Chapter 1: General Aspects – Current and Future Perspectives

By definition, it is accepted worldwide that environmental risk assessment is a scientific practice that identifies and evaluates the likelihood of an activity or substance to threaten the environment in general, and/or living organisms, natural habitats and ecosystems, in particular. In other words, it is a term used to describe the overall process or method allowing (a) the identification of hazards and risk factors that have the potential to cause harm (hazard identification) and (b) the analysis and evaluation of the risk associated with that particular hazard (risk analysis and risk evaluation). It also suggests all the appropriate ways to eliminate or minimize the hazard, or control the risk when the hazard cannot be eliminated (risk control).

The Food and Agriculture Organization of the United Nations (FAO) predicted a few years ago that the global population will be over 9.1 billion by the middle of the 21st century. Accordingly, food production will have to increase by about 70% above current levels to maintain pace with demand. One plausible method for achieving this target would be to increase yields and the amount of arable land. However, the conversion of natural forests and/or other wild habitats engenders a number of well-known negative impacts on climate change and global biodiversity. Furthermore, it is accepted worldwide that such an expansion of agriculture could be responsible for approximately 12% of global warming. Several anthropogenic activities introduce extensive amounts of chemicals and pollutants into the environment on a daily basis. In this sense, the use of fossil fuels, mining, manufacturing and construction industries, among others, are the main contributors to water, air and soil pollution. Increases in improper disposal of waste, chemicals, heavy usage of air-polluting equipment and machinery, asbestos handling, soil contamination and industrial noise need to be factored for in this regard. Even our clothes, in many cases composed of artificial fibres that do not naturally degrade, when thrown away, or sent to some far-away country, as a sort of “help”, find their way to landfills. In some cases these are located close to the sea shores and eventually end up polluting the oceans. To this, we must add overfishing and overexploitation of marine resources, among others.

Most of the xenobiotics in the different environmental compartments exert their effects through cytotoxicity and genotoxicity, and by interfering with metabolic pathways. Accordingly, current awareness of the real/potential hazards of pollutants in the environment has a high interest in the use of terrestrial invertebrate and vertebrate species as indicators for monitoring pollutant-induced environmental deleterious effects. Notwithstanding, it is known that agrochemicals, among others, not only affect target organisms but concomitantly exert negative effects on non-target species.

In environmental risk assessment studies, there is an increasing interest in biomonitoring markers to provide practical indicators of biological exposure to pollutants. To achieve this goal, several endpoints for testing toxicity have been developed. Cyto- and genotoxicity have been employed on aquatic and terrestrial organisms to assess the impact of pollution on contaminated areas (in situ assays) and for screening xenobiotics after direct or indirect exposure (in vivo assays).

This book covers many non-traditional marsupial and placental mammalian species models employed to analyse the jeopardising effects of environmental pollutants, as well as examples of applications of models in integrated assessment solutions. We also hope it will provide answers or at least provide some clues to the inherent potential risk of the presence of these xenobiotics in our environment. To achieve this goal, a consideration of exposure, hazard, risk, mitigation, as well as short- and long-term monitoring is required. This information will give all interested parties, among them, regulators and safety adviser bodies, the tools needed for a better understanding of the matter in a broader context.

Many important ecosystems around the world are being constantly challenged due to growing human and industrial pressure exerted upon them. More than one million animals and plants are facing an unprecedented pattern of extinction. We are experiencing the largest biological disappearance wave since the extinction of the dinosaurs and humans could be the main cause of this massive extinction.

The use of various biomarkers in local, easily available species can be of use to evaluate the response of the biota to such pollutants. Several biological parameters mirror the interactions between toxic agents and biotic matrices. These are powerful tools that can be applied to environmental monitoring tests and studies. Their responses may reveal general deleterious effects to the organism in general, pinpointing alterations at the cellular, biochemical and molecular levels, as well as higher levels of organization.

The health of our planet and its ecosystems has deteriorated severely. There is no question about this statement. Mankind has reached for the first time in history, an unprecedented level of food security and availability of consumer goods. Unfortunately, this comes with a price tag. The different geographical areas, species and substances studied show that no region, even if far away from polluting centres, is spared from this unfortunate phenomenon. We hope that the contributions of this book will stimulate further work along these lines, while at the same time raising several flags. As scientists we have an obligation to present evidence of the damage that our planet, Earth, is being subject to. A transversal approach is needed, even in matters that do not seem unrelated, but in reality are. An example of this is light pollution in populated areas which disrupts the normal behaviour of birds and insects, altering their feeding habits and the pollination role they play in the ecosystem. This information, in turn, will help launch the debate at a civil society level, to change many of its consumer patterns, press producers and manufacturers, while at the same time demanding more stringent action on behalf of politicians and law makers to protect this planet, our home, before it's too late.

