MOORE, A.*; TUBERTY, S.R.; CREED, R.P.; Appalachian State University, Boone, NC: Effects of hyperalkalinity on the benthic macroinvertebrate community of the New River following a NaOH spill.

On October 14, 2003, 3000 gallons of sodium hydroxide spilled into the Middle Fork New River of northwestern North Carolina, due to a malfunction at a water treatment plant. A hyperalkaline plume (> pH 11.5) traveling as far as 8 km downstream of the discharge caused a complete fish/amphibian kill while only a partial kill of the macroinvertebrate (MI) community indicated by MI surveys done six days after the spill. Although it is known that acidic pH can induce stress responses in invertebrates such as molluscans, few investigations of hyperalkalinity on MI communities have been conducted. Due to the global use and storage of hyperalkaline chemicals near waterways, several questions need to be addressed. Specifically, 1) At what pH is high alkalinity a lethal dose (LD₅₀) to invertebrates like the common pleurocerid snail Elimia. 2) What period of time is required for recovery of the MI following the spill? To identify the mechanism(s) utilized by surviving snails we will a) determine whether exposure to alkaline pH can induce heat shock proteins (Hsp) in Elimia, and at what level this occurs; and b) if behavior can account for survival? Snails were collected from the Middle Fork and reared at 18˚C. LD₅₀ tests were conducted and showed Elimia to be highly tolerant of hyperalkalinity (LD₅₀ > 11.0) but demonstrated behavioral modification at pH 10.5. In order to determine what pH is necessary to induce Hsp-70 and Hsp-90 in Elimia eight snails from each treatment ranging from pH 7.0 to 12.0 (�0.3) were homogenized, centrifuged and assayed by SDS-PAGE and Western blotting for induction of Hsp. In addition to laboratory toxicity tests, quarterly MI field collections were made to assess the recovery of the Middle Fork over a one year period.