The West Lafayette team added the sediments to an artificial water channel called a "fluvarium
" and used swine manure minimally diluted with water to create their own worst-case manure "spill." Then, after 24 hours, they cleaned it up using standard operating protocols for remediating contaminated spill sites.
Effects of dredging an agricultural drainage ditch on water column herbicide concentration, as predicted by fluvarium
Peer into the secrets of the underwater world at the Fluvarium
, an underwater building that lets you see river life up close.
Ditch bed material was collected from the 0 to 5 cm (0 to 2 in) depth, immediately before dredging (hereafter referred to as pre-dredge) and immediately after dredging (hereafter referred to as dredged) for fluvarium experimental procedures described by Smith and Pappas (2007).
For the first set of experiments, hereafter referred to as "herbicide-spiked" experiments, fluvarium water was spiked to initial concentrations of 30 [micro]g [L.sup.-1] atrazine and 23.7 [micro]g [L.sup.-1] metolachlor as Bicep II Magnum and separately, 2,000 [micro]g [L.sup.-1] glyphosate as Roundup.
All data represent the average of two fluvarium runs as in experiments by Smith et al.
Pre-dredge and dredged bed materials were placed in separate troughs of a fluvarium, built based on the fluvarium described by McDowell and Sharpley (2003).
Sediments were placed in the fluvarium troughs, and contaminated water was used for 120 hours, removed, and then was replaced with contaminant-free water for 24 hours.
The nutrient concentrations were regressed against the estimated distance the fluvarium water had been conveyed at the sampling times for the initial and final 24 h periods of the adsorption studies.
In the study reported in this paper, sediments were collected from ditches draining agricultural, forested, and mixed agriculture and forest areas to determine which sediment properties influenced the release and uptake of P using an indoor stream channel fluvarium. The results are discussed in terms of how ditch management decisions can be made to decrease phosphorus (P) export from drained areas.
For the release phase, two replicates of each sediment were placed into two troughs of the fluvarium to a depth of approximately 5 cm (2 in), and the troughs were set at an angle of 5% (estimated mean slope of the three sampled sites).
For the uptake phase, 20 L (5.3 gal) of poultry litter-rich surface runoff, of 2.6 mg [L.sup.-1] DRP and 3.5 mg [L.sup.-1] total P (TP), was introduced into the fluvarium reservoir.