Bleached Kraft Mill Effluent Research Articles

Effects of point-source discharges on shortfin eels (Anguilla australis) along the Waikato River, New Zealand

ABSTRACT The Waikato River is the longest river in New Zealand and is exposed to range of anthropogenic stressors. This study investigated the effects of three major point-source discharges on resident shortfin eels Anguilla australis along the river. Shortfin eels were caught from sites upstream and downstream of discharges of bleached kraft mill effluent (BKME) from pulp and paper manufacture, sewage, and a thermal power plant. At each site, population parameters (relative abundance and age structure) and individual metrics of health such as condition factor and organ (gonad, liver, and spleen) to somatic weight ratios were measured. Blood, biochemical (hepatic 7-ethoxyresorufin-O-deethylase or EROD) and chemical markers (bile chemistry and trace elements in flesh) were also measured. Measures of exposure and response to discharges confirmed that the shortfin eels were resident at the sites sampled. The discharges had few negative impacts on individual eel health and positive responses were seen to warm water discharge. However, resident shortfin eels were immature so reproductive responses could not be determined. In conclusion, shortfin eels in this study showed few responses to the effects of the discharges except for increased resin acids, bile polycyclic aromatic hydrocarbons, and EROD at the BKME site.

Sources and pathways of halomethoxybenzenes in northern Baltic estuaries

IntroductionThousands of halogenated natural products (HNPs) are generated in the ocean and on land. A subset of these, halomethoxybenzenes (HMBs), are released from both natural and anthropogenic sources. Here we consider: 1. Brominated anisoles (BAs), transformation products of bromophenols. 2. Drosophilin A methyl ether (DAME: 1,2,4,5-tetrachloro-3,6-dimethoxybenzene), a secondary metabolite of terrestrial fungi. 3. Tetrachloroveratrole (TeCV: 1,2,3,4-tetrachloro-5,6-dimethoxybenzene), a lignin byproduct found in bleached kraft mill effluent. 4. Pentachloroanisole (PeCA), a metabolite of the wood preservative pentachlorophenol.MethodsWe examined several ecosystem compartments to determine sources and exchange processes for these HMBs: air, precipitation, rivers, forest fungi and litter, and water from northern Baltic estuaries and offshore. Samples were analyzed for HMBs by capillary gas chromatography – quadrupole mass spectrometry.Results and discussionAll four types of HMBs were found in air, and BAs, DAME and TeCV were also present in precipitation. BAs and DAME were common in rivers and estuaries, whereas TeCV was low and PeCA was below detection. DAME was identified in several species of fungi and in forest litter; TeCV was occasionally present, but BAs and PeCA were below detection. Concentrations of BAs were higher in estuaries than in rivers or offshore waters, showing that estuaries are hot spots for production. BAs were negatively or not correlated with chlorophyll-a, suggesting contribution by heterotrophic bacteria as well as known production by phytoplankton and macroalgae. DAME was negatively or not correlated with BAs and did not appear to be produced in the estuaries; fungi and forest litter containing fungal mycelia are suggested as sources. HMBs volatilize from sea and land, disperse through the atmosphere, and return via precipitation and rivers. Production and biogeochemical cycles are influenced by climate change and we suggest BAs and DAME for following partitioning and exchange processes.

Effects of point source discharges on common bully (Gobiomorphus cotidianus) along the Waikato River, New Zealand

ABSTRACT The common bully (Gobiomorphus cotidianus) was used as a bioindicator to assess the impacts of geothermal, bleached kraft mill effluent (BKME), sewage, and thermal discharges in the Waikato River, Northern New Zealand. A range of morphological and physiological parameters were measured to assess fitness in fish sampled upstream and downstream from these point sources. Isotopic signatures gave evidence that fish were resident at sites and showed a gradient corresponding to site-specific sources of carbon and nitrogen along the river. There were changes in the size range and age structure of the populations but, no physiological responses were detected. Limited impacts were observed on common bully health at individual discharge sites, or downstream where the river showed gradual deterioration in water quality, particularly nutrient enrichment, and increased turbidity. Despite the gradual deterioration in water quality no concomitant cumulative impacts were observed in common bully. Responses were largely local in nature, responding to point-source discharges. Population responses at the geothermal and BKME discharge sites warrant further study to investigate possible effects on fish recruitment.

