Volume Three Appendix 5 Standard/Parameter Interpretation of Standard/Parameter Classification Cyanobacteria (mat - Between 1 November and 30 April of the following year the CR >3mm thick) seasonal maximum mat must be <20% when river flow is < median. - At all other times the must be <50% when river flow is < median. Suitability for human - Water must not be tainted or contaminated so as to make it WS consumption unpalatable or unsuitable for human consumption after treatment. - Water treated by coagulation/filtration/ disinfection shall be able to comply with the Drinking-Water Standards for New Zealand 2005 (revised 2008). Suitability for - Water must not be rendered unsuitable for treatment WS treatment (equivalent to coagulation, filtration, and disinfection) by presence of contaminants. - The maximum turbidity limit, except that produced naturally under flood conditions, must not exceed 20 Nephelometric Turbidity Units (NTU) when rivers are at < median flow. pH - The pH range must be from 6.0 to 9.0. WS Biological Growths - The daily average carbonaceous BOD due to dissolved WS 5 organic compounds (i.e. those passing a GF/C filter) must not exceed 2mg/l. - Phytoplankton chlorophyll-a must be <0.02mg/l when rivers are at < median flow. Toxicants Toxicants NS Must not exceed the limits (µg/l -1 ) in the following list: - Aluminium 27.00 Mercury 0.06 (pH>6.5) (inorganic) Arsenic (As III) 1.00 Nickel 8.00 Arsenic (As V) 0.80 Selenium (Total) 5.00 Boron 90.00 Silver 0.02 Cadmium 0.06 Zinc 2.40 Chromium (CrVI) 0.01 Chlorine 0.40 Copper 1.00 Cyanide 4.00 Lead 1.00 Hydrogen sulfide 0.50 Manganese 1200.00 Colour or visual Measurements are to be made immediately upstream of the A clarity discharge and below the discharge after reasonable mixing. - Hue must not be changed by more than 5 points on the Munsell scale. - Turbidity must be no greater than 1.5 Nephelometric Turbidity Units. Temperature - The natural temperature of the water must not be changed by SG more than 3°C. App 5 – 21