A review of drinking-water-associated endotoxin, including potential routes of human exposure.
In the past decade efforts have been made to reduce the formation of harmful disinfection byproducts during the treatment and distribution of drinking water. This has been accomplished in part by the introduction of processes that involve the deliberate encouragement of indigenous biofilm growth in filters. In a controlled environment, such as a filter, these biofilms remove compounds that would otherwise be available as disinfection byproduct precursors or support uncontrolled biological activity in distribution systems. In the absence of exposure to chlorinated water, most biofilm bacteria are gram negative and have an outer layer that contains endotoxin. To date, outbreaks of waterborne endotoxin-related illness attributable to contamination of water used in hemodialysis procedures have been only infrequently documented, and occurrences linked to ingestion or through dermal abrasions could not be located. However, a less obvious conduit, that of inhalation, has been described in association with aerosolized water droplets. This review summarizes documented drinking-water-associated incidents of endotoxin exposure attributable to hemodialysis and inhalation. Typical endotoxin levels in water and conditions under which substantial quantities can enter drinking water distribution systems are identified. It would appear that endotoxin originating in tap water can be inhaled but at present there is insufficient information available to quantify potential health risks.
Anderson
William B
WB
Department of Civil Engineering, University of Waterloo, ON, Canada. wbanderson@uwaterloo.ca
Slawson
Robin M
RM
Mayfield
Colin I
CI
D000818:Animals; D000458:Cyanobacteria / Q000472:pathogenicity; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000008:administration & dosage / Q000592:standards / Q000633:toxicity*; D005334:Fever / Q000139:chemically induced; D015312:Hemodialysis Solutions / Q000633:toxicity; D006801:Humans; D008033:Limulus Test; D019055:No-Observed-Adverse-Effect Level; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000592:standards / Q000633:toxicity*; D018508:Water Purification; D014881:Water Supply / Q000032:analysis* / Q000592:standards
D004731:Endotoxins; D015312:Hemodialysis Solutions; D014874:Water Pollutants, Chemical