Long-term degradation of poly-lactide co-glycolide/B-tricalcium phosphate biocomposite anchors in arthroscopic repair of Bankart's lesions. A prospective study

Twenty-day-old striped bass (Morone saxatilis) larvae were exposed to a range of treated bleached kraft mill effluent (BKME) concentrations from 0 to 20% effluent by volume (v/v) under continuous flow test conditins. The experimental test concentrations in the 2–20% BKME test aquaria had a BOD5 which ranged from < 1 to 5 mg l−1, TSS 12–17 mg l−1, and true color 35–416 mg l−1. Bleached kraft mill effluent did not kill larvae exposed to it for 20 days through metamorphosis to the juvenile stage. The BKME did not alter growth in length, weight or condition factor in larvae over the 20-day exposure period as determined by multiple regression analysis. A linear regression analysis on the dry weight data at Day 20 only, however, indicated a trend of decreasing weight with increasing BKME concentration. Effluent-exposed larvae also developed normally during the 20-day study. All individuals examined completed the transformation from postlarvae to juveniles by the age of 40 days.

Comparison of membrane bioreactor technology and conventional activated sludge system for treating bleached kraft mill effluent

The purpose of this paper was to review the use of membrane bioreactor technology as an alternative for treating the discharged effluent from a bleached kraft mill by comparing and contrasting membrane bioreactors with conventional activated sludge systems for wastewater treatment. There are many water shortage problems currently in the world, some of which are more serious than others. Public concern over health and the environment, combined with increased requirements for municipalities to reuse wastewater, have created a need for new technologies that can treat wastewater to generate high quality reusable water at low cost. In several of these technologies, membrane technology could make a great contribution since membranes have the ability to produce water of exceptional purity that can be recycled for reuse in a variety of places. This reuse of wastewater is already widely practiced in many countries, which reduces net demand on water supply systems. In industry, in particular the pulp and paper industry, large volumes of water are used with a significant amount of wastewater generated. This effluent needs to be treated prior to final disposal or reuse. The commonly used biological treatment methods of aerated lagoons and activated sludge of bleached kraft mill effluent have been found to be inadequate in achieving the desired level of toxicity removal. There is, therefore, the growing demand for greener/sustainable technologies for reuse/recycling of wastewater and the membrane bioreactors treatment of these effluents has shown some greater potential as it is much cleaner and meet stringent discharge requirements than with other techniques. Key words: Membrane bioreactor, activated sludge, bleached kraft mill effluent, pulp and paper.

Composition of activated sludge settling and planktonic bacterial communities treating industrial effluent and their correlation to settling problems

Problems with deflocculation and solids separation in biological wastewater treatment systems are linked to fluctuations in physicochemical conditions. This study examined the composition of activated sludge bacterial communities in lab-scale sequencing batch reactors treating bleached kraft mill effluent, under transient temperature conditions (30 to 45 °C) and their correlation to sludge settleability problems. The bacterial community composition of settled and planktonic biomass samples in the reactors was monitored via denaturing gradient gel electrophoresis of 16S ribosomal RNA gene fragments. Our analysis showed that settled biomass has a different community composition from the planktonic biomass (49 ± 7% difference based on Jaccard similarity coefficients; p < 0.01). During times of poor sludge compression, the settled and planktonic biomass became more similar. This observation supports the hypothesis that settling problems observed were due to deflocculation of normally settling flocs rather than the outgrowth of non-settling bacterial species.

Responses in a Fathead Minnow (Pimephales promelas) Lifecycle Test and in Wild White Sucker (Catostomus commersoni) Exposed to a Canadian Bleached Kraft Mill Effluent

Abstract To evaluate currently available bioassays for their use in investigating the causes of pulp and paper mill effluent effects on fish reproduction, the responses of wild white sucker (Catostomus commersoni) collected from the receiving environment at the bleached kraft mill at La Tuque, Quebec, were compared with responses of fathead minnow (Pimephales promelas) exposed to effluent in a laboratory lifecycle test. White sucker collected at effluent exposed sites had increased liver size but none of the reproductive effects that had been documented in earlier field studies at this site. Exposure to 1, 3, 10, 30, and 100% bleached kraft mill effluent (BKME) in the lab led to significantly decreased length, but increased weight and liver size in male fathead minnow. Female length was also decreased and liver size was increased at high effluent exposures. Most effluent concentrations (1 to 30%) significantly increased egg production compared with controls. The fathead minnow lifecycle assay mirrored the effects seen in wild fish captured downstream of the BKME discharge. These results will be used to select short-term fish tests for investigating the causes of and solutions to the effects of mill effluents on fish reproduction.

