all sediments. 



Surface water samples were collected just prior to collection of 

 sediment. Surface water was collected from approximately mid-depth in 

 the water column using a Van Dorn sampler. Samples were placed in pre- 

 cleaned cubitainers and immediately placed on ice. Surface water sam- 

 ples were stored at 4°C for a maximum of one week. 



3.3 Chemical Analysis 



Routine chemical measurements were taken on both surface water and 

 porewater samples. Samples were brought to ambient temperature (20- 

 24°C) prior to making the following measurements: 



SURFACE WATER PORE WATER 



Dissolved Oxygen Dissolved Oxygen 



pH (negative log of the hydronium pH 



ion concentration (minus {H''"))) Conductivity 



Alkalinity 



Conductivity Hardness 



Alkalinity Total Ammonia-N 



Hardness Total CI (chlorine) 



Total Ammonia-N (ammonia measured H2S (hydrogen sulfide) 



as nitrogen, N) Sulfide 



Dissolved oxygen was measured using a standard Y.S.I. Model 57 

 oxygen meter with a Y.S.I. Model 5739 probe. Temperature and pH were 

 measured using a Jenco Microcomputer pH-Vision 6071 pH meter with a 

 temperature-compensating Ross electrode. Specific conductance was 

 measured using a Y.S.I. Model 35 Conductance Meter with a Y.S.I. Model 

 3401 probe. Total alkalinity was measured using the ASTM (1982) stand- 

 ard titration method. Total hardness was measured using the EDTA titra- 

 metric method (APHA 1989). Total ammonia nitrogen was determined using 

 the Nesslerization method (APHA 1989), total residual chlorine by the 

 DPD colorimetric method (APHA 1989), sulfide by the methylene blue 



15 



