Extractable Organic Halogens Research Articles

Recent advances in eco-friendly technology for decontamination of pulp and paper mill industrial effluent: a review.

The economic development of a country directly depends upon industries. But this economic development should not be at the cost of our natural environment. A substantial amount of water is spent during paper production, creating water scarcity and generating wastewater. Therefore, the Pollution Control Board classifies this industry into red category. Water is used in different papermaking stages such as debarking, pulping or bleaching, washing, and finishing. The wastewater thus generated contains lignin and xenobiotic compounds such as resin acids, chlorinated lignin, phenols, furans, dioxins, chlorophenols, adsorbable organic halogens (AOX), extractable organic halogens (EOCs), polychlorinated biphenyls, plasticizers, and polychlorinated dibenzodioxins. Nowadays, several microorganisms are used in the detoxification of these hazardous effluents. Researchers have found that microbial degradation is the most promising treatment method to remove high biological oxygen demand (BOD) and chemical oxygen demand (COD) from wastewater. Microorganisms also remove AOX toxicity, chlorinated compounds, suspended solids, color, lignin, derivatives, etc. from the pulp and paper mill effluents. But in the current scenario, mill effluents are known to deteriorate the environment and therefore it is highly desirable to deploy advanced technologies for effluent treatment. This review summarizes the eco-friendly advanced treatment technologies for effluents generated from pulp and paper mills.

The last 50 years of organic contamination of a highly anthropized tributary of the Po River (Italy)

We examined the temporal profiles of many organic micropollutants analysed in a sediment core sampled from a highly anthropized tributary of the Po River, the Lambro River. Analysed for extractable organic halogens (EOX), total petroleum hydrocarbons (C10–C40TPH), polycyclic aromatic hydrocarbons (PAHs), common legacy pollutants (DDTs, PCBs), halogenated flame retardants (PBDEs, DBDPE, TBBPA-bis, TCBPA, TBBPA, HBCDs), organotins (TBT, TPhT), antimicrobials (TCS, TCC), fragrances (AHTN, HHCB) and phthalates (DMP, DEP, DnBP, BBP, DEHP, DnOP), the dated sediment core revealed the historical record of 50 years of chemical contamination discharged into the Lambro and thereby the Po River. In this regard, the peak levels of PCBs and DDTs found in Lambro sediments were also identified in other sediment cores collected from the Po River prodelta in the Adriatic Sea, thus hundreds of kilometres downstream (Combi et al., 2020). The highest risk to aquatic organisms was associated with decades of high levels of C10–C40 TPH, PBDEs, PCBs, PAHs, DDTs, EOX, TCC, AHTN and DEHP, which in different periods of the contamination history, showed exceedances of guideline/threshold values. C10–C40 TPH and TCC, for example, were very high in the 1960s, whereas PCBs, DDTs, and PBDEs, peaked from the 1980s onward. The corresponding sums of PEC quotients ranged between 0.48 and 28.63, with a mean value (±SD) for the entire recording period of 10.62 ± 9.83. Environmental legislations and improved wastewater treatments were the main drivers of the recent downward trends observed for most of the chemicals investigated. Floods in turn resulted in macroscopic yet temporary improvements in the chemical quality of the tributary, conveying contaminated sediments into the Po River.

Vis-NIR Reflectance Spectroscopy and PLSR to Predict PCB Content in Severely Contaminated Soils: A Perspective Approach

Soil reclamation from polychlorinated biphenyls (PCBs) requires careful analysis in terms of their concentrations and spatial distribution. Conventional laboratory analysis, even if providing the careful evaluation of PCBs, is costly and time-consuming. Therefore, rapid and cost-effective techniques to replace traditional analytical approaches are required. The utility of visible-near infrared (vis-NIR) reflectance spectroscopy in conjunction with partial least square regression (PLSR) analysis was evaluated in this study. Spectral reflectance was measured in the laboratory on 28 soil samples collected in a highly contaminated area of southern Italy and chemically analysed to determine eighteen PCB congeners, their sum (PCBs18), and extractable organic halogen content (EOX). Spectroscopic data were pre-processed prior to data analysis by combining different methods. Using PLSR analysis, significant relationships were observed between the predicted and the measured content of PCBs18, EOX, and the percentage of several isomeric classes of PCBs. Although rigorous models could not be calibrated, due to the limited number of samples, the preliminary results of this study demonstrated that vis-NIR reflectance spectroscopy, coupled with PLSR, can be considered a promising method for a rapid and cost-effective prediction of PCBs.

