Advances in drilling techniques have facilitated a rapid increase in hydrocarbon extraction from energy shales, including the Williston Basin in central North America. This area overlaps with the Prairie Pothole Region, a region densely populated with wetlands that provide numerous ecosystem services. Historical (legacy) disposal practices often released saline co-produced waters (brines) with high chloride concentrations, affecting wetland water quality directly or persisting in sediments. Despite the potential threat of brine contamination to aquatic habitats, there has been little research into its ecological effects. We capitalized on a gradient of legacy brine-contaminated wetlands in northeast Montana to conduct laboratory experiments to assess variation in survival of larval Boreal Chorus Frogs (Pseudacris maculata) reared on sediments from 3 local wetlands and a control source. To help provide environmental context for the experiment, we also measured chloride concentrations in 6 brine-contaminated wetlands in our study area, including the 2 contaminated sites used for sediment exposures. Survival of frog larvae during 46- and 55-day experiments differed by up to 88% among sediment sources (Site Model) and was negatively correlated with potential chloride exposure (Chloride Model). Five of the 6 contaminated wetlands exceeded the U.S. EPA acute benchmark for chloride in freshwater (860 mg/L) and all exceeded the chronic benchmark (230 mg/L). However, the Wetland Site model explained more variation in survival than the Chloride Model, suggesting that chloride concentration alone does not fully reflect the threat of contamination to aquatic species. Because the profiles of brine-contaminated sediments are complex, further surveys and experiments are needed across a broad range of conditions, especially where restoration or remediation actions have reduced brine-contamination. Information provided by this study can help quantify potential ecological threats and help land managers prioritize conservation strategies as part of responsible and sustainable energy development.

The increasing discharge of pharmaceuticals and personal care products (PPCPs) into the environment has generated serious public concern. The recent awareness of the environmental impact of this emerging class of pollutants and their potential adverse effects on human health have been documented in many reports. However, information regarding uptake and intracellular distribution of PPCPs in hydrophytes under hydroponic conditions, and potential human exposure is very limited. A laboratory experiment was conducted using ¹⁴C-labeled triclosan (TCS) to investigate uptake and distribution of TCS in six aquatic plants (water spinach, purple perilla, cress, penny grass, cane shoot, and rice), and the subcellular distribution of ¹⁴C-TCS was determined in these plants. The results showed that the uptake and removal rate of TCS from nutrient solution by hydrophytes followed the order of cress (96%) > water spinach (94%) > penny grass (87%) > cane shoot (84%) > purple perilla (78%) > rice (63%) at the end of incubation period (192 h). The range of ¹⁴C-TCS content in the roots was 94.3%–99.0% of the added ¹⁴C-TCS, and the concentrations in roots were 2–3 orders of magnitude greater than those in shoots. Furthermore, the subcellular fraction-concentration factor (3.6 × 10²–2.6 × 10³ mL g⁻¹), concentration (0.58–4.47 μg g⁻¹), and percentage (30%–61%) of ¹⁴C-TCS in organelles were found predominantly greater than those in cell walls and/or cytoplasm. These results indicate that for these plants, the roots are the primary storage for TCS, and within plant cells organelles are the major domains for TCS accumulation. These findings provide a better understanding of translocation and accumulation of TCS in aquatic plants at the cellular level, which is valuable for environmental and human health assessments of TCS.

Organic ultraviolet filters used for protection against radiation in personal care products and other materials (e.g. textiles, plastic products) are considered emerging contaminants of aquatic ecosystem. Benzophenone-3 (BP3) and 3-(4-methylbenzylidene)camphor (4-MBC) are the most commonly used organic UV-filters and have been reported in freshwater environments due to contamination through discharges from wastewater treatment plants and swimming pools or by direct contamination from recreational activities. Our aim was to evaluate the ecotoxicological effects of these UV-filters using the freshwater caddisfly Sericostoma vittatum’ biochemical biomarkers and energy processing related endpoints (feeding behaviour, energy reserves and cellular metabolism). In laboratory trials, both compounds induced feeding inhibition of S. vittatum at 3.55 mg/kg BP3 and at concentrations ≥2.57 mg/kg 4-MBC, decreased carbohydrates content at 3.55 and 6.95 mg/kg of BP3 and 4-MBC respectively, and increased total glutathione levels at concentrations ≥1.45 and 1.35 mg/kg of BP3 and 4-MBC respectively. No significant effects were observed on endpoints associated with oxidative stress, antioxidant defences, phase II biotransformation or neurotoxicity after exposure to both UV-filters. Our results show that environmental relevant concentrations of BP3 and 4-MBC, can negatively impact freshwater insects and demonstrate the importance of monitoring the ecological effects of organic UV-filters using non-model invertebrate species.

