High Levels Of Organic Pollutants Research Articles

Water Quality Assessment of The Three Lakes of Barandabhar Forest Corridor, Central Nepal

Addressing the global challenge of securing water for both human needs and ecosystem health is crucial. This study aims to characterize the physiochemical parameters of three lakes in the Bharandabhar forest corridor, Chitwan, Central Nepal: Tiger Lake, Kalimati Lake, and Rhino Lake. During the pre-monsoon season, four different sites (Eastern, Western, Northern, and Southern) of each lake were examined. To ensure precision, five replicated water samples were collected from each site, and standard protocols were applied to analyze various physiochemical parameters, such as pH, temperature, dissolved oxygen, free carbon dioxide, total hardness, chloride, total alkalinity, conductivity, nitrate, inorganic phosphorus, and total solid matter. Also, the Water Quality Index (WQI) was calculated. Results show that physiochemical parameter values mostly align with permissible limits according to regional and international guidelines. However, the mean phosphorous concentration and pH values of Tiger and Kalimati lakes exceed these limits. Rhino Lake displayed a mildly alkaline pH, while Kalimati and Tiger lakes exhibited slightly acidic characteristics. An interesting observation is the significant negative correlation between temperature and dissolved oxygen, indicating that as temperature rises, dissolved oxygen levels decrease. Additionally, WQI suggests that all three lakes maintain good water quality. However, a concerning finding is that all three lakes exhibited hyper-eutrophic conditions based on their phosphorous concentration. The lakes face significant threats due to high levels of organic pollutants and a rapid eutrophication process. Authorities must take significant actions to safeguard the lakes and ensure their future well-being. This research highlights the urgent need for environmental protection and conservation efforts to preserve the water quality and ecological balance of the Bharandabhar forest corridor lakes for the well-being of both human communities and the ecosystem.

The benefits of restoring urban lakes in the tropics.

Lake restoration in developing economies, particularly in the tropics, is a major challenge given the severe levels of pollution from untreated wastewater and the warm climate conducive to microbial and algal growth. Restoration goals are often ill-defined or unachievable. Here we describe the successes that can be achieved through a control, compared with intervention case study of the two urban lakes in Bengaluru, India, one of the world's largest and fastest growing mega-cities. The unrestored control, Bellandur Lake, was severely polluted by 231 million litres per day (MLD) of untreated wastewater. The restoration site, Jakkur Lake, receives 10 MLD of treated wastewater and also receives some tertiary treatment by circulating the effluent through a constructed wetland before it enters the lake. The water quality of Bellandur Lake can only be described as extremely bad. Organic pollution levels in the main inflow were high (BOD5 of 199mg/l, faecal coliforms 6.9 Log MPN/100ml, total suspended solids (TSS) of 285mg/l) leading to the complete deoxygenation of lake even at the surface. The levels exceeded use-base standards for bathing water and fisheries. The high levels of organic pollution and low oxygen conditions also led to extreme levels of methane emissions that occasionally led to the lake surface catching fire. Total nitrogen (TN) and total phosphorus (TP) concentrations in the lake were extremely high (47mg/l and 6.3mg/l) respectively with low Secchi depth (SD). Despite the high nutrient levels, very little phytoplankton growth occurred (chlorophyll-a of 0mg/l), most likely due to the high TSS loads which restricted light availability. In comparison, the wastewater treatment and wetland at Jakkur Lake markedly reduced organic pollution of the main inflow (BOD5 of 32mg/l, faecal coliforms 4.1 Log MPN/100ml, TSS of 48mg/l). Levels of coliforms in the lake were above the standards for bathing waters. Total nitrogen (TN) and total phosphorus (TP) concentrations in the lake reduced (10.5mg/l, 2.4mg/l) but still classify the lake as extremely hypereutrophic. The lower TSS levels did, however, enable dense phytoplankton blooms to develop (max chlorophyll-a of 600 µg/l) which are in part responsible for the higher levels of dissolved oxygen in the lake water, albeit and as expected with large diurnal fluctuations. The comparison highlights the benefits that standard wastewater treatment provides to restore urban tropical lakes in context of rapidly urbanising catchments, and even though Jakkur Lake is by no means fully restored, it sustains water quality that allow propagation of fisheries and shore-based recreation. It also greatly contributes to greenhouse gas emission reductions. Further restoration measures are likely needed for urban tropical lakes, particularly to tackle pollutant loads in monsoon periods, but restoring community pride in the uses of a lake is an important milestone of the restoration efforts.