Thickening and Storage of Sewage Sludge Contribute to the Degradation of LAS and EOX and the Humification of Organic Matter

Land application of sewage sludge on agricultural soils can be sustainable only if pollutant contents and organic matter quality meet the requirements imposed by minimization of environmental risks. This study investigated the degradation of linear alkylbenzene sulfonates (LAS) and extractable organic halogens (EOX) and the formation of humic substances (HS) during the thickening and storage phases of sewage sludge treatment. Changes in spectroscopic properties (UV-Vis, FT-IR, and excitation-emission matrix (EEM) fluorescence) of HS were also evaluated to assess the occurrence of biological activities during these curing phases of sewage sludge (SS). Humic acids (HA), fulvic acids (FA), EOX, and LAS were extracted from sewage sludge sampled from four municipal wastewater treatment plants of different size and treatment sequence, before and after 90 days of aerobic or anaerobic storage. During storage, the loss of organic C in the SS ranged from almost null to 31%. No significant changes of FA were registered, whereas HA increased in almost all samples, up to 30%. The amount of humic substances synthesized during storage correlated with the percentage of C lost. Spectroscopic changes of FA and HA showed an increase in their aromaticity, with a corresponding decrease in the aliphatic contribution. These changes show the improved agronomical quality of SS. LAS decreased during storage up to 30%, surprisingly more under anaerobic than aerobic conditions, whereas EOX decreased significantly in all samples, even up to 81%. In conclusion, although storage may be normally considered not influencing the quality of SS, their organic matter quality improved and contamination decreased during 90 days of storage, whatever the conditions of oxygen availability applied.

MONITORING OF HEAVY METALS, EOX AND LAS IN SEWAGE SLUDGE FOR AGRICULTURAL USE: A CASE STUDY

Subsequent to the increasing diffusion of wastewater treatment, particularly in high- and middle-income countries, the sewage sludge generated should be treated and valorised in an ecological and economic way, thus contributing to the circular economy. In this study, the monitoring of Heavy Metals (HM), Extractable Organic Halogens (EOX) and Linear Alkylbenzene Sulphonate (LAS) in sewage sludge from 10 different wastewater treatment plants located in Friuli Venezia Giulia (Italy) was reported, and their macronutrient content provided. The obtained results showed, for all tested samples, that HM content in sewage sludge was below the maximum permitted limits provided for by Italian and European regulations for agricultural reuse. Comparison with a similar monitoring campaign carried out in 2006 revealed how, while wastewater treatment plants efficiently resolved water pollution, they accumulated heavy metals and other persistent toxic compounds in sludge, thus restricting their potential reuse. Consequently, consistent and regular sludge monitoring should be undertaken to prevent soil and groundwater contamination. These outcomes could be of particular relevance for the future perspective of agricultural reuse of sewage sludge in waste management practices.

Remediation of organic halogen- contaminated wetland soils using biochar

Organochlorine waste from papermaking has polluted soils worldwide, and the addition of biochar will improve polluted soils in a variety of scenarios. A field study (2014 to 2016) was conducted to investigate the application of wheat (Triticum aestivum L.) straw biochar (0, 20, 40, 60 Mg ha−1) to organic halogen-contaminated saline-alkali soil. The addition of biochar reduced the concentrations of adsorbable organic halogens (AOX) in the soil and extractable organic halogens (EOX) in reeds (Phragmites communis) by 9–94% and 14%–51%, respectively, and subsequently increased reed biomass by 1%–25%; these changes were related to the changes in different soil properties. Soil properties, such as the organic functional groups, surface properties, and pH, were improved following the addition of biochar, and some changes were maintained at heightened levels over time. The activity of urease, alkaline phosphatase, and sucrase enzymes in soil increased by 14 to 57%, 2 to 147%, and 1 to 75% as a function of increasing biochar amendment, respectively, while that of dehydrogenase decreased by 13% to 60%, which may have aided in the acceleration of AOX decomposition. The diversity of the bacterial community also increased due to biochar application, and is likely a key indicator of halogen degradation. The addition of biochar likely decreased the bioavailability of organic halogens by improving the function and structure of the microbial community, reducing their transfer to reeds grown in papermaking organochlorine-contaminated soils. Biochar may play an important role in reducing environmental contamination by organic halogens.

