Pit latrines collect human waste in ground holes with drop holes. Can be dry toilets (without water) or pour-flush systems. Typical pit depth is 3m, width 1m, with 25cm drop hole. Requires shelter (outhouse) with privacy and cleaning facilities
Defecation eliminates waste from digestive tract via anus or cloaca. Peristalsis moves fecal matter through colon to rectum. External anal sphincter is voluntary, internal is involuntary. Frequency varies from few times daily to weekly
Toxicology studies harmful effects of chemicals on people and environment. Field evolved from studying poisons to studying safety. Not everyone responds to substances identically. Exposure dose and duration significantly impact health effects
FDA tests 30 different PFAS types in diverse food samples since 2019. Nearly 1,300 U.S. market food samples tested since 2019. No PFAS detected in over 97% of Total Diet Study samples. Eight PFAS types have toxicological reference values for health assessment
Environmentally friendly countries minimize harm to ecosystems and environment. Yale University's Environmental Performance Index ranks 180 countries annually. EPI scores range from 0 (worst) to 100 (best) across 32 environmental indicators
Particulate matter is a complex mixture of solids and aerosols. PM10 particles are 10 microns or less, PM2.5 particles are 2.5 microns or less. PM2.5 comes from combustion of fuels, PM10 from various sources. PM can be primary (direct emissions) or secondary (formed through reactions)