Sediment Resuspension during Cutterhead Dredging Operations

Hayes, Donald F.; Crockett, Timothy R.; Ward, Tim J.; Averett, Daniel E.

doi:10.1061/(asce)0733-950x(2000)126:3(153)

Cited by 22 publications

(26 citation statements)

References 2 publications

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“…Although suspended solids concentrations of 1000 mg l -1 or above are considered to be very high and environmentally unrealistic in the marine ecosystem (even in the vicinity of dredging and dumping sites), concentrations below this level are still of concern. Hayes et al (2000) reported SS of 500 mg l -1 within 500 m of a hydraulic dredging operation, and maybe even up to 800 mg l -1 as far as 1200 m away from a hopper dredger (LaSalle 1990). Our experiments demonstrate that although suspended solids in this range are unlikely to cause mortality in green grouper after prolonged exposure, sublethal changes due to respiratory distress, adverse growth and developmental effects are likely to occur in the long-term if exposures continue.…”

Section: Discussionmentioning

confidence: 99%

Chronic effects of suspended solids on gill structure, osmoregulation, growth, and triiodothyronine in juvenile green grouper Epinephelus coioides

Au¹,

Pollino²,

Wu³

et al. 2004

Mar. Ecol. Prog. Ser.

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Despite suspended solids being an important water-quality parameter in the regulatory process, very little is known about the risks of prolonged exposure to high concentrations of suspended solids in fish, especially marine species. In this study, the green grouper Epinephelus coioides, an important mariculture species with a wide geographic distribution, was exposed to various concentrations (0, 50, 100, 200, 1000 and 2000 mg l -1 ) of suspended solids for 6 wk. The results showed that exposure was not lethal at environmentally realistic concentrations, and no changes in food intake, growth and RNA:DNA ratio were observed. However, damages to gill structure, including epithelium lifting, hyperplasia in the pillar system, and reduction of epithelial volume, were clearly evident, and strongly correlated with suspended solid concentration exposure. Despite the observation that serum osmolarity and haematocrit values did not change, Na + , K + -ATPase activities and chloride cells of the gill lamellae were altered, indicating that fish were experiencing osmoregulatory stress. Reduction in levels of free triiodothyronine (T3) in serum further confirmed that fish were experiencing physiological stress with suspended solids exposure. The overall results suggested that prolonged exposures can cause sub-lethal stress and compromise fish health, even though the high suspended solids we delivered were in concentrations that have been reported in coastal environments as not lethal to green grouper. KEY WORDS: Suspended solids · Grouper · Gill structure · Triiodothyronine · Osmoregulation · Growth · RNA:DNA ratio Resale or republication not permitted without written consent of the publisher

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Section: Discussionmentioning

confidence: 99%

Chronic effects of suspended solids on gill structure, osmoregulation, growth, and triiodothyronine in juvenile green grouper Epinephelus coioides

Au¹,

Pollino²,

Wu³

et al. 2004

Mar. Ecol. Prog. Ser.

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“…Because releases are difficult and expensive to measure at a dredging site, little empirical data are available on their magnitude and the processes that drive them. Research has shown that dissolved and total contaminant concentrations can vary greatly in all dimensions at distances of 100 to 300 m from the dredge head due to variability in the dredging operations and dilution by turbulent diffusion in the water column (Hayes et al 2000). A few quantitative evaluations of contaminant release have been undertaken at dredging sites.…”

Section: The 4 Rs Of Environmental Dredgingmentioning

confidence: 99%

Dredging processes and remedy effectiveness: Relationship to the 4 Rs of environmental dredging

