Environmental effects of aluminium

Aluminum Biorecovery from Wastewaters

Aluminum biorecovery is still at an early stage. However, a significant number of studies showing promising results already exist, although they have revealed problems that need to be solved so aluminum biorecovery can have a wider application and industrial upscaling. In this chapter, we revise the existing knowledge on the biorecovery of aluminum from different sources. We discuss the design, overall performance, advantages, technical problems, limitations, and possible future directions of the different biotechnological methods that have been reported so far. Aluminum biorecovery from different sources has been studied (i.e., solid wastes and primary sources of variable origin, wastewater with low concentrations of dissolved aluminum at pH-neutral or weakly acidic conditions, and acidic mine waters with high concentrations of dissolved aluminum and other metal(loid)s) and has shown that the process efficiency strongly depends on factors such as (1) the physicochemical properties of the source materials, (2) the physiological features of the used (micro)organisms, or (3) the biochemical process used. Bioleaching of aluminum from low-grade bauxite or red mud can much be achieved by a diverse range of organisms (e.g., fungi, bacteria) with different metabolic rates. Biorecovery of aluminum from wastewaters, e.g., domestic wastewater, acidic mine water, has also been accomplished by the use of microalgae, cyanobacteria (for domestic wastewater) or by sulfate-reducing bacteria (acidic mine water). In most of the cases, the drawback of the process is the requirement of controlled conditions which involves a continuous supply of oxygen or maintenance of anoxic conditions which make aluminum biorecovery challenging in terms of process design and economical value. Further studies should focus on studying these processes in comparison or in combination to existing economical processes to assess their feasibility.

Effects of rainfall characteristics on runoff quality parameters within an industrial sector in Tennessee, USA

The relationship between rainfall characteristics and pollutant discharge has rarely been investigated in industrial sectors. To address this need, we investigated the pollutant concentrations of surface runoff and the correlation between pollutant discharge and rainfall characteristics using the self-reported stormwater quality data collected under the Tennessee Multi-Sector Permit program for two industrial facilities in West Tennessee. The variation of certain stormwater quality parameters over this period was utilized as an indicator to evaluate the effectiveness of control measures implemented at these two facilities. Furthermore, the Water Quality Index (WQI) as an indicator to assess the temporal changes in stormwater quality at industrial facilities was determined using the Weighted Sum (WSM) and Canadian Council of Ministers of the Environment (CCME) methods. The principal component analysis (PCA) and Pearson correlation coefficient were utilized to understand the correlation between runoff quality parameters, rainfall characteristics, and the sources of pollutants. The results demonstrated lower WQI indices using the WSM method compared to the CCME method. The data analysis revealed that 93.1%, 100%, 86.2%, and 48.3% of Al, Mg, Cu, and Fe experienced a concentration greater than the benchmark level, respectively. There was a significant relationship between Total suspended solids (TSS) and Al, Chemical Oxygen Demand (COD), Fe, oil and grease (O&G), and Zn concentrations. As a result, TSS could be a priority pollutant for designing various best management practices (BMPs) and low impact developments (LIDs). The result of the PCA and Pearson correlation coefficient showed that Al concentration made a significant correlation with the rainfall depth and rainfall duration. This analysis also illustrated that biochemical oxygen demand (BOD₅), COD, and O&G concentrations were highly correlated with antecedent dry days (ADDs). However, pH was more related to rainfall depth and rainfall intensity. This study informs both regulatory agencies and industry stakeholders regarding the importance of evaluating self-reported stormwater quality data.

Main chemical and mineralogical components of the Rio Doce sediments and the iron ore tailing from the Fundão Dam disaster, Southeastern Brazil

Since the Fundão Dam rupture in Southeastern Brazil caused an enormous amount of iron ore tailing (IOT) to be discharged into the Doce River Catchment, various works have been published on the soil, water, and biota contamination by potentially hazardous trace metals. However, the objective of this study is to investigate changes in the main chemical composition and the mineral phases, which has not been studied yet. We present an analysis of sediment samples collected in the Doce River alluvial plain, before and after the disaster, as well as the tailing deposited. Granulometry, main chemical composition by X-ray fluorescence spectrometry, mineralogy by X-ray diffractometry, quantification of mineral phases using the Rietveld method, and scanning electron microscope imaging are shown. We conclude that the Fundão Dam rupture introduced fine particles into the Doce River alluvial plain, increasing the Fe and Al content in the sediments. The high Fe, Al, and Mn contents in the finer iron ore tailing fractions represent environmental risks for soil, water, and biotic chains. The IOT mineralogical components, mainly the muscovite, kaolinite, and hematite present in the finer particles can increase the sorption and desorption capacity of harmful trace metals depending on the natural or induced redox conditions, which are not always predictable and avoidable in the environment.

Ecofriendly Removal of Aluminum and Cadmium Sulfate Pollution by Adsorption on Hexanoyl-Modified Chitosan

The purity and safety of water as a finite resource is highly important in order to meet current and future human needs. To address this issue, the usage of environmentally friendly and biodegradable adsorbers and flocculants is essential. Chitosan, as a biopolymer, features tremendous properties as an adsorber and flocculant for water treatment. For the application of chitosan as an adsorber under acidic aqueous conditions, such as acid mine drainage, chitosan has been modified with hydrophobic hexanoyl chloride (H-chitosan) to reduce the solubility at a lower pH. In order to investigate the influence of the substitution of the hexanoyl chloride on the adsorption properties of chitosan, two chitosans of different molecular weights and of three different functionalization degrees were analyzed for the adsorption of CdSO4(aq) and Al2(SO4)3(aq). Among biobased adsorbents, H-chitosan derived from the shorter Chitosan exhibited extraordinarily high maximum adsorption capacities of 1.74 mmol/g and 2.06 mmol/g for Cd2+ and sulfate, and 1.76 mmol/g and 2.60 mmol/g for Al3+ and sulfate, respectively.

Comparative Study of Chemical Coagulation and Electrocoagulation for the Treatment of Real Textile Wastewater: Optimization and Operating Cost Estimation

Pollutants derived from real textile wastewater present a high environmental risk. This work involves the study of the removal of chemical oxygen demand (COD), color, and turbidity from Tunisian real textile wastewater by two different water treatment technologies: chemical coagulation (CC) and electrocoagulation (EC). A comparative study between these two methods was conducted based on the separation performance and operating cost (OC). The effects of different operational parameters including electrolysis time (t), voltage, and pH for EC and the coagulant concentration, initial pH, and time of slow mixing (t _sm) for CC were studied using response surface methodology. The developed quadratic models for the responses were in good agreement with the experimental data. The experiments proved the efficiency of both chemical and electrochemical techniques for the treatment of textile effluent. Indeed, by using EC, the reduction efficiencies of COD, color, and turbidity were 63.05, 99.07, and 96.31%, respectively, under optimal conditions (pH 9, t = 36.26 min, and voltage 4 V). For CC treatment, the achieved removal efficiencies of COD, color, and turbidity were 54.02, 96.21, and 93.7%, respectively, at pH 8.57, a coagulant concentration of 204.75 mg/L, and a t _sm of 28.41 min as optimal operating conditions. The OC obtained for EC and CC was about 0.47 and 0.2 USD/m³, respectively. Even if the OC of the EC process was higher as compared to the CC process, the treated water obtained by EC meets the Tunisian Standards (NT 106.03 and NT 09-14) for textile wastewater discharge into the environment and demonstrates a high potential for its reuse in various industrial activities. EC technology can be integrated into a wastewater management system that ensures a zero liquid discharge of wastewater into the environment.

