EPA Method Research Articles

Metal concentration in bottom sediments for a tropical river, geological or anthropogenic source?

The study analyzes data from a survey of metal concentrations in bottom sediments from both margins (left and right) of the lower main channel of the Orinoco River. This study aims to analyze metal concentrations in the bottom sediments of the lower Orinoco River with different geological settings and anthropological sources. El Almacen (ALM), Las Galderas (G), Los Castillos de Guayana (C), Ciudad Bolivar (CB), and Ciudad Guayana (CG) were the sampling sites. Freshwater physicochemical parameters pH, conductivity, and DO were measured in situ at each sample site. Twenty-four bottom sediment samples were collected with an Eckman grab, dried, and sieved. Trace elements Pb, Cr, Cu, Cd, Ti, and Co were measured in sediments with grain sizes <63μm. Bottom sediment analysis followed EPA method 3050B (digestion with HNO3 + HCl + H2O2). Statistical analyses included the Shapiro-Wilk test, Spearman correlation, Kruskal-Wallis test, and principal component analysis (PCA). Physicochemical parameters highlighted the marked difference between the left and the right river margins, reflecting the cross-channel heterogeneity due to the dissimilar geology and low horizontal mixing. Metal concentrations were generally low, with higher variations associated with urban and industrial sources. Pb, Cr, Cu, Cd, Ba, Ti, and Co concentrations did not generally indicate significant pollution, but potential contamination from sewage and industrial effluents was noted. The differences between the two river margins were common in all the sampling sites, reflecting the sources of water biochemistry related to geochemical origins in the Andes and the Guiana Shield, respectively. The study emphasizes the importance of sampling location within the river channel.

Mastering Snow Analysis: Enhancing Sampling Techniques and Introducing ACF Extraction Method with Applications in Svalbard

Semi-volatile organic contaminants (SVOCs) are known for their tendency to evaporate from source regions and undergo atmospheric transport to distant areas. Cold condensation intensifies dry deposition, particle deposition, and scavenging by snow and rain, allowing SVOCs to move from the atmosphere into terrestrial and aquatic ecosystems in alpine and polar regions. However, no standardized methods exist for the sampling, laboratory processing, and instrumental analysis of persistent organic pollutants (POPs) in snow. The lack of reference methods makes these steps highly variable and prone to errors. This study critically reviews the existing literature to highlight the key challenges in the sampling phase, aiming to develop a reliable, consistent, and easily reproducible technique. The goal is to simplify this crucial step of the analysis, allowing data to be shared more effectively through standardized methods, minimizing errors. Additionally, an innovative method for laboratory processing is introduced, which uses activated carbon fibers (ACFs) as adsorbents, streamlining the analysis process. The extraction method is applied to analyze polychlorobiphenyls (PCBs) and chlorinated pesticides (α-HCH, γ-HCH, p,p′-DDE, o,p′-DDT, HCB, and PeCB). The entire procedure, from sampling to instrumental analysis, is subsequently tested on snow samples collected on the Svalbard Islands. To validate the efficiency of the new extraction system, quality control measures based on the EPA methods 1668B and 1699 for aqueous methods are employed. This study presents a new, reliable method that covers both sampling and lab analysis, tailored for detecting POPs in snow.

Quantitative assessment of poly- and perfluoroalkyl substances (PFASs) in aqueous film forming foam (AFFF)-impacted soils: a comparison of analytical protocols.

Quantitatively assessing all per- and poly fluoroalkyl substances (PFASs) in an environmental sample, particularly soils impacted by aqueous film forming foams (AFFFs), has proven to be a challenge. To make such an assessment, a comprehensive sample processing procedure and analytical tool must be used. However, doubts remain whether current analytical tools such as high-resolution mass spectrometry (HRMS) with targeted quantitation and semi-quantitative analysis of suspects (Semi-Q HRMS) or total organic fluorine (TOF) are capable of accurately quantifying all non-polymeric PFASs in a sample. Further, current comprehensive soil PFAS HRMS methods are incompatible with TOF, preventing direct comparisons of the approaches. To enable direct comparisons, a soil sample processing procedure that is comprehensive as well as compatible with multiple analytical tools is needed. In this study, we assessed the performance of a previously developed soil PFAS method, EPA Method 1633, and a hybrid solid phase extraction (SPE)-based method for characterizing AFFF-impacted soil composites while maintaining compatibility with multiple analytical tools (i.e., Semi-Q HRMS and TOF). Comparative results for AFFF-impacted soil composites indicate analysis via EPA Method 1633 (as compared to the novel hybrid method) results in maybeup to 75% of the PFAS mass being missed by only analyzing for compounds listed in EPA Method 1633. Simply expanding the EPA Method 1633 analyte list was insufficient to account for the missing mass: up to 69% of the PFAS mass was still missed because of EPA Method 1633's extraction and cleanup bias. Additionally, the novel method developed offers a more comprehensive analysis with minimal reductions to sensitivity when compared to those reported in EPA Method 1633, with limits of quantification ranging from 0.12 to 2.4 ng/g as compared to 0.16-4.0 ng/g, respectively. For these reasons, an alternative hybrid SPE-based method is proposed for comprehensive evaluation of PFASs in AFFF-impacted soils.

