Effects Of Pulp Mill Effluents Research Articles

Exposure to a Brazilian pulp mill effluent impacts the testis and liver in the zebrafish

While many studies have shown that pulp mill effluents can affect ovarian physiology in fish, far fewer studies have considered the effects in males. We conducted a lab study to examine the effects of effluent from a Brazilian pulp and paper mill on hepatic and testicular morphology and various aspects of testicular physiology in the zebrafish Danio rerio. Males were exposed to lab water (control) or 4% effluent for 14 days. Effluent exposure did not affect testis size as measured by the gonadosomatic index, but contributed to morphological changes in the seminiferous tubules. The number of cysts with histopathological changes was elevated in effluent-exposed fish and the number of cysts containing spermatids was significantly reduced. The testis of effluent exposed fish had reduced levels of lactate, elevated lactate dehydrogenase activity, increased levels of reactive oxygen species and reduced levels of phosphorylated P38 mitogen-activated protein kinase (pP38 MAPK). Separate studies showed that the addition of lactate to testicular tissue incubated in vitro increased the activation of P38 MAPK. Effluent exposure also increased vacuolization, necrosis, apoptosis, hyperemia, and fat infiltration of the hepatocytes. Collectively, we provide evidence of short term effects of pulp mill effluent on testicular and hepatic physiology and biochemistry in the zebrafish.

It’s Of(fish)cial: Pulp Mill Effluent Can Alter Reproductive Cycles of Ontario Fish

Pulp and paper mills are of economic importance in Canada, however their effluent waste is being channeled into water bodies and causing a variety of negative effects in aquatic ecosystems. Pulp mill effluents are chemical compounds which are oxygen consuming, persistent, and toxic, and have the capacity to mimic physiological compounds. A review of current literature on pulp mill effluent reveals that these chemicals can mimic the reproductive hormones of fish, thereby having effects on local fish reproductive cycles. These reproductive alterations include decreased steroidogenesis, reduced gonad size, and altered expression of secondary sex characteristics that together can affect the health of wild fish populations. However, there has been considerable variation found in the effects of pulp mill effluent based on chemical composition of the pollutants, and the sex, species, and exposure duration of the affected fish. Biotreatment has been considered as a viable option for reducing the impact of effluent on fish reproduction. We suggest that alterations in reproductive cycles can have downstream effects through trophic cascades which in turn may have widespread effects on community structure. Future research should include analysis of long term consequences on multiple species in affected ecosystems, as well as further study on the use of biotreatment to reduce the impact of effluent.

The Relationship between Organic Loading and Effects on Fish Reproduction for Pulp Mill Effluents across Canada.

This study builds upon the work of a multiagency consortium tasked with determining cost-effective solutions for the effects of pulp mill effluents on fish reproduction. A laboratory fathead minnow egg production test and chemical characterization tools were used to benchmark 81 effluents from 20 mills across Canada, representing the major pulping, bleaching, and effluent treatment technologies. For Kraft and mechanical pulp mills, effluents containing less than 20 mg/L BOD5 were found to have the greatest probability of having no effects. Organic loading, expressed as the total detected solvent-extractable components by gas chromatography/mass spectrometry (GC/MS), also correlated with decreased egg laying. Exceptions were found for specific Kraft, mechanical, and sulfite mills, suggesting yet unidentified causative agents are involved. Recycled fiber mill effluents, tested for the first time, were found to have little potential for reproductive effects despite large variations in BOD5 and GC/MS profiles. Effluent treatment systems across all production types were generally efficient, achieving a combined 82-98% BOD5 removal. Further reductions of final effluent organic loadings toward the target of less than 20 mg/L are recommended and can be realized through biotreatment optimization, the reduction of organic losses associated with production upsets and selecting best available technologies that reduce organic loadings to biotreatment.

Evaluating the potential of effluent extracts from pulp and paper mills in Canada, Brazil, and New Zealand to affect fish reproduction: Estrogenic effects in fish.