Detrimental impact of fine dust on zebrafish: Investigating a protective agent against ocular-damage using in vitro and in vivo models

Pollution caused by fine dust is becoming a global problem in the aquatic environment. Many studies have investigated the hazards that fine dust may pose to terrestrial organisms; however, information on the effects on aquatic environments remain limited. In this study, the physicochemical characteristics of the fine dust associated with the captured powder or liquid state were compared using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Raw fine dust (RFD), in the captured powder state, was suspended in water (SFD), and the elemental composition, morphology, and size distribution of both were analyzed. Zebrafish were used as a model to study the effects of SFD-exposure on aquatic organisms. A fatal malformation was observed in the integuments of zebrafish exposed to SFD, specifically in the exterior and interior eye tissues. Furthermore, the exposure of SFD to Tg (flk; EGFP) zebrafish remarkably increased ocular vessel diameter expansion along with blood flow velocity. Regarding vessel diameter expansion, EA.hy926 cells exposed to SFD were adversely affected, with a significant increase in cell migration and capillary-like structure formation, which are angiogenic markers. The SFD-induced angiogenesis in vitro and in vivo was dramatically restored to normal via α/β-adenosine isolated from the anti-angiogenic brown algae Ishige okamurae extract. Taken together, the current study presents solid evidence of the altered physicochemical characteristics of SFD compared to RFD, and the detrimental impact of SFD in an aquatic in vivo zebrafish model. In addition, the protective effect of α/β-adenosine, a marine natural product, on SFD-induced angiogenesis suggests that it can be used as an agent to reduce the adverse effects of SFD on aquatic animals.

Habitat-, age-, and sex-related alterations in oxidative stress biomarkers in the blood of mute swans (Cygnus olor) inhabiting pomeranian coastal areas (Northern Poland)

The mute swan (Cygnus olor) can be considered a representative species of birds associated with the aquatic environment and responding very clearly to changes in the environment. Assuming that the condition of the mute swan population well reflects the state of the environment, this species was used in our research as a bioindicative species. Thus, the aim of our study was to elucidate the association between metal contents in soil samples collected from a habitat of mute swans and element contents in their feathers as well as the levels of biomarkers of lipid peroxidation, oxidatively modified proteins, and total antioxidant capacity in the blood of mute swans living in three agglomerations in coastal areas in the southern part of the Baltic Sea (Pomeranian region, northern Poland). We compared the effects of inhabitation, age, and sex on the ecophysiological accumulation of metals in three wintering populations of the mute swan from coastal areas of northern Poland, i.e., Słupsk, Gdynia, and Sopot. In Słupsk, the anthropogenic pressure was related predominantly to the level of Al and, to a lesser extent, to the content of Rh and Ru. We found maximum levels of lipid peroxidation biomarkers in the blood of the mute swans from Gdynia (38.20 ± 6.35 nmol MDA·mL^-1). At the same time, maximum levels of aldehydic and ketonic derivatives of oxidatively modified proteins were noted in the blood of swans from Sopot compared to the values obtained in mute swans from Słupsk and Gdynia. This trend suggesting high levels of oxidative stress biomarkers was also confirmed by a decrease in the total antioxidant capacity in these groups.

Non-invasive sampling of bats reflects their potential as ecological indicators of elemental exposure in a diamond mining area, northern Limpopo Province, South Africa

Bats have been proposed as reliable bioindicators for monitoring bioaccumulation of elements and chemicals in natural and transformed ecosystems. Non-invasive methods are becoming more popular as research moves away from destructive methodologies. We present the first concentrations of 23 elements in Mops condylurus and Tadarida aegyptiaca (Molossidae) fur and blood from an opencast diamond mine and reference area using inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of B, K, Rb and Cd in the bats' fur were significantly higher in the mining footprint compared to the reference area (P < 0.05). Other elements such as Zn and Hg were significantly higher in the blood of bats from the mining footprint than the reference area (P < 0.05), whereas Mn was significantly higher in the blood of bats from the reference area than from the mining footprint (P < 0.05). Sixteen of the 22 elements above the limit of detection, with the exception of Ba, were significantly higher in the fur samples than in the blood due to elements being incorporated over time into the fur as it grows, whereas blood reveals short-term exposure to elements. Concentrations of most of the elements were reasonably low except Al, Fe and Zn. In general, the element concentrations particularly in the fur samples were comparable with other international studies reporting elemental fur concentrations from anthropogenically impacted and natural areas. Fur and blood have the potential to be viable indicators of environmental toxicity, but research is required on toxic thresholds and physiological and ecological unknowns around element concentrations in bat tissues and organs.

Effects of Aluminium Contamination on the Nervous System of Freshwater Aquatic Vertebrates: A Review

Aluminium (Al) is the most common natural metallic element in the Earth’s crust. It is released into the environment through natural processes and human activities and accumulates in aquatic environments. This review compiles scientific data on the neurotoxicity of aluminium contamination on the nervous system of aquatic organisms. More precisely, it helps identify biomarkers of aluminium exposure for aquatic environment biomonitoring in freshwater aquatic vertebrates. Al is neurotoxic and accumulates in the nervous system of aquatic vertebrates, which is why it could be responsible for oxidative stress. In addition, it activates and inhibits antioxidant enzymes and leads to changes in acetylcholinesterase activity, neurotransmitter levels, and in the expression of several neural genes and nerve cell components. It also causes histological changes in nerve tissue, modifications of organism behaviour, and cognitive deficit. However, impacts of aluminium exposure on the early stages of aquatic vertebrate development are poorly described. Lastly, this review also poses the question of how accurate aquatic vertebrates (fishes and amphibians) could be used as model organisms to complement biological data relating to the developmental aspect. This “challenge” is very relevant since freshwater pollution with heavy metals has increased in the last few decades.

