Aquatic Receptors Research Articles

Potential Exposure of Aquatic Organisms to Dynamic Visual Cues Originating from Aerial Wind Turbine Blades

For many aquatic species, vision is important for detecting prey, predators, and conspecifics; however, the potential impacts of visual cues from offshore wind turbines have not been investigated in these crucial contexts. There is the possibility of visual cues, originating from moving wind turbine blades, propagating through the air–water interface to impact visually sensitive species. Two classes of visual cues are possible: direct motion cues originating as light reflected from moving turbine blades and indirect cues resulting from an interruption of direct sunlight causing dynamic shadowing when the sun, blade, and receptor are aligned. In both cases, the propagation of cues across the air–water interface is governed by physical principles but modulated in potentially complex ways by the aspects of the local environment that vary with time. Evidence for the extent of the exposure of aquatic organisms to the visual cues arising from moving turbine blades and for the potential response of receptor organisms is sparse. This study considers the physics involved to support the formulation and testing of robust biological hypotheses. Marine migratory salmonid species are considered as an example species because their behaviour in the marine environment is relatively well documented. This study concludes that the aquatic receptor organisms present in the uppermost layer of the sea in the vicinity of wind turbines are potentially exposed to direct motion cues originating from moving turbine blades and also, when the sun elevation angle is greater than ca. 20°, to dynamic shadowing cues.

Adsorption of Brilliant blue FCF (B1) and Allura Red (R40) colorants on cocoa shell: kinetics of the process

The use of dyes in food industrial processes is limited due to significant pollution in aquatic receptors from their wastewater. To address this issue, this study focused on evaluating the adsorption of dyes Allura Red (R40) and Brilliant blue FCF (B1) using cocoa shells (CS) as an absorbent. To achieve this, a pre-treatment was applied, which involved washing, grinding and drying at a temperature of 80 °C for 24 h, followed by a sieving process. The effect of the adsorbent dose was then analyzed and it was calculated that the optimal dose was 4 g/L. Additionally, the effect of contact time was studied through a kinetic analysis, all tests were carried out at a pH level of 2. The obtained data were fitted to kinetic models, which allowed us to conclude that the adsorption kinetics fit two different models depending on the initial solution conditions, in a range from 0 to 0.1512 mmol/L. Specifically, the Pseudo Second-Order (PSO) model fitted R40, while the Elovich model was appropriate for B1. In summary, CS was found to be a viable adsorbent for dyes in contaminated waters.

Complex mixture toxicology: Evaluation of toxicity to freshwater aquatic receptors from biodegradation metabolites in groundwater at a crude oil release site, recent analogous results from other authors, and implications for risk management

Aquatic toxicity posed by the complex mixture of biodegradation metabolites and related oxygen-containing organic compounds (OCOCs) in groundwater at typical petroleum release sites is of concern to regulatory agencies; several are using results from laboratory studies in older literature that are not appropriate analogs for risk management. Recent field studies from typical sites and natural groundwater should be utilized. In this study, OCOCs downgradient of the biodegrading crude oil release at the USGS Bemidji site were tested for freshwater aquatic toxicity using unaltered whole groundwater samples. This type of testing is optimal because the entire mixture of OCOCs present is tested directly and assessment is not affected by analytical limitations. Ceriodaphnia dubia and Pimephales promelas were tested for toxicity using USEPA Methods 1002 and 1000, which estimate chronic toxicity. OCOCs in representative samples up to the maximum concentration tested of 1710 ug/L Total Petroleum Hydrocarbons (TPH) (nC10 to nC40; without silica gel cleanup) did not result in effects relative to the lab control for C. dubia survival, or for P. promelas survival or growth; and did not result in effects above background for C. dubia reproduction. This is consistent with findings using the same testing methods and species on samples from 14 biodegrading fuel release sites: OCOCs did not cause increased toxicity relative to background at a maximum tested concentration of 1800 ug/L TPH (nC10 to nC28). Based on their toxicity testing using the same species and USEPA methods on groundwater from a biodegrading diesel release site, Washington Department of Ecology recently set a freshwater screening level for OCOCs at 3000 ug/L TPH (“Weathered DRO”). These studies indicate that, in the absence of dissolved hydrocarbons, OCOCs in groundwater from typical biodegrading fuel or crude oil releases are not toxic to C. dubia or P. promelas at typical concentrations.