Metals can react with microcystin (MC), which is released from cyanobacterial blooms through various mechanisms; these reactions may mitigate the environmental and health risks of MCs but may also cause harm to aquatic ecosystems and humans. Several studies were conducted, including laboratory tests, ecological simulations, and a field investigation of Poyang Lake. The laboratory studies showed that Fe3+, Cu2+, and Pb2+ stimulated MC photodegradation under high light intensity at the water–sediment interface, which reduced the MC accumulation in the sediment. In the laboratory studies involving the addition of metal ions to lake sediment containing adsorbed MC, MC biodegradation was inhibited by supplementing with high levels of Fe3+, Cu2+, or Pb2+. Fe3+ and Pb2+ promoted MC accumulation in the hydrophyte Eichhornia crassipes at relatively low concentrations, but this effect decreased with increasing high metal concentrations. An ecological survey in Poyang Lake during the dry season demonstrated that high Fe levels can reduce MC accumulation in the sediment, which could be the result of Fe-mediated photodegradation. The results indicate that metals involved in MC transportation and degradation may play an important role in the environmental fate of MC.

The common soil arthropod Folsomia candida can survive well when fed only maize pollen and thus may be exposed to insecticidal proteins by ingesting insect-resistant genetically engineered maize pollen containing Bacillus thuringiensis (Bt) proteins when being released into the soil. Laboratory experiments were conducted to assess the potential effects of Cry1Ab/Cry2Aj-producing transgenic Bt maize (Shuangkang 12–5) pollen on F. candida fitness. Survival, development, and the reproduction were not significantly reduced when F. candida fed on Bt maize pollen rather than on non-Bt maize pollen, but these parameters were significantly reduced when F. candida fed on non-Bt maize pollen containing the protease inhibitor E-64 at 75 μg/g pollen. The intrinsic rate of increase (rm) was not significantly reduced when F. candida fed on Bt maize pollen but was significantly reduced when F. candida fed on non-Bt maize pollen containing E−64. The activities of antioxidant-related enzymes in F. candida were not significantly affected when F. candida fed on Bt maize pollen but were significantly increased when F. candida fed on non-Bt pollen containing E−64. The results demonstrate that consumption of Bt maize pollen containing Cry1Ab/Cry2Aj has no lethal or sublethal effects on F. candida.

The study of the uptake and distribution of elements in marine environments is of great interest for understanding their pathways and accumulation. Here, we investigated in laboratory experiments the accumulation behavior of Cd in the sea anemone Bunodosoma caissarum and the mussel Perna perna. Specimens were incubated with isotopically enriched 116Cd in aquariums. Cd concentrations in the seawater and in the tissues of B. caissarum and P. perna were followed by inductively coupled plasma-mass spectrometry (ICP-MS) by means of isotope dilution analysis. Bioconcentration factors for B. caissarum and P. perna exposed to 0.9μg·L−1 of 116Cd were determined to be 80.5 and 850, respectively. P. perna specimens exposed to 4.5μg·L−1 of 116Cd reached 530. Cytosolic proteins associated with Cd from the tissues were extracted and further analyzed by size-exclusion chromatography coupled to ICP-MS. Cd accumulation could be detected in both organisms ranging from high-molecular to low-molecular species.

