Longitudinal estimates of sediment-water diffusive flux of PCB congeners in the Houston Ship Channel

Howell, Nathan; Rifai, Hanadi S.

doi:10.1016/j.ecss.2015.06.024

Cited by 4 publications

(6 citation statements)

References 21 publications

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“…To conclude, this means that the estimated risk for our case study is an underestimation rather than an overestimation, even considering the lower levels of the 90% confidence intervals. It also confirms the importance of taking into account advective dispersion pathways in risk assessments (e.g., Erickson et al, 2005;Davis et al, 2007;Reible, 2014;Howell and Rifai, 2015;Dellapenna et al, 2020).…”

Section: The Case Studysupporting

confidence: 68%

“…It is not currently known whether climate change will cause stronger and/or more frequent storms in the area, but if these occur, wind-wave currents will pose a greater problem than today for the dispersion of contaminants and fiber particles. Other studies have also shown that sedimentto-water dispersion of PCBs increases during hurricanes (Howell and Rifai, 2015;Dellapenna et al, 2020).…”

Section: The Case Studymentioning

confidence: 85%

“…Uncertainties refer to knowledge uncertainty, or epistemic uncertainty, and uncertainty in the natural variation, so called aleatory uncertainty or genuine uncertainty. For example, Howell and Rifai (2015) showed a variation in PCB fluxes due to storm surges and flooding, and Dahlberg et al (2021) showed that particle resuspension may occur even at gentle disturbance of the sediment surface. For a better understanding, measurements and analyzes performed under different environmental, seasonal and hydrological conditions are still needed.…”

Section: Discussionmentioning

confidence: 99%

“…The results further indicate that the fiberbank will likely continue to negatively affect the surrounding ecosystem if nothing is done to prevent dispersion. This outcome is probably also true for many other fiberbank deposits, and for contaminated sediments located in shallow waters (e.g., Butcher and Garvey, 2004;Davis et al, 2007;Howell and Rifai, 2015). Even archived contaminants may become exposed to dispersion because of sediment scouring during extreme weather-events like hurricanes (Dellapenna et al, 2020).…”

Section: The Case Studymentioning

confidence: 94%

“…It is known that major flood events may re-mobilize contaminants from contaminated sediments (e.g., Haag et al, 2001;Westrich and Förstner, 2005;Roberts, 2012) and that propeller wash may re-suspend contaminated sediments (e.g., Michelsen et al, 1998;Superville et al, 2014;Prygiel et al, 2015). It has also been shown that extreme weather-events like hurricanes may increase dispersion of contaminants from contaminated sediments (Howell and Rifai, 2015;Dellapenna et al, 2020). Only a few studies have considered submarine landslides and other underwater mass movements as a pathway for contaminant dispersion, but they have been highlighted in a review paper by Kane and Clare (2019).…”

Section: Introductionmentioning

confidence: 99%

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Assessing the Risk of Contaminant Dispersion From Fibrous Sediments of Industrial Origin

et al. 2021

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Unregulated discharges of wastewater from pulp and paper factories resulted in the formation of relatively thick organic (cellulose) rich sediments in shallow waters along the Swedish coast. These deposits are known as fiberbanks and are contaminated by persistent organic pollutants (POPs), metals and methylmercury, which can be dispersed by diffusion and advective processes coupled to propeller wash, high river discharges, strong wind waves and submarine landslides. Based on a case study of polychlorinated biphenyls (PCBs), one group of prevalent POPs in the fiberbanks, we present a probabilistic approach to estimate the potential risk of dispersion of fiberbank contaminants. The approach allows for estimation of the dispersal pathways that dominates the risk within a given time and provides more insight about the significance of various dispersion processes. We show that it is highly likely that chemical diffusion and advection triggered by ship-induced resuspension will disperse PCBs (sum of seven congeners; Σ7PCB) above a threshold level for environmental impact, while the likelihood of river and wind-wave generated resuspension dispersion pathways are lower (∼20%, respectively). We further show that there is approximately 5% likelihood that a submarine landslide will disperse Σ7PCB above the threshold level. The study implies that the governing parameters for risk assessment specifically should include reliable data on contaminant concentration, water depth above the fiberbank, estimation of concerned fiberbank areas, time duration of erosive fluid flows and measured diffusion. The approach provides insight into the importance of various dispersion processes. We suggest that it can be applied to support risk assessment, especially when there are limited available data and/or knowledge about the system under study.

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