Seasonal Cycling and Transport of Mercury and Methylmercury in the Turbidity Maximum of the Delaware Estuary

Gosnell, K. J.; Balcom, Prentiss H.; Ortiz, V.; DiMento, Brian P.; Schartup, Amina T.; Greene, Richard A.

doi:10.1007/s10498-015-9283-x

Cited by 36 publications

(41 citation statements)

References 49 publications

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“…Sediment THg (often used as an indicator of Hg loading) was highest near the industrial Wilmington sites and the urban area of Philadelphia and decreased as development decreased downstream, although within site variability was high at the most contaminated sites, indicating an uneven distribution of Hg contamination in the sediments. Similar patterns of loading were observed in past studies conducted on THg in sediments and striped bass on the Delaware River (Greene 2007; Reinfelder and Totten 2006; Gosnell et al 2015), which indicate that Hg in sediment and in surface water follow the same general pattern; Hg is more elevated nearer to the shoreline, and in the upper portion of zone 5 as defined by the Delaware River Basin Commission (Greene 2011). This zone begins at the DE/NJ/PA border and corresponds with the highly industrialized region near Wilmington, DE, and is also a transitional zone between the more freshwater upper portion of the estuary and the more saline lower bay, encompassing the ETM where we also observed comparatively higher MeHg concentrations in small fish.…”

Section: Discussionsupporting

confidence: 81%

“…In addition, grab samples of the top 2 cm of sediment were taken from 18-20 locations at each site for analysis to determine the range of organic carbon (measured as percent loss on ignition (%LOI)) and THg. A single surface water grab sample was taken at high tide at each site using trace-metal clean technique and filtered (0.45μm quartz fiber filter) in a laminar flow hood within 12h for dissolved and particulate MeHg and THg, as well as dissolved organic carbon (DOC) and chlorophyll (chl a ) (Balcom et al 2015; Gosnell et al 2015). Surface water temperature, salinity, dissolved oxygen, and pH was measured on site using a hand-held sensor (Hydrolab MiniSonde MS5, Hach).…”

Section: Methodsmentioning

confidence: 99%

“…PCB and mercury concentrations, particularly in the industrialized corridor, have lead in part to the establishment of fish consumption advisories throughout the estuary (DE Department of Natural Resources and Environmental Control 2016; NJ Department of Environmental Protection 2016). Our recent study in the estuarine turbidity maximum (ETM) of the river examined the relative importance of watershed and sediment sources of MeHg to the upper estuary (Gosnell et al 2015). …”

Section: Introductionmentioning

confidence: 99%

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Methylmercury Bioaccumulation in an Urban Estuary: Delaware River, USA

Buckman

Taylor

Broadley

et al. 2017

Estuaries and Coasts

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Spatial variation in mercury (Hg) and methylmercury (MeHg) bioaccumulation in urban coastal watersheds reflects complex interactions between Hg sources, land use, and environmental gradients. We examined MeHg concentrations in fauna from the Delaware River estuary, and related these measurements to environmental parameters and human impacts on the waterway. The sampling sites followed a north to south gradient of increasing salinity, decreasing urban influence, and increasing marsh cover. Although mean total Hg in surface sediments (top 4cm) peaked in the urban estuarine turbidity maximum and generally decreased downstream, surface sediment MeHg concentrations showed no spatial patterns consistent with the examined environmental gradients, indicating urban influence on Hg loading to the sediment but not subsequent methylation. Surface water particulate MeHg concentration showed a positive correlation with marsh cover whereas dissolved MeHg concentrations were slightly elevated in the estuarine turbidity maximum region. Spatial patterns of MeHg bioaccumulation in resident fauna varied across taxa. Small fish showed increased MeHg concentrations in the more urban/industrial sites upstream, with concentrations generally decreasing farther downstream. Invertebrates either showed no clear spatial patterns in MeHg concentrations (blue crabs, fiddler crabs) or increasing concentrations further downstream (grass shrimp). Best-supported linear mixed models relating tissue concentration to environmental variables reflected these complex patterns, with species specific model results dominated by random site effects with a combination of particulate MeHg and landscape variables influencing bioaccumulation in some species. The data strengthen accumulating evidence that bioaccumulation in estuaries can be decoupled from sediment MeHg concentration, and that drivers of MeHg production and fate may vary within a small region.

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Section: Discussionsupporting

confidence: 81%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Methylmercury Bioaccumulation in an Urban Estuary: Delaware River, USA

Buckman

Taylor

Broadley

et al. 2017

Estuaries and Coasts

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“…of particulate [MeHg] in coastal waters along the North American Coast. Data sources: this study, Benoit et al (1998); Balcom et al (2008); Balcom et al (2013); Chen et al (2014); Gosnell et al (2015); Guentzel et al (2001); Sunderland et al (2010); Hollweg et al (2009); see Table S1 in supporting information.…”

Section: Figurementioning

confidence: 99%

Mercury bioaccumulation increases with latitude in a coastal marine fish (Atlantic silverside,Menidia menidia)

Baumann

Conover

Balcom³

et al. 2017

Can. J. Fish. Aquat. Sci.

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Human exposure to the neurotoxic methylmercury (MeHg) occurs primarily via the consumption of marine fish, but the processes underlying large-scale spatial variations in fish MeHg concentrations [MeHg], which influence human exposure, are not sufficiently understood. We used the Atlantic silverside (Menidia menidia), an extensively studied model species and important forage fish, to examine latitudinal patterns in total Hg [Hg] and [MeHg]. Both [Hg] and [MeHg] significantly increased with latitude (0.014 and 0.048 μg MeHg g−1 dw per degree of latitude in juveniles and adults, respectively). Four known latitudinal trends in silverside traits help explain these patterns: latitudinal increase in MeHg assimilation efficiency, latitudinal decrease in MeHg efflux, latitudinal increase in weight loss due to longer and more severe winters, and latitudinal increase in food consumption as an adaptation to decreasing length of the growing season. Given the absence of a latitudinal pattern in particulate MeHg, a diet proxy for zooplanktivorous fish, we conclude that large-scale spatial variation in growth is the primary control of Hg bioaccumulation in this and potentially other fish species.

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“…This special volume includes six papers based on some of these AGU talks, and reading these papers you can clearly see many connections to topics worked on by Tom over his career. Atmospheric deposition of trace elements by wet and dry routes to coastal waters is discussed in the Gao et al (2016) paper, while estuarine processing of organic matter in the Danshuei Estuary, Taiwan, is discussed by Wu et al (2016) and mercury cycling in the Delaware estuary is covered in the Gosnell et al (2016) paper. It should be noted that the Wu et al (2016) paper was submitted just prior to its senior author's (K. K. Liu) passing, a friend and colleague whom we will greatly miss.…”

mentioning

confidence: 99%