Ecologigal Conseouence of Acidig and Heaw-Metal
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Canadian Minzralogist Vol. 14, pp.47-57 (1976) ECOLOGIGALCONSEOUENCE OF ACIDIG AND HEAW-METAL DISCHARGESFROM THE SUDBURVSMELTERS L. M. WHITBY, P. M. STOKES, T. C. HUTCHINSON eNo G. MYSLIK Institute for Environmental Studies and. Department of Botany, University of Toronto, Toron:to, Ontarto. ABSTRACT trds vastes r6gions forestibres, par facidification du sol et les 6rosions terrestres majeures subs6quetrtes. Studies have been made of the effects on temes- De plus, les m6taux lourds fondus se sont accumu- trial and aquatic ecosysiemg of heavy-oetal emis- l6s jusqu'i de trds fortes concentrations sur une sions, sulfur dioxide, and acidic rain-induced grando 6tendue, et surtout dans les sols superficiels. problems, caused by smelting activities in the Sud- Ces niveaux 6taient toxiques, meme en fabsence de bury region. The effects have been profound. Phyto- dioxyde sulfurique, i une grande vari6t6 d'espdces plankton populations have been reduced from 2,000 solutions i 'negligible' 6tudi6es dans des extraits ou dans des cells,/ml to in many of the lakes close m6tal unique. 13s am6liorations du sol avec la to the Coniston smelter, alrd around both Falcon- chaux ont eu des effets dramatiques sur 1a crois- bridge and Copper Cliff. Levels of nickel (up to sance et la survie des plantes. La proportion de m6' 6.5 ppm) and colper (up to 0.2 ppm) occur in these tal s'est trouv6e r6duite, par la meme occasion, i lakes, and these, combinetl with increased acidity, comparer i etle des sols notr-amaiores. are major obstacles to survival of primary produc- Cfraduit Par le journal) ers. The whole food chain has suffered parallel and often even greater extinctions in these lakes and especially in those to the northwest. INmooucrroN For terrestrial systems, emissions of sulfur diox- ide have directly damaged very extensive areas of Aquatic and terestrial studies of possible forest, witl soil acidificatiron and subsequent major heary-metal effects were commenced around soil erosion. In addition to this, the smelted heavy Sudbury in 1968 to determine whether parti- metals have accumulated to very high concentra- culate emissions had caused changes in the tion$ over a wide area, especially in zurface soils. physical properties of the aquatic These levels were, even in the absence of sulfur chemical and and to dioxide, toxic to a wide range of species tested in and terrestrial ecosystems in the region, oxtracts or in single-metal solutions. Lime amend- determine possible long-term consequencesof ments to soil had dramatic effects on grofih and such emissions compared with sulfur dioxide. survival of plants. Metal uptake was found to be The very high accumulation of Ni and Cu correspondingly reduced compared with uptake on especially in soils and theil patterns of distribu- unamended so,ils. tion relative to soil depth and distance from the smelter have already been reported (e.g. & Rfsur,4€ Costescu & Hutchinsot 1972; Hutchinson Whitby 1,974;Whitby & Hutchinsot 1974). T\e Des 6tudes ont 6t6 effectu6es sur les effets des toxicity of soils over an area of many square €missions de m6tal lourd, de dioryde sulfurique et miles has been emphasized and the long-term problbmes des d'acides provoqu6s par la pluie et problems described. Studies have focused on caus6s par des activit6s de fusion dans la r6gion de the Coniston smelter, which was Sudbury, sur 6cosystBmes transects from des terrestres et aquati- previously continu- ques. ks etfets ont 6t6 importants. Les populations closed in 1972 but had run de phytoplancton ont 6t6 r6duite.s de 2,000 cellules/ ously since 1913. ml i des proportions n6gligeables dans plusieurs The water bodies in the Sudbury area are lacs pGs de la fonderie Coniston, et autour de Fal- mainly small Shield lakes and mine streams. conbridge et de Copper Cliff. Des niveaux de nickel In their natural state tlese lakes are typically (usqu'ir 6.5 ppm) et de cuiwe (jusqu'i 0.2 ppm) oligotrophic, soft-water, shallow and generally apparaissent dans ces lacs et ceux-ci combin6s avec with a low conductivrly, a low organic content uno acidit6 accrue, sont des obstacl.es majeurs i and with a poor buffering oapacity. The altera' la survie des producteurs premiers. Toute la chalne tion in the chemical status of the lakes close to do nourriture a connu des extinctions parallbles et smelting astivities m6me souvent plus grandes dans ces lacs et parti- Sudbury due to mining and culidrement dans ceux du nord-ouest. can be estimatedby selectinga range of lakes at Quant aux systdmes terrestres, les 6missions de different distances from a point source such as dioxyde sulfurique ont endommag6 directement de a single smelter and determining correlations 47 48 THE CANADIAN MINERALOGIST between distance and