Evaluation of Short-Term Fish Reproductive Bioassays for Predicting Effects of a Canadian Bleached Kraft Mill Effluent

Abstract Under the Canadian Environmental Effects Monitoring (EEM) program for pulp and paper effluents, the observation of a national response pattern of decreased gonad size and increased fish condition and liver size has triggered a centralized multiagency investigation of cause (IOC) of reproductive impacts in fishes. The purpose of the component of the IOC study presented here is to compare a number of fish bioassays for determining reproductive and reproductive-endocrine effects of a bleached kraft mill effluent. The bleached kraft mill chosen for this study had demonstrated the national response pattern in previous EEM cycles. The bioassays employed to examine reproduction were fathead minnow (Pimephales promelas) 5- and 21-d, mummichog (Fundulus heteroclitus) 25-d, and zebrafish (Danio rerio) 7-d tests, all of which had egg production as the primary reproductive endpoint. Additional bioassays examining reproductive-endocrine endpoints included a 7-d mummichog test, a 7- and a 21-d threespine stickleback (Gasterosteus aculeatus) test, a rainbow trout (Oncorhynchus mykiss) 7-d test, and in vitro sex steroid receptor and plasma protein binding bioassays. The zebrafish and fathead minnow reproductive tests showed significant suppression of egg production at the 100% effluent concentration. Endocrine data derived from the tests showed that this effluent did not impact steroidogenic endpoints at any concentration. Bioassays showed that this effluent i) was capable of eliciting cytochrome P4501A induction at as low as 10% vol/vol effluent, ii) was weakly androgenic at 10% vol/vol, and iii) showed no evidence of in vivo estrogenicity. These results were consistent with in vitro receptor binding assays showing a highly variable level of androgenic equivalents over six months of effluent testing, with little evidence of estrogenic activity. Bioassay results were consistent in that the overall conclusion was that this effluent has only a weak potential to cause reproductive impairment and would likely not do so at environmentally relevant concentrations. Field studies and a fathead minnow lifecycle study conducted concurrently were in agreement with reproductive bioassay results as white sucker exposed in the receiving environment no longer had significantly reduced gonadal development. Overall, this study provided evidence that the laboratory assays evaluated for various reproductive endpoints have potential application for future IOC work.

Androgenic effects of a Canadian bleached kraft pulp and paper effluent as assessed using threespine stickleback ( Gasterosteus aculeatus)

The presence of unidentified estrogens and androgens in effluents from pulp and paper mills is well documented. However, their role in effluent effects on fish reproduction remains unclear. The objective of this study was to investigate the hypothesis that reproductive impacts of a modern pulp mill effluent are mediated by androgens and/or estrogens in the effluent. Male and female threespine stickleback were exposed to biologically treated Canadian bleached kraft mill effluent under flow-through conditions in the laboratory at 0, 1, 10 and 100% (v/v) dilutions. After 7 and 21 d of exposure, steroidogenesis was assessed using in vitro incubations of gonadal tissue in both males and females. mRNA expression of the estrogen-regulated gene vitellogenin, and the androgen-responsive gene spiggin were assessed using quantitative RT-PCR in the livers of male and posterior kidneys of female stickleback, respectively. Hepatic 7-ethoxyresorufin- O-deethylase (EROD) activity was assessed in both sexes. Effluent extracts were examined for estrogenic and androgenic bioactivity using receptor binding bioassays, and were screened for pulp and paper related extractives and steroidal androgens using GC–MS. This effluent up-regulated spiggin mRNA in the kidney of female stickleback at 10% and 100% (v/v) effluent at 21 d, but not at 7 d of exposure. This change at the mRNA expression of the gene was associated with an increase in cell height in kidney proximal tubule epithelial cells at 100% effluent after both 7 and 21 d. Liver vitellogenin mRNA in male stickleback was not induced at either 7 or 21 d. EROD was induced at 10 and 100% after 21 d of exposure in both sexes, but not after 7 d of exposure. Despite evidence of exposure to androgens, there was no reduction in steroidogenic capacity at any effluent dilution. Effluent extracts were capable of eliciting the displacement of androgens and estrogens from receptors, but androgenic potency was 4-fold greater. A screen of more than 30 androgenic androstane steroids showed no detections. Hence, the androgenic constituents in this particular effluent remain unknown.

