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Title: Bioenergetic effects of Black Rock Harbor dredged material on the polycheate 'Nephtys Incisa' : a field investigation
Authors: PTI Environmental Services.
Science Applications International Corporation
United States. Environmental Protection Agency.
Environmental Research Laboratory (Narragansett, R.I.)
Field Verification Program (Aquatic Disposal)
Johns, D. Michael.
Gutjahr-Gobell, Ruth.
Keywords: Benthos
Benthic community
Dredged material
Dredging spoil
Black Rock Harbor
Marine pollution
Aquatic pollution
Environmental effects
Water quality bioassay
Nephtys Incisa
Marine polychaete
Publisher: Environmental Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Description: Technical Report
Abstract: The primary objectives of this study were to test the applicability of biological energy techniques for use with dr edged material, to field verify the bioenergetic responses observed in the laboratory, and to determine the degree of correlat ion between the bioaccumulation of cont aminants and bioenergetic responses. Biological energetics techniques were applied to Nephtys incisa, an infaunal polychaete dominant in the benthic community at the Central Long Island Sound disposal site. Comparisons were made between the effects of Black Rock Harbor (BRH) dredged material on the physiology and bioenergetics of juvenile Nephtys incisa exposed in the laboratory and the same responses from individuals obtained in the field following the controlled disposal of BRH material. Exposure regimes used in the laboratory studies were similar to the exposure environments that had been predicted around the BRH disposal site. The laboratory data indicated that Nephtys inaisa juveniles living in contaminant-free bedded sediment are physiologically affected when exposed to BRH suspended sediment. Physiological dysfunction observed as a result of laboratory exposure to BRH material included increased maintenance costs, reduced tissue growth, and lowered net growth efficiency. Physiological changes were also noted in juvenile Nephtys inaisa collected from the area of the disposal mound. Individual worms collected from stations within the perimeter of the disposal mound (400-m radius) exhibited significant changes in aerobic metabolism and ammonia excretion rates. There was a seasonal pattern in the bioenergetic responses coupled to seawater temperature. The metabolic activity of N. incisa was minimal at temperatures below 11°C but increased by factors of 2 to 3 between 11° and 21°C. Within this latter range of temperatures, when metabolic activity was elevated, spatial differences were noted in the bioenergetic responses that parallel exposure to BRH material at the disposal site. Laboratory derived exposure-response relationships indicated a response threshold of 30 to 50 mg/𝓁 suspended BRH sediment. Field exposures were estimated from empirical physical and chemical data and field tissue residue values. These estimates indicate that when significant differences were reported for bioenergetic responses between the reference station and within the perimeter of the disposal mound, the exposures ranged from 51 to 131 mg/𝓁 BRH suspended sediment at the sediment/water interface. This range of values is similar to that reported to cause effects under laboratory conditions. There was, however, an important difference between the laboratory and field bioenergetic responses. The field data for stations 200E and 400E indicate significant decreases in respiration rates relative to the REFS station, while the laboratory treatments resulted in significant increases in respiration rates with increasing concentrations of BRH sediment. Multiple routes of exposure are suggested as an explanation for this apparent inconsistency between laboratory and field respiration rates since field N. incisa were exposed to both bedded and suspended sediments while the laboratory studies used only suspended sediments. Previous laboratory studies using bedded sediment exposure to N. incisa showed comparable patterns of response to the field data. NOTE: This file is large. Allow your browser several minutes to download the file.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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