Southern Lake Saimaa Research Articles

Recovery of Historically Contaminated Watercourse Polluted by the Chemical Wood Industry: EROD Activity in Fish as Biomarker

Despite outstanding process alterations over decades, pulp- and paper-mill-contaminated sediments and continuing exposure by the effluents may still have effects on biota. In this study, ecotoxicological impacts in the boreal watercourse were analyzed by measuring ethoxyresorufin-O-deethylase (EROD) induction from wild fish populations and from experimentally exposed fish. In order to assess the role of sediment-borne chemicals, juvenile rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory to the surface sediments of Lake Vatianjärvi and Southern Lake Saimaa, both watercourses impacted by the chemical wood industry for approximately a century. Hepatic EROD activity was also measured from roach (Rutilus rutilus) and perch (Perca fluviatilis) caught in Lake Vatianjärvi. Increased EROD activity was not observed in wild fish caught in Lake Vatianjärvi nor in rainbow trout exposed to the sediment of Lake Vatianjärvi, but it was observed in rainbow trout exposed to the sediment of Southern Lake Saimaa, probably explained by critically high concentrations of retene. The results of both the laboratory and field study indicate the absence of EROD-inducing compounds of the previously heavily contaminated Lake Vatianjärvi.

Do historical sediments of pulp and paper industry contribute to the exposure of fish caged in receiving waters?

Field experiments were conducted in early summer 2004 by caging brown trout (Salmo trutta m. lacustris) in Southern Lake Saimaa (SE Finland) for 10 days. Cages were positioned into two depths at four distances (5 to 17 km) from the pulp and paper mill; one set with direct contact to the sediment and other locating at the three meters' depth from the water surface. Resin acids were measured from sediment, water, and fish bile. Possible toxicities were investigated by measuring liver EROD-activity, HSP70-protein, and gene expression profiles by microarray. The concentration of resin acids in the sediment showed clear gradient along the distance from the mill, and their concentrations in water ranged approximately from one to 30 microg L(-1). In the trout bile, concentrations were higher near the surface than on the bottom, indicating the role of current releases as sources of resin acids. When compared to trout held upstream from the effluent source, no differences were found in liver EROD nor HSP70 in bottom cages. However, near surface, a slight but statistically significant increase in EROD and HSP70 was found. Altogether 145 genes were found to be differentially regulated at downstream sites when compared 10 km upstream from the mill. The numbers of genes at each site varied from 5 to 45 without consistent differences between bottom and surface cages. Overall, neither expression profiles nor composition of the transcription signatures made possible to conclude an overt toxicity in exposed brown trout.

Exposure assessment of fishes to a modern pulp and paper mill effluents after a black liquor spill

Conjugated resin acids (RAs) in fish bile are considered a sensitive chemical indicator of exposure to pulp and paper mill effluent, and were used in this study to monitor the post-spill situation of a lake area (Southern Lake Saimaa) contaminated by black liquor discharged from a mill in June 2003. From the exposure perspective of populations of wild roach and perch, which were studied for their bile RAs at four time periods (July 2003, September 2003, May 2004, July 2004), the exceptional event passed in 2 months or less. Perch had lower concentration of RAs in bile than roach in all sampling areas and all times. Besides the current emissions present in the water column, part of the exposure status of the roach population to RAs seemed to derive from historically contaminated sediments. In order to test this hypothesis, a laboratory experiment with perch and roach, along with three teleosts (rainbow trout, brown trout and whitefish), was conducted. The species were simultaneously exposed for 7 days to RAs (23 microg/l). We calculated a perch/roach-ratio to investigate the difference in origin of exposure between perch and roach populations in the wild and in the laboratory. One year after the spill, the perch/roach-ratio of bile RAs was 0.25 (CV 25%) at 1 km from the mill. This is in contrast to that found under the sole waterborne conditions (0.44; CV 24%), supporting the idea that sediments serve as an additional source of RAs in roach. Additionally, bioconcentration factor log BCF(bile(RA)) was calculated to assess hepatobiliary performance and the capacity to excrete RAs in fish.