Effect of the temperature control device on the emission character of condensable particulate matter from industrial heating plant

Condensable particulate matter (CPM) is one of the major emissions of primary particles in coal combustion. The removal efficiency of CPM using the temperature control device (TCD) based on the concept of a heat exchanger application with lower capital cost was investigated in an industrial heating plant. TCD operates without water and flue gas interactions and ensures efficient control of CPM emissions, and it also minimizes the potential ion accumulation in recycled WESP water, which could otherwise hinder the removal of CPM. The total mass and chemical speciation were determined by EPA method 202. The total mass of CPM was removed by 25.7–60.6% after the TCD. The CPM captured by CPM filters (CPMspa) was down to around 15–21% and the FPM also was reduced by around 11–26%. The occurrence of vapor gradient forces and thermophoresis forces could enhance the contact between CPM and water film, which was built up on the surface of the cooling tubes during the process of TCD. Then, part of the CPM was removed with a water film. The low capital and operating cost of TCD can be installed in the industrial heating plant or be set up after the WESP in the coal-fired power plant to enhance the CPM removal efficiency.

CHEMOMETRIC EVIDENCE FOR SR AND RB ISOTOPES DUE TO THE SPECIFIC SOIL CHEMISTRY IN DIFFERENT GEOGRAPHICAL REGIONS

Strontium and rubidium are the commonly used metals for isotope-ratio analysis. Moreover, this geochemical marker varies between different rock types and formations. The 87Sr/86Sr ratio has been shown to vary widely in surface rocks, so any Sr released into soils, rivers, and groundwater has an isotopic signature that reflects its source. Sr and Rb isotopes have also been used to trace agricultural products, which have incorporated Sr, along with Ca, from soils incorporating the Sr-isotope ratios of the underlying rocks. The specific conditions in the soil represent characteristic conditions of the environment which is reflected in a certain way in the plants. Despite uncertainty about the organic compounds in a sample, the content of selected elements (trace and rare earth elements, REEs) reflects the growing conditions in the environment. For that instance, in the present research, we will give focus on the inorganic compounds’ identifications, due to the more stable response to the lithogenic nature of the soil-plant interaction. For the present study, the target isotopes were 88Sr, 87Sr, 86Sr, and 85Rb. The isotope analysis was conducted with the application of ICP-MS, following the protocol provided in the EPA METHOD 6020. In the validation process, no significant interference occurred that could affect the sensitivity of the measurement of the selected isotopes. Data analysis has been applied to the comparative issues between Sr and Rb content in soil from North Macedonia and selected regions in China. Moreover, the same chemometric model was applied for data analysis for selected plant species for both regions. Data analyses has improved the significant differences within the element contents and ratios as well between both geographical regions.

Closing PFAS analytical gaps: Inter-method evaluation of total organofluorine techniques for AFFF-impacted water

Multiple poly- and perfluoroalkyl substances (PFASs) are present in aqueous film-forming foams (AFFF) used for firefighting activities. Currently, no single analytical technique provides a complete accounting of total PFASs or total organofluorine content in AFFF-contaminated samples. To provide insight into the performance of existing methods, we compared ten previously described PFAS measurement techniques. In AFFF-amended tap water, US EPA Methods 533 and 1633, adsorbable organic fluorine with particle induced gamma emission spectroscopy (AOF-PIGE) and fluorine-19 nuclear magnetic resonance (19F NMR) provided similar estimates of total fluorine. The total oxidizable precursor (TOP) assay, suspect screening, and adsorbable organic fluorine with combustion ion chromatography (AOF-CIC) yielded estimates of total organic fluorine that were about two to three times higher than the other techniques. Proximate to AFFF sources, suspect screening and modified EPA Method 1633 yielded higher results, while the TOP assay results were between the other two sets of analyses. Further from sources, suspect screening, modified EPA Method 1633, and the TOP assay yielded similar results that were 4-fold higher than results from targeted quantification methods, such as EPA Method 1633. These results are consistent with expectations about PFAS behavior and inform the selection of analytical techniques used for PFAS contamination characterization efforts.

