Influence of metal(loid) bioaccumulation and maternal transfer on embryo-larval development in fish exposed to a major coal ash spill

Optimization of preparation of NaA zeolite from fly ash for CO2 capture

The green synthesis method of fly ash-based NaA zeolite was explored to reduce the synthesis cost and environmental hazards. For the prepared NaA samples, the effects of crystallization time, solid-liquid ratio, and Si/Al ratio were systematically studied. CO2 adsorption isotherm is used for adsorption model fitting analysis and adsorption selectivity determination. According to the experimental results, the optimized NaA zeolite synthesis conditions are as follows: the Si/Al ratio of NaA zeolite is 1.4, the solid-liquid ratio is 10, and the crystallization time is 6 h. The green synthesis method reported in this study can successfully prepare NaA zeolite and exhibit excellent CO2 adsorption performance, reaching 4.34 mmol/g, with high CO2 selective adsorption ability, reaching 89.2 for N2, 257.1 for O2, and 45.8 for CH4. The adsorbed CO2 can be released for further utilization, and NaA zeolite also has strong adsorption and regeneration performance, with a ten cycle adsorption capacity only decreasing by 1.17%. In addition, the use of cheap raw materials synthesis methods will promote the large-scale industry application of green synthesis technology in the future.

Environmental Impacts of Coal Combustion Residuals: Current Understanding and Future Perspectives

On-site solid-waste impoundments, landfills, and receiving water bodies have served as long-term disposal sites for coal combustion residuals (CCRs) across the United States for decades and collectively contain billions of tons of CCR material. CCR components include fine particulate material, minerals, and trace elements such as mercury, arsenic, selenium, lead, etc., which can have deleterious effects on ecosystem functioning and public health. Effects on communities can occur through consumption of drinking water, fish, and other aquatic organisms. The structural failure of impoundments, water infiltration, leakage from impoundments due to poor construction and monitoring, and CCR effluent discharges to water bodies have in the past resulted in harmful environmental impacts. Moreover, the risks posed by CCRs are present to this day, as coal continues to account for 11% of the energy production in the United States. In this Critical Review, the legacy of CCR disposal and the concomitant risks posed to public health and ecosystems are assessed. The resiliency of CCR disposal sites in the context of increased frequency and intensity of storm events and other hazards, such as floods and earthquakes, is also evaluated. We discuss the current state of knowledge on the environmental fate of CCR-derived elements, as well as advances in and limitations of analytical tools, which can improve the current understanding of CCR environmental impacts in order to mitigate the associated risks. An assessment of the 2015 Coal Ash Final Rule is also presented, along with needs to improve monitoring of CCR disposal sites and regulatory enforcement.

Characteristics and impact of aged coal ash with slag emplaced in a karst cave: the case of Divaška jama, Slovenia

A mixture of coal bottom ash and slag, with a fraction of fly ash (CAFAS) from steam locomotives, was placed in the cave Divaška jama to delimit and level tourist trails. Emplacement began in 1914 and carried on for several decades. The CAFAS mixed with other cave material gradually changed its structure and appearance. Currently the concentration of some elements in the CAFAS (As, Cu, Hg, Ni, Pb, Zn), and also to a lesser extent in cave sediments (Cr, Cu, Ni), indicates a possibly harmful effect on sediment-associated biota based on ecotoxicological assays. Compared to the cave sediment, the CAFAS contains distinctly different mineral phases and presents a different source of radioactivity. Microbial metabolic activity of CAFAS is low, 0.22 μl O₂/gDW h, but higher than that of cave sediment. The present environmental hazards from CAFAS are estimated to be low. Whereas the emplacement of CAFAS was seen initially a long-term solution for waste disposal and management of the cave, it turned out that CAFAS enriches the underground environment with inorganic and organic compounds and disperses pollution into the cave ecosystem. After its removal from the cave, the CAFAS should be investigated thoroughly due to its susceptibility to alteration.

