Mercury Cycling in the Water Column of a Seasonally Anoxic Urban Lake (Onondaga Lake, NY)

Jacobs, L. A.; Klein, S. M.; Henry, E. A.

doi:10.1007/978-94-011-0153-0_59

Cited by 7 publications

(3 citation statements)

References 7 publications

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“…With the onset of stable stratification over the summer, PHYTO‐Hg levels in the respective strata diverged. With respect to the hypolimnetic Hg results, our PHYTO‐Hg data concur nicely with the lake‐water Hg trends found in pristine Little Rock Lake, Wisconsin, USA, and urban Onondaga Lake, New York, USA, where Hg levels peaked at the end of summer in these stratified systems [21, 22]. If samples had been collected during fall mixes, we may have seen similar Hg values again between limnetic depths.…”

Section: Discussionsupporting

confidence: 82%

Seasonal mercury levels in phytoplankton and their relationship with algal biomass in two dystrophic shield lakes

Kirkwood

Chow‐Fraser

Mierle

1999

Enviro Toxic and Chemistry

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Abstract-Our study focused on the seasonal dynamics of total Hg in the phytoplankton (living and dead) of two dystrophic shield lakes (Mouse and Ranger). Phytoplankton samples were taken from metalimnetic and hypolimnetic depths in the euphotic zone and were collected and analyzed using ultraclean techniques. In both lakes, phytoplankton Hg (PHYTO-Hg) levels (pg/L) in the metalimnion did not significantly change among dates over the season, although Ranger Lake exhibited significant differences between Hg values measured at the beginning and end of the season. In contrast, PHYTO-Hg significantly increased in the hypolimnia of both lakes by the end of the season. Combined influences of external Hg inputs, remineralization, phytoplankton sedimentation, and increased methylmercury production in the hypolimnia over the season may have contributed to these trends. A highly significant positive relationship existed between PHYTO-Hg levels and whole-water Hg levels (r 2 ϭ 0.90), and the mean bioconcentration factor for Hg between the water column and phytoplankton was significantly higher in the hypolimnion compared to the metalimnion for both lakes. In most cases, parameters associated with algal biomass had significant positive correlations with PHYTO-Hg levels. Weight-specific PHYTO-Hg (pg/mg dry weight) varied significantly over the season, and there were interlake differences with respect to seasonal trends. On the basis of these results, we recommend that future sampling regimes include collection of phytoplankton at different limnetic depths throughout the season to account for spatial and temporal variations. Weight-specific Hg levels in phytoplankton could not be explained well by the parameters tested, and the only significant regressions were with parameters reflecting algal biomass. This study provides in situ evidence of Hg accumulation in lake phytoplankton as a function of algal biomass on a seasonal basis (as opposed to biodilution) and stresses the need to confirm these trends in other lake systems.

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Section: Discussionsupporting

confidence: 82%

Seasonal mercury levels in phytoplankton and their relationship with algal biomass in two dystrophic shield lakes

Kirkwood

Chow‐Fraser

Mierle

1999

Enviro Toxic and Chemistry

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“…For example, the MeHg:TotHg ratios for most parameters typically resemble more pristine or non-contaminated sites. Contaminated sites (dashed boxes): 6, eutrophic lake influenced by urban sources in Saskatchewan, Canada (urban wastes; Jackson 1986); 7, reservoir and pond in Wanshan, China (Hg mining; Horvat et al 2003); 8, Lahontan Reservoir, Nevada, USA (gold/silver mining; Bonzongo et al 1996); 9, Onondaga Lake, New York (chloralkali plant; Henry et al 1995, Jacobs et al 1995; 9A, maximum for epilimnion; 9B, maximum for hypolimnion); 10, Clay Lake, Ontario (chloralkali plant; Parks et al 1989; 10A, maximum for epilimnion; 10B, maximum for hypolimnion). 8), remote lakes appear to produce as much MeHg as Clear Lake, but from approximately one to two orders of magnitude lower TotHg.…”