The authors examined the potential of pulp mill effluent from pulp-producing countries (Canada, Brazil, New Zealand) to affect fish reproduction. Specifically, the estrogenic effects in juvenile rainbow trout (Oncorhynchus mykiss) pulse-exposed to 11 different mill effluent extracts (intraperitoneal injections of solid-phase extraction-dichloromethane nonpolar fraction). The results indicated that effluent extracts were estrogenic in juvenile trout irrespective of the gender, as reflected by increasing level of plasma vitellogenin (VTG; Brazil > New Zealand > Canada). Despite the high variability observed among mills, differences in VTG levels were related to the type of mill process (kraft > elementary chlorine-free kraft > thermomechanical pulping). Moreover, effluent treatments did not appear to significantly decrease VTG induction. A consistent estrogenic effect was observed in those mills that process a combination of feedstocks (softwood and hardwood), with the highest increase in VTG related to eucalyptus feedstock. The results demonstrate significant estrogenic effects of pulp mill effluents on chronically exposed juvenile trout, suggesting that in vivo metabolic activation of precursors is necessary to cause the observed increases in VTG levels. This molecular estrogenic response provides a useful starting point for predicting population-level impacts through the adverse outcome pathway methodology. Environ Toxicol Chem 2017;36:1547-1555. © 2016 SETAC.

Directional genetic selection by pulp mill effluent on multiple natural populations of three-spined stickleback (Gasterosteus aculeatus).

Contamination can cause a rapid environmental change which may require populations to respond with evolutionary changes. To evaluate the effects of pulp mill effluents on population genetics, we sampled three-spined sticklebacks (Gasterosteus aculeatus) near four pulp mills and four adjacent reference sites and analyzed Amplified Fragment Length Polymorphism (AFLP) to compare genetic variability. A fine scale genetic structure was detected and samples from polluted sites separated from reference sites in multidimensional scaling plots (P < 0.005, 1000 permutations) and locus-by-locus Analysis of Molecular Variance (AMOVA) further confirmed that habitats are significantly separated (FST = 0.021, P < 0.01, 1023 permutations). The amount of genetic variation between populations did not differ between habitats, and populations from both habitats had similar levels of heterozygosity (polluted sites Nei’s Hs = 0.11, reference sites Nei’s Hs = 0.11). Still, pairwise FST: s between three, out of four, pairs of polluted-reference sites were significant. A FST-outlier analysis showed that 21 (8.4%) loci were statistically different from a neutral distribution at the P < 0.05 level and therefore indicated to be under divergent selection. When removing 13 FST-outlier loci, significant at the P < 0.01 level, differentiation between habitats disappeared in a multidimensional scaling plot. In conclusion, pulp mill effluence has acted as a selective agent on natural populations of G. aculeatus, causing a convergence in genotype composition change at multiple sites in an open environment.

Effect of pulp mill effluent on the transport of suspended sediment in the Athabasca River near Hinton, Alberta, CanadaThis paper is one of a selection of papers in this Special Issue in honour of Professor M. Selim Yalin (1925–2007).

Field and laboratory measurements of the transport of the suspended sediment from the Athabasca River near Hinton, Alberta, Canada are described. The objective of these measurements was to examine the influence of pulp mill effluent entering the river from a nearby pulp mill on suspended sediment. The results of the field measurement showed that the effluent had significant impact on the transport of the sediment. Specifically, the effluent increased the deposition rates of the sediment and caused a substantial reduction of sediment concentrations in reaches downstream of the effluent outfall. The reduction in sediment concentrations and the concomitant sediment loads can only be attributed to the pulp mill effluent as there were no abrupt changes in the hydraulic characteristics of the river in the reach of interest. These observations were confirmed by laboratory experiments that were carried out using a rotating circular flume located at the National Water Research Institute in Burlington, Ontario, Canada. The findings of this study have implications for modelling suspended sediment transport in rivers receiving bleached pulp mill effluents.

