Organic matter is a predominant control on total mercury concentration of near-surface lake sediments across a boreal to low Arctic tundra transect in northern Canada

被引：2

作者：

Galloway, Jennifer M. ^{[1
,2
,3
]}

Parsons, Michael B. ^{[4
]}

Ardakani, Omid H. ^{[1
]}

Falck, Hendrik ^{[5
]}

Fewster, Richard E. ^{[6
]}

Swindles, Graeme T. ^{[2
,3
,6
]}

Sanei, Hamed ^{[7
]}

Palmer, Michael J. ^{[8
]}

Nasser, Nawaf A. ^{[2
,3
]}

Patterson, R. Timothy ^{[2
,3
]}

机构：

[1] Geol Survey Canada, Nat Resources Canada Ressources Nat Canada NRCan R, Commiss Geol Canada, 3303-33rd St NW, Calgary, AB T2L 2A7, Canada

[2] Carleton Univ, Ottawa Carleton Geosci Ctr, Ottawa, ON K1S 5B6, Canada

[3] Carleton Univ, Dept Earth Sci, Ottawa, ON K1S 5B6, Canada

[4] Geol Survey Canada, Commiss Geol Canada, Nat Resources Canada Ressources Nat Canada NRCan R, 1 Challenger Dr, Dartmouth, NS B2Y 4A2, Canada

[5] Govt Northwest Terr, Diamonds Royalties & Financial Anal, POB 1320, Yellowknife, NT X1A 2L9, Canada

[6] Queens Univ, Geog & Chrono Ctr, Sch Nat & Built Environm, Univ Rd, Belfast BT7 1NN, North Ireland

[7] Aarhus Univ, Dept Geosci, Hoegh Guldbergs Gade 2 Bldg 1671, DK-8000 Aarhus, Denmark

[8] Aurora Res Inst, Aurora Coll, 5004-54 St, Yellowknife, NT X1A 2R3, Canada

来源：

SCIENCE OF THE TOTAL ENVIRONMENT | 2024年 / 954卷

基金：

加拿大自然科学与工程研究理事会;

关键词：

Mercury; Organic matter; Lake sediments; Subarctic; Climate change; Elemental geochemistry; GASEOUS ELEMENTAL MERCURY; FRESH-WATER ECOSYSTEMS; ROCK-EVAL PYROLYSIS; ATMOSPHERIC MERCURY; METHYL MERCURY; GRAIN-SIZE; ANTHROPOGENIC MERCURY; NORTHWEST-TERRITORIES; ACCUMULATION RATES; METHYLMERCURY FORMATION;

D O I：

10.1016/j.scitotenv.2024.176466

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Mercury (Hg) is a bioavailable and toxic element with concentrations that are persistently high or rising in some Arctic and subarctic lakes despite reduced atmospheric emissions in North America. This is due to rising Hg emissions to the atmosphere outside of North America, enhanced sequestration of Hg to sediments by climatemediated increases in primary production, and ongoing release of Hg from terrestrial reservoirs. To evaluate the influence of organic matter and other parameters on Hg accumulation in northern lakes, near-surface sediments were sampled from 60 lakes across a boreal to shrub tundra gradient in the central Northwest Territories, Canada. The organic matter of the lake sediments, assessed using programmed pyrolysis and petrology, is composed of a mixture of terrestrial, aquatic, and inert organic matter. The proportion of algal-derived organic matter is higher in sediments of lakes below treeline relative to shrub tundra sites. Total sedimentary Hg concentration is correlated to all organic matter constituents but is unrelated to latitude or lake position below or above treeline. The concentrations of Ag, Ca, P, S, U, Ti, Y, Cd, and Zn are also strong predictors of total sedimentary Hg concentration, indicating input from a common geogenic source and/or common sequestration pathways associated with organic matter. Catchment area is a strong negative predictor of total sedimentary Hg concentration, particularly in lakes above treeline, possibly due to retention capacity of Hg and other elements in local sinks. This research highlights the complexity of controls on Hg sequestration in sediment and shows that while organic matter is a strong predictor of total sedimentary Hg concentration on a landscape scale and across extreme gradients in climate and associated vegetation and permafrost, other factors such as catchment area and sources from mineralized bedrock are also important.

引用

页数：25