Post-aerobic treatment to enhance the removal of conventional and emerging micropollutants in the digestion of waste sludge

Low content of micropollutants in sewage sludge, essential to allow its safe re-use in agriculture, requires effective removals during the digestion phase. To this purpose, we investigated the performance of the anaerobic-aerobic sequential digestion process applied to real waste sludge in the removal of several classes of standard pollutants, i.e. extractable organic halogens (EOXs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), di(2-ethylhexyl)phthalate and alkylphenolethoxylates. In addition, emerging pollutants were also investigated based on their widespread occurrence and on their physicochemical characteristics and eco-toxicological relevance: quaternary ammonium compounds, a number of pharmaceuticals and selected biocides. The anaerobic step was conducted at mesophilic conditions, while two operating temperatures were tested for the post-aerobic treatment, i.e. 20 and 37 °C, respectively. Results showed that the post-aerobic digestion step enhanced the removal of all investigated standard and emerging micropollutants, even in presence of high accumulation in the anaerobic digestate (occurred for some PAHs and PCB congeners). Increased removals (up to 30%) have been generally observed at 37 °C aerobic temperature in comparison with tests at T = 20 °C for all investigated organic micropollutants, with the only exception of halogenated compounds (i.e. EOXs and PCBs). Low biodegradability and high bioaccumulation of the investigated pollutants were successfully faced by the sequential process, which has been demonstrated as an effective alternative solution to produce digested sludge for safe agricultural re-use.

Using Spectrometric Colour Measurement for the Prediction of Soil PCBs in a Contaminated Site of Southern Italy

Soil contamination with polychlorinated biphenyls (PCBs) is one the most relevant environmental problem in the SIN (Site of National Interest) of Taranto (Apulia Region, Southern Italy) and the surrounding area. Evaluation of PCB contents and their spatial distribution is an essential pre-requisite for soil remediation. Conventional laboratory analyses, although useful and irreplaceable for a precise and detailed evaluation of these contaminants, are costly and time-consuming, thus not very suitable for investigation over large areas. Then, there is a need to develop/validate alternative, rapid and cost-effective techniques, to use as substitutive of integrative to conventional analytical approaches. In this study, the usefulness of soil colour, based on spectrometric measurements, coupled with regression analysis, was assessed. Until now, never an analogous investigation has been realised. Twenty-eight soil samples, previously collected within an area (the ex-MATRA) highly contaminated by the disposal of oil used as dielectric fluid, composed by a mixture of PCB congeners, were used in the investigation. Colour coordinates in different colour systems were calculated from spectroradiometric measurements over the soil samples. Eighteen PCB congeners (i.e. 12 dioxin-like PCBs and six non-dioxin-like “indicator” PCBs), their sum (PCBs18) and the extractable organic halogen content (EOX)—which is an expression of the total content of halogen in organochlorine compounds, including the PCBs—were determined through conventional laboratory analysis. Simple linear regression analysis was carried out to predict the values of PCBs and EOX on the basis of colour variables. Excellent predictive models (R2 > 0.80) for PCBs18 and EOX, as well as for some of the individual PCB congener, resulted from the regression analysis. Thus, spectroscopic determination of soil colour can be considered as a promising tool for a rapid screening of PCBs in contaminated soils.

Simultaneous biodegradation of organic (chlorophenols) and inorganic compounds from secondary sludge of pulp and paper mill by Eisenia fetida