Water pollution remediation in Kazakhstan: evaluating bacterial consortiums for organic pollutant decomposition

Abstract Wastewater treatment is one of the key problems that has to be solved by environmental biotechnology. Wastewater bioremediation is one of the most efficient and safest methods to replenish water resources. The aim of this study is to investigate the potential of using bacterial consortiums for reducing the organic load in wastewater, specifically focusing on water samples collected from three water bodies in central and northern Kazakhstan, which are known for their high levels of organic pollution. This study utilized bacterial strains from a microorganism collection to create consortiums. These consortiums were used to treat wastewater from polluted water bodies in Kazakhstan, focusing on parameters like COD, BOD5, ammonia, and phosphate. The methodology involved culturing strains, collecting water samples, and analyzing various parameters. Statistical analysis was performed to assess the results. The study found that two bacterial consortiums, 7BLB and 7BLPA, were the most effective in reducing COD, ammonia, and ammonia nitrogen in wastewater. The consortium 6BLP was highly effective at reducing phosphate levels, surpassing acceptable standards. Hydrogen levels met regulatory requirements in all cases. The study recommends further investigation of these consortiums’ impact on other water quality indicators and suggests conducting field experiments in natural water ponds.

In silico simulations and molecular descriptors to predict in vitro transactivation potencies of Baikal seal estrogen receptors by environmental contaminants

Baikal seals (Pusa sibirica) are vulnerable to high levels of organic pollutants. Here, we evaluated the transactivation potencies of bisphenols (BPs) and hydroxylated polychlorinated biphenyls (OH-PCBs) via the Baikal seal estrogen receptor α and β (bsERα and bsERβ) using in vitro and in silico approaches. In vitro reporter gene assays showed that most BPs and OH-PCBs exhibited estrogenic activity with bsER sub-type-specific potency. Among the BPs tested, bisphenol AF showed the lowest EC50 for both bsERs. 4′-OH-CB50 and 4′-OH-CB30 showed the lowest EC50 among OH-PCBs tested for bsERα and bsERβ, respectively. 4-((4-Isopropoxyphenyl)-sulfonyl)phenol, 4′-OH-CB72, and 4′-OH-CB121 showed weak bsERα-specific transactivation. Only 4-OH-CB107 did not affect both bsERs. In silico docking simulations revealed the binding affinities of these chemicals to bsERs and partially explained the in vitro results. Using the in silico simulations and molecular descriptors as explanatory variables and the in vitro results as objective variables, the quantitative structure-activity relationship (QSAR) models constructed for classification and regression accurately separated bsER-active compounds from non-active compounds and predicted the in vitro bsERα- and bsERβ-transactivation potencies, respectively. The QSAR models also suggested that chemical polarity, van der Waals surface area, bridging atom structure, position of the phenolic-OH group, and ligand interactions with key residues of the ligand binding pocket are critical variables to account for the bsER transactivation potency of the test compounds. We also succeeded in constructing computational models for predicting in vitro transactivation potencies of mouse ERs in the same manner, demonstrating the applicability of our approach independent of species-specific responses.