Fish as bioindicators: coal and mercury pollution in Colombia's ecosystems

Mining in Colombia affects 488,672 ha (298,391 in coal mining and 190,281 in gold mining). However, Colombia has insufficient studies on mining and its repercussions, which limits estimates of mining impacts on ecosystems and the human population. Due to the rise of mining activities in Colombia, the negative impacts generated by coal and Hg will also continue to increase. This review analyzes national information levels on coal and Hg in island/coastal/marine as well as freshwater ecosystems and human groups using fishery resources as a framework. This is because fish are the main source of animal protein in marine coastal-island and mainland communities. Here, 15 of 32 Colombian departments have records on total mercury (THg) in water, sediments, fish, and human communities. Around 205 ton/year of mercury is discharged into the ecosystem. In human hair for example (15.3 to 50.15 μg/g), mercury exceeds the international maximum levels allowed (ILA) and the national standard (5.0 μg/g). Mercury levels in freshwater fish show 3.3 μg/g of THg and levels in marine and coastal-island fish are 1.2 μg/g THg exceeding the ILA (0.5 μg/g) standard for fish that will be consumed. Carnivorous species have a THg between 0.04 and 2.55 μg/g suggesting bioaccumulation and magnification of heavy metals. These findings were then compared with available international information.

Patterns of Trace Element Accumulation in Waterfowl Restricted to Impoundments Holding Coal Combustion Waste

Waterfowl are often exposed to and readily accumulate anthropogenic contaminants when foraging in polluted environments. Settling impoundments containing coal combustion waste (CCW) enriched in trace elements such as arsenic (As), selenium (Se), and mercury (Hg) are often used by free-ranging migratory and resident waterfowl and represent potential sources for contaminant uptake. To assess accumulation of CCW contaminants, we experimentally restricted waterfowl to a CCW-contaminated impoundment and quantified trace element burdens in blood, muscle, and liver tissues over known periods of exposure (between 3 and 92 d). From these data we developed models 1) to predict elemental bioaccumulation with increased exposure time, and 2) to predict muscle/liver burdens based on concentrations in blood as a nondestructive sampling method. Although Hg and As did not bioaccumulate in our waterfowl, we observed an increase in Se concentrations in muscle, liver, and blood tissues over the duration of our experiment. Furthermore, we found that blood may be used as an effective nondestructive sampling alternative to predict muscle and liver tissue concentrations in birds contaminated with Se and As through dietary exposure. These data provide unique insights into accumulation rates of contaminants for waterfowl utilizing habitats contaminated with CCW and demonstrate the efficacy of nonlethal sampling of waterfowl to quantify contaminant exposure. Environ Toxicol Chem 2020;39:1052-1059. © 2020 SETAC.

Evidence for unmonitored coal ash spills in Sutton Lake, North Carolina: Implications for contamination of lake ecosystems

Coal combustion residuals (CCRs, also known as "coal ash") contain high concentrations of toxic and carcinogenic elements that can pose ecological and human health risks upon their release into the environment. About half of the CCRs that are generated annually in the U.S. are stored in coal ash impoundments and landfills, in most cases adjacent to coal plants and waterways. Leaking of coal ash ponds and CCR spills are major environmental concerns. One factor which may impact the safety of CCRs stored in impoundments and landfills is the storage area's predisposition to flooding. The southeastern U.S., in particular, has a large number of coal ash impoundments located in areas that are vulnerable to flooding. In order to test for the possible presence of CCR solids in lake sediments following Hurricane Florence, we analyzed the magnetic susceptibility, microscopic screening, trace element composition, and strontium isotope ratios of bottom sediments collected in 2015 and in 2018 from Sutton Lake in eastern North Carolina and compared them to a reference lake. The results suggest multiple, apparently previously unmonitored, CCR spills into Sutton Lake from adjacent CCR storage sites. The enrichment of metals in Sutton Lake sediments, particularly those with known ecological impact such as As, Se, Cu, Sb, Ni, Cd, V, and Tl, was similar to or even higher than those in stream sediments impacted by the Tennessee Valley Authority (TVA) in Kingston, Tennessee, and the Dan River, North Carolina coal ash spills, and exceeded ecological screening standards for sediments. High levels of contaminants were also found in leachates extracted from Sutton Lake sediments and co-occurring pore water, reflecting their mobilization to the ambient environment. These findings highlight the risks of large-scale unmonitored spills of coal ash solids from storage facilities following major storm events and contamination of nearby water resources throughout the southeastern U.S.