Present research communicates the role of Eisenia fetida in converting pulp and paper mill sludge into valuable products by removing the high concentration of different chlorophenols and metals present in the sludge. Pulp and paper mill sludge was toxic to Eisenia fetida and therefore, it was mixed with composted material in different ratio of experimental set up such as Set up: 1, (95:5), Set up: 2 (80:20) and Set up: 3 (50:50) on dry weight basis. We found very promising results by the application Eisenia fetida in the sludge. Eisenia fetida removed all the twelve different chlorophenols more than 95 % from the sludge which is declared as carcinogenic compounds by United States Environmental Protection Agency (US-EPA) in 90 days of incubation. Heavy metals concentration was decreased significantly during the incubation period whereas some metal concentration was also increased in the sludge due to mineralization. Carbon (C) and Nitrogen (N) were increased in the composted material, C:N ratio for Set 1 9:4 in Set 2 13:4 and Set 3 18:4 was observed which acts as soil conditioner. Whereas some other metals like (Ca, Mg, Na, K, Fe and Zn) was increased that are essential for the plant growth. There was great reduction in adsorbable organic halogen (AOX) 95 % and extractable organic halogen (EOX) 90 % as compare to control. Eisenia fetida also removed pentachlorophenol (PCP) from the sludge with artificially increased concentration about 100 mg/kg. By observing chlorophenols concentration, metals and carbon–nitrogen ratio, Eisenia fetida is acting as a potential candidate for the reclamation of industrial sludge. The result indicated that vermicomposting with Eisenia fetida is better option to manage the sludge or convert the sludge into nutrient-rich composted material in a short span of time.

Biomineralization of 2,3,4,6-Tetrachlorophenol by Bacillus sp. and Staphylococcus sp. Isolated from Secondary Sludge of Pulp and Paper Mill

ABSTRACTThree 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP)-mineralizing bacteria were isolated from the secondary sludge of a pulp and paper industry. The isolates used 2,3,4,6-TeCP as a source of carbon and energy and were capable of degrading this compound, as indicated by stoichiometric release of chloride and biomass formation. Based on 16S rRNA gene sequence analysis, the bacteria were identified as Bacillus megaterium (CL3), Staphylococcus suciri (CL10), and Bacillus thuringensis (CL11). High-performance liquid chromatography (HPLC) analysis revealed that these isolates were able to degrade 2,3,4,6-TeCP at higher concentrations (600 mg/L or 2.5 mM). A consortia of the isolates completely removed 2,3,4,6-TeCP from the sludge obtained from a pulp and paper mill within 2 weeks when supplemented at a rate of 100 mg/L or 0.43 mM. A bacterial consortium also significantly reduced absorbable organic halogen (AOX) and extractable organic halogen (EOX) by 63% and 68%, respectively, from the sludge. These isolates have a high potential to remove 2,3,4,6-TeCP and may be used for remediation of pulp paper mill waste containing 2,3,4,6-TeCP.

Removal of 2,4,5‐trichlorophenol by bacterial isolates from the secondary sludge of pulp and paper mill

2,4,5-trichlorophenol (2,4,5-TCP) mineralizing bacteria were isolated from the secondary sludge of pulp and paper industry. These isolates used 2,4,5-TCP as a source of carbon and energy and were capable of degrading this compound, as indicated by stoichimetric release of chloride and biomass formation. Based on 16S rRNA sequence analysis, these bacteria were identified as Kocuria sp. (CL2), Bacillus pumillus (CL5), Pseudomonas stutzeri (CL7). HPLC analysis revealed that these isolates were able to degrade 2,4,5-TCP at higher concentrations (600 mg/l or 3.0 mM). A consortia of these isolates completely removed 2,4,5-TCP from the sludge obtained from pulp and paper mill within 2 weeks when supplemented at a rate of 100 mg l(-1) . Bacterial consortium also significantly reduced absorbable organic halogen (AOX) and extractable organic halogen (EOX) by 61% and 63%, respectively from the sludge. These isolates have high potential to remove 2,4,5-TCP and may be used for remediation of pulp paper mill waste containing 2,4,5-TCP.

Sewage sludge quality from small wastewater treatment plants

The authors evaluated the quality of sewage sludges of 10 typical small-scale wastewater treatment plants receiving mainly domestic or urban wastewaters from an area characterised by a prevalently rural economy, with only small contributions from industrial effluents. In view of their direct distribution on agricultural land and/or utilisation to produce good-quality compost, in addition to macronutrients (carbon, nitrogen, phosphorus, potassium), micronutrients (calcium, magnesium, iron, boron, molybdenum) and toxic metals, sludges were analysed for extractable organic halogens, polychlorinated biphenyls, dibenzo-p-dioxins and furans, polycyclic aromatic hydrocarbon, di-2-(ethyl-hexyl)phthalate, nonylphenol, nonylphenolethoxylates and linear alkylbenzene sulfonates. Contaminant loads were generally low and did not represent a potential limitation for use in agriculture at the currently allowed rates. Results were examined by principal component analysis of the whole dataset, which did not show any significant grouping according to treatment plant origin, water source and type of treatment, and confirmed the substantial homogeneity of the sludges with respect to both toxic metals and organic contaminants.