chemical parameters. were collected in June L969 and 1970 at sites Similarly, the biological changes *^nicl might at least 100 m from ro-adways.A1l sites were be occurring can be deter,minedbv field studies on hill tops, where the plumes from smelter (e.g. primary productivity, standing crop, algal stacks impinge most often. cell numberso species diversity) and by labora- In 1,969, natarul vegetation was collected tory bioassay of lake waters with standard test twice (June and August), at nine of the sites. organisms. In many instances,a speciespresent at one site Such data have been acquired over the past was absent at several others, especially at sites six years. The lakes selected range from 1.6 close to the smelter where plant cover and km to 12.0 km from the Coniston smelter. speciescomposition were poor. MarsRrAr,s AND METHoDs Analytical methods Methods for the analysis and determination Choice of tenestrial sampling areas of pH, conductivity, loss on ignition, total The Coniston smelter was selected as the heavy-metalconcentrations, water-soluble metals, focus for the terrestrial studies (Fig. 1). Conis- water-soluble sulfate etc. have been described ton is off the main ore bodies, and away from previously (Hutchinson & Costescu L972; Hut- dykes; no tailings are nearby, and only a small chinson & Whitby 7974, 1.975;Whltby 1974). area around it is covered by slag heaps. Samples of natural vegetation were washed Sites were chosen at distances from 0.g to to remove all surface contamination, rinsed in 50 km from the Coniston smelter. selected to 5 changesof deionized water, then dried for 48 traverse Dreisinger's 1970 isopleths @reisinger hours at 6O"C. O.2g plant material was predi- 1970). Soil samples from lOcmdepth profiles gested for 16 hours in 3 ml concentrated nitric- \5 \/ r'/ / / I L--j---J--J-1-J milss L==+_=J km Ftc.- l.-Sketch map of the Sudbury region, with sites marked for soil and vegetation samples and lakes in which.bioassays were carried out. The lines marked 20, l0 anC 5 join points indicating number of damaging fumigations noted in l97l (after Dreisinger 1970). ECOLOGICAL CONSEQUENCES OF DISCIIARGES FROM SUDBURY SMELTERS 49 perchloric acid (ratio 1:1), then heated to 75"C germinated before planting. After 28 days, the in a sandbath for 5 hours. Each sample was plants were harvested and treated in a similar diluted to 10 rnl with deionized water without manner to the field-experiment plants. filtering. Rainfall-dustfall samples were collected Aquatic studies throughout the sampling region during 1970 Most of the methods used in the algal bio- and l97I (Ilutchinson & Whitby 1975). assays of lake waters from the Sudbury region All samples were analyzed for Ni, Cu, Co, have been described in detail (Ilutchinson & N, Zt, Mn, and Fe by atomic-absorption spec- Stokes 1975). I-ake waters were collected from trophotometry. a ftmgo of water bodies arranged along a tran- sect south of the Coniston smelter (Fig. 1). Algal growth Bioassayslor seeding using root counts were expressedas cells per ml of original elongation as nt index lake-water sample. Algal cells were preserved The radicle elongation of germinated seedlings in the field using Lugol's iodine. was used as a method for assayingthe toxicity Water for laboratory bioassays was filtered of Sudbury soils, with root growth acting as an immediately after collection, to remove major index of soil response. A soil-water extract was debris. Four laboratory test organisms were obtained from each of the sites at three depths, used for the study of the potential ability of by shaking 33.3 g soil in 10O ml deionized wa- lake waters to support algal growth. The effect ter for 4 hours. of pH adustment and addition of nutrients on A series of bioassays was also performed to these lake-water sampleswas also tested by in- determine the effects of single-metal salts in creasing the pH of the acidic lake waters to nutrient solution (Whitby & Hutchinson 1974; 6.8 and by addition of a one-tenth strength so' whitby 1974). lution of Bolds Basal Medium (BBM), an in- organic algal nutrient solution. Field and greenhouse experiments Chemical methods were standard atomic- Field experiments were conducted during the absorption spectrophotometry for heavy metals summers of. 1,969-L971.Experiments were con- and a modified barium-chloride turbimetric ducted at nine sites - L.5, 1.7, I.9, 3.8, 7.4, method for sulfate. 1A.4,13.5, 19.3 and 49.8 km from the Coniston smelter. Four lm-square plots were set out at Rnsurts each site. One plot was left untreated, one plot fertilized with 100 g So-Green 7-7-7 ferllJtzer, Terrestrial studies one plpt was limed to pH 7, and the fourth The physical and chemical properties of the plot both limed to pH 7 and fertilized with 1O0g soils have been extensively reported (Ilutchin- So-Green 7-7-7 fertrlizer.