A Decade of Research on the Environmental Impacts of Pulp and Paper Mill Effluents in Canada: Development and Application of Fish Bioassays

Laboratory tests have been used to assess the regulatory and research questions related to the effects of pulp mill effluents on aquatic biota. Acute, short-term laboratory tests have clearly shown the improvement in final effluent quality following installation of secondary treatment at Canadian pulp mills. In an effort to predict and investigate impacts on wild fish, laboratory bioassays were developed to examine sublethal endpoints: induction of hepatic mixed function oxygenase activity and reduction of sex steroid concentrations. These laboratory assays have been used to assess whole effluents, specific chemicals, and components of pulp mill processes, and to discriminate between historical and present-day effluent discharges. These tests have shown that induction of mixed-function oxygenase activity and reduction of sex steroid concentrations are produced by effluents from a variety of mill types, with and without chlorine bleaching, in hardwood and softwood pulping facilities, and before and after effluent treatment. These short-term bioassays have enabled reductions in sex steroid concentrations to be linked to mill process streams, and have provided information on effective waste stream treatment. Longer term, life-cycle fish bioassays have shown that chronic exposure to pulp mill effluents commonly results in growth enhancement, liver enlargement, and decreases in gonad size, secondary sex characteristics, and fecundity. These long-term laboratory exposures are able to mimic the most commonly observed alterations of wild fish exposed to pulp mill effluents: increases in condition factors, increases in liver-somatic indices, and decreases in gonadosomatic indices. This pattern of response is a combination of nutrient enrichment with metabolic disruption. The most sensitive and biologically meaningful endpoint is decreased reproduction in fish life-cycle exposures. As the laboratory tests move forward into the next decade, attention will focus on the reproductive endpoints and on the possibility of shortening the fish bioassays while still maintaining sensitivity and biological relevance.

Use of paired fathead minnow (Pimephales promelas) reproductive test. Part 2: Source identification of biological effects at a bleached kraft pulp mill

Reproductive effects of pulp mill effluents on fish continue to be reported in Canadian waters. Spawning delays, reduced gonad size, and altered levels of sex steroid hormones have been found in both sexes of various fish species exposed to effluents. We initiated a project to identify the source/cause of such effects. In part 1 of this two-part series, we exposed mature adult fathead minnow (FHM; Pimephales promelas) for 21 d to final treated effluent (1% and 100% v/v) from a bleached kraft pulp mill in Terrace Bay (ON, Canada). Results suggested pulp mill effluent from this mill affected reproductive indicators in FHM and effects were dependent on effluent concentration, duration of exposure, and method of data analysis. The main objective of this paper was to use the FHM assay to identify waste stream sources within the mill that affect reproductive indicators. Various process streams were selected, characterized with respect to effluent chemistry and acute toxicity, and a subset was tested on-site with the 21-d FHM bioassay. Results showed that both the combined mill effluent (before secondary treatment) and the combined alkaline stream (CALK) caused both decreased spawning events (approximately 55% for both streams) and decreased egg production (28 and 74%, respectively), and the CALK stream resulted in significant male ovipositor development. By comparing response patterns we were able to identify the CALK stream as a source of compounds at this mill affecting reproductive indicators in FHM and highlight this stream for further toxicity identification evaluation.

Evidence of Altered Gene Flow, Mutation Rate, and Genetic Diversity in Redbreast Sunfish from a Pulp-Mill-Contaminated River

To determine effects of pulp mill effluent on population genetic structure, redbreast sunfish (Lepomis auritus) were collected from several sites along the Pigeon River, NC, as well as from reference sites. Previous studies found effects on molecular, biochemical, physiological, population, and community level endpoints in these populations. The population genetic structure of these fish was determined using the randomly amplified polymorphic DNA (RAPD) technique. The level of genetic diversity was higher in the Pigeon River populations than in the reference populations. Genetic distances among populations could not be explained by drainage patterns and may have been altered by contaminant exposure. Phylogeographic analysis, maximum likelihood analysis, and assignment tests suggested that there were fewer emigrants and more immigrants in the contaminated sites than in the reference sites, suggesting that the contaminated sites may harbor "sinklike" populations. Finally, a "terminal branch amplitype" analysis (neighbor-joining and minimum-spanning trees) and maximum likelihood analysis indicated that there may be an elevated mutation rate in the polluted sites. Thus, the genetic diversity (within and among populations) in the Pigeon River populations may have been affected by altered gene flow and mutational processes as a result of pulp mill effluent discharge.

