Liming of acidified lakes and rivers in Norway

Acidification is one of the most serious environmental problems in Norway. International agreements to reduce emissions are the only acceptable solution to the acidification problem. The “Sulphur Protocol”, signed in Oslo in 1994, will certainly improve matters, but southern Norway will have large acidified areas for decades. Norwegian environmental authorities therefore carry out liming as a temporary alleviatory measure to reduce damage for freshwater ecosystems. In 1995, about NOK 92 mill, was spent on liming. Acidification has wiped out the salmon in 25 rivers, and they are threatened in another 28 rivers. Because of varying water flow and rapidly changing water quality, liming a Norwegian salmon river is a huge operation demanding sophisticated equipment. Eleven rivers carrying anadromous fish are being limed in 1995. The largest is the River Audna where liming has meant that a salmon stock could be reintroduced. Most rivers are limed using automatic lime dosers. The most sophisticated ones control the amount of lime using pH sensors and water flow to neutralize major episodes of acidic water flow, which regularly occur in Norwegian rivers.     

Liming of lakes,rivers and catchments in Norway

Despite a slight reduction in the level of acidic deposition in Norway, acidification of lakes and rivers continues. The Norwegian Liming Project (1979–84) demonstrated that lime treatment can be an effective measure against acidification of watercourses given appropriate adaptation to local conditions. Liming in Norway is difficult because of (1) large amounts of precipitation, (2) short retention time of lakes, and (3) episodic changes in water chemistry. In 1988 NOK 14 mill. has been allocated to operational liming and research. We report here on chemical and biological responses from lime treatment of a lake, a river and a catchment. Lake Store Hovvatn was limed in 1981 and successfully stocked with brown trout. Before reliming in 1987, fish growth had ceased, but increased post liming. The River Audna has been continuously limed since 1985. Sea trout fisheries have improved, and the stocking of Atlantic salmon smolts at the mouth of the river in 1986 has already resulted in the return of spawners. Liming of the entire terrestrial catchment to the pond Tjønnstrond in 1983 by helicopter was also successful; stocked brown trout have survived to the present.     

Mercury in fish muscle in acidified and limed lakes

The concentration of Hg in muscle was monitored during 10 to 12 years in different size and age groups of pike (Esox lucius) and perch (Perca fluviatilis). The study was performed in one reference and five lime treated lakes. Before liming, the highest levels of Hg in fish were measured in a lake with an annual mean pH just above 5.0. Lower levels were obtained both in lakes which were more acidified and in those which were less acidified. After the start of liming, the fastest and largest changes were obtained in the lakes which were moderately acid before liming (mean pH 5.4–5.8). In small perch, the Hg-concentration was markedly reduced in two years and showed an 80 % decrease in ten years. A slower response was registered in the lakes originally having about 0.5 units lower pH. In the most acidified lake (pH 4.9) the concentrations even increased the first years after liming, but decreased again later on. The possible mechanisms involved are discussed.     

Liming in Ontario: Short-term biological and chemical changes

The short-term results of a 5-yr experimental lake neutralization program involving whole-lake liming of Trout and Bowland Lakes are reviewed. Whole-lake liming did not prevent spring melt pulses of acid and Al in a zone situated under the ice nearshore. Liming did improve whole-lake water quality in a previously acidified lake (Bowland Lake) so that lake trout (Salvelinus namaycush) could be restocked successfully. In situ bioassays showed a statistically significant improvement in survival of overwintering lake trout eggs after liming. Lake trout fry exposed during spring melt also showed increased survival rates after liming except at one site in Trout Lake where liming did not prevent the occurrence of 100% mortality. The resident yellow perch (Perca flavescens) population in Bowland Lake exhibited short-term increases in survival and in recruitment the first year following neutralization. Growth rate responses differed among age cohorts. A preliminary shoal liming experiment in Laundrie Lake suggested that nearshore spawning shoals which are not necessarily protected by whole-lake liming may be protected by treatment with fine calcite gravel.     

