Effect on Ecology:Decrease in pH primarily affects oceanic calcifying organisms, such as
corals and shellfish; may also directly affect reproduction or other physiology of marine
organisms or indirectly cause negative impacts through their food resources
Effect on Human Health and Well-Being:No likely effects
Polution Problem: Transformation of Chemicals
Definition: Transformation of many chemicals, including chlorinated hydrocarbons (car-
cinogens), especially over long periods of time in groundwater.
Causes: Chemicals are used in industrial metal degreasing and electronics manufacturing
and find their way into the groundwater or other waterways.
Effect on Ecology: As they undergo change in groundwater, can lead to new hazardous
chemicals.
Effect on Human Health and Well-Being:Such contaminated groundwater can poison
drinking water and lead to various human health problems, including cancer.
Polution Problem: Aquatic Debris
Definition:Aquatic debris (or trash) in fresh and saltwater waterways.
Causes:Shipping accidents, Landfill erosion, or dumping of trash.
Effect on Ecology: Aquatic wildlife swallowing plastic bags, strangulation by plastic six-
pack rings, entanglement of wildlife in nets (Figure25.11).
Effect on Human Health and Well-Being: Adversely affects recreation and aesthetic
enjoyment.
Let’s close this section and look at a few other effects of water pollution on human health.
According to the World Health Organization (WHO), diarrheal disease is responsible for
the deaths of 1.8 million people every year. It was estimated that 88% of that burden is
attributed to unsafe water supply, sanitation, and hygiene, and is mostly concentrated in
the children of developing countries.
Such waterborne diseasescan be caused by protozoa, viruses, bacteria, and intestinal
parasites. Protozoal infections can be caused by sewage, non-treated drinking water, animal
manure, poor disinfection, and groundwater contamination; some viruses and bacteria are
water-borneandcanbefoundindrinkingwater,sewage,contaminatedseafood,orunsanitary
recreational water; and parasitic infections are usually caused by contaminated drinking
water.