Removal of Lead, Cadmium, and Aluminum Sulfate from Simulated and Real Water with Native and Oxidized Starches

The separation of toxic pollutants such as Pb2+, Cd2+, and Al3+ from water is a constant challenge as contamination of natural water bodies is increasing. Al3+ and especially Pb2+ and Cd2+ are ecotoxic and highly toxic for humans, even in ppb concentrations, and therefore removal below a dangerous level is demanding. Herein, the potential adsorber material starch, being ecofriendly, cheap, and abundantly available, was investigated. Thus, four different native starch samples (potato, corn, waxy corn, and wheat starch) and two oxidized starches (oxidized potato and corn starch) were comprehensively analyzed with streaming potential and charge density measurements, SEM-EDX, ATR-FTIR, 1H-NMR, and TGA. Subsequently, the starch samples were tested for the adsorption of Pb2+, Cd2+, and Al3+ from the respective sulfate salt solution. The adsorption process was analyzed by ICP-OES and SEM-EDX, and the adsorption isotherms were fitted comparing Langmuir, Sips, and Dubinin-Radushkevich models. Oxidized starch, for which chemical modification is one of the simplest, and also native potato starch were excellent natural adsorber materials for Al3+, Cd2+, and especially Pb2+ in the low concentration range, exhibiting maximum adsorption capacities of 84, 71, and 104 µmol/g for oxidized potato starch, respectively.

Red mud with other waste materials as artificial soil substitute and its effect on Sinapis alba

Despite efforts to utilise bauxite residue, the amount of red mud stored in reservoirs is increasing. This paper aims to evaluate the potential of red mud and other sludge waste types as a soil substitute by monitoring plant development. Pot experiments were carried out testing two types of mixtures: dredging sludge from Lake Balaton mixed with garden soil and the sewage sludge and soil blend. These were then treated with red mud (15 and 30% w/w). The plants were under-, while the roots were more developed in the sewage sludge mix than the dredging sludge blend and the control soil. In the sewage amendment, the phosphorous content increased while the calcium content was lower than in the other soil types and the optimum. The metals uptake of the plants was a factor of the red mud quantity. Lead, nickel, titanium and silicon had elevated concentrations parallel to higher red mud content, but only the nickel exceeded the threshold of the Hungarian legislation. Silicon and titanium were beneficial for plant growth, compensating for the potentially toxic effects of lead and nickel. Results suggest that the red mud in a mixture with either sewage sludge or dredging sludge can act as catalysts for the growth rate of test plants, allowing their utilisation as secondary raw materials.

Are we neglecting earth while conquering space? Effects of aluminized solid rocket fuel combustion on the physiology of a tropical freshwater invertebrate

Space launchers often use aluminized-solid fuel ("propergol") as propellant and its combustion releases tons of Al₂O₃ and HCl that sink in terrestrial and aquatic environments, polluting and decreasing water pH. We studied the impact of these events on the biochemical/physiological performance of the freshwater shrimp Macrobrachium jelskii, with wild specimens collected from a non-impacted site in French Guiana. In the laboratory, shrimps were exposed for one week to: i) undisturbed conditions; ii) Al₂O₃ exposure (0.5 mg L^-1) at normal pH (6.6); iii) decreased pH (4.5) (mimicking HCl release in the environment) with no Al₂O₃; or iv) Al₂O₃ 0.5 mg L^-1 and pH 4.5, representing the average conditions found in the water bodies around the Ariane 5 launch pad. Results showed that shrimps bioaccumulated aluminium (Al) regardless of water pH. The combined effect of Al₂O₃ and low pH caused the most impact: acetylcholinesterase and carboxylesterase activities decreased, indicating neurotoxicity and reduced detoxification capacity, respectively. Animal respiration was enhanced with Al₂O₃ and pH variations alone, but the synergic interaction of both stressors caused respiration to decrease, suggesting metabolic depression. Oxidative damage followed a similar pattern to respiration rates across conditions, suggesting free radical-mediation in Al toxicity. Antioxidant activities varied among enzymes, with glutathione reductase being the most impacted by Al₂O₃ exposure. This study shows the importance of addressing space ports' impact on the environment, setting the bases for selecting the most appropriate biomarkers for future monitoring programs using a widespread and sensitive crustacean in the context of an increasing space-oriented activity across the world.

Current and Future Ecological Status Assessment: A New Holistic Approach for Watershed Management

The Paiva River catchment, located in Portugal, integrates the Natura 2000 network of European Union nature protection areas. Resorting to topography, climate and land-use data, a semi-distributed hydrological model (Hydrological Simulation Program–FORTRAN) was run in order to simulate the hydrological cycle of the river and its tributaries. The model was calibrated over a 25-year period and validated within a 31-year period. Its performance was verified by comparing the recorded and simulated daily flows. The values of the Nash–Sutcliffe coefficient of efficiency of 0.95 and 0.76, and coefficient of determination of 0.95 and 0.82, were achieved for calibration and validation, respectively, thus showing a quite satisfactory model performance. Subsequently, the climate change impacts on temperature and precipitation, as well as their extremes, and on the flowrates were also assessed for a future period (2041–2070) under two anthropogenic forcing scenarios (representative concentration pathways 4.5 and 8.5). A procedure for selecting the most relevant metrics for assessing the ecological condition of the Paiva River was developed based upon a set of 52 invertebrate families sampled. Correspondence analyses were carried out for biological datasets (traits/metrics) with physicochemical and land use/land cover matrices separately. Out of all variables, water quality and flow and agriculture land use explained most of the variance observed. The integrated analysis undertaken in the present study is an important advance when compared to previous studies and it provides key information to stakeholders and decision-makers, particularly when planning suitable adaptation measures to cope with changing climates in the forthcoming decades.

Climatic effects on water quality in areas with acid sulfate soils with commensurable consequences on the reproduction of burbot (Lota lota L.)

Due to discharge from acid sulfate (a.s.) soils, watercourses and coastal areas in the Gulf of Bothnia are periodically heavily acidified with high concentrations of potentially toxic metals. Data on water quality from 2005 to 2014 in an embanked lake, an estuary of four rivers in western Finland, showed repeated events with acidic water (pH < 5.5) with high concentrations of Al. Size fractionation and species modeling of Al showed that a significant part of the Al occurred as highly toxic small-size fractions (dissolved < 1 kDa and colloidal 1 kDa-0.45 µm) as free ions and complexed to sulfate. The larval abundance of the burbot (Lota lota L.) was shown to be sensitive to acidity during the wintertime spawning migration and spawning. Bearing in mind the importance of estuaries of the northern Baltic Sea as spawning and nursery areas of fish, the reoccurring failure in the reproduction of fish may cause a more serious threat for the lake and adjacent coastal fish stocks than the spectacular, but less frequent, mass kills of adult fish. This demonstrates the close relationship between climate, hydrology, water geochemistry and the aquatic coastal ecosystem in areas affected by a.s. soils. As the current forecast of climate chance indicates warmer winters with more continuous runoff, the effects can become even more prominent. This study also shows that the annual larvae abundance of burbot may be used as a bioindicator and an instrument for the fisheries for obtaining more comprehensive knowledge of the ecological effects of acidic metal discharge from a.s. soils.

