While there are no guidelines for ammonia in sediments or sediment pore waters, there are for marine and estuarine waters. The current Australian and New Zealand guideline of 910 lg total NH3–N/L for 95% species protection (at 20 C and pH 8), was derived using a species sensitivity distribution (SSD) of chronic no observed effects concentration (NOEC) data, calculated from a dataset of 19 acute and two chronic endpoints
(ANZECC/ARMCANZ, 2000).The Australian and New Zealand guideline values are termed ‘trigger values’, to indicate that exceedance is the trigger for further action,
rather than being simply a pass or fail number