Catalytic Ozonation in Pulp and Paper Industry Wastewater Treatment: A Bibliometric Analysis

AbstractThe pulp and paper industry is one of the most significant industrial water polluters, generating large volumes of wastewater with high levels of organic pollutants, suspended solids, and other contaminants. Catalytic ozonation has emerged as a promising technique for the treatment of pulp and paper industry wastewater. Numerous reviews have presented the research on catalytic ozonation; however, open literature is missing a bibliometric analysis. Therefore, this article presents a bibliometric analysis of the research available on catalytic ozonation in pulp and paper industry wastewater treatment. A total of 578 documents extracted from the Scopus database have been examined via VOSviewer, MS Excel, and Rstudio to identify the research trends, influential authors, and research institutions in the field. The results reveal that the number of publications on the topic has increased significantly in recent years. This study also identified several influential authors, institutions, and highlighted future research directions in the field. Overall, the study provides insights into the state of research on catalytic ozonation in pulp and paper industry wastewater treatment and could help guide future research efforts in this area.

Catalytic Pollutant Upgrading to Dual-Asymmetric MnO2 @polymer Nanotubes as Self-Propelled and Controlled Micromotors for H2 O2 Decomposition.

Industrial and disinfection wastewater typically contains high levels of organic pollutants and residue hydrogen peroxide, which have caused environmental concerns. In this work, dual-asymmetric MnO2 @polymer microreactors are synthesized via pollutant polymerization for self-driven and controlled H2 O2 decomposition. A hollow and asymmetric MnO2 nanotube isderived from MnO2 nanorods by selective acid etching and then coated by a polymeric layer from an aqueous phenolic pollutant via catalytic peroxymonosulfate (PMS)-induced polymerization. The evolution of particle-like polymers iscontrolled by solution pH, molar ratios of PMS/phenol, and reaction duration. The polymer-covered MnO2 tubing-structured micromotors presented a controlled motion velocity, due to the reverse torque driven by the O2 bubbles from H2 O2 decomposition in the inner tunnels. In addition, the partially coated polymeric layer can regulate the exposure and population of Mn active sites to control the H2 O2 decomposition rate, thus avoiding violent motions and massive heat caused by vigorous H2 O2 decomposition. The microreactors can maintain the function of mobility in an ultra-low H2 O2 environment (<0.31wt.%). This work provides a new strategy for the transformation of micropollutants to functional polymer-based microreactors for safe and controlled hydrogen peroxide decomposition for environmental remediation.

English

Agriculture, which accounts for 70% of water abstractions worldwide, plays a major role in water pollution. Resulting pollution poses risks to aquatic ecosystems and humans. With the aim of evaluating the saprobic state of four hydro systems subject to pollution from intensive rubber cultivation, the present study was carried out within and around the Hevecam rubber plantation in Niete, South Region of Cameroon. The study was done from September 2019 to December 2020 with monthly sampling, physico-chemical water analysis and determination of ciliate diversity and distribution. Water in the study stations was acidic (6.40&plusmn;0.31CU), with average temperature (25.20&plusmn;0.56&deg;C) and conductivity of up to 761.8 &micro;s/cm. Conductivity values coupled with phosphates (up to 29.7 mg/L), herbicide residues are indicators of agricultural pollution on water quality. Station N2 showed the greatest ciliate abundance and species richness. The long dry season of 2020 showed the highest diversity and abundance. The saprobic index indicated moderate to high levels of organic pollution (2.16 to 3.67). Water quality was degraded with the impact of the agricultural pollution due to the presence of herbicide and fertilizer residues at stations N2 and N4. High levels of phosphates and nitrates have resulted in an increased organic load reflected in the saprobic indices; indicating average to high organic pollution. &nbsp; Key words: Saprobic, Hevecam, organic pollution, anthropogenic, water quality.

Parasites as Biological Indicators: the Impact of Environmental Quality on the Infections of Lamproglena clariae (Crustacea) on Clarias gariepinus Along the Vaal River, South Africa.