Development of zooplankton in relation to lime treatment in two acidified lakes

Zooplankton has been studied in Lakes Östra Nedsjön and Ömmern (1974–94), two acidified lakes in South-Western Sweden. The former lake was first limed in 1971–73, and secondly in 1982. The first liming increased the pH-level from ca. 5.3 to 6, and the second one from ca. 5.8 to 7–7.5. The pH-value in Lake Ömmern was about 6.1 in 1973, but decreased to 5.3 in 1981, when liming raised the value to 6.5–7. After the first liming in Lake Ö. Nedsjön, the rotatorians represented in average 1% of the total volume of zooplankton. Among the copepods, which made up ca. 22% of the volume, Cyclops was frequent, and both Eudiaptomus gracilis and Heterocope appendiculata were recorded. After the second liming on the other hand the rotatorians increased to in average 28% of the total volume, while the volume of copepods was only ca. 6%. Heterocope disappeared, and Eudiaptomus and Cyclops, usually favoured by liming, were rare. Consequently the supply of larger forms of crustaceans, suitable as fish food was severely reduced. In Lake Ömmern the effects of acidification within the zooplankton were moderate. The species richness was about the same as in unacidified lakes. After liming the development of zooplankton was similar to that in most other limed lakes, i. e. increased frequency of rotatorians, cladocerans and Cyclops spp. In Lake Ö. Nedsjön, however, the small zooplankton volumes and the elimination of copepods was in contrast to the zooplankton development in other limed lakes and in unacidified ones.     

Alkalinity destruction by sediment organic matter dissolution during neutralization of acidified lakes

In this study we report on the effect of sediment, from an acidified lake, on the neutralization of the acidified water column. The results of this experimental study show that organic acids (presumably humic or fulvic acids) can dissolve from the sediment and destroy alkalinity as measured by a Gran plot analysis. Alkalinity destruction by organic acid dissolution was shown to be a function of pH. Some Na ion exchange for sediment H⁺ was also observed. This ion exchange was shown to be a function of pH and Na concentration.     

Manganese Deficiency in Canola Induced by Liming to Ameliorate Soil Acidity

Applying lime to ameliorate soil acidity has been observed to induce manganese (Mn) deficiency in canola (Brassica napus L.) crops grown on acid sandy soils near Albany and gravelly acid sands of the Great Southern Districts of southwestern Australia. These soils were often Mn-deficient in patches for wheat (Triticum aestivum L.) production when they were newly cleared for agriculture requiring application of Mn fertilizer to ensure grain yields were not reduced by the deficiency. Since then, these soils have acidified and in the 1990s, canola started to be grown on these soils in rotation with wheat and lupins (Lupinus angustifolius L.). These limed soils may now have become marginal to deficient in Mn for canola production. The effect of liming may change the effectiveness of fertilizer Mn. In addition, the effect of liming on the residual value of Mn fertilizer applied to these soils for canola production is unknown. Therefore, a glasshouse experiment was conducted using Mn deficient sand. Three levels of finely-powdered calcium carbonate were added and incubated in moist soil for 42 days at 22±2°C to produce 3 soils with different pH values [1:5 soil:0.01 M calcium chloride (CaCl₂)]: 4.9 (original soil), 6.3, and 7.5. Five Mn levels, as solutions of Mn sulfate, were then added and incubated in moist soil for 0, 50, and 100 days before sowing canola. To estimate the residual value (RV) of incubated Mn for canola production, the effectiveness of the incubated Mn was calculated relative to the effectiveness of Mn applied just before sowing canola (freshly-applied Mn). The RV of the incubated Mn was determined using yield of dried canola shoots, the Mn application level required to produce 90% of the maximum shoot yield, and Mn content in dried shoots (Mn concentration in shoots multiplied by yield of dried shoots). As measured using both yield of dried shoots and Mn content of dried shoots, the residual value of Mn decreased with increasing soil pH and with increasing period of incubation of Mn with moist soil. The critical Mn concentration, for 90% of the total yield of dried canola shoots, was (mg Mn kg^?1) ～17 in youngest mature growth (apex and youngest emerged leaf, YMG), and ～22 for the rest of dried shoots. These values were similar to current critical values for un-limed soils suggesting critical Mn concentrations remain the same for limed soils. Plant testing of canola is recommended if soils are to be limed to ameliorate soil acidity. When plant tests indicate a high likelihood of Mn deficiency, foliar Mn sprays need to be applied to that crop to ensure Mn deficiency does not reduce grain production that year, and fertilizer Mn needs to be re-applied to the soil when sowing the next crop to reduce the likelihood of Mn deficiency for subsequent crops.     