Oxidative Stress and Sex Steroid Levels in Fish Following Short-Term Exposure to Pulp-Mill Effluents

This study investigates the relationship between oxidative stress and reproductive dysfunction in wild white sucker (Catostomus commersoni) with short-term exposures to pulp-mill effluent. Hepatic oxidative damage, as quantified using 2-thiobarbituric acid-reactive substances (TBARS), was often increased with effluent exposure within 4–8 d, but responses varied by species, sex, and effluent. Fatty acyl-coenzyme A (CoA) oxidase (FAO) and ethoxyresorufin O-deethylase (EROD) activities were also significantly induced between 4 and 8 d of exposure. There were marked species differences in oxidative stress, as TBARS, FAO, and EROD responses in white sucker differed dramatically from those of longnose sucker (Catostomus catostomus) exposed under identical conditions. Exposure for 8 d to pulp-mill effluent delayed ovulation in white sucker, and these delays were independent of changes in circulating testosterone and 17α,20β-dihydroxy-4-pregnen-3-one titers. Evaluations of the effects of pulp mill effluent on in vivo plasma steroid levels and in vitro steroidogenic capacities were compromised due to caging stress. In vivo preexposure to pulp-mill effluent did not reduce in vitro ovarian follicle steroidogenic capacities when exposed to additional reactive oxygen species (ROS) generators. Endocrine and oxidative stress parameters may be interrelated, as the in vivo administration of ferric nitrilotriacetate (Fe3+NTA) significantly reduced circulating sex steroids. Administration of a superactive GnRH analog containing a dopamine inhibitor significantly increased TBARS within 24 h, indicating endocrine status is capable of modifying oxidative stress responses. This study provides new knowledge regarding the onset of oxidative stress and changes in reproductive endpoints in fish following pulp-mill effluent exposure. The authors gratefully acknowledge the technical assistance of P. Boutot, C. Chisholm, S. Currie, K. Daynes, M. Edwards, M. Gray, E. LeBlanc, L. Luxon, C. Portt, D. Stevens, and G. Tetreault. We thank D. Roy of the Atlantic Salmon Federation for the loan of fish tanks. We thank the anonymous reviewers for their constructive comments, which greatly strengthened the article. This work was supported by Canadian Network of Toxicology Centers (CNTC), Department of Fisheries and Oceans (DFO), Environment Canada, and Natural Sciences and Engineering Research Council (NSERC) of Canada grants to G. Van Der Kraak. K. D. Oakes received financial support from CNTC, DFO, NSERC, and the Ontario Graduate Scholarship program.

Gill morphometry and hematology of juvenile chinook salmon chronically exposed to treated (elemental chlorine-free) bleached kraft pulp mill effluent at low temperature to simulate winter exposure

We used an on-site mobile laboratory to assess the effects of pulp mill effluent on juvenile (~0.9 g) chinook salmon, Oncorhynchus tshawytscha (Walbaum in Artedi, 1792), that normally overwinter under ice in the upper Fraser River at Prince George, British Columbia. After a 28-day exposure at 0.4–2.7 °C to secondary-treated bleached kraft mill effluent (TBKME; 0%, 2%, 4%, 8%, or 16%) under both normoxic and hypoxic (~67% air saturation) conditions, hematocrit (Hct), leucocrit (Lct), and differential white blood cell counts were determined and gills were examined for gross and fine morphometry. TBKME had no effect on either Hct or Lct, but the highest TBKME concentration (16%) increased lymphocyte numbers, reduced secondary lamellae numbers, and increased the blood–water diffusion distance of secondary lamellae. Given the relatively high TBKME concentration, compared with actual discharges to the river, and the small physiological changes observed, it appears that chronic winter exposure of juvenile chinook salmon to TBKME under hypoxic winter conditions is unlikely to produce major disturbances to these aspects of the fish's physiology.

Effects of pulp mill effluent on benthic assemblages in mesocosms along the Saint John River, Canada.