Anthropogenic activities influence the natural equilibrium of freshwater ecosystems resulting in negative ecological impacts. Differences in the infection variables of Lamproglena clariae in relation to variable water quality influenced by metal pollution were studied at six sites along the Vaal River, South Africa (March 2017 and October 2018). From each sampling site, in situ water quality parameters, water and sediment samples, and a minimum of 10 Clarias gariepinus were collected. Lamproglena clariae specimens collected from the gills of C. gariepinus were used to calculate the prevalence, mean intensity, and mean abundance of the parasite. Metal concentrations in water and sediment were analysed with inductively coupled plasma-optical emission spectrometry and inductively coupled plasma-mass spectrometry. Parasite intensity correlated negatively with some water quality parameters (conductivity, salinity, pH, total dissolved solids, and dissolved oxygen). Negative correlations were found between L. clariae (intensity and prevalence) and metal concentrations (Cu, Cr, Zn, Cd) in water. Parasite infections were influenced negatively at sites with high metal concentrations recorded in sediment and water and high levels of organic pollution. Sites that were found to be more polluted had lower mean intensity and mean abundance of L. clariae, indicating pollution affects the survival of this ectoparasite.

Relating land-use/land-cover patterns to water quality in watersheds based on the structural equation modeling

Understanding the relationships between land-use/land-cover (LULC) patterns in watersheds and water quality is of great significance for exploring the causes of non-point source pollution and scientific planning of land use. Multivariate regression methods have often been used to examine the response of specific water contaminants to LULC patterns. However, this also resulted in overlooking the ecological process and biased parameter estimates caused by redundancy where some landscape metrics are strongly correlated. In this study, based on “source-sink” landscape theory, Redundancy Analysis (RDA) and Partial Least Squares Structural Equation Modeling (PLS-SEM) were used to investigate the relationship between LULC patterns and water quality in the surrounding sub-watersheds of the Danjiangkou Reservoir in the dry and rainy seasons. The results showed that water quality parameters were characterized by seasonal differences. In the dry season, only the proportion of the watershed occupied by urban landscapes (P_Urban) had a significant impact on water quality in watersheds (β = 0.835, p < 0.001), so the water quality was only affected by point source pollution in the dry season. In the rainy season, specific water contaminants were categorized as organic and inorganic pollutants. The “sources” of organic and inorganic pollutants were agricultural and urban land, respectively. However, natural vegetation was not only a “sink” of inorganic pollutants, but also a “source” of organic pollutants. Furthermore, agriculture and natural vegetation mediated the effects of landscape spatial configuration on the water quality, yet landscape aggregation negatively moderated the relationship between urban and organic pollution. Therefore, watersheds with high landscape aggregation have small agricultural landscapes and large natural vegetation landscapes where water quality is affected by low levels of inorganic pollution and high levels of organic pollution. However, organic pollution from urban sources was aggravated by watersheds with low landscape aggregation. This study revealed the relationships between LULC patterns and water quality in watersheds and reflected the ecological process to a certain extent.

Study of phytoplankton flora and its use as a biomonitoring tool to determine the water quality of Krishnasayar Lake, Burdwan, West Bengal, India

AbstractThe present study focused on biomonitoring approaches involving the phytoplankton composition, density and diversity, and their relationships, with changes in environmental variables, and to determine the pollution status of Krishnasayar Lake in the Burdwan District of West Bengal, India. A total of 29 phytoplankton taxa belonging to Chlorophyceae (13), Cyanophyceae (9), Bacillariophyceae (5) and Euglenophyceae (2) were observed. The phytoplankton density exhibited a maximum value of 12,633 cells/litre in the post‐monsoon season and a minimum value of 7,266 cells/litre in the pre‐monsoon season. The results of two multivariate proficiencies (cluster analysis; CCA) indicated the distribution of phytoplankton groups are influenced by pH, electrical conductivity, and the nitrate, phosphate, potassium and dissolved oxygen concentrations. Various diversity indices, including the Shannon–Wiener Diversity Index, Gleason Species Richness Index, Pielou Evenness Index and Naughton Dominance Index, were explored to illustrate the seasonal phytoplankton fluctuations. The Shannon–Wiener Diversity Index values (2.524, 2.331 and 2.666, respectively, for the pre‐monsoon, monsoon and post‐monsoon seasons) indicate the moderation level of pollution status of the lake. The present study also highlights biomonitoring is a reasonable technique for establishing ecological conditions of lakes by considering the organisms within them, including planktonic algae, macrophytes, benthic macroinvertebrates, crustaceans and fishes on the basis of a single indicator species or a combination thereof. The present study used planktonic algae to determine changes in surrounding environmental conditions. As some of the studied phytoplankton species exhibit specific ecological preferences, their presence can indicate the health of that system. As examples, Coelastrum microporum, Pandorina morum and Euglena viridis indicate high levels of organic pollution. Krishnasayar Lake is integrated with the Krishnasayar ecological park, being affected by large levels of anthropogenic disturbance attributable mostly to uncontrolled and careless activities of some visitors, annual cultural activities, other programmes, etc., meaning relevant management activities are needed to protect the lake from further degradation.