Health concerns on provisional tolerable weekly intake of aluminium in children and adults from vegetables in Mandi-Gobindgarh (India)

Metallurgical industrial processes have been reported to cause higher aluminium (Al) exposure in humans through plant food intake due to higher soil Al content and acidification of soil resulted from industrial acid rains. Mandi-Gobindgarh is critically environmentally polluted steel industrial town in India in which Al is used for deoxidation, grain refining and alloying in steel production. The Al processing has been reported to release Al into the environment, and therefore present study was undertaken to investigate the dietary Al exposure in children and adult population of Mandi-Gobindgarh from consumption of vegetable food stuffs grown in the fields around steel industries. Thirteen vegetable types including fruit vegetables, root vegetables, and leafy vegetables (LVs) along with soil samples were collected from agricultural fields around M-site (Mandi-Gobindgarh industrial site) and C-site (control non-industrial site) and analysed for Al on WD-XRF. Higher vegetable Al content was reported due to higher soil Al content and higher acidic soil pH at M-site than C-site. Correlation coefficient data have shown positive correlation of plant/vegetable Al with soil Al whereas negative correlation with soil pH at both the sites. Hierarchical cluster analysis based on vegetable Al content and bioaccumulation factor depicted higher number of clusters of vegetables at M-site (3-clusters) than C-site (2-clusters). The hazard quotients for Al intake in children and adults were found less than one. However, the weekly dietary Al exposure data have shown more than provisional tolerable weekly intake of 2 mg/kgbw/week in them from two LVs (Spinach and Brassica) from M-site than C-site which increases health concerns in humans from Mandi-Gobindgarh.

Phytoneuston and Chemical Composition of Surface Microlayer of Urban Water Bodies

The concentration of chemical and biological parameters in the ecotone of the surface microlayer (SML) occurring between the hydrosphere and the atmosphere of urban water bodies was investigated. Parallel, sub-surface water (SUB) analyses were carried out to compare the SML properties with the water column. The concentrations of trace metals, macronutrients, nutrients, chlorophyll a, pheophytin, abundance and biomass of phytoplankton and the number of heterotrophic bacteria in both studied layers were analyzed. Each of the studied groups of chemical parameters was characterized by specific properties of accumulation. Trace metals occurring in concentrations below 1 ppm, such as Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Zn and metalloid As, were accumulated to a higher degree in SML than in SUB. Macroelement concentrations, with the exception of Mg, were lower in the SML compared to the SUB. Nutrients, autotrophic and heterotrophic microorganisms occurred in the SML to a higher degree than in the SUB. Bacillariophyceae dominated the analyzed water bodies, which are typical for the spring period, as well as Chrysophyceae, Chlorophyceae, Dinophyceae and Euglenophyceae. Cyanobacteria dominated in one of the ponds. The abundance of individual phytoplankton groups was significantly correlated with Ca, K, Na, P-org, SO42−, F−, Al and Sr.

Genotoxic Effects of Environmental Pollutant Heavy Metals on Alburnus chalcoides (Pisces: Cyprinidae) Inhabiting Lower Melet River (Ordu, Turkey)

The lower Melet River is a drinking water source that is surrounded by hazelnut grove, agricultural lands, resulting in the accumulation of genotoxic agents such as mining activities, various domestic and agricultural wastes. Therefore, it receives many domestic and agricultural wastes that contain the genotoxic agent. This study was aimed to assess the heavy metal concentrations in water, sediment, and bioaccumulation in the tissues of Alburnus chalcoides. Comet assay and micronucleus test were used to evaluate the genotoxic effects on the blood cells of A. chalcoides. The concentrations of heavy metals and metalloid in the water, in the sediments and in the muscle of fish were in the order of Fe > Al > Mn > As > Zn > Cu > Ni > Cr > Cd = Pb = Co, Fe > Al > Mn > Zn > Cu > Pb > Cr > As > Co > Ni > Cd and Fe > Zn > Al > Mn > Cu > Pb > As > Cr > Ni > Co > Cd, respectively. The blood cells of fish collected from the polluted location showed significantly higher DNA damage and micronucleus frequency compared to the reference location (p < 0.05). The study indicated that the DNA integrity of A. chalcoides was affected by heavy metals which originated from many anthropogenic sources.

Transfer of elements released by aluminum galvanic anodes in a marine sedimentary compartment after long-term monitoring in harbor and laboratory environments

Cathodic protection by galvanic anodes (GACP) is often used to protect immerged metallic structures in harbor environments, especially GACP employing aluminum-based anodes. To follow a previous study that was performed in a laboratory on Al-anode, two monitoring periods were performed in parallel, one in an in situ environment (in the Port of Calais) for 42 months and the other in a laboratory for 18 months, to evaluate the transfer of metals constituting the Al-anode towards the sedimentary compartment. During each monitoring, two conditions of agitation of water (weak and strong) were compared, and different factors of sediment quality were used to assess the enrichment and potential toxic effects of these released metals. The results showed that the dissolution of Al-anode-induced a greater Zn enrichment of sediment than an Al enrichment. This is in contrast with the abundance of these elements present in the composition of the anode and suggested a potential toxic effect for marine organisms with regards to the discovered Zn level, especially in confined areas.

Assessment of trace metal contamination in the marine sediment, seawater, and bivalves of Parangipettai, southeast coast of India

Industrial and domestic discharge into the coastal environment has driven us to propose an integrated approach to delineate stations contaminated with metals on the Parangipettai coast by collecting sediment and seawater samples monthly at 18 stations from 2015 to 2017. Descriptive statistics revealed that the concentrations of some metals in the sediment and seawater samples were beyond the permissible level. Further, factor analysis showed a sampling adequacy of 0.90 with high positive loading for Ni (0.94), Cd (0.91), Co (0.90), Pb (0.89), and Zn (0.87) in sediment samples. The degree of contamination by metals was evaluated using pollution indices. The results of the contamination index revealed that some stations in the study area were moderately polluted, and those of the ecological index showed that open sea was under low risk while other stations were in the moderate-to-high-risk category. The results obtained are essential to establish the reference condition for a comparative study in similar environments in the tropical regions.

