Reverse osmosis water treatment plants are becoming the preferred means of generating potable water for many eastern North Carolina communities. At these facilities, reject brine solutions—sometimes containing up to 10 times the initial concentration of dissolved solids—are created and often discharged into estuarine waters. Several state and federal agencies have expressed concern over the potential ecological impacts this wastewater could have on these sensitive environments. Monitoring of a brine discharge site in Currituck County, North Carolina revealed significantly higher conductivity values within ~50 m of the point source. One group of organisms that have proven useful in other studies for monitoring impact of anthropogenic pollution in estuaries is Foraminifera. Foraminifera are abundant microorganisms that are widespread in most marginal-marine and marine environments; nevertheless, individual taxa are highly selective of their habitat. Nearly all species build shells (tests) that are preserved in coastal sediments, allowing for reconstruction of previous marine conditions. Species abundance data was collected from surface and sub-surface samples taken in the area surrounding the brine point source. Two taxa (Ammobaculites spp. and Ammotium sp.) accounted for 98.5% of all normalized specimens. Abundance is significantly less in the sub-surface samples (Student’s t-test, p<0.0001), likely due to taphonomic effects. Abundance does not appear correlated with discharge of the wastewater; instead, natural parameters appear to affect abundance in an assemblage to a greater degree. Species distribution is similar in surface and sub-surface samples. Foraminiferal diversity is significantly less near the discharge based on one sample collected within 5 m of the discharge site; samples at greater distances do not appear affected. Loss of diversity within a few meters of the discharge site is consistent with previous studies, but more data would be needed to confirm the results observed at this site.
