http://www.digitaljournal.com/news/environment/detecting-fecal-pollution-in-norwegian-watercourses/article/386130

Detecting fecal pollution in Norwegian watercourses

Posted Jun 9, 2014 by Tim Sandle
A set of novel methods for the detection of fecal pollution in Norwegian watercourses has been designed. The methods can give answers as to whether the contamination is a result of human or animal excreta.
Glass representation of the bacterium Escherichia coli
Glass representation of the bacterium Escherichia coli
Luke Jerram
Fecal contamination in water is one of the most common reasons for human diseases. Fecal water contamination occurs when excreta from humans or animals enter a water source due to a sewage leakage or inadequate wastewater treatment. The object of the new method is to assess whether the water pollution poses a health risk or not.
The new method is based on scanning water for traces of the bacterium Escherichia coli (E. coli is a key indicator of fecal pollution). Fecal contamination measured in terms of the E. coli can be the result of wastewater leakage, effluent discharge after inefficient sewage treatment, or agricultural runoff containing animal fecal matter entering surface and/or groundwater.
The new tool set for tracking contaminative sources consists of two steps. The first is to perform a microbiological test to determine whether a water source is affected by fecal contaminants or not. This is based on a standard 18-hour test for the detection and quantification of E. coli in water samples.
With the second step, which is based on genetic markers, scientists only concentrate on the fecally positive water samples from the first step. In doing this, well characterized markers, for humans, cows and horses can be detected and assessed. This helps us to quickly identify the major sources of contamination in a water catchment. This is based on looking for different types of E. coli (what are termed serotypes).
The study has been carried out by the Norwegian Institute for Agricultural and Environmental Research, Bioforsk.