Chapter 17 Human Health and Environmental Risks

Three categories of human health risks physical biological chemical

Biological Risks Infectious diseases- those caused by infectious agents, known as pathogens. Examples: pneumonia and venereal diseases

Biological Risks Chronic disease- slowly impairs the functioning of a person’s body. Acute diseases- rapidly impair the functioning of a person’s body.

Historical Diseases Plague - bacterium called Yersinia pestis which is carried by fleas. When rats and/or mice and people live close to each other, the bacterium by transferred by flea bites Malaria – protist in genus Plasmodium, transmitted by mosquitoes Tuberculosis – bacterium called Mycobacterium tuberculosis. Primarily affects lungs

Emergent Diseases HIV/AIDS Ebola Mad Cow Disease Bird Flu West Nile Virus Zika Virus

Chemical Risks Neurotoxins- chemicals that disrupt the nervous system Carcinogens- chemicals that cause cancer Teratogens- chemicals that interfere with the normal development of embryos or fetuses Allergens- chemicals that cause allergic reactions Endocrine disruptors- chemicals that interfere with the normal functioning of hormones in an animal’s body

Carcinogens

Teratogens

Dose-Response Studies LD50- lethal dose that kills 50% of the individuals ED50- effective dose that causes 50% of the animals to display the harmful but nonlethal effect

Synergistic interactions- when two risks come together and cause more harm that one would. For example, the health impact of a carcinogen such as asbestos can be much higher if an individual also smokes tobacco.

Asbestos fibers

Routes of Chemical Exposure

A December 2011 study conducted by the FDA found the average lead concentration in the 400 lipsticks it tested for that substance was 1.11 ppm, with results ranging from the detection limit of 0.026 ppm to the highest value of 7.19 ppm.

A research study conducted in 2013 by UC Berkeley's School of Public Health found that lead was present in 24 of the 32 lipstick samples they tested, but at levels that were within safety guidelines (estimated lead intake for the product with the highest lead concentration was between 3% and 12% of the acceptable daily intake).  http://www.snopes.com/medical/toxins/lipstick.asp

Effects of Lead on Children: Nervous system and kidney damage. Learning disabilities, attention deficit disorder, and decreased intelligence. Speech, language, and behavior problems. Poor muscle coordination. Decreased muscle and bone growth. Hearing damage. Seizures, unconsciousness, and death. http://serendip.brynmawr.edu/bb/neuro/neuro00/web2/Patel.html

A study called “Lead poisoning and the deceptive recovery of the critically endangered California condor”, concluded that up to 88 percent of condors in the wild show some signs of lead exposure. The damage is severe enough that on average 20 percent of the population must be pulled out of the wild and treated for poisoning every year in order to survive, said study lead author Myra Finkelstein, an environmental toxicologist at the University of California-Santa Cruz. https://www.wired.com/2012/06/condors-and-lead-bullets/

Bioaccumulation bioaccumulation- an increased concentration of a chemical within an organism over time

Biomagnification Biomagnification- the increase in a chemical concentration in animal tissues as the chemical moves up the food chain.

Persistence Persistence- how long a chemical remains in the environment

DDT Dichlorodiphenyltrichloroethane Dichlorodiphenyltrichloroethane is a colorless, crystalline, tasteless, and almost odorless organochlorine known for its insecticidal properties and environmental impacts.  Formula: C14H9Cl5 IUPAC ID: 1,1'-(2,2,2-Trichloroethane-1,1-diyl)bis(4-chlorobenzene) Molar mass: 354.49 g/mol Boiling point: 500°F (260°C) Density: 990 kg/m³ Melting point: 227.3°F (108.5°C)

Risk Analysis

Qualitative Risk Assessment Making a judgment of the relative risks of various decisions Probability- the statistical likelihood of an event occurring and the probability of that event causing harm

Quantitative Risk Assessment The approach to conducting a quantitative risk assessment is: Risk= probability of being exposed to a hazard X probability of being harmed if exposed

Stockholm Convention In 2001, a group of 127 nations gathered in Stockholm, Sweden, to reach an agreement on restricting the global use of some chemicals 12 chemicals were to be banned, phased out, or reduced These include DDT, PCBs, and certain chemicals that are by-products of manufacturing processes.