PM21 New Advances in Estimating Effects of Toxicants on Populations
Exhibit Hall
8:00 AM - Monday
(PM301) An Outdoor Microcosm Design for Evaluating the Potential Effects of an Antifoulant on Marine Communities.
Hoberg, J1, Biever, R1, Giddings, J2, Sousa, J1, Balcomb, R3, 1 Springborn Smithers Laboratories, Wareham, MA, USA2 Parametrix, Inc, Corvallis, OR, USA3 Ciba Specialty Chemicals Corp., Tarrytown, NY, USA
ABSTRACT- Outdoor microcosms were developed to assess the effects of an active ingredient of marine antifouling paints on marine life. The physical design included 16 pools constructed from 15 x 15 cm x 2.4 m pressured treated timbers stacked four high, lined with EPDM aquatic horticulture liners, and filled with 10 cm of masonary sand covered with 1 cm of natural marine sediment and 35 cm (1850 L) of unfiltered seawater. The natural sediment and seawater served as a biological inoculum. Additional species (two grasses, an amphipod, polychaete, snail and bivalve) were added to supplement the native organisms. Three times weekly, 30% of the water was replaced with fresh seawater to simulate tidal flushing and reintroduction of indigenous organisms. Pools were allowed to mature for 4 weeks before dosing with the test substance at four environmentally relevant concentrations. Three pools per treatment and four control pools were established. During the treatment phase replacement water was dosed at each refill to maintain the desired concentrations in the microcosms. The exposure was terminated after 10 weeks. Biological parameters monitored were: phytoplankton and periphyton taxa, numbers, pigment concentrations and productivity; zooplankton taxa and numbers; macroinvertebrate taxa and numbers; macrophyte biomass. The amount of parent substance and its primary degradate were measured in water 7 times over the course of the study. Statistical analyses of populations and community data were used to determined treatment-related effects. At the end of the exposure period, the original species were well established within the microcosms and many additional species had colonized the systems. The data collected during the exposure phase were sufficient to determine that treatment-related reductions in the phytoplankton population occurred. Treatment-related effects were not detected in the other communities examined (periphyton, zooplankton, and macroinvertebrates).
Key words: marine, microcosm, antifoulant, community