Multi- and Trans-Generational Effects on Daphnia Magna of Chlorpyrifos Exposures.

Chlorpyrifos, a broad-spectrum neurotoxic organophosphate insecticide, is subject to atmospheric and hydrolytic transport from application sites to aquatic ecosystems. Across the landscape, concentrations in surface water can vary spatially and temporally according to seasonal use practices. Standardized bioassays can provide a screening-level understanding of aquatic receptor acute and chronic toxicity. However, these bioassays do not address ecologically relevant exposure patterns that may impact fitness and survival within and across generations. The aim of the present study was to evaluate the utility of a second-tier, screening-level methodology employing Daphnia magna multi- and transgenerational bioassays spanning four generations to investigate the effect of variable chronic chlorpyrifos exposure. The multigenerational assay consisted of continuous chlorpyrifos exposure across four consecutive 21-day bioassays using progeny from the previous assay for each successive generation. In the transgenerational assay, only the parent (F0) generation was exposed. For both assays, survival and reproduction were assessed across treatments and generations. Results indicated that (1) following continuous chlorpyrifos exposure at ecologically relevant concentrations to four generations of D. magna, the highest treatment showed an apparent tolerance response for both survival and reproductive success in the F3 generation, and (2) chlorpyrifos exposure to the F0 generation did not result in treatment effects in the unexposed F1, F2, and F3 generations in the apical endpoints of survival and reproduction. Employing a suite of acute and chronic bioassays, including chronic exposures spanning multiple generations, allows for a more robust screening-level evaluation of the potential impact of chlorpyrifos on aquatic receptors for variable periods of exposure. Environ Toxicol Chem 2022;41:1054-1065. © 2021 SETAC.

Toxicity inhibition strategy of microplastics to aquatic organisms through molecular docking, molecular dynamics simulation and molecular modification

In the present study, the combined toxic effect of microplastics and their additives (five) on aquatic organisms (zebrafish) was studied using full factorial design method, molecular docking, and molecular dynamics (MD) simulation technology. The aquatic toxicity control programmer was designed to improve the optimal combination of plasticizer and microplastics based on the design of environment-friendly phthalic acid ester (PAE) derivatives. First, a total of 64 groups of microplastic-additives were designed using the full factorial design method. Next, the microplastic-additives and aquatic receptor protein were docked together, and the binding energy of these complexes was calculated using the MD simulation method. The results revealed that the aquatic toxicity effects of different microplastic-additive combinations were variable; therefore, the optimal combination of microplastics exhibiting the lowest aquatic toxicity effect could be screened out. Base on the analyzing the bonding effect and surrounded amino acid residues between the microplastic additives and receptor protein, the main driving forces for the binding of the microplastic-additive and the protein were hydrophobic force, hydrogen bonding force and electrostatic force. The main effects and the second-order interaction of the microplastic-additives combination were analyzed using the fixed-effect model. The main additives that affect the aquatic toxicity of the microplastics can be known. In addition, based on the MD simulation of the molecular replacement of PAE derivatives, the optimal level of component combination of low aquatic toxicity effect of microplastics was constructed.

Modelling the attenuation of flowback chemicals for a soil-groundwater pathway from a hypothetical spill accident

Flowback water from shale gas operations contains formation-derived compounds, including trace metals, radionuclides, and organics. While accidental releases from storage tanks with flowback water are low-probability events if multiple containment barriers are put in place, they cannot be entirely excluded. Here the natural attenuation potential of deep unsaturated zones and groundwater was explored using predictive modelling involving a hypothetical leak from a storage tank. Actual chemical concentrations from flowback water at two shale gas wells with contrasting salinity (12,300 and 105,000 ppm TDS) in the Beetaloo Sub-basin (Northern Territory, Australia) served as input to the one-dimensional HYDRUS model for simulating chemical transport through the unsaturated zone, with groundwater at 50 and 100 m depth, respectively. Subsequent chemical transport in groundwater involved the use of a three-dimensional analytical transport model. For a total of 63 chemicals the long-term attenuation from dilution and dispersion in unsaturated sediments and groundwater was calculated. Predicted environmental concentrations for aquatic receptors were compared with no-effect levels of individual chemicals to derive risk quotients (RQ) and identify chemicals of no concern to ecosystem health (i.e. RQ <1). Except for salinity and radium-228 in one of the two wells, RQ < 1 for all other chemicals. The initial approach considered testing of toxicity to individual chemicals only. When direct toxicity assessments (DTAs) were used to account for effects of chemical mixtures, the required DTA-derived safe dilution factor for 95% species protection was 1.8 to 2.5 times higher than the dilution factor accounting for dispersion and dilution only. Accounting for biodegradation, sorption and radioactive decay decreased chemical concentrations in unsaturated sediments to safe levels using the DTA for all chemicals. The study highlighted the importance of incorporating DTA in chemical risk assessments involving complex chemical mixtures. Improved understanding of fate and transport of flowback chemicals will help effectively manage water-quality risks associated with shale gas extraction.

