Microbial and heavy metal contamination of treated hospital wastewater in Thailand.
OBJECTIVE
To determine the microbial and heavy metal contamination of treated hospital wastewater


METHODS
Methods of treating wastewater were acquired by questionnaires. Chlorine concentration, pH, bacteria and parasites in treated wastewater were tested in the individual hospitals. Heavy metal concentrations were measured by atomic absorption spectrophotometry.


RESULTS
In 2002, 72 hospitals were included in the present study. The common methods of treating wastewater were activated sludge and oxidation ditch. Bacteria exceeded standard numbers, pathogenic bacteria and parasites were found in two-thirds of the hospitals. Heavy metals, namely lead, chromium and cadmium, in the hospital effluent did not exceed standard concentrations.


CONCLUSIONS
Micro-organisms exceeding standard levels were found in treated wastewater in two-thirds of the hospitals. Lead, chromium and cadmium levels in hospital effluent were in an acceptable range.
Danchaivijitr
Somwang
S
Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok. sisdc@mahidol.ac.th
Wongchanapai
Wichai
W
Assanasen
Susan
S
Jintanothaitavorn
Duangporn
D
D000818:Animals; D001419:Bacteria / Q000302:isolation & purification*; D002104:Cadmium / Q000032:analysis; D002857:Chromium / Q000032:analysis; D006801:Humans; D007854:Lead / Q000032:analysis; D008284:Maintenance and Engineering, Hospital / Q000592:standards*; D019216:Metals, Heavy / Q000032:analysis*; D010271:Parasites / Q000302:isolation & purification*; D018570:Risk Assessment; D013785:Thailand; D014865:Waste Disposal, Fluid / Q000592:standards*; D014867:Water / Q000469:parasitology*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D002857:Chromium; D007854:Lead