Table 4.3. Toxicity and ammonia concentrations in sediment 

 porewater in 1990 and 1991. Toxic units = 100/LC50, where 

 LC50 is the % dilution that kills 50% of the exposed Cerio- 

 daphnia dubia in 48 hours. Ammonia concentrations in the 

 porewater are expressed as total ammonia nitrogen, N, in 

 mg/1. 



1990 



Total Ammonia-N 



mn 



37.8 

 25.6 



35.4 

 42.7 



41.5 

 59.8 



DP 286.3 1.4 23.8 



1991 



CR 324.8 1.1 34.2 



CR 326.4 1.5 51.2 



SS 292.2 2.8 33.5 



SS 313.0 1.1 28.6 



DP 286.3 1.4 30.5 



33 