Biological recovery of two previously acidified,metal-contaminated lakes near Sudbury Ontario,Canada

Studies are reported on two small lakes at Sudbury, Ontario located close to a nickel-copper smelter which closed in 1972. At that stage, Baby Lake had a pH of 4.0–4.2 while the adjacent Alice Lake had a pH 5.9–6.3. Both lakes were almost entirely devoid of algae and had neither Zooplankton nor fish. Soon after the closure of the smelter, with its large airborne volume of sulphur dioxide and of copper and nickel containing particulates, the chemistry of the lakes began to change. By 1985, Baby Lake had changed from pH 4.0 to 6.8 and is now at pH 7.2. The pH of Alice Lake increased from a low of 5.9 in the early 1970s to 6.9–7.4 in the mid 1980s and is now at 7.3. Copper and nickel concentrations also decreased in both lakes during this period. The first biota found in the lakes in the post-smelter stage in the early 1980s were benthic red chironomids, planktonic rotifers, and a limited number of phytoplankton species, of which Rhizosolenia was the most common. By the 1990s, 13 phytoplankton species were present in each lake, with a substantial Zooplankton fauna (14 species) of rotifers, copepods, and cladocerans. There are now numerous insect larvae in the sediment and some small fish in both lakes. The biological recovery, which followed substantial reductions in acidity and in soluble nickel and copper concentrations in the waters, is a slower process than chemical recovery and is initially characterized by the dominance of a few species.     

Pathways of chemical recovery in acidified,metal-contaminated lakes near Sudbury,Ontario, Canada

This paper describes the recovery pathways of two lakes situated near the Coniston nickel-copper smelter. These lakes were exposed to very intense airborne pollution, including SO₂, H₂SO₄, Ni and Cu, during the 60 year operation of the smelter. After the closure of the Coniston smelter in 1972 and the subsequent improvement in air quality, the water quality in both lakes began to improve. Despite their proximity and exposure to similar inputs, the lakes differed both in the rate and magnitude of recovery. This study demonstrates the capacity of lakes to recover from chemical stresses over a very short period. Changes in Cu and Ni concentration could be predicted, while changes in pH, measured as H⁺, could not. The reasons for this discrepancy as well as the processes and lake parameters that control chemical recovery are discussed.     

Losses and recoveries of fish populations in acidified lakes of southern Finland in the last decade

Acid-induced fish damage in small lakes in southern Finland was studied in a fish status survey of eighty lakes from 1985–1987. Later, twenty of these lakes were selected for further monitoring. A sampling of these lakes from 1988–1989 showed that the decrease in some perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations still continued. The results from the same lakes in 1992 showed that successful reproduction had taken place with many of the perch populations that had been close to extinction in 1985. In contrast, no signs of recovery in the roach populations were detected. The explanation for the appearance of new cohorts of perch could have been the decrease in acid deposition but the exceptional hydrological conditions of winters in the early 1990s may also have affected them. The different responses of the perch and roach populations were interpreted as a consequence of the different sensitivity of these two species to acidification. Even a slight improvement in the water quality has resulted in the appearance of strong new year-classes of perch, but not of roach. Therefore, more improvement in water quality is needed until a sensitive species like roach can reproduce again.     

Structure and productivity of epiphytic algal communities onLobelia dortmanna L. in acidified and limed lakes

The epiphytic algal community growing onLobelia dortmanna L. was studied in two acidified lakes in southwestern Sweden from May through October 1980; Lake Gårdsjön (pH 4.3 to 4.7) and L. Högsjön (pH 6.3 to 6.7 after liming in 1978/79). In both lakes a layer of firmly attached diatoms,Eunotia veneris andE. rhomboidea, covered theLobelia leaves. Scanning electron microscope study revealed a mucoid matrix, and in L. Gårdsjön, heavy cover of detritus. The spring period in L. Gårdsjön was characterized by red algaBatrachospermum sp., which was followed by the appearance ofBinuclearia sp., andMougeotia spp. Blue-green algae appeared during the warmer period of the year. The spring period in L. Högsjön was characterized by the development of desmids. Diatoms dominated the community in the summer while green algae appeared in autumn. The biomass in L. Gårdsjön showed spring and late summer maxima, while in L. Högsjön it increased gradually reaching a maximum in autumn. Chlorophylla concentration was highest in L. Gårdsjön in late summer. Primary productivity rates calculated per unit substrate surface area at 1.0 m depth were highest in early summer and decreased in late summer. The results suggest that the liming of L. Högsjön caused significant structural changes in the epiphytic community, favoring diatoms and green algae, especially desmids. Blue-green algae were characteristic for L. Gårdsjön despite that lake's low pH. Productivity rates at 1.0 m depth show similar trends in both lakes.     

