Laboratory-scale evaluation of algaecide effectiveness for control of microcystin-producing cyanobacteria from Lake Okeechobee, Florida (USA).

Growth of microcystin-producing cyanobacteria in Lake Okeechobee (Florida, USA) and surrounding waters has resulted in adverse health impacts for humans and endangered species, as well as significant economic losses. As these issues worsen, there is growing pressure for efficacious solutions to rapidly mitigate harmful algal blooms (HABs) and protect critical freshwater resources. Applications of USEPA-registered algaecides as management tactics meet many decision-making criteria often required by water resource managers (e.

Relationship among aqueous copper half-lives and responses of Pimephales promelas to a series of copper sulfate pentahydrate concentrations.

Copper algaecide exposures in situ are often of shorter duration than exposures for static toxicity experiments because aqueous concentrations in situ dissipate as a function of site-specific fate processes. Consequently, responses of organisms to static copper exposures may overestimate effects following in situ exposures. To understand the role of exposure duration for altering responses, Pimephales promelas survival was compared following static (96 h) and pulse (1.

Cell density dependence of Microcystis aeruginosa responses to copper algaecide concentrations: Implications for microcystin-LR release.

Along with mechanistic models, predictions of exposure-response relationships for copper are often derived from laboratory toxicity experiments with standardized experimental exposures and conditions. For predictions of copper toxicity to algae, cell density is a critical factor often overlooked. For pulse exposures of copper-based algaecides in aquatic systems, cell density can significantly influence copper sorbed by the algal population, and consequent responses.

Influence of CuSO and chelated copper algaecide exposures on biodegradation of microcystin-LR.

Copper exposures from algaecide applications in aquatic systems are hypothesized to impede bacterial degradation of microcystin (MC), a cyanobacterial produced hepatotoxin. Despite regulatory implications of this hypothesis, limited data exist on influences of copper-exposures on MC-degrading bacteria and consequent MC-degradation. In this study, influences of copper-algaecide concentrations and formulations on bacterial composition and microcystin-LR (MCLR) degradation were investigated.

A risk-based approach for identifying constituents of concern in oil sands process-affected water from the Athabasca Oil Sands region.

Mining leases in the Athabasca Oil Sands (AOS) region produce large volumes of oil sands process-affected water (OSPW) containing constituents that limit beneficial uses and discharge into receiving systems. The aim of this research is to identify constituents of concern (COCs) in OSPW sourced from an active settling basin with the goal of providing a sound rational for developing mitigation strategies for using constructed treatment wetlands for COCs contained in OSPW. COCs were identified through several lines of evidence: 1) chemical and physical characterization of OSPW and comparisons with numeric water quality guidelines and toxicity endpoints, 2) measuring toxicity of OSPW using a taxonomic range of sentinel organisms (i.

Influence of commercial (Fluka) naphthenic acids on acid volatile sulfide (AVS) production and divalent metal precipitation.

Energy-derived waters containing naphthenic acids (NAs) are complex mixtures often comprising a suite of potentially problematic constituents (e.g. organics, metals, and metalloids) that need treatment prior to beneficial use, including release to receiving aquatic systems.

Effects of environmental conditions on aerobic degradation of a commercial naphthenic acid.

Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation.

Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP.

Comparative responses of freshwater organisms to exposures of a commercial naphthenic acid.

Comparative toxicity studies using unconfounded exposures can prioritize the selection of sensitive sentinel test species and refine methods for evaluating ecological risks of complex mixtures like naphthenic acids (NAs), a group of organic acids associated with crude oils and energy-derived waters that have been a source of aquatic toxicity. The objectives of this study were to compare responses of freshwater aquatic organisms (vertebrate, invertebrates, and a macrophyte; in terms of acute toxicity) to Fluka commercial NAs and to compare measured toxicity data with peer-reviewed toxicity data for other commercial NA sources and energy-derived NA sources. Exposures were confirmed using high performance liquid chromatography.

Cellular and aqueous microcystin-LR following laboratory exposures of Microcystis aeruginosa to copper algaecides.

Microcystin release from algal cells influences use of copper-algaecides in water resources. Accurate data regarding relationships between copper-algaecide exposures and responses of microcystin-producing algae are needed to make informed management decisions. Responses of Microcystis aeruginosa were measured in terms of cellular microcystin-LR (MC-LR), aqueous MC-LR, and chlorophyll-a following exposure to CuSO4 and copper-ethanolamine.