Carbon source and phosphorus recovery from iron-enhanced primary sludge via anaerobic fermentation and sulfate reduction: Performance and future application

Anaerobic fermentation and sulfate reduction (AF-SR) was firstly used for recovery of carbon sources and phosphorus from Fe-enhanced primary sludge (Fe-sludge). With FeCl₃ dosage of 30 mg Fe/L, 63.0% of the chemical oxygen demand (COD) and 97.3% of the phosphorus were concentrated from sewage into Fe-sludge. Batch anaerobic fermentation tests of Fe-sludge with and without sulfate addition (AF-SR and control) were performed. The results showed that volatile fatty acid concentrations of the control and AF-SR were 211.0 and 270.2 mg COD/g volatile suspended solids, respectively. Furthermore, 33.2% (control) and 56.2% (AF-SR) of the total phosphorus in Fe-sludge was released. The recovery performances of carbon source and phosphorus were calculated based on struvite precipitation. The available carbon source of the AF-SR system was 44.5% higher than that of the control. A novel integrated wastewater and sludge treatment process based on chemically enhanced primary sedimentation and AF-SR is proposed for future application.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Concentrations of Thirteen Trace Metals in Scales of Three Nototheniid Fishes from Antarctica (James Ross Island, Antarctic Peninsula)

In this study, we assessed concentrations of 13 trace metals in the scales of Notothenia coriiceps, Trematomus bernacchii and Gobionotothen gibberifrons caught off the coast of James Ross Island (Antarctic Peninsula). Overall, our results for scales broadly match those of previous studies using different fish and different organs, with most metals found at trace levels and manganese, aluminium, iron and zinc occurring at high levels in all species. This suggests that scales can serve as a useful, non-invasive bioindicator of long-term contamination in Antarctic fishes. High accumulation of manganese, aluminium, iron and zinc is largely due to high levels in sediments associated with nearby active volcanic sites. Manganese, vanadium and aluminium showed significant positive bioaccumulation in T. bernacchii (along with non-significant positive accumulation of iron, zinc, cobalt and chromium), most likely due to greater dietary specialisation on sediment feeding benthic prey and higher trophic species. Levels of significance in bioaccumulation regressions were strongly affected by large-scale variation in the data, driven largely by individual differences in diet and/or changes in habitat use and sex differences associated with life stage and reproductive status. Increased levels of both airborne deposition and precipitation and meltwater runoff associated with climate change may be further adding to the already high levels of manganese, aluminium, iron and zinc in Antarctic Peninsula sediments. Further long-term studies are encouraged to elucidate mechanisms of uptake (especially for aluminium and iron) and possible intra- and interspecific impacts of climate change on the delicate Antarctic food web.

Effects of aluminium and cadmium on hatching and swimming ability in developing zebrafish

Aluminium and cadmium are biologically non-essential metals with a role in neurodegenerative and neuromuscular diseases. As an attractive model for neurobehavioural studies, zebrafish at 6 h post fertilization were exposed to 9, 18, 36 and 72 μM CdCl₂ and 50, 100 and 200 μM AlCl₃, respectively, for 72 h, and motility such as distance moved, mean velocity, cumulative movement, meander and heading were measured by DanioVision equipment. The hatching time was also analysed. A delay in the exit from the chorion was observed in all treated larvae with respect to the controls. CdCl₂ acted on the exit from the chorion of larvae with a dose-dependent delay. By contrast, the delay caused by AlCl₃ was greater at low concentrations. A dose-dependent reduction in swimming performance was observed in the larvae exposed to CdCl₂. Instead, for those exposed to AlCl₃, swimming performance improved at higher concentrations although values were in general lower than those of control. All the parameters had a similar trend except the meander parameter which showed a dose-dependent reduction. These data show that cadmium and aluminium can delay hatching and alter swimming ability in the early developmental stages of zebrafish, albeit with different effects, suggesting that exposure to sublethal concentrations of both metals can change behavioural parameters.

Effective adsorption of trace phosphate and aluminum in realistic water by carbon nanotubes and reduced graphene oxides

In this study, carbon nanotube (CNT) and reduced graphene oxide (rGO) were studied for their potentials as novel adsorbents for trace concentrations of phosphorus and aluminum in water and wastewater. Static adsorption results demonstrated that CNT and rGO employed in this study removed up to 65.6% of total dissolved Al and 98.9% of P from a natural surface water and a secondary wastewater effluent. Hydrogen-bonding interactions between CNT/rGO and oxyanions were hypothesized to contribute to the adsorption process. Accordingly, acetaminophen (AAP), a pharmaceutical compound known to form hydrogen bonding with CNT, was spiked into the real water as a competitor for P and Al adsorption. Subsequent sorption results showed that the presence of AAP reduced Al and P adsorption by CNT and rGO by 9.3%-18.4% and 11.2%-18.2%, respectively. These results suggest that hydrogen bonding interactions with CNT/rGO influenced the adsorption of P and Al species. In addition, pH effect investigation on Al/P removal further verified the above opinion. Overall, this study provided important evidence and insights into CNT/rGO adsorption of P and Al species from water and wastewater, which expanded our understanding on the ability of carbonaceous nanomaterials for advanced water and wastewater treatment.

Inter-species and inter-colony differences in elemental concentrations in eggshells of sympatrically nesting great cormorants Phalacrocorax carbo and grey herons Ardea cinerea

We compared the concentrations of 17 heavy metals and essential elements in post-hatching eggshells of two waterbirds, the obligate piscivorous great cormorant Phalacrocorax carbo (GCM) and the more omnivorous grey heron Ardea cinerea (GHR), breeding sympatrically in eight mixed colonies in Poland. We found significant inter-species and inter-colony differences in the levels of most of the elements. GHR had significantly higher concentrations of Al, which can be explained by its very low stomach pH: an acidic environment favours the release of Al compounds. Differences in Mn, Ni, Cu, Se and Hg concentrations can be attributed to the various contributions of fish and other aquatic organisms to the diet, and to the exploration of different habitats (GCM exclusively aquatic, GHR a wider range) and microhabitats (GCM, in contrast to wading GHR, dive for food, exploring the whole depth range of water bodies), differently exposed to contamination by those elements from sediments. Inter-colony differences were related to the level of industrialisation. We recorded higher levels of some elements in the eggshells (Fe, Mn in both species and Cr, Ni and Zn in GCM) collected in industrialised areas, which may be associated with the negative environmental impact of industrial areas.

Selective sensing of Al3+ ions by nitrophenyl induced coordination: imaging in zebrafish brain tissue

A selective sensing of Al³⁺ ions by nitrophenyl induced coordination has been developed and applied for the detection of Al³⁺ in the brain tissue of zebrafish.

Simultaneous release of polyphosphate and iron-phosphate from waste activated sludge by anaerobic fermentation combined with sulfate reduction

Iron is widely used in sewage treatment systems and enriched into waste activated sludge (WAS), which is difficult and challenging to phosphorus (P) release and recovery. This study investigated simultaneous release performance of polyphosphate and iron-phosphate from iron-rich sludge via anaerobic fermentation combined with sulfate reduction (AF-SR) system. Batch tests were performed, with results showing that AF-SR system conducted a positive effect due to the relatively low solubility of ferrous sulfide in comparison with ferric phosphate precipitates. Simulation study was performed to investigate the total P release potential from actual waste activated sludge, finding that about 70% of the total P could release with the optimized pH of 7.0-8.0 and the theoretical S^2-/Fe²⁺ molar ratio of 1.0. A potential new blueprint of a wastewater treatment plant based on AF-SR system, towards P, N recovery and Fe, S, C recycle, was finally proposed.

