Peter Beckett

Ecosystem recovery after emission reductions: Sudbury, Canada

A case history is presented describing the ecosystem changes that accompanied the nearly 90% reduction of SO2 and metal particulate emissions from Sudbury smelters during the past 25 years. The instances of severe ground-level fumigations that caused acute damage to vegetation in an area of approximately 1,000 km2 have been nearly completely eliminated. Significant improvements in water quality have also occurred in many of the estimated 7,000 acid-damaged lakes. Several species of acid-sensitive phytoplankton, Zooplankton and insects have invaded lakes where improvements have occurred. Epiphytic lichens have reinvaded the former “lichen desert” that once extended out 7 km from the smelters. Sensitive species such as Evernia mesomorpha and Usnea hirta now exist throughout the area. The vascular plant communities have been relatively slow to recover in the most severely damaged terrestrial areas. Metal-tolerant grasses (e.g. Agrostis scabra. Deschampsia caespitosa) were the first species to invade the barrens. Acid- and metal-contamination of soil, severe microclimate conditions, and the damaging effects of insect pests appear to delay recovery of terrestrial ecosystems. Recovery rates of aquatic ecosystems are also affected by a suite of physical, chemical and biotic interactions and many lakes remain severely damaged.

An evaluation of extractants for assessment of metal phytoavailability to guide reclamation practices in acidic soilscapes in northern regions

Abedin, J., Beckett, P. and Spiers, G. 2012. An evaluation of extractants for assessment of metal phytoavailability to guide reclamation practices in acidic soilscapes in northern regions. Can. J. Soil Sci. 92: 253-268. Although soil organic matter and nutrient bioavailability in metal-impacted soilscapes of Sudbury, Ontario, are potentially limiting full ecological recovery, total metal content was used as the critical driver for a 2008 ecological risk assessment. The current greenhouse study evaluated chemical extractants to predict bioavailability of nutrients and contaminant metals to indigenous grasses (Deschampsia). Single extraction methods (0.01 M strontium nitrate, water, 0.01 M calcium chloride, 0.1 M sodium nitrate, 1.0 M ammonium nitrate, 0.1 M lithium nitrate, 1.0 M magnesium chloride, 0.11 M acetic acid, 1.0 M ammonium acetate, 0.05 M ammonium-EDTA, pore water) were examined to assess availability of potentially phytotoxic metals and nutrients in smelter-impacted soils. Extraction procedures to predict phytoavailability were either soil concentration or plant tissue concentration and element dependent. Total and extractable metal concentrations were more correlated for regional contaminant metals (e.g., copper, lead, arsenic, selenium) released by the smelting industry than non-contaminant ones (e.g., iron, calcium, potassium, boron, zinc, molybdenum). The lack of relationship between total and extractable concentrations for most non-contaminant metals suggests total concentration is not a good indicator of phytoavailability for nutrient elements. Stronger correlations between shoot tissue and extractable concentrations were observed for less aggressive extractants (pore water, water, lithium nitrate) reflecting their suitability in predicting phytoavailability over most aggressive ones (except ammonium nitrate).

Comparative Soil Metal Analyses in Sudbury (Ontario, Canada) and Lubumbashi (Katanga, DR-Congo)

DR-Congo is a main world producer of copper (Cu) and cobalt (Co). Several hydrometallurgical plants and smelters also produced zinc, arsenic, and cadmium as by-products. In Sudbury (Canada), the production of nickel, copper and other metals has been maintained at high levels while industrial SO2 emissions have been reduced by approximately 90% through combination of industrial technological developments and legislated controls. Metal analysis in the present study revealed that the levels of copper and cobalt in soils from mining sites in the Lubumbashi (DR-Congo) were up to 200 fold higher compared to contaminated Sudbury sites and tailings. Zinc content in soil samples from some mining areas in Lubumbashi was at least 70 times higher compared to samples from the Sudbury area. Nickel content in soil samples from Lubumbashi were much lower compared to the Sudbury Region samples. Overall, this study confirms that the African Copper belt region is among the ten most polluted areas in the world.

Metal Content in Soil and Black Spruce (Picea mariana) Trees in the Sudbury Region (Ontario, Canada): Low Concentration of Arsenic, Cadmium, and Nickel Detected near Smelter Sources

Several studies have reported high metal concentrations in soil within the vicinity of smelters in the Sudbury (Ontario) region. Continued investigation and monitoring of soil and vegetation are essential to the understanding of ecosystem recovery following the reduction of emissions from smelters and the establishment of a reforestation program. The concentrations of Cd, Co, Cu, Fe, Ni, and Zn, found in the present study were within the limits set by Ontario Ministry of Environment and Energy (OMEE) guidelines even in sites within the vicinity of the Falconbridge Smelters. The levels of these elements in black spruce (Picea mariana) tissues were much lower and far below the toxic levels for vegetation. This is the first documented report of metal content in black spruce populations in the Sudbury region.

Molecular and ecological characterisation of plant populations from limed and metal-contaminated sites in Northern Ontario (Canada): ISSR analysis of white birch (Betula papyrifera) populations

The Greater Sudbury region in Northern Ontario is known as one of Canadas most ecologically disturbed regions because of the effects of heavy metal pollution. The main objectives of the present study were to assess the effects of soil liming of sites contaminated with metals on species richness and abundance, forest health in general, and to determine the level of genetic variability in white birch populations from Northern Ontario. Shannon-Wiener diversity index and tree species richness values were higher in populations from limed and control sites compared to the unlimed areas. A significant improvement in forest population health (measured using a scale of 1 to 10) in limed sites over the unlimed areas was observed. Key results revealed no significant difference for metal content in white birch (Betula papyrifera) leaves from limed compared to unlimed sites. But higher levels of Al, Ca, Mg, Mn, Ni, Sr, and Zn in leaves compared to the bioavailable amount in soil were observed. The levels of genetic variability in white birch populations were moderate to high, ranging from 30% to 79% of polymorphic loci. A high level of genetic variability such as observed in the present study is usually associated with long term sustainability in plant populations. No association was found between metal accumulation in soil or plants and the levels of genetic variation.

