Transport and fate of phosphorus during and after manure spill simulations
Animal manure spills contribute to P loading of surface waters and little is known about the effectiveness of the current manure spill clean-up methods to mitigate P contamination. Manure spill clean-up consists of containing, removing, and land applying the contaminated water column, while P-enriched fluvial sediments remain in place. Therefore, the objectives of this study were to (i) understand how P partitions between the water column and fluvial sediments during a manure spill, and (ii) evaluate the efficacy of current manure spill clean-up methods to remediate manure contaminated sediments. Manure spill simulations were conducted using fluvarium techniques and sediments collected from three drainage areas of two drainage ditches. Sediments with the greatest clay content (33%) resulted in a significantly greater P buffering capacity (10.3 L kg–1) and removed P from the water column at the greatest rate during the manure spill simulation relative to sediments with < 6% clay. Phosphorus uptake length for all sediments ranged from 574 to 815 m and the adsorption flux ranged from 8.9 to 16.7 mg m–2 h–1. After simulating the current manure spill remediation methods, P desorbed to the water from all sediments exceeded the Environmental Protection Agency total P criteria (0.076 mg L–1) for the region by at least 67%. Furthermore, results from this study suggest that the current manure spill remediation method needs refining to mitigate P from the total fluvial system water column and sediment following a spill.