env health final- chap 9 water quality

Coagulation

remove suspended material (1) - agent: aluminum sulfate

Sedimentation

make heavy particles settle to the bottom of tanks for collection (2)

Filtration

remove smaller particles (3)- fine layers of sand and charcoal

Disinfection

destroy pathogens (4)- chlorine

dr.mckay

added fluoride to public water to prevent tooth decay

treatment of aquifers

not aesthetically pleasing, use ultrafine filter

protozoan agents (responsible for waterborne illnesses)

Cryptosporidiosis and Giardiasis

bacteria(responsible for waterborne illnesses)

Cholera, Typhoid fever, E. coli, Legionnaires

virus(responsible for waterborne illnesses)

Hepatitis A

Cryptosporidiosis

protozoal parasite, oocysts in poop of infected person, contaminant drinking water. can survive chlorine treatment

symptoms: watery diarrhea, stomach cramps, nausea, vomiting, and fever

Oocyst

resistant to env conditions and disinfection methods like chlorine, release sporozoites in new host and multiply

Amebiasis

protozoal parasite, produce cysts in human feces, transmitted through ingesting cysts in water or food contaminated by feces

symptoms: invasive intestinal diseases (dysentary, appendicitis)

Giardiasis

protozoal parasite, produces cysts in contaminated food and water

symtoms: gastrointestinal effects such as chronic diarrhea, sometimes asymtomatic

Cyclosporiasis

protozoal parasite, ingestion of food and water with cysts or oocysts

symptoms: watery diarrhea

Typhoid Fever

bacteria, fecal-contaminated water and food

symptoms: fever, diarrhea, death

E. Coli Infection

bacteria, intestines of people and animals (cattle)

symptoms : diarrhea

Cholera

bacteria, inadequate infrastructure for processing water causing food/water to be contaminated

symptoms: 50% fatality when untreated, diarrhea

viruses

more resistant to chlorine and uv radiation (sewage treatment processes), virus laden human stools

norovirus

ingestion of contaminated food/water + close contact with those infected

symptoms: diarrhea, 24-72hrs

viral hepatitis

person to person contact (fecal-oral route) contaminated food (shellfidh, fruits and veggies), countries with poor sanitation most pop is drinking water

travelers/missionaries visit developing countries should avoid drinking tap water

guinea worm disease

roundworm, worms forms larvae that enter water, infect crustaceans then are ingested into the body by unfiltered water. in stomach larvae turn into worm, female worms grow up to 7ft and then exit the body via foot causing blisters

legionellosis

bacteria,legionnaires disease+ pontiac fever (milder form w/o pneumonia)

sym: fever,cough, pneumonia, 15% fatality rate. grows in water cooling systems (ac)

chemicals in water supply

pharmaceuticals and ppcps (personal care products), Water can be contaminated by toxic chemicals causing cancer, reproductive, and heart issues.

• Examples: Cr⁶⁺, arsenic, lead, fluoride, pesticides, DBPs.

Water Disinfection By-Products (DBPs)

• Disinfecting water (chlorine, chloramines, etc.) creates disinfection by-products (DBPs).

• Chlorine → THMs, a common DBP.

• Possible links to cancer and reproductive issues, but health effects are still unclear.

Ocean Pollution

• Coastal areas receive billions of gallons of treated/untreated wastewater → sewage contamination.

• Heavy rain + urban runoff add microbes, nutrients, and toxins to ocean water.

• Too many nutrients → harmful algal blooms → low oxygen → fish kills and marine harm.

• Pollution can cause GI, respiratory, skin, and eye infections in swimmers.

• Beaches close when water quality standards are exceeded.

Ocean Pollution – Oil Spills

• Oil spills from tankers and offshore drilling harm shorelines, fish, mammals, and birds.

• 1989 Exxon Valdez: major tanker spill in Alaska.

• 2010 Deepwater Horizon: largest accidental marine oil spill in history.

vulnerable groups

children,elderly, immunocompromised patients (chemotherapy, steriods, hiv/aids)

freshwater quota

9000 cubic meters annually

water scarcity

> 1000 cubic meters per person annually

two regions with high pop growth rates and severe water scarcity

africa (sub-saharan and north) and near east (middle east)