Metal Pools, Fluxes, and Budgets in an Acidified Forested Catchment on the Precambrian Shield, Central Ontario, Canada

Abstract

Atmospheric emissions of metals have decreased in North America; yet, metals remain an environmental concern due to their environmental persistence and toxicity to biota. In this study, pools and mass budgets were calculated for 15 metals in an acidified forested catchment in Central Ontario. Metals that were enriched in bulk deposition over background average values (As, Cd, Pb, Zn) were generally enriched in the forest floor and upper lake sediment. While the metal pool in vegetation is small compared with the soil pool, internal cycling of metals via litterfall is comparable to atmospheric deposition, soil water, and stream fluxes. Partitioning coefficients calculated from metal concentrations in soil water and bulk soil suggest that Cd, Mn, Ni, and Zn are the most mobile. The mineral soil and lake sediments were sinks for most metals, while the wetland was a source of metals during the study year, which was a drought year. Overall, lithogenic metals (Al, Ba, Co, Fe, Mn, Rb, Sr, Zn) primarily from a weathering source generally exhibited net export from the catchment, while metals contained in atmospheric pollution (As, Cd, Cr, Cu, Ni, Pb, V) exhibited net retention. Despite the acidified nature of the catchment, it functions to retain many pollutant metals.

A landscape-scale approach to examining the fate of atmospherically derived industrial metals in the surficial environment

“…The significance of atmospheric industrial metals across the wider landscape is likely to be more complex, reflecting rates of atmospheric deposition relative to sediment generation (by physical, biological and chemical weathering) and sediment transport rates (by aeolian, fluvial and colluvial processes). A substantial body of literature has focussed on quantifying the inputs, flows and retention of atmospherically derived industrial metals through watersheds using a mass balance approach, often in areas experiencing relatively high rates of industrial metal enrichment (Landre et al, 2010;Lindberg and Turner, 1988;Watmough and Dillon, 2007). However, despite collected aerosol samples universally recording industrial metal enrichment (e.g.…”

“…Arimoto et al, 1995;Huang et al, 2001;Marx et al, 2014b;Witt et al, 2006) there are few studies which examine the relative significance of the deposition of industrial metals across a variety of environmental archives (e.g. Landre et al, 2010;Rose et al, 2012;Starr et al, 2003;Watmough and Dillon, 2007), where they may potentially concentrate or dilute depending on the behaviour of individual metals (e.g. their particle reactivity) and hydrological and geomorphic processes.…”

The fate of atmospheric metal pollutants in the landscape, Snowy Mountains, south-eastern Australia

“…At a landscape scale, however, the distribution and abundance of anthropogenic metals in the terrestrial environment is known to be moderated by post-depositional processes which can remobilise metals originally derived from the atmosphere or cause metals to become more concentrated or diluted within surface sediments (Bacardit et al, 2012;Balogh et al, 2000;Brännvall et al, 2001b;Foster and Charlesworth, 1996;Klaminder et al, 2006b;Kober et al, 1999;Landre et al, 2010;Lidman et al, 2014;Lindberg and Turner, 1988;Salomons and Förstner, 1984a;Salomons and Förstner, 1984b;Starr et al, 2003;Steinnes and Friedland, 2006;Sutherland, 2000;Swain et al, 1992;Watmough and Dillon, 2007;Yang and Rose, 2005;Young, 2013). These processes are important because they control the degree to which atmospheric metals are incorporated into the environment and therefore determine their ecological impact (Kabata-Pendias and Mukherjee, 2007).…”

“…The significance of atmospheric industrial metals across the wider landscape is likely to be more complex, reflecting rates of atmospheric deposition relative to sediment generation (by physical, biological and chemical weathering) and sediment transport rates (by aeolian, fluvial and colluvial processes). A substantial body of literature has focussed on quantifying the inputs, flows and retention of atmospherically derived industrial metals through watersheds using a mass balance approach, often in areas experiencing relatively high rates of industrial metal enrichment (Landre et al, 2010;Lindberg and Turner, 1988;Watmough and Dillon, 2007).…”

“…Arimoto et al, 1995;Huang et al, 2001;Marx et al, 2014a;Witt et al, 2006) there are few studies which examine the relative significance of the deposition of industrial metals across a variety of environmental archives (e.g. Landre et al, 2010;Rose et al, 2012;Starr et al, 2003;Watmough and Dillon, 2007), where they may potentially concentrate or dilute depending on the behaviour of individual metals (e.g. their particle reactivity) and hydrological and geomorphic processes.…”