Uptake of organic xenobiotics by benthic invertebrates from sediment contaminated by the pulp and paper industry

Uptake of pulp and paper mill-derived pollutants by benthic invertebrates from sediment in Southern Lake Saimaa, eastern Finland, was studied. Two groups of benthic invertebrates (Diptera and Oligochaeta) were analyzed for their concentrations of resin acids (RAs), chlorophenolics (CPs) and β-sitosterol. The samples were collected 1 and 3 km downstream from the mill. In laboratory experiments Chironomus plumosus (a dipteran) and Lumbriculus variegatus (oligochaete) were exposed for 14 d to sediments collected from the same locations. The concentrations of RAs, CPs and β-sitosterol were higher in the areas downstream from the mill than those in the upstream reference area in both the feral and laboratory-exposed animals. Examination of the possible conjugation of contaminants revealed hydrolyzable fractions of RAs in Diptera, C. plumosus and L. variegatus. The results indicate both the bioavailability uptake of contaminants and uptake by benthic fauna when exposed to pulp and paper mill-contaminated sediment.

Sediment echosounding survey in southern Lake Saimaa (Finland): early post-glacial low-water phase identified as sharp erosional horizons in glacial clays

Key words: isostatic land upliftLake Saimaasediment echosoundingpost-glacial periodwater level historypollen analysis

Stratigraphy of Wood-derived Sterols in Sediments Historically Contaminatedby Pulp and Paper Mill Effluents

Sterols and their metabolites are recognized as hormonally active compounds in many earlier studies. Therefore, identification and quantification of selected phytosterols related to developments in pulping and wastewater treatment of pulp and paper industry were studied from sediment cores of two Finnish lakes. Indicating the period of maximal emissions, the highest total concentration of sterols, 1970 μg/g dry weight, was detected in the stratified sediment of central Lake Paijanne, dated to the mid-1970s (depth 12–15 cm). After notable changes in processes and effluent treatment, the amounts of sterols in effluents must have diminished, as shown by the sterol content in the sediment downstream from the mills. Therefore, the concentrations were about 10% of the historical maximum in the surface sediment (depth 0–3 cm) in both downstream sites investigated at Lake Paijanne. However, these concentrations were clearly over the natural background (10–50 μg/g) occurring in the subsamples of the pre-industrial phase (depth 36–44 cm) as well as in the reference site of southern Lake Saimaa, the second investigated lake. At a nearby site of a pulp and paper mill in southern Lake Saimaa, sterols were most abundant (1760 μg/g dry weight) in the sediment layer 0–5 cm despite the improved process control during last few decades. This study showed the abundance of ecotoxicologically harmful compounds in downstream sediment sites of pulp and paper industry.

Fish community responses to pulp and paper mill effluents at the southern Lake Saimaa, Finland

The fish community in sublittoral and profundal waters, at stony shores, and densities of vendace larvae were studied in the southern Lake Saimaa, Finland. The objective was to investigate the possible recovery of fish populations after modernizations at the pulp and paper mills discharging into the lake. Sublittoral and profundal waters were studied by gill net trial fishings, stony shores by electrofishing, and vendace larvae by beach seine. The research area was divided in a polluted (0.5–4.0% effluent), an intermediate (0.1–0.5%) and a ‘clean’ reference area. The fish community in sublittoral and profundal waters in the lake was dominated (>60%) by perch and roach. Relative abundance of fish was highest in the polluted area, and lowest in the reference area. The number of species caught was similar among areas. The abundance of bleak and ruffe was highest in the polluted area, while the abundance of vendace and whitefish was highest in the intermediate and reference area. The fish fauna of stony shores in the lake was dominated by bullhead, stone loach and minnow, densities were lowest at polluted shores and highest in the intermediate area. Minnow, apparently a more sensitive species to pulp mill effluents, were not caught at the most polluted shores. The catch of vendace larvae was similar among areas, larvae were also caught in the vicinity of the mills. Compared with before the modernization at the mills, the relative abundance of perch in the polluted area was increased, ruffe decreased, while populations of whitefish and vendace showed signs of recovery. These changes may be explained by the reduced nutrient load and toxicicity of pulp mill effluents. At present, the fish community in the polluted area can be considered typical for a moderate eutrophication.