Recovery of previously acidified lakes near Coniston,Canada following reductions in atmospheric sulphur and metal emissions

The purpose of the present study was to assess the rate of recovery of acidified lakes located near the town of Coniston following an abrupt reduction in atmospheric SO₂ and metal emissions at the Coniston smelter which closed in 1972. The water chemistry of several lakes was studied over a period of 16 yr (1968–1984). In one extremely acidic lake close to the smelter, the pH increased from 4.05 in 1972 to 5.8 in 1984. Conductivity, as well as concentrations of SO₄, Cu, Ni, Co, Mn, and Zn decreased by 60% to 90% in the lake water during the same period. In another initially less acidic lake nearby, the increase in pH was less dramatic, while the decrease in conductivity, SO₄, and some metals was similar to that of the more acidic lake. Local SO₄ deposition decreased approximately 75 % while Cu and Ni deposition decreased by 90% following closure of the Coniston smelter. These results indicate that even severely acidified lakes can improve within a few years following a substantial reduction in atmospheric S emissions; and that in some regions recovery can occur due to reductions in SO₂ emissions even in the absence of concurrent NO_x control.     

Seasonal and long-term temporal patterns in the chemistry of Adirondack lakes

There is considerable interest in the recovery of surface waters from acidification by acidic deposition. The Adirondack Long-Term Monitoring (ALTM) program was established in 1982 to evaluate changes in the chemistry of 17 Adirondack lakes. The ALTM lakes exhibited relatively uniform concentrations of SO₄ ^2?. Lake-to-lake variability in acid neutralizing capacity (ANC) was largely due to differences in the supply of basic cations (Ca²⁺, Mg²⁺, K⁺, Na⁺; C_B) to drainage waters. Lakes in the western and southern Adirondacks showed elevated concentrations of NO₃ ^?, while lakes in the central and eastern Adirondacks had lower NO₃ ^? concentrations during both peak and base flow periods. The ALTM lakes exhibited seasonal variations in ANC. Lake ANC was maximum during the late summer or autumn, and lowest during spring snowmelt. In general Adirondack lakes with ANC near 100 Μeq L^?1 during base flow periods may experience decreases in ANC to near or below 0 Μeq L^?1 during high flow periods. The ALTM lakes have exhibited long-term temporal trends in water chemistry. Most lakes have demonstrated declining SO₄ ^2?, consistent with decreases in SO₂ emissions and SO₄ ^2? in precipitation in the eastern U.S. Reductions in SO₄ ^2? have not coincided with a recovery in ANC. Rather, ANC values have declined in some ALTM lakes. This pattern is most likely due to increasing concentrations of NO₃ ^? that occurred in most of the ALTM drainage lakes.     

Heavy metals in perch (Perca fluviatilis L.) from two acidified lakes in the salpausselkä esker area in Finland

Hg concentrations in muscle and Cd, Pb, Al, Zn and Fe concentrations in muscle, liver and kidney ofPerca fluviatilis from two acidified lakes in the Salpausselkä esker area in Southern Finland were studied. The metal concentrations in perch from the Tiilijärvi lakes were similar to those in other acidified Finnish lakes. Only Hg concentrations correlated strongly with the age and size of perch. The need for age correction in studies on the Hg concentrations on perch was noticed. The highest concentrations of Cd, Pb and Zn occured in kidney and those of Al and Fe in liver.     

Liming acid streams: Aluminium toxicity to fish in mixing zones

Liming to neutralize acidic surface waters involves a possible risk of toxicity to fish due to precipitation or changes in speciation of Al. We report the response of captive brown trout to the experimental liming of an acid stream rich in Al. Within 15 m of lime dosing 0.22 µm filterable Al fell from 580 to 230 µg L^?1, and to 120 jig L^?1, within 30 m, though total Al was unchanged. After 24 hr, fish mortality was 100% at untreated acidic sites, 80% up to 30 m downstream of liming, declining to zero within 100 m. Mortality was 70% at 15 m below the confluence of an acidic tributary with the limed stream, despite little change in pH or total Al concentration. Mortalities were significantly correlated with concentrations of Al and Fe in gill tissues, and with 0.22 µm filterable Al and Fe in the water, but not with particulate Al or Fe. AI(OH)₄ ^?, precipitating A1 or polymeric hydrolysis products are all possible causes of the observed toxicity. Iron may have also have contributed, but the stream concentrations of this metal were relatively low. The practical conclusion is that changes in Al chemistry, where waters of differing acidity mix, may be important in some circumstances where river systems are limed selectively.     

