Umuwa – Total Dissolved Solids
1997-1999: Umuwa – Total Dissolved Solids
There are three operating supply bores: two solar-pumped bores (B1 and B2) and one diesel-pumped bore which is generally used as a backup. The community’s water use is believed to be about 60 KL/d (1800 KL/month). The regional groundwater quality study in 1997 found that the three community bores had good quality water with 390-670 mg/L TDS (Fitzgerald et al., 2000). However, two additional bores sampled at the Umuwa campground were more saline with 1520 and 1800 mg/L TDS, and also had elevated fluoride concentrations. This level of salinity is unacceptable according to the Australian Drinking Water Guidelines (1966).
“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.
Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.
The sample from the diesel bore contained Clostridium perfringens spores, which suggests some contamination with faecal matter in the past, but too long before sampling for other indicator organisms to survive. A potential source of contamination to the aquifer is the periodical disposal in the bush of sewage from the town’s septic tanks.
In the 1999 investigation, water samples from two hand pumps located at Umuwa camping grounds showed a high level of faecal streptococci and also the presence of Clostridium perfringens spores (Piazinska, 2000). Both hand pumps are located within the camping grounds that are used, at times, by large numbers of people. The absence of thermotolerant coliforms indicates that the contamination may have occurred some time before sampling.
No guideline value has been set for Clostridium perfringens in drinking water. If used as
an indicator and detected in drinking water, immediate action should be taken, including
investigation of potential sources of faecal contamination.
Clostridium spp are anaerobic, sulfite-reducing, spore-forming bacilli. There are a number of species, of which C. perfringens is uniquely of faecal origin. Largely because it is anaerobic, C. perfringens rarely multiplies in water environments. The spores are smaller than protozoan cysts and oocysts. They are exceptionally resistant to unfavourable conditions in water environments, including temperature and pH extremes, and are also resistant to
disinfection processes such as chlorination…