Reproductive, biochemical, physiological, and population responses in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) downstream of two elemental chlorine‐free pulp and paper mills

AbstractPerch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations in a state of late vitellogenesis were studied downstream of two pulp and paper mills and at upstream references in southern Lake Saimaa, Finland. The mills used elemental chlorine‐free bleaching and activated sludge effluent treatment technologies. The exposure of fish to pulp mill effluents, as measured by concentrations of chlorophenolics in the bile and liver ethoxyresorufin‐O‐deethylase (EROD) activity, was low and almost similar to the references. Nevertheless, bile resin acid concentrations in exposed perch and roach (260–320 μg/ml) and bile β‐sitosterol concentrations in exposed roach (1.5–3.5 μg/ml) were, respectively, 10 to 30 times and 2 to 5 times higher compared with the references. Reproductive parameters like plasma 17β‐estradiol and testosterone levels were lower in exposed male and female perch but the same in roach. Vitellogenin concentrations in plasma and liver cytosol of roach were similar. Gonad weight and fecundity were lower in exposed female perch but similar in roach. The relative liver weight was higher in exposed roach but not in perch. The body condition and immunologic parameters in fish were the same. The growth and age at maturity of exposed perch and roach were similar to the references. The size and age distribution of perch in the recipient of one of the mills was shifted toward smaller and younger fish. Our results show that several reproductive variables were altered in late vitellogenic perch in the vicinity of the mills, but they were not altered in roach.

Reproductive, biochemical, physiological, and population responses in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) downstream of two elemental chlorine-free pulp and paper mills.

Perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations in a state of late vitellogenesis were studied downstream of two pulp and paper mills and at upstream references in southern Lake Saimaa, Finland. The mills used elemental chlorine-free bleaching and activated sludge effluent treatment technologies. The exposure of fish to pulp mill effluents, as measured by concentrations of chlorophenolics in the bile and liver ethoxyresorufin-O-deethylase (EROD) activity, was low and almost similar to the references. Nevertheless, bile resin acid concentrations in exposed perch and roach (260-320 micrograms/ml) and bile beta-sitosterol concentrations in exposed roach (1.5-3.5 micrograms/ml) were, respectively, 10 to 30 times and 2 to 5 times higher compared with the references. Reproductive parameters like plasma 17 beta-estradiol and testosterone levels were lower in exposed male and female perch but the same in roach. Vitellogenin concentrations in plasma and liver cytosol of roach were similar. Gonad weight and fecundity were lower in exposed female perch but similar in roach. The relative liver weight was higher in exposed roach but not in perch. The body condition and immunologic parameters in fish were the same. The growth and age at maturity of exposed perch and roach were similar to the references. The size and age distribution of perch in the recipient of one of the mills was shifted toward smaller and younger fish. Our results show that several reproductive variables were altered in late vitellogenic perch in the vicinity of the mills, but they were not altered in roach.