Neurotoxicity of chlorpyrifos and chlorpyrifos-oxon to Daphnia magna

Chlorpyrifos (CPF) is a widely used broad-spectrum organophosphate insecticide. CPF elicits neurotoxic effects in exposed organisms by inhibiting the activity of acetylcholinesterase enzymes (AChE), which prolongs nerve transmission and results in neurotoxic symptoms and death at high doses. While CPF is capable of eliciting neurotoxic effects, chlorpyrifos-oxon (CPFO) is the primary neurotoxicant agent. Aquatic organisms bioactivate CPF to CPFO through the Cytochrome P450 phase I metabolic pathway following exposure to CPF. Additionally, in the environment, CPF transforms to CPFO, primarily through photo-oxidation. As both compounds can be transported in air and water to aquatic ecosystems, there is the potential for exposure to non-target organisms. The potential for adverse impacts on aquatic receptors depends on patterns of exposure and toxicity of individual compounds and the mixture. To study the neurotoxicity of these compounds, a 48 h acute and 21 d chronic Daphnia magna bioassay was conducted independently with CPF and CPFO. Acute bioassay results show a median lethal concentration (LC50) of 0.76 μg L-1 for CPF and 0.32 μg L-1 for CPFO, suggesting that CPFO is 2.4 times more acutely toxic to D. magna. Acute assay results were also used to derive Benchmark Dose Levels of 0.58 μg L-1 for CPF and 0.25 μg L-1 for CPFO. However, neither compound elicited an effect on reproduction or growth at relevant chronic exposures. As D. magna are a small and relatively sensitive species, and the AChE inhibition adverse outcome pathway is highly conserved, these results may be cautiously extrapolated in assessing adverse impacts on aquatic receptors.1

Techno-economic analysis of olive wastewater treatment with a closed water approach by integrated membrane processes and advanced oxidation processes

Abstract In this paper, a reliable treatment process for olive mill wastewaters (OMWW) is proposed. In order to develop a more sustainable process with polyphenols recovery and water reuse, two treatment schemes have been simulated by using a process simulator (SuperPro Designer®), depending on wastewater characteristics; the first applied for ‘biological’ effluents by using membrane technology (microfiltration MF, ultrafiltration UF, nanofiltration NF and reverse osmosis RO), the second for wastewaters containing pesticides, in which RO is replaced with an advanced oxidation process for pesticide degradation. The results of the process analysis showed that the final permeate is a treated water suitable for both disposal in aquatic receptors and for civil or agriculture reuse. Moreover, the results of a techno-economic analysis of the proposed processes is presented, carried out by means of a life cycle cost analysis, considering the mass and energy balances obtained from process analysis. The analysis showed that the first scenario is more economically feasible. In detail, the treatment cost (€/m3 of OMWW) was 253 and 292 €/m3 for the first and second case study, respectively. However, the second process scheme result is inappropriate if the wastewater to be treated does not come from biological olive processing.

Human and Aquatic Toxicity Potential of Petroleum Biodegradation Metabolite Mixtures in Groundwater from Fuel Release Sites.