Characterization of Adsorbed Hydrocarbons in Deposit Sands and Well Fracture in the Burgos Basin

Objective: The objective of this research is to determine the potential adsorption by the solids carried by the hydrocarbon production stream to the surface by characterization to identify its origin. Theoretical framework: In the natural gas producing wells of the Burgos Basin, there is the presence of solids in the production fluids, these can be from the reservoir or from fracture. The reservoir solids are created from the carbonates, sandstones and shales inside the well, the fracture solids are better known as props, they are mixed with the drilling fluid so that inside the well they act as packs in the fractures where the hydrocarbon can flow for extraction. In this Basin, horizontal hydraulic fracturing is used for the extraction of hydrocarbons, the solids present adsorb part of the hydrocarbons and are contaminated with them. Method: Sand samples from 4 wells were used, which were extracted with Soxhlet equipment to separate the organic content of the sand. Using ASTM (2003) and US EPA (1996) methods D5369-93 and 3540C-3541 as a reference. Subsequently, the hydrocarbon concentrate was fractionated using the method reported in the manual of soil analysis techniques of Fernández et al., (2006) who adapted the methods 3600C, 3610B and 3611B of the US EPA (1996). The analytical method consisted of reading the spectra of each fraction in a UV-Visible Shimadzu UV-1800 spectroscopy equipment and by FT-IR spectrophotometry, in a Nicolet iS10 equipment, with a DTGS KBr detector. The physical characterization of the sands was performed by recording the particle size using the API-RP56 standard. Finally, X-ray diffraction is used to determine the phases of the sands by the method 05LA-34080109-DRX-MP-01. Results and discussion: The amount of total hydrocarbon extracted from the sands was in a range of 2,975-0,060 gr. The identification of hydrocarbons extracted by Uv-Visible and FTIR showed functional groups of aliphatic, polycyclic and nitrogen compounds. The particle size of the sands was measured between 45-311 nm. And finally RX identified the type of sand to analyze, being well 1: reservoir sand, well2: fracture sand, well 3: fracture sand and well 4: reservoir sand. Implications of the research: This research presents a study on the classification of the type of sands that are being dragged to the surface with the hydrocarbon stream of well production. These are data that show a fact that occurs and gives the certainty of what happens at the bottom of the well. Originality/value: The analysis of the results allows decisions to be taken to prevent corrosion and plugging problems of surface equipment, which can cause explosions such as the one of September 19, 2012 in the PEMEX gas pipeline at the Km 19 Measuring Center in Reynosa, Tamps. Mexico.

Comparison of arsenic adsorption efficiency between macroalgae and seagrass on the shorelines of Jazan Province, Saudi Arabia

The aim of this study was to measure consequences of the arsenic pollution released from a sewage treatment plant into the seawater in Jazan province in the southwest of Saudi Arabia. The impact of the release of arsenic on the ecosystem is the adsorption of arsenic by sea plants. To do so, samples were collected alongside a distance of seven kilometers from the treatment plant. The algae samples: Sargassum sp., Cladophora sp., and seagrasses: Halodule uninervis and Cymodocea rotunda were digested in nitric acid, and the assays of arsenic levels were taken by ICP-AES according to EPA methods. The results showed that algae are more efficient than seagrass with absorbing arsenic. Also, the treatment plant was not the only source of arsenic contamination, as ships and boats were adding more arsenic to the ecosystem.

Ineffectiveness of phosphorus-containing amendments to reduce Pb bioaccessibility in an urban alkaline soil.

