Table 4. Dissolved organic-matter acid dissociation constants and site densities for the Link River to Keno Dam reach of the Klamath River, Oregon, resulting from two best-fit optimizations of 24 measured alkalinity titration curves.


[Abbreviations: pK_a, acid dissociation constant; std. dev., standard deviations; –, not applicable]


Acid group	Model parameter	Optimization number 1 (2 acid distributions)	Optimization number 2 (2 monoprotic acids)
1 (Carboxylics)	Site density	0.1751	0.1925
	pKa mean	5.502	5.584
	pKa std. dev.	0.047	–
2 (Phenolics)	Site density	0.5828	0.6466
	pKa mean	9.738	9.594
	pKa std. dev.	0.050	–

First posted March 1, 2013