The potential toxicity to human and aquatic receptors of petroleum fuel biodegradation metabolites (oxygen‐containing organic compounds [OCOCs]) in groundwater has been investigated as part of a multi‐year research program. Whole mixtures collected from locations upgradient and downgradient of multiple fuel release sites were tested using: 1) in vitro screening assays for human genotoxicity (the gamma‐H2AX assay) and estrogenic effects (estrogen receptor transcriptional activation assay), and 2) chronic aquatic toxicity tests in 3 species (Ceriodaphnia dubia, Raphidocelis subcapitata, and Pimephales promelas). In vitro screening assay results demonstrated that the mixtures did not cause genotoxic or estrogenic effects. No OCOC‐related aquatic toxicity was observed and when aquatic toxicity did occur, upgradient samples typically had the same response as samples downgradient of the release, indicating that background water quality was impacting the results. This information provides additional support for previous work that focused on the individual compounds and, taken together, indicates that OCOCs from petroleum degradation at fuel release sites are unlikely to cause toxicity to human or freshwater receptors at the concentrations present. Environ Toxicol Chem 2020;39:1634–1645. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Innovative Contaminant Mass Flux Monitoring in an Aquifer Subject to Tidal Effects

AbstractExposure from groundwater contamination to aquatic receptors residing in receiving surface water is dependent upon the rate of contaminated groundwater discharge. Characterization of groundwater fluxes is challenging, especially in coastal environments where tidal fluctuations result in transient groundwater flows towards these receptors. This can also be further complicated by the high spatial heterogeneity of subsurface deposits enhanced by anthropogenic influences such as the mixing of natural sediments and backfill materials, the presence of subsurface built structures such as sheet pile walls or even occurrence of other sources of contaminant discharge. In this study, the finite volume point dilution method (FVPDM) was successfully used to characterize highly transient groundwater flows and contaminant mass fluxes within a coastal groundwater flow system influenced by marked tides. FVPDM tests were undertaken continuously for more than 48 h at six groundwater monitoring wells, in order to evaluate groundwater flow dynamics during several tide cycles. Contaminant concentrations were measured simultaneously which allowed calculating contaminant mass fluxes. The study highlighted the importance of the aquifer heterogeneity, with groundwater fluxes ranging from 10−7 to 10−3 m/s. Groundwater flux monitoring enabled a significant refinement of the conceptual site model, including the fact that inversion of groundwater fluxes was not observed at high tide. Results indicated that contaminant mass fluxes were particularly higher at a specific monitoring well, by more than three orders of magnitude, than at other wells of the investigated aquifer. This study provided crucial information for optimizing further field investigations and risk mitigation measures.

Manipulating redox conditions to enhance in situ bioremediation of RDX in groundwater at a contaminated site

Surficial application of waste glycerol (WG) for enhanced bioremediation was tested in situ at an old military range site to address hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated groundwater. This treatment was effective in inducing strong reducing conditions (range: −4 to −205 mV) and increasing the concentrations of organic carbon (from 10 to 729 mg/L) and fatty acids (from 0 to 940 mg/L) concomitantly with a decrease in RDX concentrations (range: 17 to 143 μg/L) to below detection limits (0.1 μg/L) in 2 of the 3 monitoring wells (MWs) evaluated. None of these changes were observed in the control MW. RDX disappeared without the detection of any common anaerobic nitroso degradation intermediates, with the exception of one MW where the concentration of organics did not significantly increase (range: 10 to 20 mg/L), suggesting the conditions were not favourable for biodegradation. Ecotoxicological analysis suggested that the use of WG may have some dose-related deleterious effects on different soil and aquatic receptors. Analysis of the microbial community composition, using 16S rRNA gene amplicon sequences, which provided insight into whether the process design had selected for and stimulated the optimal microbial populations, indicated co-existence of numerous Operational Taxonomic Units (OTUs) belonging to groups known to be capable of RDX degradation under anaerobic conditions, with a positive link between Geobacter spp. enrichment and the presence of RDX nitroso metabolites. Overall, the results from this field test show that this treatment process can provide an effective long-term, semi-passive remediation option for RDX contaminated groundwater.