Urban soils contaminated by historical and current anthropogenic activities present an alarming human health risk requiring redress. Federal and state governments continue to lower residential soil lead (Pb) screening standards, which will likely require new risk-based approaches to address urban soil Pb contamination. Phosphorus (P) soil amendments have long been presented as a solution to sequester Pb, thereby reducing exposure risk. In this study, P-containing sources (biosolids incinerator ash, poultry litter, biosolids compost, and triple superphosphate) of varying solubilities were assessed as soil amendments to reduce Pb bioaccessibility and serve as an inexpensive remediation strategy for urban soil. Contaminated soil (1624mg kg-1Pb, pH 7.43) from Cleveland, OH, was treated with the four P-containing soil amendments at a 1:5Pb:P molar ratio and two combination treatments at 1:10Pb:P molar ratio and incubated for 3 months. A batch equilibration analysis was also conducted to assess reduction in in vitro bioaccessible Pb (IVBA Pb). Pb bioaccessibility was evaluated using US EPA Method 1340 at pH 1.5 and the Physiologically Based Extraction Test pH 2.5 at 1 and 3 months. In general, treatments were ineffective in reducing IVBA Pb regardless of IVBA extraction method, incubation duration, batch equilibration analyses, or P source. The results of this study suggest P-containing amendments are not suitable to address Pb exposure in the study soil. Site-specific efficacy testing to determine reductions in IVBA Pb from P-containing amendments should be performed before making recommendations for remediation of Pb-contaminated urban soil.

Determination of long half-life radioisotopes by mass spectrometry techniques in NORM materials

This work proposes a new approach for the analysis of radionuclides in NORM-type solid materials included in a European-level intercomparison test (Environmental Radiation Monitoring, REM2020), provided by the Environmental Radiation Monitoring group of the Joint Research Centre (JRC). The measurement techniques employed are inductively coupled plasma mass spectrometry (ICP-MS), using both quadrupole analyzer-equipped instruments (Q-ICP-MS) and high-resolution instruments with magnetic sector analyzer (HR-ICP-MS), and atomic emission spectroscopy (ICP-OES).Initially, the samples undergo microwave digestion using EPA methods adapted to the environmental matrix, yielding a nitric acid solution suitable for subsequent chemical analysis.Isotopes 40K, 235U, 238U, 230Th, and 232Th have been quantified due to their relevance from both radiological and environmental perspectives. An additional advantage of the proposed method is that besides determining concentrations and activities, it is also possible to ascertain the isotopic relationships of the radionuclides present in the samples, thereby determining whether the radiation originates from natural or anthropogenic sources.

The Representativeness of Subslab Soil Gas Collection as Effected by Probe Construction and Sampling Methods

AbstractSubslab soil gas (SSSG) samples were collected as part of an investigation to evaluate vapor intrusion (VI) into a building. The June 2015 Office of Solid Waste and Emergency Response (OSWER) VI Guide (U.S. Environmental Protection Agency [U.S. EPA] 2015) does not provide specific, detailed recommendations regarding how to collect SSSG samples. The data collected in this study will be used to provide input into future OSWER VI Guidance documents on SSSG sample collection. To this end, three different types of subslab sampling ports were constructed with various sampling techniques within a hexagon‐shaped grid in near proximity to each other. Conventional‐, Vapor Pin‐, and California‐style ports were established in duplicate for continual analysis by onsite gas chromatography‐electron capture detection (GC‐ECD). Triplicate ports were established to evaluate active and passive long‐term sampling methods to determine short range temporal differences. Active sampling methods included evacuated stainless‐steel canisters fitted with capillary flow controllers (Modified U.S. EPA Method TO‐15 [U.S. EPA 1999a]) and sorbent tubes collected using a syringe (Modified EPA TO‐17 [U.S. EPA 1999b]). The Passive sampling method used was sorbent tube samples collected following the EPA TO‐17 sampling method (Modified). This study did not identify any systematic differences in sample results between conventional, Vapor Pin, and CA‐style probes for used in SSSG sampling. The decisions for site management would probably be the same for data from any subslab port style, active or passive sampling techniques over durations less than 2 weeks.

