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 "
HARD COPY OF MEMO AND PUBLICATIONS WILL BE MAILED OUT NEXT WEEK (JULY 8, 1996) ---------------------------- In Reply Refer To: Mail Stop 412 July 2, 1996 OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM 96.07 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 analysis. 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. /S/ David A. Rickert Chief, Office of Water Quality Attachment This memorandum references Office of Water Quality Technical Memorandum 94.09. Keywords: Analysis, protocol, surface water Distribution: Regional and District Water-Quality Specialists