Use of multiple lines of evidence to provide a realistic toxic substances control act ecological risk evaluation based on monitoring data: D4 case study

D4 (octamethylcyclotetrasiloxane) is a high-production-volume cyclic volatile methyl siloxane with a wide range of industrial and consumer applications. This study conducted a robust ecological risk evaluation for D4 using exposure data collected under a nation-wide environmental monitoring program facilitated under the Toxic Substances Control Act (TSCA). This ecological risk evaluation was conducted consistent with the principles outlined in the U.S. Environmental Protection Agency's (EPA's) Guidance to Assist Interested Persons in Developing and Submitting Draft Risk Evaluations under TSCA (U.S. EPA 2017a). The evaluation examined multiple lines of evidence (LoEs) to determine the potential risks from D4 to aquatic receptors in rivers and streams in the United States from municipal wastewater treatment plant (WWTP) discharges and discharges from manufacturing, processing, and/or formulating (MPF) facilities after onsite wastewater treatment. The LoEs consisted of comparing D4 concentrations measured in water and sediment to toxicity thresholds derived from laboratory studies; comparing D4 concentrations measured in biota tissue to critical target lipid body burdens (CTLBBs); comparing fugacity-based chemical activities between toxicity thresholds and measured environmental concentrations; and assessing benthic macroinvertebrate community structure and habitat suitability. The approach taken moves beyond a standard deterministic hazard quotient approach to incorporate more advanced methods for risk prediction, using distributions rather than conservative point estimates of exposure to obtain a realistic view of the probability of harm, consistent with EPA's stated intent to “strive to utilize probabilistic approaches for exposure assessments included in a risk evaluation” (U.S. EPA 2017b). The risk evaluation concluded there is negligible risk to water column and sediment receptors from D4 discharged from MPF facilities after onsite wastewater treatment or from municipal WWTPs that may treat a mix of industrial and consumer wastewater.

Decentralized wastewater treatment systems: Efficiency and its estimated impact against onsite natural water pollution status. A Romanian case study

Abstract The paper proposes discussions of some concrete datasets resulted for three solutions of wastewaters management systems applied in case of a Romanian petroleum chemical company. These management options, differing especially in type (centralized or decentralized system) and wastewaters treatment system, were emphasized, mainly by real datasets on treatment performance, polluting species removals, risk of some residuals in treated effluents and natural watercourse nearby, but also environmental impact assessment, using the alternative methodology of global pollution index (I*GP). Interpreting datasets based on in-time analyzed physical-chemical quality indicators and river characteristics, it was estimated the standard quality classification of receiving watercourse as ‘medium’ (water quality indices, WQI = 55.58 − 67.47), affected more or less by treated effluents discharged in it. The environmental risks of some selected residuals in treated effluents and natural aquatic receptor were assessed by the risk quotient (RQ) which appreciated the risk of residuals toward aquatic life as no to low-medium level, with few exceptions. The impact assessment results conclude an admissible pollution status of natural water receptor due to company wastewaters mechanical–chemical–biological treatment plant activities, in decentralized (I*GP = 1.73) and centralized (I*GP = 1.83) system, but generating discomfort effects to aquatic life due to only mechanical–chemical treatment plant operating in decentralized system (I*GP = 2.205). Direct discharge of un-treated industrial wastewaters had been interdicted. These real results underline that decentralized systems are reliable, qualitatively efficient and costly effective, offering long-term solution, and that all wastewaters management strategies of petroleum chemical company had been adapted to specific on-site functioning situations.

ENVIRONMENTAL SYSTEM ENGINEERING (ESE): MODELING AND OPTIMIZATION OF A TEXTILE EFFLUENT DISCOLORATION PROCESS BY SORPTION

&lt;p&gt;Nowadays, an interdisciplinary field of engineering that focuses on analytical and/or empirical models represented by mathematical, data-driven and biotic structures combined with physical, biological and ecological processes in water, air and eco-systems is developing, &lt;em&gt;i.e.&lt;/em&gt; environmental system engineering (ESE). In this system, environmental modeling and process optimization acts together for solving problems with environmental systems, especially for minimizing pollution, or eco-toxicological effects.&lt;/p&gt;&lt;p&gt;The present paper proposes the study of modeling and optimization of an environmental system (&lt;em&gt;i.e&lt;/em&gt;. textile wastewater treatment system based on sorption onto indigene peat) for its discoloration (consequently, decreasing of color, organic and inorganic loads of effluent discharged in aquatic receptor, or inside reused). All performed laboratory tests consisted in 22 hours-sorption experiments onto peat applied for a real colored textile effluent, organized with respecting of an empirical planning by a central active composite rotatable 2&lt;sup&gt;3&lt;/sup&gt; order design, considering as independent variables the peat dose (X&lt;sub&gt;1&lt;/sub&gt;), pH (X&lt;sub&gt;2&lt;/sub&gt;), and temperature (X&lt;sub&gt;3&lt;/sub&gt;), and as optimization criterion, or decision function, the discoloration degree, or color removal (Y, [%]). The mathematical model was found adequate for the textile wastewater treatment, and the optimal operational conditions for highest discoloration efficiency were proposed.&lt;/p&gt;