Degradation of 2,4,6-trichlorophenol by bacteria isolated from secondary sludge of a pulp and paper mill

Bacterial strains capable of degrading trichlorophenol (2,4,6-TCP) were isolated from the secondary sludge of a pulp and paper mill and were characterized. These isolates were identified as Planococcus rifietoensis (CL4) and Bacillus pumilus (CL5), based on their 16S rRNA sequence analysis. These isolates were able to grow and utilize 2,4,6-TCP as their source of carbon as well as energy. HPLC analysis and stoichometric release of chloride in the medium confirmed the degradation ability of these isolates. Removal efficiency of 2,4,6-TCP by these isolates was discovered to be high. They were able to remove 90% of 2,4,6-TCP when grown at a concentration of 600 mg L(-1). Inoculation of these bacteria completely removed 2,4,6-TCP within 2 weeks from the sludge of the pulp and paper mill when supplemented at the rate of 100 mg L(-1). Absorbable Organic Halogen (AOX) and Extractable Organic Halogen (EOX) were significantly reduced by 63% and 70% respectively from the sludge due to inoculation of these bacteria. These isolates have high potential to remove 2,4,6-TCP and may be used for removal of 2,4,6-TCP from pulp paper mill waste.

Hybrid NAA for study of organic halogens in precipitation in Beijing, China

Abstract The rainwater samples were collected from Beijing, China, from May 2006 to November 2007 and measured by a hybrid neutron activation analysis (NAA) method combining with gas chromatography (GC) for the concentrations and distribution of extractable persistent organic halogens (EPOX = EPOCl + EPOBr + EPOI), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs). The average concentrations of EPOCl, EPOBr and EPOI in all the samples were 102, 0.18, and 0.31 μg/L, respectively. The relative proportions of the known organochlorines (84 PCB congeners + 10 OCPs) to total EPOCl were 0.03–1.44%, which implied that most of EPOCl measured in rainwater were unidentified. Significant correlations between the logarithms of the concentrations of EPOCl and EPOBr (r = 0.65, p < 0.0001) or EPOI (r = 0.72, p < 0.0001) and between the concentrations of EPOBr and EPOI (r = 0.79, p < 0.0001) were observed, which suggested that EPOCl, EPOBr and EPOI in rainwater might mainly come from the similar sources. There were no clear seasonal trends for the concentrations of EPOX. PCBs in rainwater were dominated by tetra-CB and tri-CB. The homologue was consistent with the technical PCB products in China, which indicated that PCBs in the environment mainly came from the historical usage of technical PCB products.

Long-term changes in the effluent loads from pulp and paper mills, the introduction of BAT technology, and their effects on extractable organic halogens concentrations in sediment in part of the Bothnian Bay

The Bothnian Bay at Kemi, which is the northernmost basin of the Gulf of Bothnia in the Baltic Sea, is affected by effluents from point sources such as pulp and paper mills and municipal sewage plant. During the period 1988-2008, the accumulated values of effluent volume, BOD7, CODCr, Tot-P, Tot-N, TSS and AOX from these point sources fell considerably as follows: 1) effluent volume by 24%, BOD7 by 92%, CODCr by 74%, Tot-P by 79%, Tot-N by 38%, TSS by 76% and AOX by 93%. The decrease in the effluent loadings is due to the introduction of Best Available Techniques (BAT) for the production processes and wastewater treatment at the pulp and paper mills. According to the long-term monitoring program that has been carried out every third year between 1997-2009, the decreasing trend in EOX-concentrations in the top 2 cm of the bottom sediment reflects the decrease in organochlorine discharges (AOX) from the mills. In 1997, the EOX concentrations in bottom sediment varied between 3-70 μg of Cl g(-1) (dry weight), and in 2009 between 1.2-31 μg of Cl g(-1) (dry weight).