Responses of Lyngbya wollei to algaecide exposures and a risk characterization associated with their use.

To make informed decisions regarding management of noxious algal growths, water resource managers require information on responses of target and non-target species to algaecide exposures. Periodic treatments of Phycomycin®-SCP (sodium carbonate peroxyhydrate) followed by Algimycin®-PWF (gluconate and citrate chelated copper) to control Lyngbya wollei growths for ten years provided an opportunity for a risk evaluation of treated coves in Lay Lake, AL. Abiotic sediment characteristics (acid soluble copper concentrations, acid volatile sulfides, percent organic matter and cation exchange capacity) and survival of Hyalella azteca and Chironomus dilutus were measured in sediment samples from treated and untreated coves to assess the bioavailability of potential copper-residuals.

Evaluation of the utility of six measures for algal (Microcystis aeruginosa, Planktothrix agardhii and Pseudokirchneriella subcapitata) viability.

Standard algal toxicity tests are used to discern responses of algae to a variety of exposures including pesticides, personal care products and complex mixtures such as runoff and effluents. There are concerns regarding the accuracy, precision and utility of algal viability measures used as endpoints in algal toxicity test protocols. To definitively evaluate six algal viability measures, algae were heat-treated to produce known live:dead cell ratios.

Effects of simulated oilfield produced water on early seedling growth after treatment in a pilot-scale constructed wetland system.

Seed germination and early seedling growth bioassays were used to evaluate phytotoxicity of simulated oilfield produced water (OPW) before and after treatment in a subsurface-flow, pilot-scale constructed wetland treatment system (CWTS). Responses to untreated and treated OPW were compared among seven plant species, including three monocotyledons: corn (Zea mays), millet (Panicum miliaceum), and sorghum (Sorghum bicolor); and four dicotyledons: lettuce (Lactuca sativa), okra (Abelmoschus esculents), watermelon (Citrullus lanatus), and soybean (Glycine max). Phytotoxicity was greater in untreated OPW than in treated OPW.

Role of sediments in modifying the toxicity of two Roundup formulations to six species of larval anurans.

The role of sediment in modifying the toxicity of the original formulation of Roundup® and Roundup WeatherMAX® was examined in aqueous laboratory tests. Six species of anurans (Bufo fowleri, Hyla chrysoscelis, Rana catesbeiana, Rana clamitans, Rana sphenocephala, and Rana pipiens) were exposed at Gosner stage 25 to concentrations of the 2 herbicide formulations in 96-h, static, nonrenewal experiments in the presence and absence of sediment. All species tested had lower median lethal concentration values in water-only exposures of both formulations compared with exposures with sediment.

Treatment of oil and grease in produced water by a pilot-scale constructed wetland system using biogeochemical processes.

Constructed wetland treatment systems (CWTSs) can effectively remove many constituents that limit beneficial use of oilfield produced water. The objectives of this investigation were: (1) to assess the effect of mass loadings of oil and grease (O & G) on treatment performance in pilot-scale subsurface flow and free water surface CWTS series having sequential reducing and oxidizing cells, and (2) to evaluate effects on treatment performance of adding a pilot-scale oil-water separator. Increase in O & G mass loading from 5 to 20 mg min(-1) caused decreases in both dissolved oxygen concentration and sediment redox potential, which affected treatment performance.

Comparative toxicity of two glyphosate formulations (original formulation of Roundup® and Roundup WeatherMAX®) to six North American larval anurans.

The toxicity of two glyphosate formulations (the original formulation of Roundup® and Roundup WeatherMAX®) to six species of North American larval anurans was evaluated by using 96-h static, nonrenewal aqueous exposures. The 96-h median lethal concentration values (LC50) ranged from 1.80 to 4.

Responses of Lyngbya magnifica Gardner to an algaecide exposure in the laboratory and field.

Predicting responses of organisms exposed to toxic materials in the field from results produced in laboratory studies and confirming those predictions has been a central question in aquatic toxicology since its inception. A field treatment of a cyanobacterium and laboratory measurements of responses to algaecide exposures provided an opportunity to address that question. This research involved predicting the response of Lyngbya magnifica to an algaecide exposure (Phycomycin SCP) in the laboratory and evaluating that prediction with a comparable exposure in the field.