Bridges

Gustavson

Schroeder

et al. 2010

Integr Envir Assess & Manag

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Timely and effective remediation of contaminated sediments is essential for protecting human health and the environment and restoring beneficial uses to waterways. A number of site operational conditions influence the effect of environmental dredging of contaminated sediment on aquatic systems. Site experience shows that resuspension of contaminated sediment and release of contaminants occur during dredging and that contaminated sediment residuals will remain after operations. It is also understood that these processes affect the magnitude, distribution, and bioavailability of the contaminants, and hence the exposure and risk to receptors of concern. However, even after decades of sediment remediation project experience, substantial uncertainties still exist in our understanding of the cause-effect relationships relating dredging processes to risk. During the past few years, contaminated sediment site managers, researchers, and practitioners have recognized the need to better define and understand dredging-related processes. In this article, we present information and research needs on these processes as synthesized from recent symposia, reports, and remediation efforts. Although predictions about the effect of environmental dredging continue to improve, a clear need remains to better understand the effect that sediment remediation processes have on contaminant exposures and receptors of concern. Collecting, learning from, and incorporating new information into practice is the only avenue to improving the effectiveness of remedial operations.

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“…The hydrodynamic conditions of a river vary with many factors, including anthropogenic activities like dredging (Hayes et al, 2000;Je et al, 2007), trawling (Durrieu de Madron et al, 2005;Ferré et al, 2008), and operation of water conservation projects, and natural factors like wind, storm, and tide (Ferré et al, 2008;Pusceddu et al, 2005). Among these factors, water conservation projects play a key role in influencing the hydrodynamic conditions of a river.…”

Section: Introductionmentioning

confidence: 99%

Effect of water–sediment regulation of the Xiaolangdi Reservoir on the concentrations, bioavailability, and fluxes of PAHs in the middle and lower reaches of the Yellow River

Dong

Xia

Wang³

et al. 2015

Journal of Hydrology

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Keywords:Bioavailability Polycyclic aromatic hydrocarbons (PAHs) Suspended sediment (SPS) Dams Water conservation project Water quality s u m m a r yThe water-sediment regulation of the Xiaolangdi Reservoir is conducted to control the relationship between riverine runoff and sediment transport of the Yellow River; however, there is no research about the effect of water-sediment regulation on the bioavailability and fluxes of hydrophobic organic compounds (HOCs). In this study, water and suspended sediment (SPS) samples were collected downstream of the Xiaolangdi Reservoir before, during, and after the water-sediment regulation in 2013. The 16 priority polycyclic aromatic hydrocarbon (PAH) concentrations of freely dissolved, total dissolved, and SPS-associated were determined. During water regulation, water discharged from the reservoir at a high flow rate led to the resuspension of downstream sediment. During sediment regulation, the sediment ejected from the reservoir resulted in higher SPS concentrations than that during water regulation. Both the freely and total dissolved PAH concentrations in river water during sediment regulation were the highest, followed by the concentrations during water regulation and before regulation. The freely dissolved PAH concentrations in river water during the water-sediment regulation were 2-11 times higher than those before water-sediment regulation. This was due to the fact that the resuspended sediment during water-sediment regulation could release PAHs into water phase, and more contaminants were released from the SPS during sediment regulation than during water regulation. The fluxes of sediment and the 16 priority PAHs (R 16 PAHs) during water-sediment regulation contributed to 32.4% and 35.7% of their annual fluxes, respectively, which were higher than the contribution (22.6%) of water discharge. This study suggested that the water-sediment regulation might reduce the long-term retention of sediment and PAHs in the reservoir. However, the environmental risk of PAHs as well as other contaminants downstream of the reservoir and in the estuary might increase during that period. Therefore, the effect of water-sediment regulation on the bioavailability and environmental risk of HOCs should be considered in the operation and management of the Xiaolangdi Reservoir in the future.

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Sediment Resuspension during Cutterhead Dredging Operations

Cited by 22 publications

References 2 publications

Chronic effects of suspended solids on gill structure, osmoregulation, growth, and triiodothyronine in juvenile green grouper Epinephelus coioides

Chronic effects of suspended solids on gill structure, osmoregulation, growth, and triiodothyronine in juvenile green grouper Epinephelus coioides

Dredging processes and remedy effectiveness: Relationship to the 4 Rs of environmental dredging

Effect of water–sediment regulation of the Xiaolangdi Reservoir on the concentrations, bioavailability, and fluxes of PAHs in the middle and lower reaches of the Yellow River

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