The effects of pulp and paper mill effluent on physiological and hematological endpoints in fingerling largemouth bass (Micropterus salmoides)

The purpose of this study was to evaluate the effects of bleached kraft mill effluent on selected physiological and hematological endpoints in fingerling largemouth bass (Micropterus salmoides). Fish were exposed for 35 days to surface water collected at sites up- and downstream from a pulp and paper mill treatment-effluent discharge. The condition factor, spleen somatic index, and pronephros cellularity were statistically significantly decreased in fish exposed to the downstream site, compared to the upstream site. There was also a shift from lymphocytes to neutrophils in peripheral blood of fish exposed to the downstream site. Hematocrit values and the liver somatic index were statistically significantly increased in fish in the downstream exposure. These results indicate that in-stream exposure to elemental-chlorine-free pulp and paper mill effluents produce a generalized stress response, leading to potential immunosuppression in fish.

Removal of AOX, total nitrogen and chlorinated lignin from bleached Kraft mill effluents by UV oxidation in the presence of hydrogen peroxide utilizing TiO2 as photocatalyst

The pulp and paper industry is the sixth largest polluter discharging a variety of gaseous, liquid, and solid wastes into the environment. Effluents from bleached Kraft mill effluents (BKME) are polluting waters to a great extent These effluents cause considerable damage to the receiving waters if discharged untreated since they have high levels of biological oxygen demand (BOD), chemical oxygen demand (COD), chlorinated compounds (measured as AOX), suspended solids (mainly fibers), fatty acids, tannins, resin acids, lignin and its derivatives, sulfur and sulfur compounds, etc. This study aimed to remove adsorbed organic halogen (AOX), total nitrogen, and lignin-degrading products in the wastewater (4,500 m(3)/h) from the paper mill in the pulp and paper industry, which is discharged to sea from a plant located in western Turkey. The photocatalytic degradation of AOX, total nitrogen, and chlorinated lignin in BKME have been investigated in different parameters, such as time, H(2)O(2) and TiO(2) concentration. In addition, for investigating the effect of chlorine on the removal of lignin, pure lignin solution was prepared in equal amounts to chlorinated lignin degradation products found in BKME. The same experiments were conducted for this solution. Experiments were carried out in photocatalytic reactor made of Pyrex glass. The mercury lamp was used as a radiation source. All irradiation was carried out under constant stirring. The existence of dissolved O(2) is an important factor which increases the photocatalytic degradation. Hence, we used an air pump for the aeration of the wastewater solutions. The temperature of the wastewater was controlled and adjusted to 25 degrees C by thermostat pump in conjunction with a cooler. At the end of all experiments, AOX, total nitrogen and lignin concentrations were analyzed according to standard methods. All experiments were performed in duplicate and average values were used. When the effect of H(2)O(2) and time were investigated, it was observed that the AOX concentration increased from 3.0 to 11.0 mg/L by only UV. However, when H(2)O(2) was added, AOX concentration decreased from approximately 3.0 to 0.0 mg/L. The optimal conditions for the removal of AOX appear to be an initial H(2)O(2) concentration of 20.0 mL/L and reaction time of 50 min. In addition, at the same experiment conditions, it was seen that the total nitrogen concentration decreased from 23.0 to 15.0 mg/L by only UV and by increasing H(2)O(2) concentration, the concentration of 20.0 mL/L H(2)O(2) appears to be optimal (9.0 mg/L). The AOX, total nitrogen and lignin degradation products and pure lignin go through a minimum when the concentration of H(2)O(2) and TiO(2) increases at constant pH and UV intensity. The kinetics for the degradation of AOX, total nitrogen and lignin degradation products followed a pseudo-first order law with respect to the products, and the degradation rates (min(-1)) for the UV/TiO(2)/H(2)O(2) system were higher than that of the corresponding values for the UV/H(2)O(2) system. The AOX, total nitrogen and lignin concentration go through a minimum when the concentration of H(2)O(2) and TiO(2) increases at constant pH and UV intensity. It was found that the UV/TiO(2)/H(2)O(2) system has proved capable of the degradation of total nitrogen as well as chlorinated and degraded lignin in BKME. The photocatalytic process can be considered a suitable alternative for the remove of some compounds from the BKME. Nevertheless, further studies should be carried out to confirm the practical feasibility of BKME. Another result obtained from the study is that pre-purification carried out with UV/TiO(2)/H(2)O(2) photocatalytic process may constitute an important step for further purification processes such as adsorption, membrane processes, etc.