Assessment of the risk to public health from soil contamination on the territory of solid waste landfills

Introduction. Domestic waste management is an extremely important issue for all countries of the world, especially for the countries of the former Soviet Union, as the current state of solid waste disposal in Ukraine is extremely unsatisfactory. According to the European Commission, the amount of waste in the European Union has increased in recent years to more than 2.5 billion tons per year. The results of the Waste Atlas report on the world's 50 largest landfills show that 64 million people are affected by the 50 largest landfills every day. Ukraine has a total of 6045 landfills and dumpsites. The general trend in Ukraine, in contrast to European countries, is a low level of recycling and utilization of solid waste and a high rate of landfill disposal. The vast majority of landfills (80 to 90%) operate in overload mode. Landfills, in particular solid waste landfills, are the main pollutants of the atmosphere, hydrosphere and soil. Therefore, determining the level of environmental hazard of heavy metals in the soil as a result of the impact of landfills and solid waste dumps is very important. Objective. The purpose of the article is to determine the impact of solid waste landfills on public health due to soil contamination with heavy metals. Methodology. In order to determine the level of environmental hazard of household waste storage at landfills and dumps, the paper assesses the risk to public health from soil contamination in the area of the Hrybovychi landfill (Lviv oblast), Rohan landfill (Kharkiv oblast), and Novovodolazhske landfill (Kharkiv oblast). The risk to public health from soil contamination at solid waste landfills was assessed using the traditional US EPA method and a new method for determining the potential risk to public health from soil contamination with heavy metals. Results. The article compares two fundamentally different methodological approaches to determining the level of environmental hazard of soil contamination with heavy metals. The risk to public health from soil contamination on the territory of solid waste landfills according to the US EPA method corresponds to hazard class 5 (extremely high hazard level) according to all calculations. The results of the assessment of the potential risk to public health from soil contamination using the new method at solid waste landfills correspond to hazard classes 2-4. Comparison of methodological principles for assessing the risk to public health from soil pollution has shown the advantages of using the new method of potential risk assessment. The use of the new method of assessing the potential risk to public health from soil pollution will help improve science-based management of household waste and direct financial resources to reduce the environmental hazard of soil and land pollution in Ukraine. Scientific novelty. The article presents an improved method for assessing the risk to public health from soil pollution, which represents the scientific novelty of the work Practical significance. Determining the environmental hazard of soil pollution due to the impact of landfills and solid waste dumps makes it possible to prioritize the implementation of environmental protection measures and will contribute to the implementation of environmentally sound environmental management, so the research is of practical importance.

Optimized Approach for Measuring Ethylene Oxide in Mobile Source Exhaust.

There is a growing awareness of the health impacts of ethylene oxide (EtO) and its role as a carcinogenic and mutagenic air contaminant of concern. Given the need to better understand EtO emissions and associated health effects, it is imperative to overcome the significant challenges associated with EtO measurement in complex air matrices, such as combustion emissions. This work focused on addressing these challenges by evaluating the utility of widely used canister-based EtO ambient measurement approaches, EPA Methods TO-15 and TO-15A, to investigate the presence of EtO in heavy-duty diesel vehicle (HDDV) exhaust. Chassis dynamometer testing was performed on two HDDVs and emissions samples were collected and analyzed following TO-15/TO-15A. Initial testing utilizing TO-15 led to the identification of a diesel exhaust constituent, ethyl nitrite, that coeluted with EtO during analysis and contributed large positive bias. An optimized TO-15A analytical approach was developed and utilized to measure EtO in diesel exhaust from two HDDVs in additional dynamometer tests. Using this optimized approach, EtO was not detected in HDDV exhaust in these tests. This work highlights the importance of utilizing this optimized approach to accurately quantify EtO in mobile source exhaust and may also be needed for testing other combustion sources.

CaO/SiC alkaline fillers for High-Temperature reduction of mercury (II)

The reduction of Hg2+ to Hg0 through high temperature is a crucial technique for mercury monitoring. However, this application encounters two challenges: suboptimal thermal conditions in the reaction zone leading to incomplete decomposition of Hg2+ and the susceptibility of the decomposed Hg0 to re-oxidation by Cl species. This work proposes a novel alkaline filler with alkaline earth metal oxides (AEMOs) as the active component, which enhances the thermal conditions of the reaction while effectively removing Cl species. DFT reveals increased adsorption energies of AEMOs for HCl and Cl with the growing atomic period. Further comparison of the electronic structures and adsorption behaviors between AEMOs and Cl species indicates a similar trend in electron transfer and electron density at the bond critical points. The frontier molecular orbital analysis shows a positive correlation between orbital energy level difference and adsorption energy. Experimental validation of the DFT results, combined with a comparison of costs and de-HCl performance, identifies CaO as the optimal active component. Subsequently, the CaO is loaded onto SiC, and the impact of precursor and loading ratio on the composite performance is investigated through experiments and characterization. The optimal preparation method involves using calcium acetate monohydrate as the precursor with a loading rate of 50 %. Finally, the developed alkaline filler is tested in a Hg-CEMS for industrial application, it shows errors of below 7 % compared to the EPA Method 30B results, validating its industrial feasibility. This work offers a practical solution for Hg2+ high-temperature reduction in industrial settings.