Potential of combined advanced oxidation – Biological process for cost-effective organic matters removal in reverse osmosis concentrate produced from industrial wastewater reclamation: Screening of AOP pre-treatment technologies

While reverse osmosis (RO) technology is playing an important role in industrial wastewater reclamation, safe and cost-effective RO concentrate (ROC) disposal becomes challenging due to high levels of organic pollutants. The present study assessed the feasibility of combined advanced oxidation – biological process for organics removal in real ROC. Four advanced oxidation processes (AOPs) were evaluated for ROC pre-treatment, including UV/H2O2, UV/Persulfate (PS), Fenton and Fluidized bed reactor (FBR)-Fenton processes. Based on the results of process optimization and cost evaluation, FBR-Fenton was identified as the most cost-effective pre-treatment technology with a chemical cost of S$0.519/m3. Under the optimum operating conditions with 10 mM H2O2, 1.25 mM Fe2+, pH 3 and HRT of 1 h, continuous FBR-Fenton process increased the BOD5/COD ratios in ROC by 4.2–10.0 times, while the COD removal efficiency was in the range of 30.9–59.8%. A biological activated carbon (BAC) column with EBCT of 120 min was combined with FBR-Fenton for continuous treatment of ROC. Over the 120-day operation, the combined system performed consistent organics removal in ROC with an average COD removal efficiency of 69%. The average effluent COD level in ROC was observed to be 26 mg/L. Both LC-OCD data and fluorescence EEM spectra suggested humic substances to be the dominant organic species in ROC, FBR-Fenton could achieve significant humic substances removal and biodegradability enhancement in ROC. High-throughput sequencing demonstrated Planctomycetes to be top dominant phylum in BAC media with high salinity influent, and FBR-Fenton process promoted its proliferation for higher COD removal efficiency in ROC.

Characterization of pharmaceuticals industrial effluent using GC\u2013MS and FT-IR analyses and defining its toxicity

The physicochemical analysis of collected effluent sample for different parameters shown results as pH (pH 5.6 ± 0.11) slightly acidic, high conductivity (1563.34 ± 176 μs cm−1), total dissolved solids (920.34 ± 137 mg L−1), high BOD (7253.34 ± 1022 mg L−1), and COD (756.67 ± 1124 mg L−1) in the effluent sample. The results of heavy metals concentration are viz. as [Cu (1.98–2.56), Co (0.26–0.53), Cd (0.10–0.50), Ni (0.04–0.07), Pb (0.58–1.2), Mn (0.58–1.05), Cr (1.47–1.51), Zn (2.61–3.5), Fe (1.72–2.13), As (0.05–0.09), and Hg (0.003–0.006)]. Results revealed the higher concentration of BOD, COD, TDS, and conductivity and also the concentration of lead. Results of GC–MS also confirmed the high levels of organic pollutants in effluent. Further the effluent toxicity was evaluated by employing genotoxocity assays with the use of Allium cepa L. (onion) root tip cells. Genotoxicity measured mitotic index (MI) and chromosomal aberrations (CAs) in root tip cells obtained after treatment with effluent of 6.25, 12.5, and 25% concentration (v/v). The results of root growth test showed that inhibition of root growth occurred at effluent concentration ≥ 50% (v/v). The lowest MI was recorded (MI = 9.6%) in 25% of effluent concentration, showing a significant reduction in mitotic index compared with control which MI = 64.1%. Further, the chromosomal aberration was investigated in root tip cell after treating with different concentration ranges of effluent exhibiting various CA, viz. c-mitosis, chromosome loss, chromosome break, micronucleated cells, etc. The result suggests that the effluent contained toxic constituents, which imposed cytotoxic and genotoxic hazard.

