Pharmaceuticals, chemical ingredients from prescription drugs and over the counter drugs, are cannot really be treated in the wastewater treatment process. The WHO has found trace concentrations in drinking water, normally below 0.1 parts per billion. They vary from place to place and some water is more contaminated than other sources. As of right now, it is uncertain of this effect on humans, however, as seen in Last Call in the Oasis, hormone disruptors have shown to cause problems in fish and frogs. Some male fish and amphibians have been feminized where they produce eggs due to these chemicals. This has led to some worries about hormone disruption as well as antibiotic resistance in humans.

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