Evaluation of conditions to minimize mercury losses from leaching test eluates

A series of experiments are described that provide recommendations of modifications to leaching test specifications to minimize losses of mercury from eluates during leaching tests and management of analytical samples. EPA methods of the Leaching Environmental Assessment Framework (LEAF) were used as a reference point for what steps are most likely to see losses, including filtration, storage of unpreserved mercury contaminated material, and materials of construction for vessels. The potential sorption of mercury to borosilicate glass and PTFE lab materials was tested to determine what materials are suitable to replace HDPE and polypropylene. The experimental findings indicate that bottles constructed of PTFE and Type I (borosilicate) glass are recommended as extraction and containment vessels for mercury-containing liquids. Type I syringe filtration of aqueous mercury samples at pH 2 through 9 through 0.45 µm PTFE filters housed in polypropylene is acceptable; however, sorption losses were observed to occur at pH > 9. Storage of unpreserved liquids containing mercury over extended leaching test intervals did not lead to significant losses of mercury when coupled with minimized headspace. All mercury-containing eluates should include preservation with Optima HNO3 to a 1 % concentration and gold (III) standard to a concentration of 200 µg/L, followed by refrigeration at <6 °C prior to analysis.

Management of inorganic elements by overwintering physiology of cold hardy larvae of European corn borer (Ostrinia nubilalis, Hbn.).

The European corn borer (Ostrinia nubilalis, Hbn.), enters diapause, a strategy characterized by arrest of development and reproduction, reduction of metabolic rate and the emergence of increased resistance to challenging seasonal conditions as low sub-zero winter temperatures. The aim of this study was to investigate the potential role of inorganic elements in the ecophysiology of O. nubilalis, analysing their content in the whole body, hemolymph and fat body, both metabolically active, non-diapausing and overwintering diapausing larvae by ICP-OES spectrometer following the US EPA method 200.7:2001. O nubilalis as many phytophagous lepidopteran species maintain a very low extracellular sodium concentration and has potassium as dominant cation in hemolymph of their larvae. Changes in hemolymph and the whole body sodium content occur already at the onset of diapause (when the mean environmental temperatures are still high above 0ºC) and remain stable during the time course of diapause when larvae of this species cope with sub-zero temperatures, it seems that sodium content regulation is rather a part of diapausing program than the direct effect of exposure to low temperatures. Compared to non-diapausing O. nubilalis larvae, potassium levels are much higher in the whole body and fat body of diapausing larvae and substantially increase approaching the end of diapause. The concentration of Ca, Mg, P and S differed in the whole body, hemolymph and fat body between non-diapausing and diapausing larvae without a unique trend during diapause, except an increase in their contents at the end of diapause.

Quantitative Measurements of Hazardous Gas Effluents from the Combustion of Crew Waste Simulant in Microgravity

Abstract In August 2021, Blue Origin launched their un-crewed NS-17 mission aboard their New Shepard launch vehicle. Among the scientific payloads was NASA’s Orbital Syngas Commodity Augmentation Reactor (OSCAR), a flight-capable test rig allowing the combustion of ~10 g of simulated astronaut trash. Developed at NASA’s Kennedy Space Center, OSCAR measured differences in the combustion of complex mixed waste materials between terrestrial gravity and microgravity conditions. OSCAR is self-contained and collects its own effluent gases, which were subsequently analyzed for trace volatile organic compounds (VOCs) with a modified EPA Method TO-15. It was found that combustion in microgravity produced higher levels of VOCs (2,883 mg measured VOCs per kg trash) than for analogous triplicate (terrestrial) laboratory experiments (1,237±286 mg measured VOCs per kg trash with 95% confidence interval), indicating significant differences that were consistent with previously reported combustion efficiencies. Also, the concentrations of the measured VOCs were compared to NASA’s Spacecraft Maximum Allowable Concentrations (SMAC) values. These results provide a basis for understanding important design considerations for spacecraft waste disposal systems as NASA and their commercial partners develop crewed vehicles for missions to the Moon and Mars.