Effects of Pulp and Paper Mill Effluents on Reproduction, Bile Conjugates and Liver MFO (Mixed Function Oxygenase) Activity in Fish at Southern Lake Saimaa, Finland

Reproductive indices like gonad size, fecundity, egg size and sex steroid levels of estradiol-17β and testosterone, vitellogenin in the blood as well as bile conjugates and liver 7-ethoxyresorufin O-deethylase (EROD) activity were studied in populations of perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) and experimentally exposed juvenile whitefish (Coregonus lavaretus L. s.l.) at the Southern Lake Saimaa (S.E. Finland). Our studies showed that the introduction of elemental chlorine free (ECF) bleaching and secondary treatment of effluents in a modern activated sludge plant at the mill in 1992 have substantially reduced the exposure of feral and caged fish to organochlorines. The liver EROD activity was noticeably lower in feral and caged fish near the mill indicating lesser impacts on the liver mixed function oxygenase (MFO) system. However, at the mill site, liver EROD activies in feral and caged fish still tend to be one to four times higher than at the reference sites. Significantly decreased plasma estradiol-17β and testosterone concentrations in perch and roach in the period of development of the gonads (autumn and winter) indicate that there were endocrine disrupting compounds present in the lake receiving ECF pulp and paper mill effluents. Cause-effect relationships, however, are difficult to establish.

Expression of the Vitellogenin Gene in the Liver of Juvenile Whitefish (Coregonus lavaretus L. s.l.) Exposed to Effluents from Pulp and Paper Mills

Juvenile whitefish (Coregonus lavaretus L. s.l.) were exposed by caging in the field to diluted effluents from three operating pulp, paper, and paperboard mills in Southern Lake Saimaa, Finland. The expression of the vitellogenin gene, used as a biomarker of estrogenic contamination of effluents, was measured using a Northern blotting method. Increased mRNA levels, the most specific and reliable evidence for estrogen receptor-mediated actions in vivo, were found in fish caged in the vicinity of one of three mills studied. This mill was found to discharge wood-derived compounds, such as sterols and resin acids, into Lake Saimaa in amounts considerably exceeding those from the other two mills. The increased vitellogenin gene expression suggests that the effluent is a source of estrogenic contaminants.

Effects of pulp and paper mille effluents on reproduction, bile conjugates and liver MFO (mixed function oxygenase) activity in fish at Southern Lake Saimaa, Finland

Reproductive indices like gonad size, fecundity, egg size and sex steroid levels of estradiol-17β and testosterone, vitellogenin in the blood as well as bile conjugates and liver 7-ethoxyresorufin O-deethylase (EROD) activity were studied in populations of perch ( Perca fluviatilis L.) and roach ( Rutilus rutilus L.) and experimentally exposed juvenile whitefish ( Coregonus lavaretus L. s.l.) at the Southern Lake Saimaa (S.E. Finland). Our studies showed that the introduction of elemental chlorine free (ECF) bleaching and secondary treatment of effluents in a modern activated sludge plant at the mill in 1992 have substantially reduced the exposure of feral and caged fish to organochlorines. The liver EROD activity was noticeably lower in feral and caged fish near the mill indicating lesser impacts on the liver mixed function oxygenase (MFO) system. However, at the mill site, liver EROD activies in feral and caged fish still tend to be one to four times higher than at the reference sites. Significantly decreased plasma estradiol-17β and testosterone concentrations in perch and roach in the period of development of the gonads (autumn and winter) indicate that there were endocrine disrupting compounds present in the lake receiving ECF pulp and paper mill effluents. Cause-effect relationships, however, are difficult to establish.

Biomarker responses in whitefish (Coregonus lavaretus L. s.l.) experimentally exposed in a large lake receiving effluents from pulp and paper industry.