We used mesocosms to examine the impact of different concentrations of pulp mill effluent (PME) on structural and functional endpoints of a benthic assemblage in the Saint John River (NB, Canada) during 1999 and 2000. Previous studies on this effluent's effects produced conflicting results, with field surveys suggesting a pattern of mild nutrient enrichment, while laboratory toxicity tests linked effluent exposure to moderate contaminant effects. Experimental treatments included three concentrations of sulfite pulp mill effluent (0, 5, 10% v/v PME). Endpoints for the assessment included algal biomass and taxonomic composition, benthic invertebrate abundance and composition, and insect emergence. Low concentrations of PME increased periphyton biomass and caused changes in community structure within the diatom-dominated community. Pulp mill effluent addition had little effect on several structural endpoints measured for benthic invertebrates, including abundance and taxonomic richness, but significantly changed community composition. For both periphyton and benthic invertebrates, community composition endpoints were more sensitive indicators of PME exposure. Insect emergence was a highly relevant functional endpoint. When benthic and emerged insects were combined, total abundance increased with PME addition. Results from two trophic levels, which provided multiple lines of evidence, indicated that the main impact of these PME concentrations is nutrient enrichment rather than effluent toxicity. Our findings also suggest that benthic invertebrate and periphyton assemblages, algal biomass production, and insect emergence are sensitive response measures. Future studies may confirm this observation. The consideration of both functional and structural endpoints at different trophic levels can greatly improve our understanding the effects of discharges to rivers. Such an understanding could not have been obtained using standard assessment techniques and illustrates the value of mesocosms and the benthic community assemblage approach in environmental assessment.

The effects of pulp mill effluent on the sex steroid binding protein in white sucker ( Catostomus commersoni) and longnose sucker ( C. catostomus)

The objective of this study was to characterize the effects of pulp mill effluent on the properties of the sex steroid binding protein (SBP) in the plasma of white sucker ( Catostomus commersoni) and longnose sucker ( C. catostomus). SBPs which specifically bind estradiol and testosterone with high affinity ( k D∼3 nM) and low capacity ( B max∼73–81 nM) were identified in both species. Subsequent studies determined if the properties of the SBP in white sucker exposed to bleached kraft mill effluent (BKME) at Terrace Bay, ON, and in longnose sucker exposed to BKME at Grande Prairie, AB. differed from appropriate reference fish. There were no effects of BKME exposure on the binding affinity ( k D) of the SBP in either species, but there was a significant increase in the binding capacity ( B max) of longnose sucker SBP exposed to BKME. The livers of naı̈ve white sucker exposed to effluent at Terrace Bay or a bleached sulfite/groundwood mill in Edmundston, NB, rapidly accumulated compounds of differing hydrophobicity that bound to both the white sucker and goldfish ( Carassius auratus) SBP. Conversely, there was reduced accumulation of SBP ligands in the bile of effluent-exposed fish. We have demonstrated that constituents present within pulp mill effluent bind to both the white sucker and goldfish SBP, and that native species residing downstream of pulp mill effluents may experience modifications in the properties of their SBP.

Sestonic bacterial nutrient limitation in a northern temperate river and the impact of pulp-mill effluents

Bacterial growth limitation and the effect of pulp-mill effluents (PME) on sestonic bac- teria were studied in a northern temperate river (the Fraser River, British Columbia, Canada). Nutri- ent addition experiments demonstrated that sestonic bacterial growth was potentially limited by P. Experiments were done by adding N, P, or organic carbon to 2 l microcosms of river water. The addi- tion of P (singly, and in combination with N and C) increased bacterial production (rate of 3 H-thymi- dine incorporation) and activity ( 14 C-glucose uptake), while the addition of N or organic carbon did not. The inflow of PME into the Fraser River increased bacterial abundance, activity, and production in 2 ways. First, P in the PME increased native bacterial abundance and processes, and second, PME provided a source of active bacteria to the river.

