Site pH EC Al Fe B Pb Zn Mn NH3-N NO3-N Cl- SO42- TN TP TOC
*Trigger 7-8 20-250             0.01       0.2-0.3a 0.01  
**Trigger     0.055b - 0.37 0.0034 0.008 1.9 0.9c 0.7d          
EC: electrical conductivity; TP: total phosphorus; NH3-N: ammonia-nitrogen; NO3-N: nitrate-nitrogen; TOC: total organic carbon; SO42-: sulfate.
*ANZECC default trigger values designated for physical and chemical stressors in tropical Australia for slightly disturbed ecosystems for Lowland river [31]. Trigger values are used to assess risk of adverse effects due to nutrients, biodegradable organic matter and pH in various ecosystem types.
**ANZECC Trigger values for toxicants at 95% level of protection of species for typical slightly-moderately disturbed systems [31].
aLower values from rivers draining rainforest catchments.
bTrigger value of aluminum at pH > 6.5.
cTotal ammonia as NH3-N at pH 8.
dThe values have been calculated using a hardness of 30 mg l-1 CaCO3.
Table 2c: Freshwater quality trigger values and guidelines.