Review of zero-valent aluminium based water and wastewater treatment methods

Zero-valent metals (ZVM) are widely used to remove heavy metals, contaminants, toxicity, etc. from water and wastewater. Zero-valent aluminium (ZVAl) has large surface area and high surface reactivity. It has enormous flexibility for the in-situ application. ZVAl can be applied as either a single or a bimetallic system as well as advanced oxidation processes (AOPs). It is observed that ZVAl is capable of generating hydroxyl and sulfate radicals in water medium, which remove non-biodegradable pollutants from aqueous solution. ZVAl-based processes can remove non-biodegradable organic contaminants from water medium within a short duration. ZVAl is also used as a reducing agent. It is efficient to reduce toxic hexavalent chromium to less toxic trivalent chromium. ZVAl, in various combinations in bimetallic system (Fe/Al, Pd/Al, Cu/Al), is able to remove various contaminants from aqueous medium. Overall, it can be concluded that ZVAl-based methods for water and wastewater treatment are promising environmental technologies.

Exploring the hidden potential of a benzothiazole-based Schiff-base exhibiting AIE and ESIPT and its activity in pH sensing, intracellular imaging and ultrasensitive & selective detection of aluminium (Al3+)

The hidden potential of an AIE-ESIPT active, simple substituted benzothiazole compound has been explored.

Sequestration of Aluminium(III) by different natural and synthetic organic and inorganic ligands in aqueous solution

The speciation of Al³⁺ in aqueous solutions containing organic and inorganic ligands important from a biological (citrate (Cit^3-), gluconate (Gluc^-), lactate (Lac^-), silicate (H₂SiO₄^2-), carbonate (CO₃^2-), fluoride (F^-)) and industrial (Gantrez^®; polymethyl-vinyl-ether-co-maleic acids; GTZ S95 and GTZ AN169) point of view is reported. The stability constants of Al³⁺/L^z- complexes (L^z- = ligand with z^- charge) were determined by potentiometry at T = 298.15 K and 0.10 ≤ I/M ≤ 1.00 in NaCl_(aq) (in NaNO_3(aq) only for Al³⁺/GTZ S95 and Al³⁺/Gluc^- acid systems). For Al³⁺/Cit^3-, Al³⁺/Lac^- and Al³⁺/GTZ AN169^4- systems, the investigations were also carried out at 283.15 ≤ T/K ≤ 318.15. The dependence of the thermodynamic parameters on ionic strength and temperature was modelled with a Debye-Hückel type equation. Different speciation schemes of Al³⁺/L^z- systems were obtained, including protonated, simple metal-ligand, polynuclear and hydrolytic mixed species. At I → 0 M and T = 298.15 K the stability trend for the AlL^(3-z) species is: 14.28 ± 0.02, 13.99 ± 0.03, 10.16 ± 0.03, 3.16 ± 0.08, 2.84 ± 0.10 for GTZ S95, GTZ AN169, Cit^3-, Gluc^- and Lac^-, respectively. From the investigations at different temperatures, it results that the entropic contribution is the driving force of the reactions. The sequestering ability of the ligands towards Al³⁺ was investigated determining the pL_0.5 parameter at different experimental conditions, finding the following trend: Cit^3- » Gluc^- > GTZ S95^4- > GTZ AN169^4- > Lac^- for the organic ligands, and pL_0.5: F^- » CO₃^2- > H₂SiO₄^2- for the inorganic ones.

Aluminium sulfate exposure: A set of effects on hydrolases from brain, muscle and digestive tract of juvenile Nile tilapia (Oreochromis niloticus)

Aluminium is a major pollutant due to its constant disposal in aquatic environments through anthropogenic activities. The physiological effects of this metal in fish are still scarce in the literature. This study investigated the in vivo and in vitro effects of aluminium sulfate on the activity of enzymes from Nile tilapia (Oreochromis niloticus): brain acetylcholinesterase (AChE), muscle cholinesterases (AChE-like and BChE-like activities), pepsin, trypsin, chymotrypsin and amylase. Fish were in vivo exposed during 14days when the following experimental groups were assayed: control group (CG), exposure to Al₂(SO₄)₃ at 1μg·mL^-1 (G1) and 3μg·mL^-1 (G3) (concentrations compatible with the use of aluminium sulfate as coagulant in water treatment). In vitro exposure was performed using animals of CG treatment. Both in vivo and in vitro exposure increased cholinesterase activity in relation to controls. The highest cholinesterase activity was observed for muscle BChE-like enzyme in G3. In contrast, the digestive enzymes showed decreased activity in both in vivo and in vitro exposures. The highest inhibitory effect was observed for pepsin activity. The inhibition of serine proteases was also quantitatively analyzed in zymograms using pixel optical densitometry as area under the peaks (AUP) and integrated density (ID). These results suggest that the inhibition of digestive enzymes in combination with activation of cholinesterases in O. niloticus is a set of biochemical effects that evidence the presence of aluminium in the aquatic environment. Moreover, these enzymatic alterations may support further studies on physiological changes in this species with implications for its neurological and digestive metabolisms.

The occurrence and potential ecological risk assessment of bauxite mine-impacted water and sediments in Kuantan, Pahang,Malaysia

Recent bauxite mining activities in the vicinity of Kuantan, Pahang, have been associated with apparent environmental quality degradation and have raised environmental concerns among the public. This study was carried out to evaluate the overall ecological impacts on water and sediment quality from the bauxite mining activities. Water and sediment samples were collected at seven sampling locations within the bauxite mining areas between June and December 2015. The water samples were analyzed for water quality index (WQI) and distribution of major and trace element geochemistry. Sediment samples were evaluated based on geochemical indices, i.e., the enrichment factor (EF) and geoaccumulation index (I _geo). Potential ecological risk index was estimated to assess the degree to which sediments of the mine-impacted areas have been contaminated with heavy metals. The results showed that WQIs of some locations were classified as slightly polluted and contained metal contents exceeding the recommended guideline values. The EFs indicated minimal to moderate enrichment of metals (Pb, Cu, Zn, Mn, As, Cd, Cr, Ni, Co, and Sr) in the sediments. I _geo showed slightly to partially polluted sediments with respect to As at some locations. The potential ecological risk index (RI) showed that As posed the highest potential ecological risk with RI of 52.35-60.92 at two locations, while other locations indicated low risk. The findings from this study have demonstrated the impact of recent bauxite mining activities, which might be of importance to the local communities and relevant authorities to initiate immediate rehabilitation phase of the impacted area.

