DESCRIBE THE PROCESSES BY WHICH CHEMICALS MOVE THROUGH THE ENVIRONMENT

BOS 4201, Toxicology 1 Course Learning Outcomes for Unit III Upon completion of this unit, students should be able to: 3. Assess the environmental risk from the presence of chemical compounds based on their toxicity category. 3.1 Describe the processes by which chemicals move through the environment. 3.2 Identify the factors affecting the fate of chemicals in the air. 3.3 Identify the factors affecting toxicity in a population. 7. Summarize the impact of exposure to various types of environmental pollution.Unit Lesson This unit discusses the risks to the environment from chemical contamination. Historic incidents are explored in addition to the factors that affect the fate of chemicals in the environment. In the past it was thought that dilution was the solution to pollution. Chemicals were released into the environment and it was thought that these chemicals would just blow away, until researchers found persistent chemicals in locations where they were not being used. As this became known, new technologies were invented to capture or reduce the amounts of chemicals. Some chemicals are found almost everywhere in our environment. They enter our food chain and can accumulate in animals. As humans, we are at the top of the food chain and the breast-feeding infant is at the highest level. It has been theorized that they are the most exposed group to environmental contaminants. Chapter 5: Environmental Pollutants and Their Fate Pollution is defined as the any change in the characteristic of the air, water, or soil that will adversely affect the health of an organism. A pollutant is any substance released into the environment that may cause adverse effects. The ecosystem is complex, pollutants enter into the ecosystem through discharges into the atmosphere, contamination of land, and entry into water (Richards & Bourgeois, 2014, p. 89). Some examples of common pollutants include:  gases (nitrogen oxides and sulphur dioxide),  metals (lead and mercury),  organics (benzene and toluene),  noise,  photochemical oxidants (ozone), and  radioactive waste. Reading Assignment Chapter 5: Environmental Pollutants and Their Fate Click here to access the Chapter 5 PowerPoint presentation. Click here to access a PDF version of the presentation. Suggested Reading See information below. Learning Activities (Non-Graded) See information below. UNIT III STUDY GUIDE Environmental Risks BOS 4201, Toxicology 2 The fate of chemicals in the environment is affected by the process in which chemicals are moved and transformed in the environment. The processes include:  persistence in air,  persistence in water,  persistence in soil,  reactivity and degradation,  migration in ground water, and  bioaccumulation in aquatic or terrestrial organisms. The persistence of a chemical in the environment is the ability of a chemical to remain unchanged in a particular environment.