In This Article Contaminant Dispersal in the Environment

  • Introduction
  • A Selection of Relevant Books and Journals
  • Sources and Dispersal of Atmospheric Contaminants
  • Geography of Contaminant Sources and Dispersal
  • Air Pollutant Deposition and Human Health
  • Freshwater Contaminants
  • Environmental Fate of Pollutants in the Marine Environment
  • Soils and Terrestrial Ecosystems
  • Predicting the Effects of Pollutants to Ecological Systems and Human Health
  • The Role of Organisms in Environmental Monitoring and Remediation Procedures

Environmental Science Contaminant Dispersal in the Environment
by
Roberto Bargagli, Emilia Rota
  • LAST MODIFIED: 25 October 2018
  • DOI: 10.1093/obo/9780199363445-0106

Introduction

Contaminants are foreign substances or impurities affecting the composition of air, water, soil, and biota and not always creating adverse effects. However, when the term “contamination” is used in relation to the environment, food, or medicine, it usually refers to the presence of harmful substances. This article will mainly deal with the dispersal and environmental fate of pollutants, that is, those contaminants that, when critical levels are exceeded, produce measurable damages on plants, animals (including humans), or materials. A number of these substances occur naturally, being produced and released since the earliest time by volcanoes, geothermal sources, or forest fires, but their biogeochemical cycles and environmental distribution have been dramatically altered by humans through wood-burning fire, smelting of metals, and, more recently, through the huge exploitation of fossil fuels. After World War II, the production of many synthetic substances unknown to biota (xenobiotics) increased significantly and so have the number of environmental pollutants and their global-scale dispersal. This essay provides an overview of how potentially toxic substances (natural or synthetic; intentionally or accidentally released from stationary or mobile sources) enter and circulate between air, water, soil, and biota and illustrates their partitioning among different environmental compartments and their dispersal at different spatial scales, before degrading to less toxic compounds and/or ultimately sinking into sediments or soils. The unexpected and startling evidence of transport and deposition of many persistent contaminants (resistant to chemical transformation and degradation) in polar regions and the deepest ocean trenches will be highlighted. Although compartmental evaluative models are very useful to extrapolate from data obtained from small-scale measurements or experiments to regional and global estimates of environmental distribution and fate of pollutants and/or to predict ecotoxicological risks, this essay will stress the importance of epidemiological and field surveys for assessing the impact of pollutants on human health and ecosystems. The monitoring of pollutant distribution and circulation in ecosystems is essential to validate and calibrate model predictions, as well as to assess their chemical transformation in the various environmental compartments; this essay will mainly focus on pollutant bioavailability and their bioaccumulation and biomagnification along food chains. As conventional monitoring networks designed for the protection of human health and the environment do not allow to evaluate the biological effects of the chronic exposure to pollutants, the complementary role of organisms as biomonitors will be emphasized.

General Overviews

In the course of history, humankind has exerted increasing pressures and demands on Earth’s limited resources, affecting its own health as well as the quality of the environment. Papers and books in Inorganic Contaminants are helpful in understanding how the release and dispersal of anthropogenic harmful substances began with the domestication of fire, the development of metal-working techniques, and the use of fossil fuels. Xenobiotics (artificial radionuclides and synthetic organic compounds) provides an overview of some dramatic changes occurring after World War II in the number and nature of environmental contaminants and their dispersal up into the stratosphere and in all Earth’s ecosystems.

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