apes module 57 - toxicology and chemical risks

• dysentery is caused by untreated sewage in streams and rivers
• asbesto exposure can cause mesothelioma
• Mesothelioma is a type of cancer
• a neurotoxin disrupts the nervous system
• carcinogens cause cancer
• a mutagen is a specific type of carcinogen that attacks the genetic material of a cell
• an endocrine disruptor interferes with the normal functioning of hormones
• the delaney clause of 1958 bans carcinogenic food additives
• the delaney clause is an amendment of the food, drug, and cosmetic act
• the delaney clause bans FDA from approving carcinogenic additives
• the delaney clause may be too restrictive as it makes the risk level 0
• how does the delaney clause make the risk level 0?

  it applies to only 400 out of the 2,700 substances added to food, and most of these are generally recognized as safe (GRAS)
• the dose response exposes organisms to different doses of a chemical
• during a dose response, observers record responses such as mortality and behavior changes
• an acute study is short term, while a chronic study is long term
• retrospective studies monitor people that have been been exposed to an environmental hazard in the past
• prospective studies monitor people that may later be exposed to harmful chemicals
• a synergistic interaction is when two risks together cause more harm than anticipated, especially due to their harmful effects alone
• LD50 measures the lethal dose of a chemical that causes a 50% death rate
• ED50 is the effective dose of a chemical that causes 50% of individuals to experience sublethal effects
• sublethal: not lethal, but still harmful to an organism
• safe chemical concentration for animals: LD50/10
• safe chemical concentration for humans: LD50/10/100 or LD50/1000
• retrospective and prospective studies fall under the field of epidemiology
• analyzing results of retrospective and prospective studies can be complicated due to synergistic interactions
• route of exposure: ways in which individuals may be exposed to an environmental hazard
• solubility impacts where and how chemicals move in the environment
• soluble solutions perchlorate, wash off surfaces, and may runoff
• non-soluble solutions are found at higher concentrations; they are easily stored in living tissue and bioaccumulate, which causes biomagnification