. The predictive aspect of risk assessment was set by the use of the word potential. A fundamental expectation of the risk assessment process was that it should attempt to accm-ately predict adverse effects before there is evidence of disease in the population. Thus, risk assessment goes beyond the mere description of epidemiological and clinical case-control studies. In that report, the committee defined logical components of a risk assessment which still serve as guiding principles today. They were and are (a) hazard assessment or the qualitative determination that a stressor poses a hazard as evidence by causal evidence of an ill effect,... 

This step is of fundamental importance as it establishes the scope and direction of the overall assessment. It basically identifies the actual environmental values to be protected (assessment endpoints) and selects methods by which these can be measured and evaluated (measurement endpoints). 

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