Liming of Acid and Metal Contaminated Catchments for the Improvement of Drainage Water Quality

A 38 ha near-barren experimental catchment area near an abandoned Cu and Ni smelter in Sudbury, Canada was treated with 410 tons of coarse dolomitic limestone in 1994. An additional 54 tons of pelletized fine dolomite were added to 15 wetlands within the experimental catchment in 1995. The treatments significantly increased the pH and base cation concentrations in the outlet stream. Cu and Ni concentrations initially rose after the wetland treatment, but then declined to levels below those of the reference site. Bioassay tests revealed that the toxicity of the drainage water was greatly reduced by the liming, but some localized inputs of highly toxic groundwater still posed a problem for aquatic biota. The pH of surface water in the wetlands has been maintained at >6.0 for over 4 years. The wetland liming appeared to be highly effective at neutralizing drainage water, however there may be some adverse effects on wetland plant communities as a consequence.

Total and bioavailable metals in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo): relation to genetic variation in plant populations

Knowledge of total and bioavailable metal contents in soil is important for regional risk assessment and management. The main objective of the present study was to analyse the concentrations of metals in soils in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo). Genetic variation of plant populations was investigated to assess the potential impact of metal contamination on forest sustainability. The levels of copper, cobalt, zinc, arsenic, and lead were significantly higher (up to 200-fold) in mining sites in the Lubumbashi compared to the most highly contaminated Sudbury sites. The nickel content in soil samples from Lubumbashi was much lower compared to Sudbury region samples. Only 3.5% and 4 % of total copper and nickel, respectively, were phytoavailable, with values of 6%, 5.7%, 3.6%, and 5.4% for cobalt, magnesium, manganese, and zinc, respectively. There were significant positive correlations between total metal and phytoavailable metal concentrations for copper (r=0.99), nickel (r=0.86), cobalt (r=0.72), strontium (r=0.71), and zinc (r=0.66). Although genetic variation was high in Picea glauca populations from the Sudbury region, no association was found between metal contamination levels and genetic variation within and among the P. glauca populations.

Genetic analysis of Pinus banksiana and Pinus resinosa populations from stressed sites contaminated with metals in Northern Ontario (Canada)

The Sudbury region in Canada is known for the mining and smelting of high-sulphide ores containing nickel, copper, iron and precious metals. Although reports provide information of metal levels in soil and plants, knowledge of genetic effects on plants growing in contaminated areas is limited. The main objective of this study was to characterise the level of genetic diversity in Pinus banksiana and Pinus resinosa populations from the Sudbury (Ontario) region using microsatellite markers. Soil samples were analysed for concentrations of metals. High levels of metal contents in soil were observed within short distances of the smelter compared with control sites. The level of genetic diversity was very low for P. resinosa populations and moderate for P. banksiana samples. Observed heterozygosity was fivefold higher in P. banksiana populations than P. resinosa populations studied. Overall, 17 and 24% of the total genetic diversity were attributed to differences among populations for P. banksiana and P. resinosa, respectively. In general, the inbreeding was significantly higher in P. resinosa populations than P. banksiana populations and gene flows were relatively low in both species. No significant trend of the levels of genetic diversity for metal contaminated and uncontaminated sites was found.

Progress in Establishing Wetland Plants in Permanently Flooded UraniumTailings

Abstract Trials are taking place on flooded pyritic uranium tailings near the city of Elliot Lake, Ontario to establish deep water aquatic plants. It is anticipated that the wetland eventually formed will produce organic matter that will hinder oxygen penetration into the tailings and help to keep acid production to a minimum. In 1993, plots and vegetation islands of cattail, common reed, beaked sedge and wool rush were transplanted into water less than 0.75 m deep. By 1995, these plants had overcome any transplant shock and islands of several species were expanding. In 1995, a large scale transplant was undertaken to establish vegetation in deeper water. A total of 50 sites of varying depths were established within Rio Algom Limiteds Quirke Waste Management Area (WMA). These sites were planted during the month of August with 10 units of plant material with substrate from their source wetland. The term ‘unit‘ represents 2 different planting methods. One method involved placing plant roots/rhizomes and su...

Successes in Application of Biotechnologies to Mine Land Remediation in the Russian Sub-Arctic

Abstract Sub-Arctic regions, previously considered one of the largest pristine ecosystems in the world, are being subjected to increasing pressure from mining and smelting activities. The minerals industry has contributed significantly to environmental damage and deterioration in the Russian sub-Arctic. Despite a significant reduction in gaseous and particulate emissions in the recent decades, the continuing air pollution and accumulation of potentially toxic metal levels in surface soils have promoted soil erosion and nutrient depletion in topsoils that inhibit vegetation recovery near the industrial complexes in the Kola Peninsula. These cumulative impacts on regional ecosystems are further exacerbated by the changing climatic conditions. The effectiveness of rehabilitation programs initiated in 2003–04 is largely dependent on the ongoing decrease of pollutant loadings, on the improvement of physical, chemical, and biological conditions of regional soils, and also on the effectiveness and suitability of the evolving remediation technology. The pace of rehabilitation using diversified and newly developed improved remediation technologies to enhance sustainable environmental management and regional economic development needs to be accelerated.