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Chlorine bleaching technology (C process, CEH process, H process and theirs combination), which was identified as a primary formation source of PCDD/Fs, is still widely used by the vast majority of Chinese non-wood pulp and paper mills (non-wood PMs). The purpose of this study was to provide information and data support for further eliminating dioxin for non-wood PMs in China, and especially to evaluate the PCDD/Fs release reduction for those mills converting their pulp bleaching processes from CEH to ECF. The PCDD/Fs concentrations of the bleached pulp and bleaching wastewater with ECF bleaching were in the ranges of 0.13-0.8 ng TEQ kg -1 , and 0.15-1.9 pg TEQ L -1 , respectively, which were far lower than those with CEH process, indicating that the ECF process is an effective alternative bleaching technology to replace CEH in Chinese non-wood PMs to reduce dioxin release. The release factor via flue gas of the alkali recovery boiler in Chinese non-wood PMs was first reported to be 0.092 μg TEQ Ad t -1 in this study. On the assumption that pulp bleaching processes of all Chinese non-wood PMs were converted from CEH to ECF, the annual release of PCDD/Fs via the bleaching wastewater and bleached pulp would be reduced by 79.1%, with a total of 1.60 g TEQ., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In order to validate previous field observations by the authors on whitefish, Coregonus lavaretus L. s.l., a 30-day laboratory experiment with concentrations (0, 1.3, 2.3, 3.5, and 7 vol%) of bleached kraft pulp and paper mill effluent (BKME) simulating those occurring in a polluted lake was conducted. Chlorine dioxide had almost entirely replaced chlorine gas in the bleaching of pulp. As a consequence, the concentrations of adsorbable organic halogens and chlorinated phenolics (CPs) in BKME were significantly lowered compared to earlier studies. This reduction was also seen in the concentrations of CPs in the bile and CPs and extractable organic halogens in the intestinal lipids: the concentrations were low and did not depend on the dilution of BKME. In contrast, the resin acid content of bile decreased with decreasing BKME concentration. The growth of fish was speeded up in all BKME concentrations. However, at the highest BKME concentration (7 vol%) the increase was lowest. The induction of hepatic ethoxyresorufin O-deethylase (EROD) activity revealed strong dose-response relationship with BKME. At 3.5 vol% BKME (corresponding to a distance of 3.3 km from the mill sewer in the field) the EROD activity increased 12-fold. There was a tendency for lower activity of uridinediphosphate glucuronosyltransferase in the liver, but the decrease (34%; P < 0.05) was statistically significant only at 7 vol% BKME. The activity of liver glutathione S-transferase remained unchanged. All dilutions of BKME significantly depressed the concentrations of plasma immunoglobulin M (IgM). Erythrocytic concentrations of nucleotide triphosphates decreased and of sodium increased as the BKME concentration increased. Also some other blood parameters (hematocrit, hemoglobin, plasma glucose, and aspartate aminotransferase) were changed in all BKME exposures, although without obvious dependence on effluent concentration. In conclusion, there was a good agreement between field studies and laboratory experiments using BKME concentrations occurring in the field, confirming close or similar causes for responsive toxicity endpoints.

The article reviews the transition from bleaching kraft pulp with elemental chlorine to bleaching with chlorine dioxide with respect to formation of chlorinated dioxins and furans (PCDD/Fs). New data is also presented for bleaching with 100% chlorine dioxide and the effect of elemental chlorine impurities. The typical fingerprint of PCDD/Fs in pulp bleached with elemental chlorine was unique compared to all other sources such as incineration and metallurgic processes. 2,3,7,8-TCDD and 2,3,7,8-TCDF were the dominating congeners formed during the period pulp was bleached with elemental chlorine. Elimination of unchlorinated precursors lowered, but did not eliminate, the formation of 2,3,7,8-TCDD and 2,3,7,8-TCDF. The formation of 2,3,7,8-TCDD and 2,3,7,8-TCDF increases exponentially with the amount of elemental chlorine used. Replacing elemental chlorine with chlorine dioxide (with levels of elemental chlorine contamination of <0.3% in the chlorine dioxide) in pulp bleaching eliminates the formation of 2,3,7,8-TCDD and 2,3,7,8-TCDF. PCDD/Fs can also be found in background levels in ecosystems, food, soil and air as well as in unbleached pulp, bleached pulp, and paper and fiber products. Thus, the only way to determine if PCDD/Fs are present from bleaching is to make a full congener analysis and compare to known sources and processes as well as to laboratory blanks and unbleached reference samples., (Copyright © 2019 The Author. Published by Elsevier Ltd.. All rights reserved.)

In order to study immunomodulation, controlled laboratory experiments were carried out with roach (Rutilus rutilus) exposed to bleached kraft mill effluent (BKME) or spent bleach liquor (SBL) from two pulp and paper mills using elementary chlorine and chlorine dioxide for bleaching. The total number of immunoglobulin-secreting cells (ISC) and the number of specific antibody-secreting cells (ASC) were determined by ELISPOT assay. Exposure to BKME resulted in decreased numbers of ISC in the spleen. To study the capability of response against foreign antigens the fish were immunized with bovine gamma-globulin. Exposure to BKME or SBL reduced antigen-specific ASC response in fish. Moreover, the suppression of ASC response did not require exposure prior to immunization. Depuration of fish in clean water reveals that the immunosuppression caused by BKME is reversible. The ASC response in the BKME-pretreated fish returned to the same or even a higher level compared to untreated immunized fish and, in addition, the number of ISC increased greatly. The results of this study verify an earlier finding on poor antibody response due to exposure in a lake contaminated with BKME. Exposure to SBL alone suppresses antibody-mediated immunity, suggesting that compounds formed in bleaching are at least partly responsible for immunotoxic effects.