Advanced oxidation processes may transform unknown PFAS in groundwater into known products

Per- and polyfluoroalkyl substances (PFAS) are a group of fluorinated organic contaminants classified as persistent in the aquatic environment. Early studies using targeted analysis approaches to evaluate the degradation of PFAS by advanced oxidation processes (AOP) in real water matrices may have been misinterpreted due to the presence of undetected or unknown PFAS in these matrices. The aims of the present study were to (1) screen selected commercially available AOPs (UV, UV + H2O2, O3/H2O2) and UV photocatalysis in a pilot system using commercially used and novel photocatalysts (TiO2, boron nitride [BN]) for removing PFAS contaminants and (2) evaluate their role on the conversion of non-detected/unknown to known PFAS compounds in real groundwater used as drinking water supplies. Results indicated that, while AOPs have the potential to achieve removal of the EPA method 533 target PFAS compounds (PFDA [100%], PFNA [100%], PFOA [85–94%], PFOS [25–100%], PFHxS [3–100%], PFPeS [100%], PFBS [100%]), AOPs transformed non-detected/unknown longer-chain PFAS compounds to detectable shorter-chain ones under very high-dose AOP operating conditions, leading to an increase in ∑PFAS concentration ranging from 95% to 340%. As emerging PFAS treatment processes transition from lab-scale investigations of target PFAS to pilot testing of real water matrices, studies will need to consider impact of the presence of non-target long-chain PFAS to transform into targeted PFAS compounds. A promising approach to address the potential risks and unforeseen consequences could involve an increased reliance on adsorbable organic fluorine (AOF) analysis before and after advanced oxidation process (AOP) treatment.

Impact of Polluted Soil on Herbivory of Leaves and Pneumatophore Growth of Black Mangroves (Laguncularia racemosa) at Eagle Island, River State, Nigeria

Mangroves are ecosystem along the shoreline of Nigerian coast and area of active oil exploration in Nigeria. This study is on the impact of pollution on herbivory and pneumatophore growth in black mangrove at Eagle Island. Leave herbivory, pneumatophore growth, THC and heavy metal concentration in soil, root and leave were determined. The sample site was divided into: plot A (high muddiness), plot B (low muddiness), plot C (slight muddiness) and Control (little or no pollution). Random sampling was used in obtaining leaves, soil and pneumatophore from each plot. Pneumatophore height was taken with meter rule and the weight with weighing balance. The leaf image was taken using a digital handy scanner and was uploaded in a software called Image J to measure the area consumed. EPA Method 418 was used to test for Total Hydrocarbon Content (THC). Heavy metals (Cadmium, Lead, Zinc) were determined using AAS- Atomic Absorption Spectrometric method. Results revealed that control plot had highest leaf consumption (2.200±0.33cm2) compared to other plots. The heavy metals and THC concentrations in different plant parts (leaves and roots) revealed that THC was high in leaves (250.88±95.33mg/kg), while heavy metals were high in root The pneumatophores were taller and heavier in Plot A compared to Plots B and C. This study shows that pollution affects herbivory and pneumatophores growth in mangroves forest. Mitigation measures should be taken to prevent these pollutants.

Formation and migration of soluble ions in condensable particulate matter in limestone-gypsum wet flue gas desulfurization system

In this work, the emission characteristics of condensable particulate matter (CPM) and soluble ions in the inorganic components after wet flue gas desulfurization (WFGD) were investigated by adjusting the operating parameters of the limestone-gypsum WFGD system. Using a combination of US Method 202 and US EPA Method 5 as the primary measurement method, the study is an experimental study and analysis of the properties of CPM emitted from a limestone-gypsum WFGD system. Based on the measurement results, the influence of some important WFGD operating parameters on CPM emissions was evaluated. The results showed that CPM accounts for 84% of total particulate matter (TPM) emissions in desulfurized flue gas. The composition of CPM is primarily inorganic, comprising 96% of the components, with only a small portion being organic at 4%. The CPM that condensed to a solid state was generally less than 1 μm in diameter and mostly came from WFGD process. The analysis of soluble ions showed that Ca2+ and SO42- were the main ionic components in CPM. By adjusting the desulfurization operating parameters (inlet flue gas temperature, desulfurization solution temperature, desulfurization solution concentration), the concentration of soluble ions can be reduced to different degrees, so as to achieve the purpose of reducing CPM emission. This demonstrated that the CPM emission problem of limestone-gypsum WFGD system could be relieved by operating parameter optimization.