Phytotoxicity tests of solid wastes and contaminated soils in the Czech Republic

The purpose of this study was to compare the suitability of different phytotoxicity testing procedures for the evaluation of toxicity associated with both soil contamination and solid wastes, both of which can be of environmental risk to plants. Ten different representative types of contaminated soils and solid waste samples were chosen from the Czech Republic. Both solid-phase and aquatic toxicity testing procedures on mono- and dicotyledonous plants were performed using Lactuca sativa L., Sinapis alba L., Hordeum vulgare L., Triticum aestivum L., Lemna minor L., and the chlorococcal algae Desmodesmus subspicatus (syn. Scenedesmus subspicatus), strain BRINKMANN: 1953/SAG 86.81. An innovative classification scheme, using the intensity of toxic effects upon the plants, is presented in the study. Detailed chemical characterizations of both solid samples and their aquatic elutriates were carried out, using the appropriate ISO guidelines. In the solid samples, all the congeners of polychlorinated biphenyls were analyzed, together with 16 U.S. EPA polyaromatic hydrocarbons, the aggregate of C10-C40 hydrocarbons, total organic carbon, extractable organic halogens, as well as the majority of the environmentally toxic metals. In the aquatic elutriates, parameters analyzed were pH, conductivity, dissolved organic content, phenol index, main anions, and the majority of the environmentally relevant metals. Eight out of ten samples tested expressed phytotoxic properties on tested organisms. Only three of the samples were toxic to both aquatic and terrestrial organisms in the tests. This demonstrates how different substances present in different samples can express different types of toxic effects, resulting in the illogical substituting terrestrial bioassays with aquatic ones. Based upon our experience, we propose the following battery of bioassays for use in the characterization of toxic properties of solid wastes and contaminated soils: Aquatic ecosystems were tested by the algae D. subspicatus and plant L. minor; and the terrestrial ecosystems were tested by the dicotyledonous L. sativa and monocotyledonous H. vulgare. This proposed new battery of bioassays for the detection of phytotoxicity of both solid wastes and contaminated soils has higher sensitivity (as well as greater ecological relevance) compared to the battery of bioassays currently used in the Czech Republic. The tests currently used for regulatory purposes in the Czech Republic are phytotoxicity tests of elutriates, using S. alba and D. subspicatus, which have been found insufficiently sensitive to the range of different pollutants present in contaminated soils and/or solid wastes. If only aquatic bioassays are used for the toxicity testing, it is possible that the toxic effects of substances (poorly or totally) insoluble in water might be underestimated. The new proposed system of toxicity classification has proven to be both practical and sensitive. This recommended alternative battery of phytotoxicity tests includes both aquatic tests of waste elutriates (with the algae D. subspicatus along with the aquatic plant L. minor), in addition to tests of the terrestrial solid samples (with the dicotyledonous L. sativa and the monocotyledonous H. vulgare). This battery of bioassays is sufficiently sensitive, representing a majority of types of aquatic and terrestrial plants.

Physico-chemical and environmental characterisation of sediments from Cantabrian estuaries (Northern Spain)

Previous studies show that sediments of the Cantabrian estuaries (Northern Spain) contain significant concentrations of heavy metals and organic pollutants derived from intensive industrial, agricultural and urban activities. In the most polluted sediments of two estuaries (the bay of Santander and estuary of Suances), physico-chemical and environmental characterisation has been carried out. Water content, density, pH, specific surface, porosity and particle diameter distribution have been evaluated as physical parameters. Total metal contents have been analysed as inorganic parameters. Loss of ignition (LOI), phenol index and extractable organic halogens (EOX) have been determined as organic parameters. Two leachate assays have been carried out in order to evaluate the environmental behaviour of the sediments. Total availability has been analysed using the NEN 7341 test and the mobility of the pollutants has been determined using the EN 12457 leaching test at two liquid/solid ratios. The obtained results have been compared with European Union regulations. The physical parameters and inorganic compounds are very similar in the studied sediments. However, the sediments from Suances have high concentrations of LOI and EOX. The obtained correlation of the physical parameters with the particle size distribution is useful in the study of the sediment addition to ceramic process as a sediment management option. A comparison of the results obtained from the total, availability and mobility analysis of the inorganic pollutant concentrations of As, Ba, Ni, Pb and Zn present in sediments has been made, giving knowledge for the development of regulations and tools that would contribute to the integral management of the estuarine areas.

