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 was tes had traversed was anoxic, with ca. 4000 dead fish floating and hun g in shoreline vegetation. Suspended solids, nutrients, and fecal coli forms were 10- to 100-fold higher at the plume's edge (71..7 mg SS/L, 39.6 mg NH4+-N/L, and >1 x 10(6) cfu/100 mL, respectively; cfu, colony forming units, SS; suspended solids) than in unaffected reference sit es. Elevated nutrients and an oxygen sag from the plume reached the ma in estuary after ca. 5 d. Increased phytoplankton production was contr ibuted by noxious algae, Synechococcus aeruginosa and Phaeocystis glob osa (10(8) and 10(6) cells/mL, respectively) after 7 to 14 d. The toxi c dinoflagellates, Pfiesteria piscicida and a second Pfiesteria-like s pecies, increased to potentially lethal densities (10(3) cells/mL) tha t coincided with a fish kill and ulcerative epizootic. After 14 d, wat er-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 a fter 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 document ed acute impacts to surfacewaters from a concentrated swine operation, and examined some environmental policies affecting the intensive anim al operation industry.