Source apportionment of organic pollutants in fine and coarse atmospheric particles in Doha, Qatar

ABSTRACT In this study, we investigated the sources of organic pollutants associated with fine (PM2.5) and coarse (PM2.5–10) atmospheric particulate matter in Doha, Qatar based on an eight-month sampling campaign conducted from May to December 2015. Multiple organic compound tracers including 36 PAH members, 25 n-alkane homologs, 17 hopanes, and 12 steranes were used for organic aerosols source apportionment. Source apportionment based on specific molecular markers, molecular diagnostic ratios/indices, and positive matrix factorization (PMF) modeling showed that similar sources are responsible for both fine- and coarse-particle organic pollutants. PMF analysis showed that biogenic aerosols, fugitive dust emissions, gasoline engine emissions, diesel engine emissions, and heavy oil combustion were the five main pollution sources of organic aerosols, which agreed well with the results from the diagnostic ratios analysis. The conditional bivariate probability functions (CPF) and potential source contribution function (PSCF) indicated that both regional (i.e., mixed biogenic/secondary particles and oil refinery/shipping emissions) and local sources contributed to airborne organic aerosol concentrations observed at the site, depending on the wind speed and direction. It appears that the relatively high levels of organic pollutants were contributed by local anthropogenic sources, such as fossil fuel combustion, vehicular emissions, and fugitive dust emissions. The high levels of local contributions indicated that there might be great opportunities for Qatar to considerably reduce emissions so that population exposures to carbonaceous aerosols and the public health risks associated with air pollution can be minimized. Implications: Multiple organic tracers and various source apportionment techniques have been used for convincing source apportionment. It was found that both long-range and local sources have a significant impact on atmospheric carbonaceous particles in the area, depending on the wind conditions. Relatively high levels of organic pollutants attributed to local anthropogenic sources indicate that there are great opportunities for Qatar to establish and implement more efficient pollution control measures and policies. Regional sources such as petroleum refineries and shipping-vessels emissions in the Gulf region should also be regulated and managed through regional cooperation to improve the air quality in the region.

Reduction of Pollutant Parameters in Textile Dyeing Wastewater by Gambier (Uncaria gambir Roxb) Using the Multi Soil Layering (MSL) Bioreactor

Gambier (Uncaria gambir Roxb) is one of the sources of natural dyes that able to apply to the textile industry. Textile dyeing industrial wastewater using Gambier comes from several sources. Among them come from the dyeing process itself and from the fixation process wastewater using alum (Al2 (SO4)3), lime (CaO) and tunjung (FeSO4). The wastewater was characterized by high levels of organic pollutants and dyestuffs as well as compositions of fixator raw materials. This study explored the performance of two types of Multi-Soil-Layering (MSL) bioreactors in order to reduce pollutant parameters in such a wastewater. The result revealed that MSL showed good performances. The more MSL layers, the higher the reduction. Reduction of BOD5, COD, and TSS in MSL type 1 could reach 98.6%, 95.3% and 87.1% respectively, while 98.1%, 93.8% and 84.9% in MSL type 2, respectively. The MSL bioreactor could neutralize pH from pH 4.7 to be pH 7.4 and pH 7.1 and able to reduced colour from 427 PtCo to 0.4 PtCo and 1.3 PtCo as well as reduced turbidity from 47 NTU to 0.8 NTU and 1.2 NTU by MSL type 1 and MSL type 2 respectively.