Artificial Streams for Environmental Effects Monitoring (EEM): Development and Application in Canada over the Past Decade

Abstract Development of artificial stream systems has been an on-going research effort in Canada over the past decade. At the National Water Research Institute (NWRI) of Environment Canada, artificial stream systems have been developed to assess the effects of point source effluents on aquatic biota. Initial applications (1990–1994) focused on assessing the effects of pulp mill effluents on benthic invertebrate and algae communities in large western Canadian rivers. Artificial streams were then used to assess the effects of pulp mill effluents on fish in marine and estuarine environments in eastern Canada (1997–1999). Most recently (2000–2001) artificial stream systems have been developed as tools to evaluate the effects of mining effluents on fish and benthic invertebrates. In addition, multi-trophic level (algae + benthic invertebrate + fish) applications have been developed for cumulative effects bioassessment. Based upon this culmination of research and development, artificial stream systems have been incorporated into the federally legislated Environmental Effects Monitoring (EEM) program as an alternative to field surveys for assessment of pulp and paper and mining pollution. The Canadian experience in development of artificial stream systems should serve as a model to demonstrate how research tools can be incorporated into federally legislated monitoring programs.

Utility of mobile, field-based artificial streams for assessing effects of pulp mill effluents on fish in the Canadian environmental effects monitoring (EEM) program

Although the utility of artificial streams(mesocosms) as research tools for assessingeffects of contaminants on aquatic biota hasbeen recognized, their use in regulatoryprograms has been limited. We conducted threestudies to examine the utility of using mobile,field-based artificial streams to assess theeffects of pulp and paper effluents on fish asrequired in the Canadian Environmental EffectsMonitoring (EEM) program. When evaluatedagainst criteria of environmental relevance,interpretability, scientific defensibility, andcost-effectiveness, mesocosms satisfied allcriteria. Measured endpoints on fish survival,energy use (growth, gonad size) and energystorage (liver size, condition) were relevantto the detection and quantification of effluenteffects on fish. Response patterns were similarto those reported in the literature for fieldsurveys showing reduced gonad size andincreased liver size in adult mummichog (Fundulus heteroclitus) and decreased growth ofjuveniles. The flexibility of the systems tomeasure effects in multiple, replicatedtreatments under controlled effluent exposureand ambient conditions of water quality,temperature and photoperiod provided data thatcould not be obtained at these sites usingfield assessment approaches. The repeatabilityof using the same mobile, mesocosm system ofuniform design and operation at different millsites and for different receiving environmentswas unique and contributed to consistentscientific evaluation and interpretation. Thesestudies demonstrated that mesocosms producedgood quality data that fit within the requiredregulatory context of the Canadian EEM program.

Effect of pulp mill chemicals on flocculation in river water

Thousands of pulp mill chemicals have been released into the aquatic environment. Some of them may cause flocculation and deposition of an organic matrix and incoming suspended sediments downstream of pulp mills in rivers, and may have adverse impacts on aquatic ecosystems. Therefore, it is important to identify the chemicals inducing coagulation and flocculation in river water. This assists in understanding the mechanism for its formation, and will improve the transport models by including the effect of flocculation. Presented is the effect of pulp mill effluent related cationic ions and organic polymers on flocculation in river water. The experimental results show that Na+, Ca2+, fibers, hydrolytic lignin, protein, sucrose, cellulose and starch can induce flocculation in river water.

Cumulative effects assessment for the Northern River Basins Study

The primary objective of the Northern Rivers Basins Study (NRBS)was to advance the understanding of how anthropogenic developments haveimpacted the ecology of the Peace, Athabasca and Slave rivers, Canada.To investigate these multiple stressor impacts, the NRBS used acumulative effects assessment (CEA) based upon a weight of evidenceapproach. This CEA determined the exposure and effects of multiplestressors on these systems and included experimental verification ofcausality and linkage of this understanding to field data. Fish studiesconfirmed that dioxins and furans occur in the food web at low levelsacross the basins; detection frequencies for all2,3,7,8-substituted dioxin/furan congeners (2,3,7,8 TCDD/TCDF)were highest near bleached kraft pulp mills. PCDD/Fs, rather thanPCBs or organochlorine pesticides, were the chemicals of concern forhuman exposure. In addition, the recent decline in concentrations ofdioxins and furans in fish was commensurate with improvements in pulpmill treatment technologies. Throughout the basins, enrichment occurredbelow pulp mill and municipal discharges. Multiple stressor effects ofpulp mill effluent were separated from one another by using experimentsthat demonstrated that the primary impact of the mill effluent wasnutrient enrichment. River state was also greatly influenced byhydrologic impacts. In particularly, the Bennett Dam changed the ecologyof the Peace-Slave river-delta systems more than 1500~km downstream,while climate variability was an important contributing factor for thesedelta impacts. Notable contributions of the NRBS model were thecooperation among governments, aboriginal peoples, non-governmentorganizations, industry and other stakeholders, and the two-waycommunications flow among the scientific community and these groups.NRBS science was also deemed relevant because 16 questions forwarded bystakeholders focused the Study's CEA on specific issues of importancewithin the basin. In summary, the NRBS model of CEA included four keycomponents: (1) communication of stakeholder priorities to producerelevant science questions; (2) pursuit of the best availablescientific understanding of ecosystem impacts by engaginginterdisciplinary science teams; (3) assessment of futureenvironmental condition through monitoring and follow-upinvestigation; and (4) communication of results to managers toproduce appropriate regulatory change. This CEA model combines theseelements with scientific rigor to generate meaningful information tostakeholders while also improving regional assessments of riverbasins.