The influence of bedrock hydrogeology on catchment-scale nitrate fate and transport in fractured aquifers

Characterising catchment scale biogeochemical processes controlling nitrate fate in groundwater constitutes a fundamental consideration when applying programmes of measures to reduce risks posed by diffuse agricultural pollutants to water quality. Combining hydrochemical analyses with nitrate isotopic data and physical hydrogeological measurements permitted characterisation of biogeochemical processes influencing nitrogen fate and transport in the groundwater in two fractured bedrock aquifers with contrasting hydrogeology but comparable nutrient loads. Hydrochemical and isotopic analyses of groundwater samples collected from moderately fractured, diffusely karstified limestone indicated nitrification controlled dissolved nitrogen fate and delivery to aquatic receptors. By contrast nitrate concentrations in groundwater were considerably lower in a low transmissivity highly lithified sandstone and pyrite-bearing shale unit with patchy subsoil cover. Geophysical and hydrochemical investigations showed shallower intervals contained hydraulically active fractures where denitrification was reflected through lower nitrogen levels and an isotopic enrichment ratio of 1.7 between δ15N and δ18O. Study findings highlight the influence of bedrock hydrogeological conditions on aqueous nitrogen mobility. Investigation results demonstrate that bedrock conditions need to be considered when implementing catchment management plans to reduce the impact of agricultural practices on the quality of groundwater and baseflow in receiving rivers.Nitrate isotopic signatures in the groundwater of a freely draining catchment underlain by a karstified aquifer and a poorly draining aquifer with a low transmissivity aquifer.

Occurrence, environmental impacts and removal of legacy and emerging contaminants from two wastewater and one water treatment plant in Southern Ontario. Part II: environmental impacts

This is part two of a paper about the potential environmental impacts of treated effluent from a wastewater treatment plant (WWTP) discharging to the Detroit River in Windsor, Ontario, Canada. The WWTP uses conventional activated sludge with nitrification. The assessment was conducted over six months using a variety of established tests, including in vitro cell-based screening assays, as well as acute, chronic and full-life cycle in vivo exposures. Effluent monitoring included pharmaceutically active compounds and endocrine disrupting compounds. No tests reported significant toxicity. However, enhanced algal growth was observed in a Pseudokerchneriella subcapitata growth inhibition test. In full life-cycle fathead minnow exposure, liver-somatic index changes were noted in exposed fish – increases for males, decreases for females – and production of viable fry decreased. Neither alteration is thought biologically significant. Because the effluent is diluted substantially by the receiving water, the level of risk posed to aquatic receptors and the environment is probably negligible.

Spatial and temporal trends in contaminant concentrations in Hexagenia nymphs following a coal ash spill at the Tennessee Valley Authority's Kingston Fossil Plant.

A dike failure at the Tennessee Valley Authority Kingston Fossil Plant in East Tennessee, United States, in December 2008, released approximately 4.1 million m(3) of coal ash into the Emory River. From 2009 through 2012, samples of mayfly nymphs (Hexagenia bilineata) were collected each spring from sites in the Emory, Clinch, and Tennessee Rivers upstream and downstream of the spill. Samples were analyzed for 17 metals. Concentrations of metals were generally highest the first 2 miles downstream of the spill, and then decreased with increasing distance from the spill. Arsenic, B, Ba, Be, Mo, Sb, Se, Sr, and V appeared to have strong ash signatures, whereas Co, Cr, Cu, Ni, and Pb appeared to be associated with ash and other sources. However, the concentrations for most of these contaminants were modest and are unlikely to cause widespread negative ecological effects. Trends in Hg, Cd, and Zn suggested little (Hg) or no (Cd, Zn) association with ash. Temporal trends suggested that concentrations of ash-related contaminants began to subside after 2010, but because of the limited time period of that analysis (4 yr), further monitoring is needed to verify this trend. The present study provides important information on the magnitude of contaminant exposure to aquatic receptors from a major coal ash spill, as well as spatial and temporal trends for transport of the associated contaminants in a large open watershed.