A risk assessment approach to identifying constituents in oilfield produced water for treatment prior to beneficial use.

A risk assessment approach incorporating exposure pathways and calculated risk quotients was applied to identifying constituents requiring treatment prior to beneficial use of oilfield produced water (OPW). In this study, risk quotients are ratios of constituent concentrations in soil or water to guideline concentrations for no adverse effects to receptors. The risk assessment approach is illustrated by an example of an oilfield water produced from non-marine geologic strata of a rift basin in sub-Saharan Africa.

Campus parking lot stormwater runoff: physicochemical analyses and toxicity tests using Ceriodaphnia dubia and Pimephales promelas.

Campus parking lot stormwater (CPLSW) runoff can mobilize a variety of constituents from vehicular and atmospheric deposition that may pose risks to receiving aquatic systems. The objective of this study was to characterize CPLSW and to discern potential constituents of concern that may affect aquatic biota in receiving systems. Characterization of CPLSW included analyses of metals, oil and grease, and general water chemistry.

Performance of a pilot-scale constructed wetland system for treating simulated ash basin water.

A pilot-scale constructed wetland treatment system (CWTS) was designed and built to decrease the concentration and toxicity of constituents of concern in ash basin water from coal-burning power plants. The CWTS was designed to promote the following treatment processes for metals and metalloids: precipitation as non-bioavailable sulfides, co-precipitation with iron oxyhydroxides, and adsorption onto iron oxides. Concentrations of Zn, Cr, Hg, As, and Se in simulated ash basin water were reduced by the CWTS to less than USEPA-recommended water quality criteria.

Spatial and temporal patterns of periphyton chlorophyll a related to pulp and paper mill discharges in four US receiving streams.

Nutrients in pulp and paper mill effluent (PPME) have been implicated in increased periphyton chlorophyll a (chl a) downstream of discharges. These findings are largely based on short-term studies conducted in artificial stream channels or mesocosms and often in oligotrophic systems, and it is unclear if long-term chl a patterns in higher-nutrient systems would show similar response. We conducted a long-term study of 4 receiving waters (Codorus Creek, Pennsylvania; the Leaf River, Mississippi; and the McKenzie and Willamette rivers, Oregon) in which periphyton samples and associated data on water quality (nitrogen and phosphorus concentrations, pH, color, and conductivity) and 2 physical habitat variables (depth and current velocity) were collected over an 8-y period from multiple sites upstream and downstream of PPME discharges.

A long-term, multitrophic level study to assess pulp and paper mill effluent effects on aquatic communities in four US receiving waters: lessons learned.

Lessons learned from the development, implementation, and initial 8 y of study findings from a long-term study to assess the effects of pulp and paper mill effluents on receiving waters are summarized as a conclusion to a series of articles (this issue) on study findings. The study, based on industry-defined information needs, was developed via a science-based experimental design into a long-term (>10 y) watershed-scale monitoring program that integrated in-stream population/ community assessment, laboratory chronic bioassays, and fathead minnow full life-cycle assays as well as water quality and effluent quality monitoring and habitat assessment in addressing the presence of effluent effects. The 4 study streams (Codorus Creek, PA; Leaf River, MS; and the McKenzie and Willamette rivers, OR) represented both bleached and unbleached kraft mill processes and effluent concentrations that ranged from near typical for the United States (0.

A long-term, multitrophic level study to assess pulp and paper mill effluent effects on aquatic communities in four US receiving waters: background and status.

An industry-funded, long-term, receiving water study was initiated in 1998/1999 to adress questions about the potential effects of pulp and paper mill effluent discharges on US receiving waters. Although the study continues, the knowledge gained to date provides an opportunity to reflect on the study development process, its progress, and its outcomes. As a backdrop to a series of articles in this special issue describing study results, this article describes the process by which study information objectives were identified as well as the process by which the experimental design was developed.

Influence of contact duration on sediment-associated copper fractionation and bioavailability.

Frequent utilization of copper formulations as aquatic herbicides and algaecides can lead to potentially elevated sediment-copper concentrations. This research investigated relationships between copper fractionation (through sequential extractions) and bioavailability in three reservoir sediments over a 60d contact duration. Copper was initially associated with exchangeable, carbonate, and oxidizable fractions for copper-amended sediments; and redistributed to the reducible and oxidizable fractions after 60d.