PUBLICATIONS: "The Use of Suspended Sediment and Associated Trace Elements in Water Quality Studies" by Arthur J. Horowitz

Date: Tue, 02 Jul 1996 14:09:53 -0400
From: "David A Rickert, Chief, OWQ, Reston, VA "


In Reply Refer To:
Mail Stop 412                                           July 2, 1996


Subject:  PUBLICATIONS: "The Use of Suspended Sediment and Associated 
          Trace Elements in Water Quality Studies" by Arthur J. Horowitz

The attached IAHS Special Publication "The Use of Suspended 
Sediment and Associated Trace Elements in Water Quality Studies" was 
prepared by Arthur Horowitz at the request of the Office of Water Quality 
(OWQ). It represents a summary of all the various suspended sediment 
studies sponsored by OWQ dating back to 1987. The first sections of the 
monograph are based on the results from the initial so-called National 
Stream Quality Accounting Network (NASQAN) "Superstudy" and deal with the 
short-term spatial and temporal variability of suspended sediment and 
associated trace elements typical of fluvial systems. These results 
provide a clear scientific basis for the use of depth- and 
width-integrated isokinetic sampling to obtain representative samples for 
both suspended sediment concentration as well as subsequent chemical 

The section on dewatering suspended sediment is based on a study carried 
out under the auspices of the Toxic Substances Hydrology Program, which 
entailed a comparison between the use of two different flow-through 
centrifuges, a tangential-flow filtration system, and standard laboratory 
centrifuges. The results from this study were used by the four National 
Water-Quality Assessment Program pilot studies to select the most 
cost-effective method to dewater suspended sediment samples for 
subsequent total trace element analyses.

The last sections of the monograph deal with problems associated with the 
determination of annual transport/fluxes and are based on the second half 
of the NASQAN "Superstudy." That study indicated that although suspended 
sediment and associated trace elements display marked short-term spatial 
and temporal variability, these variations generally are insignificant in 
the context of annual transport. In fact, of the three variables required 
for the determination of annual flux (discharge, suspended sediment 
concentration, and suspended sediment-associated chemical 
concentrations), the actual suspended sediment-associated chemical 
concentrations are the least significant. This is extremely important 
from the perspective of establishing a flux-based monitoring network 
because the chemical data are the most expensive to generate.

The monograph was initially prepared as an OWQ Technical Memorandum to 
cover a variety of water quality concepts related to suspended sediment 
and associated chemical constituents. It was intended that this 
memorandum precede the development of a suspended sediment sampling and 
processing protocol that would be analogous to the recently issued 
protocol on the sampling and processing of whole-water samples for the 
subsequent determina-tion of dissolved trace elements. The preparation of 
the suspended sediment protocol is currently underway; that protocol will 
be issued upon completion and thorough field testing.

                                David A. Rickert
                                Chief, Office of Water Quality


This memorandum references Office of Water Quality Technical Memorandum 

Keywords:       Analysis, protocol, surface water

Distribution:   Regional and District Water-Quality Specialists