In 2006, soils were collected to a depth of 3.3 m from 4 locations at two sites south of Breckenridge, CO.  Effluent discharge piping was buried approximately 1.2 m in depth centered in ~30-cm of gravel, with buried depth varying slightly with topography.  Soil samples were collected in depth increments of 30-cm; the 30-cm of soil directly above and below gravel was sampled in 15-cm increments since this zone was considered likely affected by the effluent stream. 

Soils were air-dried and passed through a 2-mm sieve, then analyzed for NO3-N using 2M KCl and P using a modified sequential P extraction procedure, determining concentrations of: 1) water soluble; 2) soluble and loosely bound; 3) Al-bound; 4) Fe-bound; 5) occluded (i.e. Fe coated); and 6) Ca bound P.  Nitrate-N concentrations were lower than expected, potentially due to leaching, plant utilization, or denitrification.  The majority of P at both sites was bound to the Ca phase, likely due to parent mineralogy.  Differences existed at both sites for pH, but the overriding factor affecting P forms was likely redox.  Reduced conditions caused the dissolution of ferric-bearing P mineral phases and the subsequent re-precipitation of Al- and Ca-bound P phases.  Overall, systems have been successful at immobilizing P and appear to have an extended life expectancy.