Section: Biotamentioning

confidence: 99%

Is Clear Lake Methylmercury Distribution Decoupled From Bulk Mercury Loading

Suchanek

Eagles‐Smith

Harner

2008

Ecological Applications

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Clear Lake is the site of the abandoned Sulphur Bank Mercury Mine, active periodically from 1873 to 1957, resulting in approximately 100 Mg of mercury (Hg) being deposited into the lake's ecosystem. Concentrations of total (primarily inorganic) Hg (TotHg) in Clear Lake are some of the highest reported worldwide for sediments (up to 4.4 x 10(5) ng/g [ppb dry mass]) and water (up to 4 x 10(-1) microg/L [= ppb]). However, the ratio of methylmercury (MeHg) to TotHg at Clear Lake indicates that the methylation process is mostly decoupled from bulk inorganic Hg loading, with Hg in lower trophic level biota significantly less than anticipated compared with other Hg-contaminated sites worldwide. This may be due to several factors, including: (1) reduced bioavailability of Hg derived from the mine (i.e., cinnabar, metacinnabar, and corderoite), (2) the alkaline nature of the lake water, (3) the shallow depth of the lake, which prevents stratification and subsequent methylation in a stratified hypolimnion, and (4) possible dilution of MeHg by a highly productive system. However, while bulk inorganic Hg loading to the lake may not contribute significantly to the bioaccumulation of Hg, acid mine drainage (AMD) from the mine likely promotes Hg methylation by sulfate-reducing and iron-reducing bacteria, making AMD a vehicle for the production of highly bioavailable Hg. If Clear Lake were deeper, less productive, or less alkaline, biota would likely contain much more MeHg than they do presently. Comparisons of MeHg:TotHg ratios in sediments, water, and biota from sites worldwide suggest that the highest production of MeHg may be found at sites influenced by chloralkali plants, followed by sites influenced by gold and silver mines, with the lowest production of MeHg observed at cinnabar and metacinnabar Hg mines. These data also suggest that the total maximum daily load (TMDL) process for Hg at Clear Lake, as currently implemented to reduce contamination in fishes for the protection of wildlife and humans, may be flawed because the metric used to implement Hg load reduction (i.e., TotHg) is not directly proportional to the critical form of Hg that is being bioaccumulated (i.e., MeHg).

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“…Almost all of these dams display periods of stratification and development of an anoxic hypolimnion in the deepest part of their reservoirs (International Commission on Large Dams, 2003). Stratified reservoirs exhibit a great potential for increased MMHg production in the hypolimnion of their water column and/or in the anoxic zone of their sediments (Parks et al, 1989;Bloom and Effler, 1990;Watras et al, 1994;Jacobs et al, 1995). Discharged waters also contain high levels of organic matters (OM) and hydrogen sulfides (RH 2 S).…”

Section: Introductionmentioning

confidence: 98%

Mercury sources and transformations in a man-perturbed tidal estuary: The Sinnamary Estuary, French Guiana

Muresan¹,

Cossa²,

Coquery³

et al. 2008

Geochimica et Cosmochimica Acta

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The distribution, partition and speciation of mercury (Hg) were studied along the redox gradient of an anthropogenically perturbed tropical estuary, the Sinnamary Estuary in French Guiana. This system is a partially mixed estuary characterized by an anoxic freshwater end-member, while the marine end-member consists of the Amazon Plume.The set up of an artificial oxygenation system in the anoxic freshwater end-member generates sharp gradients of major chemical species (iron, sulfides, etc.) coupled with intense organic matter (OM) turnover. The coexistence of oxygenated waters and dissolved sulfides in an organic rich environment depicts the Upper Sinnamary Estuary (USE: part of Sinnamary Estuary under the tidal influence but upstream of the salt intrusion) as a potential site for Hg methylation. The concentrations of all mercury compounds (HgT) in the unfiltered samples (HgT UNF ), in the dissolved (HgT D ) and particulate (HgT P ) phases of the USE average 11 ± 3, 6 ± 2 and 5 ± 3 (i.e. 600 ± 200 pmol g À1 ) pmol L À1 , respectively. Average concentrations of monomethylmercury (MMHg) in the unfiltered (MMHg UNF ), dissolved (MMHg D ) and particulate (MMHg P ) phases were 3.7 ± 1.0, 2.0 ± 0.9 and 1.8 ± 1.2 (i.e. 220 ± 130 pmol g À1 ) pmol L À1 , respectively. Water oxygenation and sulfides concentrations emerged to play a critical role in controlling MMHg levels. Additionally, iron cycling, acid-base mechanisms, and redox-dependent processes were involved in the MMHg partitioning between phases.Overall, the USE constitutes a biogeochemical reactor that gathers partitioning and methylation processes. The permanent MMHg inputs from the anoxic freshwater end-member combined with the intense endogenous Hg methylation ensures highMMHg levels in both dissolved and particulate phases. To illustrate, the USE exports 60 ± 20% more MMHg UNF than it imports: 5.5 ± 0.7 vs. 3.5 ± 1.2 kg year À1 .

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Mercury Cycling in the Water Column of a Seasonally Anoxic Urban Lake (Onondaga Lake, NY)

Cited by 7 publications

References 7 publications

Seasonal mercury levels in phytoplankton and their relationship with algal biomass in two dystrophic shield lakes

Seasonal mercury levels in phytoplankton and their relationship with algal biomass in two dystrophic shield lakes

Is Clear Lake Methylmercury Distribution Decoupled From Bulk Mercury Loading

Mercury sources and transformations in a man-perturbed tidal estuary: The Sinnamary Estuary, French Guiana

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