Recent advances in brewery wastewater treatment; approaches for water reuse and energy recovery: a review

Brewery industry is one of the largest users of water and characterized by high levels of organic pollutants, and requires higher attention for remediation before discharge to the environment. This paper aims at providing a review of methods for treating brewery wastewater based implications using the state-of-the-art biological treatment technologies leading to water reuse and/or energy production. This could be linked to resource recovery as a sound and economic approach to alleviate fresh water scarcity and shortage of energy supply. In this review, the components of various bioreactors (i.e. membranes bioreactors, fluidized bed bioreactor and anaerobic bioreactors) and how efficiently these reactors can be utilized for treating and reuse of brewery wastewater are highlighted.

Risk Assessment and Heavy Metal (Cu and Ni) Contamination in Sediments of Shatt Al-Arab Canals, Iraq

The present study aims at investigate the relationships between physic-chemical and seasons to determined heavy metals (copper Cu and Nickel Ni) contaminated of sediments of Shat Al-Arab canals. The pH, Electrical Conductivity (EC), Total Organic Carbon (TOC), Oil and grease were measured. The study investigated the effects of season on the sediment characteristics of Shat Al-Arab canals. Data analyses were done using analysis of variance, Tukey's multiple range, Pearson correlation coefficient and descriptive statistics. pH, EC and TOC were significantly higher at dry season (7.44 ± 0.129), (544.212 ± 133.8 μcm/cm2) and (13.94 ± 2.157%) respectively, than at wet season (P<0.05). However, hydrocarbons (Oil and grease) was significantly higher at wet season (4360 ± 1129 mg/l) than at dry season (1920 ± 638.3) (P<0.05). The presence of high levels of organic pollutants indicates organic pollution and stress. Positive and negative Pearson correlation relationship between both heavy metals and physic-chemical parameters were found. Contamination of sediments was assessed on basis of contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI) Potential Ecological Risk (Eir) and Potential Ecological Risk Index (RI). Results of geo-accumulation index (Igeo) indicated that sediments were uncontaminated with Cu, uncontaminated to moderately pollution with Ni.

Respuestas macroinvertebrados acuáticos a la presión humana en una cuenca tropical volcánica alta: Río Birrís, Volcán Irazú (Costa Rica)

Background. Tropical mountain rivers are strategic sources of water for human development while biological communities are indicators of the status of these ecosystems. However, volcanic basins close to large urban areas are affected by increasing human pressures that threaten the future of these ecosystems and their benefits to society. Goals. This paper analyzes the evolution of the responses of the aquatic macroinvertebrate assemblages in the face of increasing pressures in the Birris River basin, which is essential for providing food and energy for the Greater Metropolitan Area of Costa Rica. The hypothesis that volcanic headwater communities are highly vulnerable to human impacts was tested. Methods. Composition and structure of aquatic macroinvertebrate assemblages were assessed along main river channels over two years. Results. The spatial variability of assemblages was related to organic pollution and the self-purification capacity of the river. Temporal variability was mainly explained by the intra-annual climate variability (seasonality). Macroinvertebrate assemblages were dominated by Chironomidae (Diptera), Simuliidae (Diptera), and Baetidae (Ephemeroptera) throughout the year. High flows during the rainy season (May to December) reduced density while diversity peaked at the end of that season. Ephemeroptera and Trichoptera reached their maximum abundance during the dry season, while Diptera showed maximum richness at the end of the rainy season. Conclusions. Biological communities showed spatial and temporal adaptations to the main environmental stresses, including high levels of organic pollution. However, the high slope of river channels favors the self-purification processes, which offer an opportunity for the recovery of ecological integrity combined with control of the organic discharges. More information is needed on taxonomy and autoecology of aquatic fauna and flora in these fragile volcanic environments that are strategic for the protection of water resources in the tropics.

Evidence of colloidal transport of PAHs during column experiments run with contaminated soil samples.

