Standard Laboratory Analysis Methods – Livestock Management and Water Quality on US Forest Service Grazing Allotments

Contact Person: Dr. Kenneth W. Tate

Participants: Lea Kromschroeder, Donna Dutra, Rob Atwill, Scott Oneto, USDA Forest Service – Region 5, Stanislaus National Forest, Plumas National Forest, Tahoe National Forest, Shasta-Trinity National Forest, Klamath National Forest.

Comment or Questions?

All samples will be analyzed for fecal coliform and indicator E. coli concentration (colony forming units [cfu] per 100 mL of water) by direct one step membrane filtration (0.45 µm nominal porosity filter) and incubation on a selective agar  via standard method SM9222D (Eaton et al. 2005). Selective agar used for fecal coliform will be Difco mFC Agar (Becton, Dickinson and Company, Spars, MD, USA) and CHROMagar E. coli (ChromAgar, Paris, France) for indicator E. coli. These analyses will be conducted within 8 hours of sample collection, samples will be held on ice following collection until analysis. Standard quality assurance measures were implemented during each sample event/laboratory batch including: field duplicates, laboratory duplicates, laboratory blanks, and laboratory spikes.

Total nitrogen (TN) and total phosphorus (TP) concentrations (ppm) will be determined on non-filtered sub-samples following Yu et al. (1994) and standard method SM4500-P.D (Eaton 2005), respectively. Ammonium-nitrogen (NH4-N), nitrate-nitrogen (NO3-N), soluble reactive phosphorus (PO4-P) will be determined on filtered (0.45 µm) sub-samples following Doane and Horwath (2003), Verdouw et al. (1978), and standard method SM4500D (Eaton et al. 2005), respectively. Minimum detection limits will be 0.01 ppm for TN, NH4-N, and NO3-N; 0.005 ppm for TP and PO4-P.  These analyses will be conducted within 28 days of sample collection. Samples will be frozen within 24 hours of collection and kept frozen until analysis. Standard quality assurance measures were implemented during each sample event/laboratory batch including: field duplicates, laboratory duplicates, laboratory blanks, and laboratory spikes.

Doane, T. A., and W. R. Horwath. 2003. Spectrophotometric determination of nitrate with a single reagent. Analytical Letters 36:2713-2722.

Eaton, A. D., L. S. Clesceri, E. W. Rice, A. E. Greenberg, and M. A. H. Franson. 2005. Standard methods for the examination of water and wastewater: Centennial edition. Washington DC: American Public Health Association. 1368 p.

Verdouw, H., C. J. A. Vanechteld, and E. M. J. Dekkers. 1978. Ammonia determination based on indophenol formation with sodium salicylate. Water Research 12:399-402.

Yu, Z. S., R. R. Northup, and R. A. Dahlgren. 1994. Determination of dissolved organic nitrogen using ersulfate oxidation and conductimetric quantification of nitrate-nitrogen. Communications in Soil Science and Plant Analysis 25:3161-3169.