The Benefits of Biotreatment for Reducing the Effects of Pulp and Paper Mill Effluents on Fish Reproduction in Laboratory Tests

Abstract Pulp and paper mill effluents have been reported to cause changes in reproductive indicators of fish in laboratory and field studies. These changes include reduced egg production and gonad size, and altered hormone levels and expression of secondary sex characteristics. We examined the performance of biotreatment plants for their potential in abating effects of pulp and paper mill effluents on fish reproduction under laboratory conditions. A bleached kraft mill effluent (BKME) treated in an aerated lagoon and a thermomechanical pulp mill effluent (TMPE) treated by aerobic sludge in a sequential batch reactor were selected for study. Mature fathead minnows (Pimephales promelas) were exposed to effluents before and after biotreatment under continuous renewal conditions for 21 days. Egg production was monitored daily, while morphometric parameters (length, weight, gonad size), secondary sexual characteristics, and steroid hormone and vitellogenin levels were measured at the end of the effluent exposure. The effluent from both mills before biotreatment impaired the reproductive capacity of minnows (egg production) at concentrations of 10 and 20% vol/vol, but not at 2% vol/vol. Exposure to biotreated effluents from both mills at concentrations of 2, 10, 20, and 40% vol/vol caused no significant differences in overall reproductive capacity of minnows as compared with controls. These results indicate that biotreatment can significantly improve the quality of a BKME and an effluent from a TMP mill with respect to the reproductive capacity of fish as determined in laboratory tests.

ULTRA-TRACE ANALYSIS OF MULTIPLE ENDOCRINE-DISRUPTING CHEMICALS IN MUNICIPAL AND BLEACHED KRAFT MILL EFFLUENTS USING GAS CHROMATOGRAPHY–HIGH-RESOLUTION MASS SPECTROMETRY

A comprehensive gas chromatographic-high-resolution mass spectrometric (GC-HRMS)-based method was developed that permitted the simultaneous determination of 30 estrogenic endocrine-disrupting chemicals (EDCs) and related compounds, including surfactants, biogenic and synthetic steroids, fecal sterols, phytoestrogens, and plasticizers, in wastewater. Features of the method include low sample volume (~40 ml), optimized Florisil cleanup to minimize matrix interferences and optimized analyte derivatization to improve sensitivity via GC-HRMS. Detection limits were in the low- to mid-ng/L range, and recoveries were greater than 60% for most target analytes. This new method allows for high throughput analysis of many organic wastewater contaminants in a complex matrix with relative standard deviation of less than 15% for most measurable compounds. The applicability of the method was demonstrated by examining wastewater samples from different origins. Compounds such as di(2-ethylhexyl)phthalate, cholesterol, cholestanol, and other cholesterol derivatives were measured in much higher concentrations in untreated sewage and were reduced substantially in concentration by the treatment process. However, steroidal compounds, particularly estrone (E1), 17beta-estradiol (E2), and estriol (E3), as well as plant sterols (except stigmastanol), were greater in the treated municipal wastewater versus the untreated effluent. Plant and fungi sterols, stigmastanol and ergosterol, were found largely associated with bleached kraft mill effluent (BKME) as compared to the municipal effluents.

Anaerobic Biodegradation of Sterols Contained in Kraft Mill Effluents

Bleached kraft mill requires large quantities of water and chemicals reactives and generates effluents containing active organic compounds. Specifically, hormonal changes in fish and their communities have been demonstrated, which could be attributed to endocrine-disrupting chemicals (EDCs) contained in kraft mill effluents. This chronic toxicity is attributable to extractive compounds, such as resin acids, sterols, and fatty acids. The goal of this work is to evaluate the methanogenic toxicity and anaerobic biodegradation of stigmasterol and beta-sitosterol. A continuously anaerobic filter (AF) was used for the anaerobic biodegradation of stigmasterol and beta-sitosterol. Three phases were evaluated. In phase I, an elementary chlorine-free bleached kraft mill effluent was fed to the reactor whereas in phases II and III, the effluent was supplemented with increasing stigmasterol and beta-sitosterol concentrations. The AF displays high performance in biological oxygen demand (BOD5) removal (up to 94%); however, only 50% of the chemical oxygen demand (COD) was removed. Simultaneously, the AF system shows a great ability to remove beta-sitosterols (77-100%) and stigmasterols (87-95%). No negative effect on the methanogenic activity inhibition was shown by beta-sitoesterols and stigmasterol. However, a mixture of beta-sitosterols and stigmasterols (ratio 1:1) caused a less than 10% reduction in methanogenic activity.