Roach (Rutilus rutilus), from a unpolluted lake, were caged in a lake receiving treated waste waters from a pulp and paper mill 16 km upstream, and simultaneously a group of fish were held in cages in the unpolluted reference lake. The level of serum immunoglobulin of the fish kept in cages in these lakes was quantified. Serum immunoglobulin levels decreased when the fish were transferred to the contaminated lake and remained significantly reduced for the 8-week period fish were monitored. In another experiment fish were immunized with bovine gamma-globulin (BGG) after 5 weeks caging in the lakes. The kinetics of specific antibody synthesis were determined by assaying the number of antibody secreting cells in the spleen using enzyme-linked immunospot assay and by measuring the concentration of specific antibody in the serum. The peak response of the effluent exposed fish against BGG was lower than that for fish kept in the unpolluted reference lake, and the antibody titers, due to immunization, increased more slowly in the exposed fish. These results demonstrate that subchronic exposure of fish in a lake receiving treated waste waters from a bleached kraft mill affects the antibody-mediated immunity resulting in, besides lower levels of Ig, weak responsiveness against antigen.

The studies were performed on perch (Perca fluviatilis) caught outside Husum and Iggesund kraft pulp mills in 1985 and 1987, respectively, and the results were compared to previous observations from 1984 to 1985 in the receiving waters of the Norrsundet kraft pulp mill. The studies revealed that the biochemical and physiological variables, i.e., EROD activity, gonad size, number of lymphocytes, carbohydrate metabolites, and plasma ion composition, can be used as sensitive and reliable indicators of toxic effects on natural populations of fish exposed to conventional chlorine-bleached kraft mill effluents. However; the effects were generally less pronounced and indicated less geographic extension than those seen in perch previously investigated in the receiving waters of the Norrsundet kraft pulp mill. Based on these studies on perch at Husum and Iggesund and the previous studies at Norrsundet it can be concluded that the chlorine-bleached kraft mill effluents cause serious disturbances to vital biochemical and physiological functions, which can affect the health status and presumably also the survival of the fish. Finally, the responses do not reflect the present situation in the receiving waters since all three mills have taken extensive measures for process alterations and discharge reductions after the time of the investigations.

Long-term immobilization ratios of strontium (Sr2+) and cesium (Cs+) in paper sludge ash-based geopolymer (PS-GP) were investigated in one year. PS-GP paste specimens were prepared in the conditions of 20 °C and 100% R.H., using two kinds of paper sludge ash (PS-ash). Two kinds of alkaline solution were used in the PS-GP as activator. One was prepared by diluting aqueous Na-disilicate (water glass) with seawater. Another was a mixture of this solution and caustic soda of 10 M concentration. When seawater was mixed into the alkaline solution, unstable fixations of Sr2+ and Cs+ were greatly improved, resulting stable and high immobilization ratios at any age up to one year, no matter what kind of PS-ash and alkaline solution were used. Element maps obtained by EPMA exhibited nearly even distribution of Cs+. However Sr2+ was biased, making domains so firmly related to Ca2+ presence. The mechanism that seawater stabilizes immobilization of Sr2+ and Cs+ was discussed in this study, but still needs to further investigation. Chemical composition analyses of PS-GP were also conducted by SEM-EDS. Two categories of GP matrix were clearly observed, so called N-A-S-H and C-A-S-H gels, respectively. By plotting in ternary diagrams of SiO2-(CaO + Na2O)-Al2O3 and Al2O3-CaO-Na2O, compositional trends were discussed in view of ‘plagioclase gels’ newly found in this study. As a result, it is suggested that the N-A-S-H and C-A-S-H gels should be strictly called Na-rich N-C-A-S-H and Ca-rich N-C-A-S-H gels, respectively.

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In this work, for the first time, a detailed analysis of the preparation of reactive indicator papers (RIPs) based on silver-containing nanocomposites derived from silver fumarate was carried out. Thermolysis products are silver-containing nanocomposites containing silver nanoparticles uniformly distributed in a stabilizing carbon matrix. The study of the optical properties of silver-containing nanocomposites made it possible to outline the prospects for their application in chemical analysis. RIPs were made by impregnating a cellulose carrier with synthesized silver fumarate-derived nanocomposites, which change their color when interacting with chlorine vapor. This made it possible to propose a method for the determination of chloride ions with preliminary oxidation to molecular chlorine, which is then separated from the solution by gas extraction. The subsequent detection of the active zone of RIPs using colorimetry makes it possible to identify mathematical dependences of color coordinates on the concentration of chloride ions. The red (R) color coordinate in the RGB (red-green-blue) system was chosen as the most sensitive and promising analytical signal. Calibration plots of exponential and linear form and their equations are presented. The limit of detection is 0.036 mg/L, the limits of quantification are 0.15–2.4 mg/L, and the time of a single determination is 25 min. The prospects of the developed technique have been successfully shown in the example of the analysis of the natural waters of the Don River, pharmaceuticals, and food products. [ABSTRACT FROM AUTHOR]