Brownfield soils may contain high levels of organic pollutants particularly polycyclic aromatic hydrocarbons (PAHs). It is essential to predict their migration and fate and to evaluate the risk of transfer to sensitive targets, such as water resources, ecosystems and human health. In this study, soil samples have been taken from an experimental contaminated site of former steel activities located at Homecourt (Lorraine, France). These samples have been lixiviated in laboratory column in water-saturated condition at room temperature. The effluent has been collected by fraction and analysed by a standard method giving total concentration of each of 16 PAHs. The breakthrough curves of 16 PAHs significantly evolve in the same way according to the volume of effluent and tend to vanish to 12-15 pore volumes. If several PAHs remain at a concentration below the solubility, others clearly exceed this threshold. Material balance sheets show that only a very small fraction of PAHs is mobilised. These results are interpreted by postulating that PAHs are transported by the solution not only in the dissolved state but also by associations with particulate or dissolved organic matter.

Recovery of potassium from landfill leachate concentrates using a combination of cation-exchange membrane electrolysis and magnesium potassium phosphate crystallization

Simultaneous removal of high levels of organic pollutants and recovery of nutrients from concentrates generated from the nanofiltration (NF) or reverse osmosis membrane separation process is a significant environmental challenge. In this study, a combined cation-exchange membrane electrolysis (CEME)/magnesium potassium phosphate crystallization process for the recycling of NF concentrates generated from treating landfill leachate was developed. These NF concentrates contained high levels of organics, ammoniacal-nitrogen, chloride as well as valuable potassium ions. The removal of these pollutants and feasibility of potassium recovery were evaluated. This study demonstrated that the proposed combined process can effectively remove 82%, 99%, 34%, 99% of organic matter, ammoniacal-nitrogen, total nitrogen, and chloride ions, respectively, while simultaneously allowing recovery of chloride and potassium ions from NF concentrates as beneficial products (gaseous chlorine and valuable magnesium potassium phosphate precipitates, a buffered fertilizer, respectively) and collection of a further electrolysis by-product (hydrogen). The recovered gaseous chlorine was reused on site as a decolorizing agent for synthetic dye containing wastewater and complete decolorization was achieved. The results indicate that recycling of NF concentrate via the CEME electrolysis/magnesium potassium phosphate crystallization process is feasible.

Peculiarities of Development of Phytoplankton as an Indicator of the Ecological State in Modern Hydrochemical Conditions of Masrik River

This paper is related to the study of hydrochemical characteristics and the phytoplankton of the river Masrik. For planktonic study, algae were selected from 3 sampling sites: two from tributaries of the river and one from the river Masrik. Hydrochemical monitoring includes 9 sampling points. The study includes the spring of 2014 and the summer of 2013. According to the hydrochemical research of water, the pH ranged from 6.5-7.3. In 2014, the pH was lower compared with the spring of the previous year. Among tested anions, in some areas, relatively high level of sulfates were reached 80 -120 mg /L. Total hardness ranged from 0,6-5,6 mg-eqv /L, and the total mineralization - was ranged from 60 to 430 mg /L. Studies of heavy metals revealed a relatively high content of lead, nickel and chromium in water. Visual assessment revealed a significant organic pollution of Masrik river, which confirmed by high levels of BOD5 in water in 2014. In Masrik river mainly 3 groups of algae were detected: diatoms, green and blue-green. Dominant group was diatoms. Dominated types of algae were β-mezosaprobs (about 53%), which indicated the average level of organic pollution of the river. As a part of the green algae Spirogira sp. was found. The maximum number of phytoplankton in the investigated areas was 16,854,000 cells / L, and the biomass was 162g /m3, the minimum rates - respectively 464 000 cells /l in and 2.8 g/m3 for biomass. In water samples well developed whorls algae of the genus Chara were found, which presence indicates anthropogenic pollution. Thus, in a more acidic environment, the presence of high levels of organic pollution creates favorable conditions for the growth and development not only phytoplankton such as algae, but also for macrophytes, which indicates the reduction of ecological status of rivers.