Endothall species selectivity evaluation: northern latitude aquatic plant community

Species selectivity of the aquatic herbicide dipotassium salt of endothall (Aquathol® K) was evaluated on plant species typically found in northern latitude aquatic plant communities. Submersed species included Eurasian watermilfoil (Myriophyllum spicatum L.), curlyleaf pondweed (Potamogeton crispus L.), Illinois pondweed (Potamogeton illinoensis Morong.), sago pondweed (Potamogeton pectinatus L.), coontail (Ceratophyllum demersum L.), elodea (Elodea canadensis Michx.) and wildcelery (Vallisneria americana L.). Emergent and floating-leaf plant species evaluated were cattail (Typha latifolia L.), smartweed (Polygonum hydropiperoides Michx.), pickerelweed (Pontederia cordata L.) and spatterdock (Nuphar advena Aiton). The submersed species evaluations were conducted in 7000 L mesocosm tanks, and treatment rates included 0, 0.5 1.0, 2.0, and 4.0 mg/L active ingredient (ai) endothall (dipotassium salt of endothall). The exposure period consisted of a 24-h flow through half-life for 7 d. The cattail and smartweed evaluation was conducted in 860 L mesocosm tanks, and the spatterdock and pickerelweed evaluations were conducted in 1600 L mesocosm tanks. Treatment rates for the emergent and floating-leafed plant evaluations included 0, 0.5, 2.0 and 4.0 mg/L ai endothall, and the exposure period consisted of removing and replacing half the water from each tank, after each 24 h period for a duration of 120 h. Biomass samples were collected at 3 and 8 weeks after treatment (WAT). Endothall effectively controlled Eurasian watermilfoil and curlyleaf pondweed at all of the application rates, and no significant regrowth was observed at 8 WAT. Sago pondweed, wildcelery, and Illinois pondweed biomass were also significantly reduced following the endothall application, but regrowth was observed at 8 WAT. Coontail and elodea showed no effects from endothall application at the 0.5, 1.0, and 2.0 mg/L application rates, but coontail was controlled at 4.0 mg/L rate. Spatterdock, pickerelweed, cattail, and smartweed were not injured at any of the endothall application rates

Long-term effects of dredging operations program. Interim report: Long-term evaluation of plants and animals colonizing contaminated estuarine dredged material placed in both upland and wetland environments

47 p.Contaminated sediment was dredged from Black Rock Harbor, Connecticut, in October 1983 and placed in aquatic, upland, and wetland environments as part of the Field Verification Program (FVP), conducted during the period 1981-1986. Laboratory tests were conducted on the sediment prior to dredging to evaluate potential contaminant mobility under each of the disposal alternatives. Prior to dredging for upland disposal and wetland creation at the FVP field site, upland tests (i.e., plant and earthworm bioassays) and wetland tests (i.e., plant, sandworm, snail, and mussel bioassays) were conducted. Laboratory test results were subsequently field verified at the field test site at Tongue Point, Bridgeport, CT. The results of the upland disposal and wetland creation portions of the FVP, and the changes occurring since completion of the FVP for each disposal environment, are summarized herein. The emphasis of this report is on the contaminant mobility of heavy metals. This interim report includes data collected through 1989. Contaminant mobility and the progressive development of the upland and wetland ecosystems at this site will be evaluated until September 1995.http://gbic.tamug.edu/request.ht