ENVIRONMENTAL SYSTEM ENGINEERING (ESE): MODELING AND OPTIMIZATION OF A TEXTILE EFFLUENT DISCOLORATION PROCESS BY SORPTION

Nowadays, an interdisciplinary field of engineering that focuses on analytical and/or empirical models represented by mathematical, data-driven and biotic structures combined with physical, biological and ecological processes in water, air and eco-systems is developing, i.e. environmental system engineering (ESE). In this system, environmental modeling and process optimization acts together for solving problems with environmental systems, especially for minimizing pollution, or eco-toxicological effects. The present paper proposes the study of modeling and optimization of an environmental system (i.e. textile wastewater treatment system based on sorption onto indigene peat) for its discoloration (consequently, decreasing of color, organic and inorganic loads of effluent discharged in aquatic receptor, or inside reused). All performed laboratory tests consisted in 22 hours-sorption experiments onto peat applied for a real colored textile effluent, organized with respecting of an empirical planning by a central active composite rotatable 23 order design, considering as independent variables the peat dose (X1), pH (X2), and temperature (X3), and as optimization criterion, or decision function, the discoloration degree, or color removal (Y, [%]). The mathematical model was found adequate for the textile wastewater treatment, and the optimal operational conditions for highest discoloration efficiency were proposed.

Scientific Symposium “Small Solution for Big Water-Related Problems: Innovative Microarrays and Small Sensors to Cope with Water Quality and Food Security”

This issue presents the conclusive results of two European Commission funded Projects, namely Universal Microarrays for the Evaluation of Fresh-water Quality Based on Detection of Pathogens and their Toxins (MicroAQUA) and Rationally Designed Aquatic Receptors (RADAR). These projects focused their activities on the quality of drinking water as an extremely important factor for public health of humans and animals. The MicroAQUA Project aimed at developing a universal microarray chip for the detection of various pathogens (cyanobacteria, bacteria, viruses and parasitic protozoa) and their toxins in waters. In addition, the project included the detection of select species of diatoms, which represent reliable bio-indicators to assess overall water quality. Large numbers of compounds are released into the environment; some of these are toxins such as endocrine disrupting compounds (EDCs) and can affect the endocrine, immune and nervous systems of a wide range of animals causing alterations such as reproductive disorders and cancer. Detection of these contaminants in water systems is important to protect sensitive environmental sites and reduce the risk of toxins entering the food chain. A modular platform for monitoring toxins in water and food production facilities, using biosensors derived from aquatic organisms, was the main goal of RADAR Project.

Using microbiological tracers to assess the impact of winter land use restrictions on the quality of stream headwaters in a small catchment

Diverse land use activities can elevate risk of microbiological contamination entering stream headwaters. Spatially distributed water quality monitoring carried out across a 17km2 agricultural catchment aimed to characterize microbiological contamination reaching surface water and investigate whether winter agricultural land use restrictions proved effective in addressing water quality degradation. Combined flow and concentration data revealed no significant difference in fecal indicator organism (FIO) fluxes in base flow samples collected during the open and prohibited periods for spreading organic fertilizer, while relative concentrations of Escherichia coli, fecal streptococci and sulfite reducing bacteria indicated consistently fresh fecal pollution reached aquatic receptors during both periods. Microbial source tracking, employing Bacteroides 16S rRNA gene markers, demonstrated a dominance of bovine fecal waste in river water samples upstream of a wastewater treatment plant discharge during open periods. This contrasted with responses during prohibited periods where human-derived signatures dominated. Differences in microbiological signature, when viewed with hydrological data, suggested that increasing groundwater levels restricted vertical infiltration of effluent from on-site wastewater treatment systems and diverted it to drains and surface water. Study results reflect seasonality of contaminant inputs, while suggesting winter land use restrictions can be effective in limiting impacts of agricultural wastes to base flow water quality.