Parasitic Protozoons Survive Waste Water and Drinking Water Treatment Plants in Galicia

Parasitic Protozoons Survive Waste Water and Drinking Water Treatment Plants in Galicia

ScienceDaily (Feb. 23, 2011) — Researchers from the Galician Institute of Food Quality have detected parasitic protozoons in the effluent discharged from waste water and drinking water treatment plants in Galicia (Spain), as well as in the water in recreational areas. The protozoons studied, which are members of the Cryptosporidium and Giardia genuses, cause intestinal upsets in cattle and immunosuppressed people.

"The presence of two resistent forms of protozoons, the oocysts from the Cryptosporidium genus and cysts of the Giardia genus, is one of the greatest public health problems in water supply, because these parasites can easily survive our water treatment systems," says José Antonio Castro Hermida, a scientist at the Galician Institute for Food Quality in the Xunta de Galicia (regional government).

A team led by this researcher took 232 water samples in 55 Galician towns, and confirmed the presence of these infectious life forms in waste water treatment plants, drinking water treatment plants, and recreational areas.

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Giardia cysts appeared in 96% of the waste water samples discharged from treatment plants, at levels of up to 6,000 per litre, while 64% of samples contained Cryptosporidium oocysts. These figures were 36.5% and 32.7%, respectively, in the case of drinking water treatment plants, and around 60% in recreational areas, for both protozoons.

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