technical features
Table 1. Correlations between va rious Eclox™ luminometer, Eclox™ pH meter and water laboratory test results. Test
pH (field) Lum inometer % inhibition Luminometer % inhibition Luminometer % inh ibition luminometer % inhibition Luminometer % inhibition Luminometer % inhibition
Where
x
n
182 182 182 182 182 182 182
7.4 18 18 18 18 18 18
RSD
Correlation test
n
5.3 65 65 65
pH (EcloxTM)
182 182 182 182 182
65 65 65
pH (Eclox™) pH !field) Total chlorine Free chlorine TDS HPC22
182 182
x 7.4 7.4 7.4 0.12 0.08 48 5
RSD
R2
p
5.3
<0.001 0.003 0.031 0.004 0.005 0.21 0.008
0.98 0.47
5.3 5.3 62 83 58 530
0.02 0.42 0.36
See Figure 1
<0.001 0.23
See Figure 2
n = number of samples tested X = mean of sample results RSD = relative standard deviation of sample results P = Probab;l;ty of correlation, where <0.05 would be considered s;gnificant R2 = linear correlation factor contribution to overall variation, where 0.5 =50% contribution
Ocher tests available in the kit, along with the manufacturer's claimed test ranges, are: • Arsenic test strips (Range 0-4 mg/L, LOO = 0.1 mg/L) • Pesticide/ nerve agents test scri ps (presence/absence indication only) • C hlorine test kit {Range 0-8 mg/L free ch lorine) • Colour comparison chart (Range 0-90 Hazen) • Total dissolved solids meter {Range 02000 mg/L) • pH meter • Mustard gas rest kit (LOO= 1 mg/L) (Note: chis kit was withheld in the country of origin and was not available for assessment). Further in formation can be fou nd on the company website: http://www. severn tren tservices. com/i nstru men cation prod uccs/potable_warer_assessmen c/i ndex.jsp
IQ-Tox™ kit The IQ-Tox™ kit supplied by Kingwood Diagnostics, US, measures rhe uptake of a fl uorescencly labelled sugar by a live crustacean, Daphnia magna, to measure water toxicity. Such Daphnia exposed to contaminated water exhibit reduced or no fluorescence when exposed to UV light. Each rest uses 18 individual organisms; if fo ur or more organisms are adversely affected then the water sample may be toxic to humans.
The IQ-Tox™ kit, has greater sens itivity to some contaminants relative to Eel ox TM, according to the manufacturer's specifications and also co nfirmed by results from the US EPA ETV Program. This kit uses exotic crustaceans and is not deployable in the field, due to Australian quarantine requirements. However, we were able to eval uate it in our quarantine approved laboratory. Further information can be found on the company website: http:/ /www.kingwooddiagnostics.com/
Yean water sources, were tested in the DPI Environmental Health & Chemistry laboratory {not in the field) using the EcloxTM kit for pH, total dissolved solids (TDS) and luminometer % inhibition. Test repeatability was determined by conducting measu rements on seven samples, recalibrati ng rhe test equ ipment and rhen repeating the measurements. Reproducibility was determined by turning off the instruments and recalibrating and repeating the measurements the following day.
Experimental
Spiked water samples Spiked water samples were produced by addition to de-ionised water. The pesticides selected were technical chlorpyrifos {organophosphace insecticide), formu lated glyphosace (systemic herbicide of low human toxicity) and formulated paraquat {contact herbicide of high human toxicity). These pesticides are in common use and regarded as sentinel co mpounds for a range of herbicides and pesticides. The inorganic toxicants were arsenic {as arsenate) and cyan ide (as potassium cyanide) . These inorganic toxicants are regarded as high risk and potentially available fo r contamination of drinking water. The toxicant additions were made at several concentrations, including Suggested No Adverse Response Levels (SNARL) and estimated human lethal dose.
Drinking water samples As part ofYarra Valley Water's routine mon itoring program, samples are taken from various points throughout their distribution system and tested for a range of water quality parameters by their contract laboratory {WSL Consultants). Routine tests included total coliforms, E. coli, free and total chlorine, pH and turbidity. Total coliforms, place count and E. coli were determined using WSL internal laboratory methods. Free and total ch lorine were determined using the method APHA 4500-CI G and pH using method APHA 45 00-H• B. Over a five week period during October November 2004, approximately 200 duplicate samples, from a wide range of northern and eastern suburbs outlets supplied from che Silvan, Winneke and Yan
Three concentrations of each spiking agent were prepared, covering a concentration
Journal of the Australian Water Association
Water
MAY 2007 83