Chapter 1: General Aspects – Current and Further 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 threatening 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 (1) the identification of hazards and risk factors that have the potential to cause harm (hazard identification) and (2) 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 (FAO) of the United Nations predicted a few years ago that the global population would 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. Disruptions in transport and production of basic commodities due to unforeseen circumstances, such as the present war in Ukraine, have revealed once again the caveats of this model. 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, fossil fuels, mining, manufacturing and construction industries, among others, are the main contributors to water, air and soil pollution. An increase in improper disposal of waste and chemicals, heavy usage of air-polluting equipment and machinery, asbestos handling, soil contamination and industrial noise also need to be factored in. 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” from more economically privileged nations, find their way to landfills. In some cases, these are located close to the seashores and eventually pollute the oceans. To this, we must add overfishing and overexploitation of marine resources, which complicate matters further.

Most xenobiotics in the different environmental compartments exert their effects through cytotoxicity and genotoxicity, interfering with metabolic pathways. Accordingly, current awareness of the real/potential hazards of pollutants in the environment has a high-ranking interest in using 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 also concomitantly exert negative effects on non-target species as well.

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 end points for testing toxicity have been developed. Molecular techniques, plus cyto- and genotoxicity tests, have been employed on aquatic and terrestrial organisms to assess the impact of pollution on contaminated areas (in situ assays) and to screen xenobiotics after direct or indirect exposure (in vivo assays).

This book covers many non-traditional amphibian species models employed to analyse the jeopardizing 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 some clues, to the inherent potential risk of the presence of these xenobiotics in our environment. To achieve this goal, consideration of exposure, hazards, risks, mitigation, and short- and long-term monitoring is required. This information will give all interested parties, e.g., regulators and safety advisory bodies, the tools needed for a better understanding of the matter in a broader context.

Many important ecosystems around the world are constantly challenged due to growing human and industrial pressure exerted upon them. More than 1 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 event.

The use of various biomarkers in local, easily available species can be useful 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 on the organism in general, pinpointing alterations at the cellular, biochemical and molecular levels, as well as at higher levels of organization.

The health of our planet and its ecosystems has severely deteriorated. There is no question about this statement. Humankind has reached an unprecedented level of food security and availability of consumer goods for the first time in its history. 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 in 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 subjected to. A transversal approach is needed, even in matters that do not seem to be related 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, in turn, many of its consumer patterns, press producers and manufacturers, while at the same time demanding more stringent action on behalf of politicians and lawmakers to protect this planet, our home, before it is too late.

Our global society needs to table down actions and set rules to evaluate and considerably reduce the real and potentially hazardous environmental factors 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, not self-evident equation 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. 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 the long-term effects of the substances used. Available information about the toxicity 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 understand this concept. According to the World Health Organization (WHO), it is defined as “... 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: electromagnetic fields (produced by high-power lines, electrical wiring, appliances, mobile phones, computers, 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 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 applied to in situ and 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 also concomitantly exert negative effects on other non-target species.

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, offering relevant tools for evaluating risk and providing a framework for practical discussions. These will, in turn, foster the decisions and actions required to reduce the environmental health risk from environmental factors. This book presents some real-life examples, extending concepts (of hazardous factors) to living species that may stimulate new research lines 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 while at the same time aiming for 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 to applied research. While basic research is needed to shed more light on the fundamentals, applied research is required 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 field of environmental risk assessment by using 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.