Our global society needs to table down actions and set rules to evaluate and considerably reduce the real and potentially hazardous factors in the environment that can, as previously stated, result in health risks for all forms of life (including Homo sapiens sapiens). Despite major positive contributions in the field of health, due to the immense progress achieved in science, technology and industrialization, the interaction between environmental risk and health is an often intricate equation, not self-evident, that involves a variety of not only social, political and economic but also lifestyle factors. This cannot be emphasized enough. Health depends on the good quality of environmental “basic ingredients”, such as air, water, soil and food, among others. We believe that the ultimate challenge in this matter is to weigh-in short-term positive gains, while, at the same time, taking into account long-term effects of substances used. Available information about the toxic effects of heterogeneous xenobiotics, continuously released into human habitats, inadvertently, deliberately or by non-regulated industrial discharges on biological components of the environment, is inconclusive.

There is no clear-cut definition of the concept of environmental health. Various openings help us in the understanding of this concept. According to the World Health Organization (WHO), it is defined by “all the physical, chemical and biological factors external to a person and all the related factors impacting upon behaviours. It encompasses the assessment and control of those environmental factors that can potentially affect health. It is targeted towards preventing disease and creating health-supportive environments…”. For the National Environmental Health Association, this concept refers to “the protection against environmental factors that may adversely impact human health or the ecological balances essential to long-term human health and environmental quality, whether in the natural or man-made environment”. A third definition by the National Institute of Environmental Health Science also involves the criterion that “the social environment encompasses lifestyle factors like diet and exercise, socioeconomic status, and other societal influences that may affect health”.

In general terms, our health and the health of many other species are negatively affected by five broad categories of environmental hazards, namely, electromagnetic fields (produced by high-power lines, electrical wiring, appliances, mobile phones, computers, and TV sets, etc.), radiation (including nuclear fallout from weapons testing, fission materials from nuclear power plants and their respective accidents, leaking radioactive disposal sites, air travel and X-rays), toxic chemicals (some organochlorines, phthalates, polybrominated flame retardants, perfluorinated substances, bisphenol-A) and several toxic metals, among others, which have been shown to have endocrine-disrupting properties, and soil mineral depletion as a complex environmental hazard.

By definition, health risk assessment in its quantitative and/or qualitative determinations includes variants such as the type of risk involved and the severity of response, within or without a probabilistic context. In this regard, risk-based methods of analysis play a strategic role in identifying and ranking adverse responses or the structure of the effects of exposure vis-à-vis environmental factors.

Many compounds can be hazardous if not used appropriately and may present a real risk to the environment by contaminating soil, water and air. Most of the pollutants in the different environmental compartments exert their effects through cytotoxic, genotoxic and metabolically toxic mechanisms. In pollution studies, there is an increasing interest in biomonitoring markers of biological exposure to pollutants. To achieve this goal, several end-points for the three above-mentioned factors have been used in aquatic and terrestrial invertebrates and vertebrates species on contaminated areas (in situ assays) and to screen for xenobiotics after direct or indirect exposure (in vivo assays).

The use of species as indicators for monitoring pollutant-induced deleterious environmental effects will raise the current awareness of real and potential hazards. It is also known that most environmental pollutants not only affect target organisms but concomitantly exert negative effects on non-target species as well.

Invertebrate and vertebrate animal models have been used for decades in acute and chronic toxicity tests for hazard identification. They can be very efficient screening systems that have a major role to play in toxicity research, because certain aspects of their biology, physiology and genetic characteristics make them suitable models in ecotoxicological and genotoxicological studies.

This volume aims to shed some light on the matter, whilst offering relevant tools for evaluating risk and providing a framework of practical discussions. These will foster decisions and actions required to reduce the environmental health risk against environmental factors. This book presents some real-life examples, extending concepts (of hazardous factors) to living species that may stimulate new research ideas and trends in the relevant fields.

Available information has been compiled from a diversity of sources, in an attempt to achieve a representative global and geographical balance, as far as possible, whilst at the same time aiming at high-quality studies. We believe that this book is unique in this sense.

The scientific community is starting to envisage that the time has come for a shift in emphasis away from basic towards applied research. While basic research is needed in order to shed more light on the fundamentals, applied research is required in order to find solutions to the many problems the world faces, e.g. overpopulation, excessive use of the Earth's natural resources and pollution.

Many researchers from different parts of the world have contributed to the chapters of this book. We hope that this volume will meet the expectations and needs of all those interested in the environmental risk assessment field of study by the use of widely available species worldwide. Finally, we also hope that the examples included in the different chapters of this book will awaken the ability to search for new organisms in local and regional ecosystems to pursue further studies in ecotoxicology and genotoxicology.