Physiological and biochemical biomarker responses were studied in juvenile whitefish (Coregonus lavaretus L. s.l.) exposed experimentally to effluent from the forest industry. The large study area (609 km2), Southern Lake Saimaa, in Southeast Finland, receives 330,000 m3 d-1 of biologically and 55,000 m3 d-1 of chemically treated effluents, discharged from two integrated elementary chlorine free (ECF) bleached kraft pulp and paper mills, from one ECF pulp mill, and from one mill producing unbleached pulp and cardboard. The assessment of exposure to effluent discharged from the mills was based on lake water chlorophenolics (CPs) and resin acids (RAs) measured in samples collected from the 22 experimental sites along the area. Despite the low levels of effluent constituents in the lake, they were still accumulated in detectable levels in fish bile, indicating an exposure to the bioactive compounds of effluents. In comparison to the reference area, a two- to four-fold increase in ethoxyresorufin O-deethylase (EROD) activity was observed in whitefish exposed in the vicinity (1-6 km) of all the mills. However, cytochrome P450 1A1 (CYP1A1) gene expression was increased in only one of the receiving areas, indicating higher sensitivity of the EROD activity in the present study. There were no statistically significant correlations between EROD activity and the ambient water concentrations of the CPs, the RAs, or effluent dilution expressed by water sodium concentration. Neither bile chlorophenolics nor bile resin acids showed a significant correlation with EROD. No significant changes in circulating reproductive steroids, 17beta-estradiol and testosterone, in juvenile whitefish were observed. The vitellogenin gene was expressed in the vicinity of the pulp mill discharging the most wood-derived compounds, i.e. resin acids and wood-sterols, including beta-sitosterol. No differences were observed in plasma immunoglobulin M, glucose, or lactate concentrations between the effluent sources.

Distribution of Halogenated Organic Material in Sediments from Anthropogenic and Natural Sources in the Gulf of Finland Catchment Area

Organochlorine compounds present in effluents from the pulp and paper industry are regarded as a potent threat to the environment. Total organohalogen concentrations are commonly measured in sediment as extractable organic halogen (EOX). Spacial and vertical levels of EOX were determined in areas likely to be affected by organochlorine pollution in Lake Saimaa, along the Kymi River, and around the Gulf of Finland. High levels of EOX were found in samples from southern Lake Saimaa and the Kymi River. Spacial EOX distribution indicated that there is transport of organochlorines from the Kymi River to the eastern Gulf of Finland, and EOX results from the Kotka area showed that substantial, widespread, organochlorine pollution persists 30 km off the coast. Sediments from Vyborg Bay (Russia) and from Tallinn Bay and Ihasalu Bay (Estonia) contained low amounts of EOX. Results from 73 stations indicated that pollution from chlorine bleaching and municipal water chlorination remains localized. Vertical EOX distri...

Distribution of Halogenated Organic Material in Sediments from Anthropogenic and Natural Sources in the Gulf of Finland Catchment Area

Organochlorine compounds present in effluents from the pulp and paper industry are regarded as a potent threat to the environment. Total organohalogen concentrations are commonly measured in sediment as extractable organic halogen (EOX). Spacial and vertical levels of EOX were determined in areas likely to be affected by organochlorine pollution in Lake Saimaa, along the Kymi River, and around the Gulf of Finland. High levels of EOX were found in samples from southern Lake Saimaa and the Kymi River. Spacial EOX distribution indicated that there is transport of organochlorines from the Kymi River to the eastern Gulf of Finland, and EOX results from the Kotka area showed that substantial, widespread, organochlorine pollution persists 30 km off the coast. Sediments from Vyborg Bay (Russia) and from Tallinn Bay and Ihasalu Bay (Estonia) contained low amounts of EOX. Results from 73 stations indicated that pollution from chlorine bleaching and municipal water chlorination remains localized. Vertical EOX distri...

Chlorophenolic and isotopic tracers of pulp mill effluent in sedimenting particles collected from southern lake saimaa, Finland

