Harmful Effects of Chemicals - Ecological Perspective - Lecture Slides, Slides of Ecology and Environment

Download Harmful Effects of Chemicals - Ecological Perspective - Lecture Slides and more Slides Ecology and Environment in PDF only on Docsity! There are other ways to estimate the harmful effects of chemicals • Case reports provide information about people suffering some adverse health effect or death after exposure to a chemical. • Epidemiological studies, which compare the health of people exposed to a particular chemical (the experimental group) with the health of a similar group of people not exposed to the agent (the control group), but limited by: – Too few people have been exposed to high enough levels of a toxic agent to detect statistically significant differences. Docsity.com There are other ways to estimate the harmful effects of chemicals – Usually takes a long time. – Closely linking an observed effect with exposure to a particular chemical is difficult because people are exposed to many different toxic agents throughout their lives and can vary in their sensitivity to such chemicals. – Cannot evaluate hazards from new technologies or chemicals to which people have not yet been exposed. Docsity.com How far should we go in using pollution prevention and the precautionary principle? • Some are pushing for much greater emphasis on pollution prevention. • Do not release into the environment chemicals that we know or suspect can cause significant harm. – Look for harmless or less harmful substitutes for toxic and hazardous chemicals. – Recycle them within production processes to keep them from reaching the environment. Docsity.com How far should we go in using pollution prevention and the precautionary principle? • The precautionary principle advocates when there is reasonable but incomplete scientific evidence of significant or irreversible harm to humans or the environment from a proposed or existing chemical or technology, we should take action to prevent or reduce the risk instead of waiting for more conclusive scientific evidence. – New chemicals/technologies would be assumed to be harmful until scientific studies could show otherwise. – Existing chemicals/technologies that appear to have a strong chance of causing significant harm would be removed from the market until their safety could be established. Docsity.com How far should we go in using pollution prevention and the precautionary principle? • In 2000, a global treaty banned or phased out the use of 12 of the most notorious persistent organic pollutants (POPs), also called the dirty dozen. The list includes DDT and eight other pesticides, PCBs, and dioxins. • In 2007, the European Union enacted regulations known as REACH (for registration, evaluation, and authorization of chemicals) that put more of the burden on industry to show that chemicals are safe. – REACH requires the registration of 30,000 untested, unregulated, and potentially harmful chemicals. – The most hazardous substances are not approved for use if safer alternatives exist. – When there is no alternative, producers must present a research plan aimed at finding one Docsity.com The greatest health risks come from poverty, gender, and lifestyle choices • The best ways to reduce one’s risk of premature death and serious health problems are to: – avoid smoking and exposure to smoke – lose excess weight – reduce consumption of foods containing cholesterol and saturated fats – eat a variety of fruits and vegetables – exercise regularly – drink little or no alcohol – avoid excess sunlight – practice safe sex Docsity.com Estimating risks from technologies is not easy • The more complex a technological system, and the more people needed to design and run it, the more difficult it is to estimate the risks of using the system. • The overall reliability or the probability that a person, device, or complex technological system will complete a task without failing is the product of: – Technology reliability. – Human reliability. Docsity.com Most people do a poor job of evaluating risks • Many people deny or shrug off the high-risk chances of death (or injury) from voluntary activities they enjoy, such as: – Motorcycling (1 death in 50 participants). – Smoking (1 in 250 by age 70 for a pack-a-day smoker) – Hang gliding (1 in 1,250). – Driving (1 in 3,300 without a seatbelt and 1 in 6,070 with a seatbelt). Docsity.com Several principles can help us evaluate and reduce risk • Compare risks. • Determine how much risk you are willing to accept. • Evaluate the actual risk involved. • Concentrate on evaluating and carefully making important lifestyle choices. Docsity.com Three big ideas • We face significant hazards from infectious diseases such as flu, AIDS, diarrheal diseases, malaria, and tuberculosis, and from exposure to chemicals that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine systems. • Because of the difficulty in evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution prevention. • Becoming informed, thinking critically about risks, and making careful choices can reduce the major risks we face. Docsity.com