Effects of transient temperature conditions on the divergence of activated sludge bacterial community structure and function

The effect of temperature fluctuations on bacterial community structure and function in lab-scale sequencing batch reactors treating bleached kraft mill effluent was investigated. An increase in temperature from 30 to 45 °C caused shifts in both bacterial community structure and function. Triplicate reactors were highly similar for 40 days following startup. After the temperature shift, their community structure and function started to diverge from each other and from the control. A multi-response permutation procedure confirmed that the variability in community structure between transient and control reactors were greater than that among the triplicate transient reactors. The fact that these disturbances manifest themselves in different ways in apparently identical reactors suggests a high degree of variability between replicate systems.

Effect of substrate variability on activated sludge kinetics during the treatment of bleached kraft mill effluent

Solids retention time (SRT) is the primary control parameter for activated sludge units. However, treatment performance in full-scale systems at pulp mills does not appear to be a direct function of SRT. To determine the extent to which substrate variability masks the effects of SRT, the effect of SRT on activated sludge treatment kinetics and stoichiometry during bleached kraft mill effluent (BKME) treatment were investigated during a three year laboratory study. The treatment performance was monitored by biochemical oxygen demand (BOD), chemical oxygen demand (COD), and respirometric assays using BKME, methanol, formate, and acetate as substrates to monitor the activity of different populations of biomass. BOD removal was unaffected by SRT, however COD removal increased with increasing SRT and increasing influent BOD concentration. The BKME respirometric kinetics were constant with respect to SRT. The methanol and acetate degradation rates were variable, but were not a function of SRT. The maximum formate degradation rate increased with SRT, as did the yield on formate. Changing wastewater characteristics produced larger changes in treatment kinetics than those produced by changing the SRT (over a range from 6 to 30 days) or by the addition of an aerobic selector. The proportion of the formate metabolic rate relative to the methanol metabolic rate varied over the course of the project with the wastewater composition. The time required to adapt to different BKME batches varied from 5 to 30 days, and did not seem to depend on any of the measured variables (BOD, COD, or SRT).Key words: activated sludge, respirometry, kinetics, BKME, SRT, selector.

A Decade of Research on the Environmental Impacts of Pulp and Paper Mill Effluents in Canada: Field Studies and Mechanistic Research

Studies conducted in Sweden in the early 1980s provided some of the first evidence that effluents from some pulp mills were capable of inducing toxic responses in fish at very low concentrations in the receiving environment. In response to these findings, studies were initated in Canada and impacts of primary treated bleached kraft mill effluent on reproductive function in fish were found. Reproductive impacts in fish were not limited to mills that used chlorine in the bleaching process and were also evident at some mills that employed secondary effluent treatment. In 1992, new federal regulations were passed under the Canadian Environmental Protection Act to control releases of dioxins and furans, and a new Pulp and Paper Effluent Regulation under the Fisheries Act set stricter limits for biological oxygen demand and total suspended solids. Very importantly, the new regulations included requirements for environmental effects monitoring (EEM) at all mill sites. This allowed the effectiveness of the control limits in protecting fish, fish habitat, and human use of fisheries resources to be assessed. At the same time, the Minister of the Environment launched an intensive government, industry, and university research program. Results from this research program along with feedback from the EEM program would then be used to define what additional control actions might be necessary. This article reviews the field studies and mechanistic research conducted in Canada following the implementation of the new federal regulations. Great progress has been made in this area, first demonstrating reproductive effects at various locations, then determining the mechanisms responsible for the reproductive effects at specific sites, followed by the demonstration of partial recovery in reproductive function following process and treatment changes in response to the new regulations. However, it is clear from the results of the first two cycles of the EEM program that mill effluents still affect the local receiving environments at a number of locations across Canada, and that continued research combining field studies, bioassay application, and chemical identification is required. Completion of this assessment would not have been possible without the helpful comments and scientific reviews provided by Drs. John Carey, Jim Maguire, Kelly Munkittrick, Glen Van Der Kraak, Jim Sherry, and Olöf Sandstrom.