Role of Metabolic Genes in Blood Aluminum Concentrations of Jamaican Children with and without Autism Spectrum Disorder

Aluminum is a neurotoxic metal with known health effects in animals and humans. Glutathione-S-transferase (GST) genes and enzymes play a major role in detoxification of several heavy metals. Besides a direct relationship with oxidative stress; aluminum decreases GST enzyme activities. Using data from 116 Jamaican children; age 2–8 years; with Autism Spectrum Disorder (ASD) and 116 sex- and age-matched typically developing (TD) children; we investigated the association of polymorphisms in three GST genes (GSTP1; GSTM1; and GSTT1) with mean blood aluminum concentrations in children with and without ASD. Using log-transformed blood aluminum concentration as the dependent variable in a linear regression model; we assessed the additive and interactive effects of ASD status and polymorphisms in the three aforementioned GST genes in relation to blood aluminum concentrations. Although none of the additive effects were statistically significant (all p > 0.16); we observed a marginally significant interaction between GSTP1 Ile105Val (rs1695) and ASD status (p = 0.07); even after controlling for parental education level and consumption of avocado; root vegetables; and tuna (canned fish). Our findings indicate a significantly lower (p < 0.03) adjusted geometric mean blood aluminum concentration for TD children who had the Val/Val genotype (14.57 µg/L); compared with those with Ile/Ile or Ile/Val genotypes who had an adjusted geometric mean of 23.75 µg/L. However; this difference was not statistically significant among the ASD cases (p = 0.76). Our findings indicate that ASD status may be a potential effect modifier when assessing the association between GSTP1 rs1695 and blood aluminum concentrations among Jamaican children. These findings require replication in other populations.

Aluminum toxicity risk reduction as a result of reduced acid deposition in Adirondack lakes and ponds

In 1990, the US Congress amended the Clean Air Act (CAA) to reduce regional-scale ecosystem degradation from SO _x and NO _x emissions which have been responsible for acid deposition in regions such as the Adirondack Mountains of New York State. An ecosystem assessment project was conducted from 1994 to 2012 by the Darrin Fresh Water Institute to determine the effect of these emission reduction policies on aquatic systems. The project investigated water chemistry and biota in 30 Adirondack lakes and ponded waters. Although regulatory changes made in response to the 1990 CAA amendments resulted in a reduction of acid deposition within the Adirondacks, the ecosystem response to these reductions is complicated. A statistical analysis of SO₄, pH, Al, and DOC data collected during this project demonstrates positive change in response to decreased deposition. The changes in water chemistry also have lowered the risk of Al toxicity to brook trout (Salvelinus fontinalis [Mitchill]), which allowed the re-introduction of this species to Brooktrout Lake from which it had been extirpated. However, pH and labile aluminum (Al_im) fluctuate and are not strongly correlated to changes in acid deposition. As such, toxicity to S. fontinalis also is cyclic and provides rationale for the difficulties inherent in re-establishing resident populations in impacted aquatic environments. Overall, aquatic ecosystems of the Adirondacks show a positive response to reduced deposition driven by changes in environmental policy, but the response is more complex and indicates an ecosystem-wide interaction between aquatic and watershed components of the ecosystem.

Fire Blight Control: The Struggle Goes On. A Comparison of Different Fire Blight Control Methods in Switzerland with Respect to Biosafety, Efficacy and Durability

Fire blight (FB), caused by Erwinia amylovora, is one of the most important pome fruit pathogens worldwide. To control this devastating disease, various chemical and biological treatments are commonly applied in Switzerland, but they fail to keep the infection at an acceptable level in years of heavy disease pressure. The Swiss authorities therefore currently allow the controlled use of the antibiotic streptomycin against FB in years that are predicted to have heavy infection periods, but only one treatment per season is permitted. Another strategy for controlling Erwinia is to breed resistant/tolerant apple cultivars. One way of accelerating the breeding process is to obtain resistant cultivars by inserting one or several major resistance genes, using genetic engineering. To date, no study summarizing the impact of different FB control measures on the environment and on human health has been performed. This study consequently aims to compare different disease-control measures (biological control, chemical control, control by antibiotics and by resistant/tolerant apple cultivars obtained through conventional or molecular breeding) applied against E. amylovora, considering different protection goals (protection of human health, environment, agricultural diversity and economic interest), with special emphasis on biosafety aspects. Information on each FB control measure in relation to the specified protection goal was assessed by literature searches and by interviews with experts. Based on our results it can be concluded that the FB control measures currently applied in Switzerland are safe for consumers, workers and the environment. However, there are several gaps in our knowledge of the human health and environmental impacts analyzed: data are missing (1) on long term studies on the efficacy of most of the analyzed FB control measures; (2) on the safety of operators handling streptomycin; (3) on residue analyses of Equisetum plant extract, the copper and aluminum compounds used in apple production; and (4) on the effect of biological and chemical control measures on non-target fauna and flora. These gaps urgently need to be addressed in the near future.

Aluminium (Al) fractionation and speciation; getting closer to describing the factors influencing Al(3+) in water impacted by acid mine drainage

Acid mine drainage (AMD) severely impacts the water chemistry of a receiving resource, changing the occurrence, speciation and toxicity of metals such as Aluminium (Al). The toxicity of Al is determined by its speciation represented by the labile monomer Al fraction or Al(3+). The purpose of the study was to combine fractionation and Visual MINTEQ speciation to calculate the effect of AMD altered water chemistry on Al speciation and Al(3+) concentration. Water in rivers impacted by AMD presented with monomeric Al (Almon) concentrations between 0.35 and 15.37mgL(-)(1) which existed almost exclusively in the toxic labile form (98%). For the reference site, Almon was less than 2% (10μgL(-1)), suggesting significantly lower Al toxicity. Principal component analysis plots illustrated that labile Al was directly related to the total Al and iron concentrations and strongly influenced by parameters such as pH, electrical conductivity, sulphate and dissolved organic carbon. Visual MINTEQ modelling was used to determine the primary Al species distribution. The dominant form of Al in AMD impacted water was AlSO4(+), which increased proportionally with the sulphate and Al(3+) concentration. Heavily impacted areas, presented with an average of 1mgmL(-)(1) Al(3+), which poses a potential human health risk. A novel centrifugal ultrafiltration method was investigated as an alternative to determining Almon to simplify the speciation of Al. Monomeric and centrifugal ultrafiltrated (<10kD) Al fractions were significantly similar (p=0.74), suggesting that ultrafiltration may present a time, energy and cost saving alternative to organic extraction of Almon.

Toxicity, mechanism and health effects of some heavy metals

Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects.