Biomarker Responses by Crucian Carp (Carassius Carassius) Living in a Pond of Secondary Treated Pulp Mill Effluent

Biochemical and histological biomarkers by the adult crucian carp (Carassius carassius (L.)) living in a biologically treated pulp mill effluent were studied. Enocell pulp mill in Uimaharju, Finland, discharges its effluents through a waste water pond to the River Pielisjoki. This pond harbours an introduced crucian carp population that apparently reproduces on site. The objective of the present study was to measure possible hormonal effects of treated pulp mill effluent on crucian carps living in a wastewater pond. Adult fish were collected for analysis by traps. A reference population was sampled from a small natural pond. Blood and bile samples were taken for analyses of hemoglobin, hematocrit, testosterone, triiodothyronine (T3), thyroxine (T4), vitellogenin, organic chlorine compounds, resin acids and neutral wood-based compounds. In addition, a histological analysis of male gonads was made. The exposed fish had higher concentration of organic chlorine compounds, resin acids and β-sitosterol in bile compared to the reference fish. The same compounds could also be found in sediment of the wastewater pond. The exposed male fish had higher liver somatic index (LSI), lower gonad somatic index (GSI), lower haemoglobin and haemocrit, but higher T3 than in the reference fish. In addition, in an average, increased plasma testosterone concentration and decreased thyroxin (T4) levels were found in the exposed male fish. No vitellogenin production was found in the exposed male fish and some females showed decreased vitellogenin levels. The histological structure of the gonads in the exposed males was normal. The results suggest more anti-estrogenic than estrogenic effects of pulp mill effluents on the crucian carp.

Biomarker responses by crucian carp () living in a pond of secondary treated pulp mill effluent

Biochemical and histological biomarkers by the adult crucian carp ( Carassius carassius (L.)) living in a biologically treated pulp mill effluent were studied. Enocell pulp mill in Uimaharju, Finland, discharges its effluents through a waste water pond to the River Pielisjoki. This pond harbours an introduced crucian carp population that apparently reproduces on site. The objective of the present study was to measure possible hormonal effects of treated pulp mill effluent on crucian carps living in a wastewater pond. Adult fish were collected for analysis by traps. A reference population was sampled from a small natural pond. Blood and bile samples were taken for analyses of hemoglobin, hematocrit, testosterone, triiodothyronine (T 3 ), thyroxine (T 4 ), vitellogenin, organic chlorine compounds, resin acids and neutral wood-based compounds. In addition, a histological analysis of male gonads was made. The exposed fish had higher concentration of organic chlorine compounds, resin acids and β-sitosterol in bile compared to the reference fish. The same compounds could also be found in sediment of the wastewater pond. The exposed male fish had higher liver somatic index (LSI), lower gonad somatic index (GSI), lower haemoglobin and haemocrit, but higher T 3 than in the reference fish. In addition, in an average, increased plasma testosterone concentration and decreased thyroxin (T 4 ) levels were found in the exposed male fish. No vitellogenin production was found in the exposed male fish and some females showed decreased vitellogenin levels. The histological structure of the gonads in the exposed males was normal. The results suggest more anti-estrogenic than estrogenic effects of pulp mill effluents on the crucian carp.