Analysis of metals and EOX in sludge from municipal wastewater treatment plants: A case study

The monitoring of extractable organic halogen (EOX) and heavy metal contents in sludge coming from 10 different municipal wastewater treatment plants (MWWTP) located in Friuli Venezia Giulia (Italy) is reported. In this work, sludge samples drawn from sludge treatment units have been digested and analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for metal evaluation. Samples were also extracted and analyzed by microcoulometric titrations, following modified DIN 38414 T17 standard, for EOX analysis. Analytical results showed a slight enrichment of the contents of certain metals (Cd < 2 mg/kg, Cr < 51.5 mg/kg, Cu < 105.8 mg/kg, Hg < 1.4 mg/kg, Ni < 35.9 mg/kg, Pb < 58.7 mg/kg, Zn < 410.1 mg/kg, Ba < 317.1 mg/kg, Co < 1 mg/kg, Mo < 5 mg/kg, Mn < 106.7 mg/kg), so almost all of the sludge would be suitable for agricultural use following Italian and European regulations. The evaluation of EOX was carried out by using hexane and ethyl acetate as extraction solvents, and a measurable organic halogen content (ranging from 0.31 to 39.5 mg Cl/kg DM) was clearly detected in the sludge. The lowest concentrations of EOX were found in sludge coming from the smallest MWWTPs, which is to be considered more suitable for agricultural use. Additionally, analytical assays on composts, peat and soils were performed to compare EOX concentrations between these matrices and sludge.

Extractable organic halogens (EOX) in sediments from selected Polish rivers and lakes—a measure of the quality of the inland water environment

EOX in sediments from the two main Polish rivers (the Vistula and the Oder/Odra) as well as five lakes was assayed coulometrically and its values examined with respect to the location of the sample collection points. EOX values were found to increase near industrial areas and large urban agglomerations, although mean values—comparable for rivers and lakes—were similar to those recorded elsewhere. EOX tends to rise as TOC does so. On the other hand, the EOX:TOC ratio decreases sharply in the case of lakes, since TOC values there are roughly one order of magnitude higher than in rivers. Furthermore, the contents of selected polychlorinated biphenyls and organochlorine pesticides are directly related to EOX values. These relationships constitute a basis for the application of EOX as a parameter reflecting the level of organochlorine compounds in environmental quality evaluation.

Sediment, Perch (Perca fluviatilis L.) and Bottom Fauna as Indicators of Effluent Discharged from the Pulp and Paper Mill Complex at Kemi, Northern Finland

This paper compares the long-term data of EOX (Extractable Organic Halogens) determinations in sediments, trichloroguaiacol, i.e. 3,4,5-trichloroguaiacol and 4,5,6-trichloroguaiacol, determinations in the bile of perch (Perca fluviatilis L.) and changes in bottom fauna communities (Pontoporeia affinis L., Mesidotea entomon L., Valvata spp. L.) during 1994–2003. The study area is located at Kemi, on the Gulf of Bothnia, Northern Finland, and is affected by effluent discharged from the pulp and paper mills of Stora Enso Oyj and Oy Metsa-Botnia Ab. The Kemi municipal sewage plant, and River Kemijoki also impose a load in the same area. The main purpose of the study was to assess whether the state of the exposed water ecosystem has improved on the basis of the concentrations of organochlorine compounds in sediment and in perch, due to the modernisation of the wastewater treatment at the mills. In addition, we also investigated whether the changes in the bottom fauna community indicate an improvement in the purification of the effluents. The results indicate that the concentrations of trichloroguaiacols (<ng g−1) in perch reflect the decreased discharges of chlorinated substances from the mills. The EOX concentrations in bottom sediments have also decreased to below 50 μ of Cl g−1 in most parts of the study area, which is in good agreement with the reduction in the discharge of organochlorines. According to the long-term changes in bottom fauna, the reduction in the discharge of organochlorine compounds due to modernisation of the pulp mills is reflected in a recovery of the benthic fauna, especially Valvata spp. L. and Pontoporeia affinis L.