Impacts to a coastal river and estuary from rupture of a large swine waste holding lagoon

We tracked a swine waste spill (4.13 x 10(7) L) into a small receiving river and estuary. After 2 d, a 29-km freshwater segment that the wastes had traversed was anoxic, with ca. 4000 dead fish floating and hung in shoreline vegetation. Suspended solids, nutrients, and fecal coliforms were 10- to 100-fold higher at the plume's edge (71..7 mg SS/L, 39.6 mg NH(4)(+)-N/L, and >1 x 10(6) cfu/100 mL, respectively; cfu, colony forming units, SS; suspended solids) than in unaffected reference sites. Elevated nutrients and an oxygen sag from the plume reached the main estuary after ca. 5 d. Increased phytoplankton production was contributed by noxious algae, Synechococcus aeruginosa and Phaeocystis globosa (10(8) and 10(6) cells/mL, respectively) after 7 to 14 d. The toxic dinoflagellates, Pfiesteria piscicida and a second Pfiesteria-like species, increased to potentially lethal densities (10(3) cells/mL) that coincided with a fish kill and ulcerative epizootic. After 14 d, water-column fetal coliforms generally were at 10(2) to 10(3) cfu/100 mL. But where the plume had hovered for the first 5 d, surface sediments mostly yielded greater than or equal to 10(4) cfu/100 mL slurry, and after 61 d densities in surficial sediments were still at 10(3) to 10(4) cfu/100 mL. Dinoflagellate and euglenoid blooms developed and moved down-estuary, where they were detected after 61 d. This study documented acute impacts to surfacewaters from a concentrated swine operation, and examined some environmental policies affecting the intensive animal operation industry.