Liming acidic waters in Norway: National policy and research and development

Since 1983, the Norwegian environmental authorities have given financial support to operational liming and research following recommendation given by the Norwegian Liming Project (1979–1984). Liming all acid waters in Norway would require an annual expenditure exceeding NOK (Norwegian Kroner) 300 × 10⁶. The funding level for 1988 is NOK 14 × 10⁶ and will probably increase to NOK 30 mill. by 1990, including NOK 1 to 3 mill. for research and development. Priority is given to lakes and rivers whose fishing is open to the public, and to save or restore valuable fish populations. Local support in the form of voluntary labor is a condition for financial aid. Two salmon rivers are currently included in the program. T h e Norwegian Institute for Water Research (NIVA) plays an important role in liming research and development in Norway. The aims of this research are twofold: to document the chemical and biological response to neutralization and liming, and to improve liming strategy to obtain cost efficient liming activities.     

Liming the acid lake Hovvatn,Norway: A whole-ecosystem study

Hovvatn, a 1-km² chronically-acidified lake in southernmost Norway, was treated with 200 tonne of powdered limestone in March 1981. An additional 40 tonne were added to a 0.046 km² pond (Pollen) draining into Hovvatn. The lakes were stocked with brown trout in June 1981 and in each subsequent year. At ice-out pH rose from 4.4 to 6.3 (Hovvatn) and 7.5 (Pollen), Ca and alkalinity increased, and total Al decreased by 120 μg L^?1. None of the other major ions exhibited significant changes in concentration. Total organic Cand Pincreased after liming. The phytoplankton community was dominated by chrysophytes and did not change significantly following liming. The zooplankton community was typical of acid lakes prior to liming. There was a clear succession in species dominance following treatment, although no new species immigrated to the lakes. Zoobenthos changed from a community characterized by low abundance and reduced number of species to increased abundances of oligochaetes, mayflies and chironomids. Hovvatn and Pollen were barren of fish prior to stocking. The stocked fish showed remarkably high growth rate during the first years. Liming apparently improved conditions for zoobenthos, enhancing the processing of fine detritus which in turn resulted in elevated levels of TOC and P in the lakewaters during the first year after liming. The “oligotrophication” process typical of acid lakes was temporarily reversed by liming. The interactions between groups of organisms in Hovvatn and Pollen indicates that many years are required before a new steady-state can be attained following liming.     

Rapid softening of acidified peppers: effect of oxygen and sulfite

Evidence was found for two previously unreported, nonenzymatic reactions that affected texture retention in acidified red bell peppers. First, oxygen was found to cause rapid softening of the pepper tissue such that it lost at least 40% of the initial tissue firmness within 2 weeks after acidification. Second, sulfite added to the acidified peppers prevented the softening caused by oxygen. Combined addition of sulfite and calcium chloride resulted in better retention of tissue firmness during extended storage than the addition of either component by itself.     

Molybdenum Requirements of Dry Bean with and without Liming

Molybdenum (Mo) is an essential micronutrient for crop plants, and its deficiency has been reported in many parts of the world. Two greenhouse experiments were conducted with the objective to determine Mo requirements of dry bean (Phaseolus vulgaris L.) grown on a Brazilian Oxisol with and without liming. The Mo treatments were 0, 5, 10, 15, and 20 mg kg^?1. In one experiment dolomitic lime was added at the rate of 2.5 g per kg of soil before the application of Mo treatments and incubated 5 weeks before sowing. In other experiments, Mo treatments were same as the lime-added experiment but no lime was added. Most of the growth, yield, and yield components were significantly increased with the addition of Mo in both the experiment. Growth, yield, and yield components were increased in a quadratic fashion when Mo was applied in the range of 0 to 20 mg kg^?1. Maximum shoot dry weight was obtained with the addition of 17 mg Mo kg^?1 in the experiment with Mo rates without lime and 9.69 mg Mo kg^?1 in the experiment of Mo rates with lime application. Maximum seed yield was obtained with the application of 10.48 mg Mo kg^?1 in the experiment that did not receive lime along with Mo treatments and 10.28 mg Mo kg^?1 in the experiment that received lime along with Mo treatments. Similarly, the maximum number of pods per plant was obtained with the addition of 9.33 mg Mo kg^?1 in the experiment that did not receive lime and 8.83 mg Mo kg^?1 in the experiment that did receive lime. Maximum root length was obtained with the addition of 12.38 Mo kg^?1 in the experiment that did not receive lime and 9.75 mg Mo kg^?1 in the experiment that received lime. Maximum root dry weight was obtained with the addition of 11.67 mg Mo kg^?1 in the experiment that did not receive lime and 9.28 mg Mo in the experiment that received lime. Soil properties determined after harvest of dry bean plants were not influenced significantly with the addition of Mo in the Oxisol under investigation.