Sediment traps were used to collect settling particles at two stations upstream of a pulp and paper mill and at four stations along the effluent gradient in Southern Lake Saimaa. The particle samples were collected monthly from May to October 1991. Trap materials were analyzed for concentration and stable isotopic composition of organic carbon and nitrogen. The May 1991 trap samples and water and surface sediment samples from the trap locations were also analyzed for chlorophenolics. The trapped particle flux in May was 6.4 g(dry wt.)/m2/day at the station closest to the pulp mill (3.3 km) and decreased to 2.6 g(dry wt.)/m2/day at the farthest station (16.1 km). The organic carbon content of the particles varied from 10.5% to 22.1% and was the highest at the station nearest to the mill. There was a strong point source signal in the nitrogen isotope composition of effluent material. The other sampling times revealed a similar pattern. The total concentration of chlorophenols, chloroguaiacols and chlorocatechols was 0.8, 17.1 and 16.3 μg/g (dry wt.) particles, respectively, at the nearest station and decreased downstream. The total extractable organic halogens in particles exhibited a similar concentration pattern to the identified chlorinated compounds. While about 60% of chloroguaiacols and about 90% of chlorocatechols are removed by sedimentation or degradation processes in the recipient area, most of the chlorophenols and adsorbable organic halogens are transported through the system.

PCA and PLS methods applied to ecotoxicological data: Ecobalance project

Within a case study ‘Ecobalance’, the fate and effects of various chlorinated and non-chlorinated organic compounds and some heavy metals discharged from pulp and paper mills into water, sediment and aquatic animals were studied in a recipient area of southern Lake Saimaa, SE Finland. The main aim of the project was to find an empirical link between chemical emission parameters and ecotoxicological effects expressed in the ecosystem. As part of the \‘Ecobalance’ project, principal component analysis (PCA) and partial least squares (PLS) methods were used to interpret the data of the lake area. The PLS method was used to estimate the lake area affected by mill effluents and to calculate the fraction of wastewater in sampling sites. The study area is mainly affected by one pollution source. There is, however, also another pollution source, another pulp mill located near the research area. The effect of this source can be seen in the sites near the outer margin of the area. The effect of the major source effluents can be clearly seen in the data of exposed animals and sediment samples. © 1996 by John Wiley & Sons, Ltd.

Sorption of high molecular weight chlorolignin on sediment

Sorption characteristics of organic compounds determine largely their fate in the aquatic environment. In this study, sorption of chlorolignin on sediments was studied in the laboratory. Chlorolignin is a major by-product of pulp bleaching with chlorine chemicals. The sediments were from the Baltic Sea and from Southern Lake Saimaa, Finland. The influence of bleaching process, pH and molecular weight on the sorption was determined in addition to studies for sorption kinetics and isotherms. The results show that the sorption of chlorolignin on sediment is a two phase process in which the fast phase takes about 6 h. Equilibrium was reached in most cases in 50 h which was the longest time studied. High molecular weight compounds sorbed most, especially at low pH. Only a part of the sorbed material desorbed when the sediment was shaken with clean water. Much higher sorption coefficients were determined for fresh water sediment than for Baltic Sea sediment.

Biotransformation and other toxicological and physiological responses in rainbow trout ( Salmo gairdneri Richardson) caged in a lake receiving effluents of pulp and paper industry

Hatchery reared immature rainbow trout ( Salmo gairdneri Richardson) were transferred to eight field stations at the southern Lake Saimaa (SE Finland). They were caged in the receiving water body of effluents from a mill producing chlorine bleached kraft pulp and printing paper. The controls were caged upstream to the sewer. The microsomal cytochrome P-450 content, NADPH cytochrome c reductase and monooxygenase enzyme activities as well as conjugation reactions with glucuronic acid and glutathione were studied in the liver, kidney and gills. Conjugated metabolites of chlorophenolics in the bile and some physiological blood parameters were investigated. The caging in polluted water increased the monooxygenase enzyme activities. Compared to control trout, up to 7 times induction of liver 7-ethoxyresorufin O-deethylase (EROD) activity was observed at the nearest caging station, 3 km from the effluent outlet. Activity of EROD was the best indicator for the induction caused by pulp and paper mill effluent, however, pentoxyresorufin O-dealkylase was also responsive. Analysis of conjugated chlorinated phenolics in the bile showed highest concentrations at the caging station nearest to the mill and displayed good distance related decreases. The levels of conjugated toxicants found in control fish indicated a low contamination of the whole southern Lake Saimaa.