Cumulative impacts assessment along a large river, using brown bullhead catfish (Ameiurus nebulosus) populations

The effects of point-source and diffuse discharges on resident populations of brown bullhead catfish (Ameiurus nebulosus (LeSueur, 1819)) in the Waikato River (New Zealand) were assessed at sites both upstream and downstream of point-source discharges. At each site, the population parameters, relative abundance, age structure, and individual indices, such as condition factor, organ (gonad, liver, and spleen) to somatic weight ratios, and number and size of follicles per female, were assessed. Physiological (blood), biochemical (hepatic ethoxyresorufin-O-deethylase [EROD] and plasma steroids), and other indicators (bile chemistry and liver metals) of exposure or response also were measured. No impacts on brown bullhead health were obvious at individual geothermal, municipal sewage, or thermal discharge sites or cumulatively along the river. Brown bullhead from the bleached kraft mill effluent site showed elevated levels of EROD, decreased numbers of red blood cells, increased numbers of white blood cells, and depressed levels of sex steroids. However, growth rates, condition factor, age structure, and gonadosomatic index suggest that discharges with significant heat or nutrients benefit catfish despite physiological impairment at one site. Consideration of brown bullhead population-level responses to discharges in a monitoring framework revealed three different population-level response patterns resulting from the point-source discharges.

Improved aerobic biodegradation of abietic acid in ECF bleached kraft mill effluent due to biomass adaptation

Kraft pulp mill effluents contain elevated concentrations of resin acids, chiefly abietic and dehydroabietic acid, and other lipophilic wood constituents. Resin acids, if not efficiently removed during wastewater treatment, can be responsible for chronic toxicity in aquatic systems. The objective of this study was to investigate the biological removal of abietic acid (AbA) during the treatment of elemental chlorine free (ECF) kraft mill effluents in aerobic lagoons and to assess its improvement with time as a result of biomass adaptation. Under these conditions, the average removal efficiencies of AbA and BOD 5 attained in the aerobic lagoon were high and exceeded 80% and 95%, respectively. Microbial inhibition of non-acclimated and acclimated biomass by AbA was not detected in batch bioassays. Kinetic studies showed that the K s and V m values equalled 76.7 mg AbA/l and 0.011 l/h, respectively, for the non-acclimated biomass, and 1678 mg AbA/l and 0.13 l/h, respectively, for the acclimated biomass.

Irrigation model of bleached Kraft mill wastewater through volcanic soil as a pollutants attenuation process

An irrigation process through volcanic soil columns was evaluated for bleached Kraft mill effluent pollutants retention. The system was designed to remove color and phenolic compounds and a simple kinetic model for determining the global mass transfer coefficient and the adsorption rate constant was used. The results clearly indicate that the global mass transfer coefficient values ( K c a) and the adsorption rate constants are higher for the irrigation processes onto acidified soil. This means that the pretreatment of washing the volcanic soil with an acid solution has a positive effect on the adsorption rate for both pollutant groups. The enhanced adsorption capacity is partially explained by the activation of the metal oxides present in the soil matrix during the acid washing process. Increasing the flow rate from 1.5 to 2.5 ml/min yielded higher ( K c a) values and adsorption rate constants for both pollutant groups. For instance, regarding color adsorption onto acidified soil, there is an increment of 43% in the ( K c a) value for the experiment with a flow rate of 2.5 ml/min. Increasing the porosity of the column from 0.55 to 0.59, yielded a decrease in the ( K c a) values for color and phenolic compounds adsorption processes. Onto natural soil for example, these decreases reached 21% and 24%, respectively. Therefore, the ( K c a) value is dependent on both the liquid-phase velocity (external resistance) and the soil fraction in the column (internal resistance); making forced convection and diffusion to be the main transport mechanisms involved in the adsorption process. Analyzing the adsorption rate constants ( K c a)/ m, phenolic compounds and color adsorption rates onto acidified soil of 2.25 × 10 −6 and 2.62 × 10 −6 l/mg min were achieved for experiment 1. These adsorption rates are comparable with other adsorption systems and adsorbent materials.