Interspecific and locational differences in metal levels in edible fish tissue from Saudi Arabia

Metal levels in fish have been extensively studied, but little data currently exists for the Middle East. We examined the levels of metals and metalloids (aluminum, arsenic, copper, manganese, selenium, zinc, and mercury) in the flesh of 13 fish species collected from three fishing sites and a local fish market in Jeddah, Saudi Arabia. We tested the following null hypotheses: (1) there are no interspecific differences in metal levels, (2) there are no differences in metal levels in fishes between market and fishing sites, (3) there are no size-related differences in metal levels, and (4) there are no differences in selenium:mercury molar ratio among different fish species. There were significant interspecific differences in concentrations for all metals. There was an order of magnitude difference in the levels of aluminum, arsenic, mercury, manganese, and selenium, indicating wide variation in potential effects on the fish themselves and on their predators. Fishes from Area II, close to a large commercial port, had the highest levels of arsenic, mercury, and selenium, followed by market fishes. Mercury was positively correlated with body size in 6 of the 13 fish species examined. Mercury was correlated positively with arsenic and selenium, but negatively with aluminum, cobalt, copper, manganese, and zinc. Selenium:mercury molar ratios varied significantly among species, with Carangoides bajad, Cephalopholis argus, Variola louti, and Ephinephelus tauvina having ratios below 10:1. These findings can be used in risk assessments, design of mercury reduction plans, development of fish advisories to protect public health, and future management decision-making.

Cyanotoxin management and human health risk mitigation in recreational waters

The occurrence and severity of harmful cyanobacterial or blue-green algal blooms (HABs) have increased in recent decades, posing a serious threat of illness to humans. In some countries, water contaminated with cyanotoxins that is used for drinking or haemodialysis has posed a particularly serious risk. However, it is now recognized that recreational exposure to natural toxins by skin contact, accidental swallowing of water or inhalation can also cause a wide range of acute or chronic illnesses. In this review, we focus on the importance of cyanotoxin management in recreational waters. The symptoms related with HAB poisonings, the recommended safety concentrations limit for cyanobacteria and cyanotoxins in such waters, as well as early health hazard indicators of their presence and their monitoring are all discussed. We also present in this review an overview of the methods developed in recent decades for eliminating cyanobacteria and the toxic compounds that they produce.

The combined effects of urea application and simulated acid rain on soil acidification and microbial community structure

Our aim was to test the effects of simulated acid rain (SAR) at different pHs, when applied to fertilized and unfertilized soils, on the leaching of soil cations (K, Ca, Mg, Na) and Al. Their effects on soil pH, exchangeable H(+) and Al(3+) and microbial community structure were also determined. A Paleudalfs soil was incubated for 30 days, with and without an initial application of urea (200 mg N kg(-1)soil) as nitrogen (N) fertilizer. The soil was held in columns and leached with SAR at three pH levels. Six treatments were tested: SAR of pH 2.5, 4.0 and 5.6 leaching on unfertilized soil (T1, T2 and T3), and on soils fertilized with urea (T4, T5 and T6). Increasing acid inputs proportionally increased cation leaching in both unfertilized and fertilized soils. Urea application increased the initial Ca and Mg leaching, but had no effect on the total concentrations of Ca, Mg and K leached. There was no significant difference for the amount of Na leached between the different treatments. The SAR pH and urea application had significant effects on soil pH, exchangeable H(+) and Al(3+). Urea application, SAR treated with various pH, and the interactions between them all had significant impacts on total phospholipid fatty acids (PLFAs). The highest concentration of total PLFAs occurred in fertilized soils with SAR pH5.6 and the lowest in soils leached with the lowest SAR pH. Soils pretreated with urea then leached with SARs of pH 4.0 and 5.6 had larger total PLFA concentrations than soil without urea. Bacterial, fungal, actinomycete, Gram-negative and Gram-positive bacterial PLFAs had generally similar trends to total PLFAs.

Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia

The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant.

Assessment of metal status in drainage canal water and their bioaccumulation in Oreochromis niloticus fish in relation to human health

The purpose of this study was to assess metal concentrations (Al, Cd, Pb, Hg and Ni) in Sabal drainage canal (Al-Menoufiya Province, River Nile Delta, Egypt) water as well as their accumulation in some selected organs (skin, muscles and kidneys) of Oreochromis niloticus fish to evaluate their hazard levels in relation to the maximum residual limits for human consumption. Drainage canal water was found to be heavily polluted with metals which far exceeded the permissible limits. It was found that metals accumulated in organs of O. niloticus in concentrations higher than those of canal water. Kidneys of O. niloticus contained the highest concentrations of the detected metals, while skin appeared to be the least preferred site for the bioaccumulation of metals as the lowest metals concentrations were detected in this tissue. The present study shows that fish organs contained high levels of metals exceeding the permissible limits values. Metals in muscle of fish were higher than the maximum permissible concentrations for human consumption. Thus, consuming fish caught from drainage canals is harmful to the consumers.

Temporal scales and patterns of invertebrate biodiversity dynamics in boreal lakes recovering from acidification

Despite international policy implementation to reduce atmospheric acid deposition and restore natural resources from cultural acidification, evidence of ecological recovery is equivocal. Failure to meet recovery goals means that acidification still threatens biodiversity in many areas of the world. Managers thus need information to manage biodiversity, especially its components that are sensitive to stress (acid-sensitive taxa). We analyzed 20-year time series (1988-2007) of water quality and littoral invertebrates in acidified and circum-neutral lakes across Sweden to evaluate regional biodiversity dynamics and the extent to which changes in water quality affect these dynamics. We used multivariate time series modeling to (1) test how individual species groups within invertebrate communities track changes in the abiotic environment and (2) reveal congruencies of taxon contributions to species group change across lakes. Chemical recovery in the lakes was equivocal, and increases of pH and alkalinity were observed in subsets of acidified and circum-neutral lakes. Time series analyses revealed two different patterns of species groups for invertebrate communities across lakes; the first species group showed monotonic change over time, while the second group showed fluctuating temporal patterns. These independent species groups correlated distinctly with different sets of environmental variables. Recovery of pH and alkalinity status was associated with species group patterns only in a few lakes, highlighting an overall weak recovery of invertebrate species. The sets of species, including acid-sensitive taxa, composing these species groups differed markedly across lakes, highlighting context-specific responses of invertebrates to environmental variation. These results are encouraging because disparate local-scale dynamics maintain the diversity of sensitive invertebrate species on a regional scale, despite persisting acidification problems. Our study can inform and help refine current acidification-related policy focused on sensitive biodiversity elements.

Assessment of sacrificial anode impact by aluminum accumulation in mussel Mytilus edulis: a large-scale laboratory test

Since the early 1960s, the application of aluminum alloy sacrificial anodes to mitigate marine corrosion has been well known. The aim of this work was to study aluminum bioconcentration in Mytilus edulis by an in vitro test performed in two tanks: the first containing non-contaminated water (NCW) and the second containing aluminum-contaminated water (CW) (530 μg L(-1)) released by sacrificial anode. The mussels were collected and examined over a period of 8 weeks. A comparison between the aluminum concentrations in the digestive glands of mussels from the CW and NCW tanks shows that the highest value (1700 mg/kg d.w.) was found in the CW mussels collected after 13 days. In NCW, the mean aluminum concentration in digestive glands during the test was 281 mg/kg d.w. The rapid concentration decrease in digestive glands is probably due to the inhibition of filtering activity due to valve closure at the high concentration as well as the induction of the detoxification response.