Table A-5. Comparison of means of organic matter deter- 

 minations by collection dates. 



Samp 1 e 



collection 



dates 



Probability that sample means differ from 

 previous means, 1973 



1973 



27 June 



14 July 



27 Aug. 



18 Sept. 



25 Sept. 



17 June 

 28 June 

 14 July 

 27 Aug. 



18 Sept. 



1 



1 



P<0.001 



p<0.001 

 p<0.001 

 p<0.001 



p<0.001 

 p<0.001 



1 



p<0.001 

 p<0.001 



1 



1. Not significant, 



Table A-6. Inorganically bound cations 

 in artificial and natural 

 sediment. 



Element 



Silicon 



Fuller's 



Patuxent silt 





dioxide 



earth 



(N = 13) 



Zn 



0.08 



0.05 



36.0 ± 2.0 



Cu 



0.04 



<0.01 



4.4 ± 0.4 



Fe 



2.6 



<0.3 



2100.0 + 94.0 



Mn 



<0.06 



0.14 



2300.0 ± 260.0 



Pb 



<0.5 



<0.5 



<10.0 



Co 



<0.1 



<0.1 



< 4.0 



Ni 



<0.3 



<0.3 



< 4.0 



Cd 











1.0 



Cr 



<0.3 



<0.3 



< 3.0 



Hg 



<0.01 



<0.01 



< 0.2 



NOTE: Extraction by 0.075 normal hydro- 



chloric-sulfuric acid (N HCI-H2SO1+) 

 and analysis by atomic absorption 

 spectroscopy. Values are mg kg" 



•1 



50 