PURPOSE OF REVIEW: Mangroves are under increasing heavy metal (HM) pollution pressure from human activities because of the rapid industrialization and urbanization in coastal areas. Field and laboratory experiments showed that the tolerance of mangrove plants to HM stress is normally a mixture of metal avoidance and scavenging of reactive oxygen species (ROS). In this review, related studies during the past few decades on the accumulation and tolerance of mangrove to HMs have been synthesized. RECENT FINDINGS: In mangroves, metal accumulation mainly occurred at the root level with restricted transport to the aerial portions of the plant. The common founded HMs, such as copper, zinc, cadmium, chromium, and mercury, generally showed high bioconcentration factor in roots, while the concentration factors for these metals in leaves were usually much lower than one. The limited translocation of the toxic metals to the aerial parts renders the mangrove plants a high endurance ability to high levels of HM stress. To protect the cellular components from oxidative damage by HMs, mangroves have developed both enzymatic and nonenzymatic antioxidant mechanisms to scavenge the ROS. In some circumstances, the changes of antioxidative enzyme activity were usually in accordance with the changes of toxic metal concentrations in plant tissues. However, the responses of antioxidative enzymes in mangroves to HM stress varied with plant species, metal type, and concentration, as well as the duration of the treatment time. More toxicity tests are needed with early life stages of mangroves to determine threshold effect concentrations under more realistic conditions.

During the Deepwater Horizon (DwH) oil spill, interactions between oil, clay particles and marine snow lead to the formation of aggregates. Interactions between these components play an important, but yet not well understood, role in biodegradation of oil in the ocean water. The aim of this study is to explore the effect of these interactions on biodegradation of oil in the water. Laboratory experiments were performed, analyzing respiration and n-alkane and BTEX biodegradation in multiple conditions containing Corexit, alginate particles as marine snow, and kaolin clay. Two oil degrading bacterial pure cultures were added, Pseudomonas putida F1 and Rhodococcus qingshengii TUHH-12. Results show that the presence of alginate particles enhances oil biodegradation. The presence of Corexit alone or in combination with alginate particles and/or kaolin clay, hampers oil biodegradation. Kaolin clay and Corexit have a synergistic effect in increasing BTEX concentrations in the water and cause delay in oil biodegradation.

The ability to calculate the oil droplet size distribution (DSD) and its dynamic behavior in the water column is important in oil spill modeling. Breaking waves disperse oil from a surface slick into the water column as droplets of varying sizes. Oil droplets undergo further breakup and coalescence in the water column due to the turbulence. Available models simulate oil DSD based on empirical/equilibrium equations. However, the oil DSD evolution due to subsequent droplet breakup and coalescence in the water column can be best represented by a dynamic population model. This paper develops a phenomenological model to calculate the oil DSD in wave breaking conditions and ocean turbulence and is based on droplet breakup and coalescence. Its results are compared with data from laboratory experiments that include different oil types, different weathering times, and different breaking wave heights. The model comparisons showed a good agreement with experimental data.

Phosphate discharged in agricultural drainage causes water quality degradation on local, regional, and national scales. Iron oxyhydroxide filter materials can potentially remove the soluble phosphate present in drainage waters. Laboratory saturated column experiments and preliminary small-scale field tests were carried out to evaluate the effectiveness and efficiency of a synthetic goethite iron oxyhydroxide (α-FeOOH) filter material for phosphate treatment. Original iron oxyhydroxide filter material (SG-IOH-O) and the same filter material regenerated with sodium hydroxide (SG-IOH-R) were assessed. Results of replicated laboratory experiments showed that columns packed with SG-IOH-O or SG-IOH-R almost totally removed phosphate (>98%) from drainage waters spiked with an additional 1 or 10 ppm phosphate-P (PO₄-P). The column experiments with SG-IOH-O or SG-IOH-R additionally indicated that contact times of only 10 to 15 s were sufficient for near complete removal of phosphate from drainage water spiked with 1 ppm PO₄-P. In an initial small-scale filter treatment system field test with SG-IOH-O, percent phosphate removal averaged 89% in the first 200 days, which then decreased to an average 40% phosphate removal in the last 80 days. Following this initial field test, two field tests, one with SG-IOH-O and the other with SG-IOH-R, were conducted concurrently over a period of 193 days, with the SG-IOH-O system phosphate removal averaging 75%, while the SG-IOH-R system phosphate removal averaged 34%. This study’s findings support possible goethite iron oxyhydroxide filter material use for drainage water phosphate treatment; however, larger-scale field investigations are needed, particularly with modified regeneration procedures.