Long-range Transport Potential Research Articles

Sediment-seawater partitioning, bioaccumulation, and biomagnification of perfluorobutane sulfonamide in marine environment

Environmental occurrence of perfluorobutane sulfonamide (PFBSA) has only been recently discovered. The current knowledge regarding the occurrence and environmental behaviors of PFBSA in the marine environment is still relatively limited. In this study, PFBSA and other 37 poly- and perfluoroalkyl substances were analyzed in seawater (n = 43), sediment (n = 43), and marine fish (n = 176) samples collected from East China Sea and Antarctic Ocean. PFBSA was detected in > 90% of seawater from East China Sea and Antarctic Ocean, with the concentrations of 1.0 − 19 ng/L and < LOD−228 pg/L, respectively. The field-based mean log-transformed sediment-seawater partitioning coefficients of PFBSA were 1.6 ± 0.19 L/kg dw and 1.1 ± 0.19 L/kg dw in East China Sea and Antarctic Ocean, respectively, which are lower than that of perfluorooctanoate and perfluorooctane sulfonate. This indicates its long-range transport potential in global oceans with ocean currents. The mean log-transformed bioaccumulation factor values of PFBSA determined in the multiple species of whole-body marine fishes from East China Sea and Antarctic Ocean were 2.3 L/kg ww and 2.4 L/kg ww, respectively, which are comparable to that of perfluoroheptanoate (2.3 L/kg ww) in marine fishes from East China Sea. We did not observe an obvious biomagnification or biodilution of PFBSA along the marine food chain in East China Sea or Antarctic Ocean. This study provides the first data on the environmental behaviors of PFBSA in the marine environment.

Global trade-driven transfer of atmospheric polycyclic aromatic hydrocarbon emissions and associated human inhalation exposure risk

Polycyclic aromatic hydrocarbons (PAHs) are of significant public concern because of their toxicity and long-range transport potential. Extensive studies have been conducted to explore the source-receptor relationships of PAHs via atmospheric transport. However, the transfer of trade-driven regional and global PAHs is poorly understood. This study estimated the virtual PAHs emission transfer embodied in global trade from 2004 to 2014 and simulated the impact of international trade on global contamination and associated human inhalation exposure risk of PAHs. Results show that trade-driven PAHs flowed primarily from developed to less-developed regions, particularly in those regions with intensive heavy industries and transportation. As the result, international trade resulted in an increasing risk of lung cancer induced by exposure to PAHs (27.8% in China, 14.7% in India, and 11.3% in Southeast Asia). In contrast, we found decreasing risks of PAHs-induced lung cancer in Western Europe (63.2%) and the United States (45.9%) in 2004. Our findings indicate that final demand and emission intensity are the key driving factors contributing to rising and falling consumption-based PAHs emissions and related health risk respectively. The results could provide a useful reference for global collaboration in the reduction of PAHs pollution and related health risks.

Metabolomic interference induced by short-chain chlorinated paraffins in human normal hepatic cells

Short-chain chlorinated paraffins (SCCPs) are an emerging class of persistent organic pollutants (POPs) that are widely detected in environmental matrices and human samples. Because of their environmental persistence, long-range transport potential, bioaccumulation potential, and biotoxicity, SCCPs pose a significant threat to human health. In this study, metabolomics technology was applied to reveal the metabolomic interference in human normal hepatic (L02) cells after exposure to low (1 μg/L), moderate (10 μg/L), and high (100 μg/L) doses of SCCPs. Principal component analysis (PCA) and metabolic effect level index (MELI) values showed that all three SCCP doses caused notable metabolic perturbations in L02 cells. A total of 72 metabolites that were annotated by MS/MS and matched with the experimental spectra in the Human Metabolome Database (HMDB) or validated by commercially available standards were selected as differential metabolites (DMs) across all groups. The low-dose exposure group shared 33 and 36 DMs with the moderate- and high-dose exposure groups, respectively. The moderate-dose exposure group shared 46 DMs with the high-dose exposure group. In addition, 33 DMs were shared among the three exposure groups. Among the 72 DMs, 9, 9, and 45 metabolites participated in the amino acid, nucleotide, and lipid metabolism pathways, respectively. The results of pathway enrichment analysis showed that the most relevant metabolic pathways affected by SCCPs were the lipid metabolism, fatty acid β-oxidation, and nucleotide metabolism pathways, and that compared with low-dose exposure, moderate- and high-dose SCCP exposures caused more notable perturbations of these metabolic pathways in L02 cells. Exposure to SCCPs perturbed glycerophospholipid and sphingolipid metabolism. Significant alterations in the levels of phosphatidylcholines, phosphatidylethanolamines, and sphingomyelins indicated SCCP-induced biomembrane damage. SCCPs inhibited fatty acid β-oxidation by decreasing the levels of short- and medium-chain acylcarnitines in L02 cells, indicating that the energy supplied by fatty acid oxidation was reduced in these cells. Furthermore, compared with low- and moderate-dose SCCPs, high-dose SCCPs produced a significantly stronger inhibition of fatty acid β-oxidation. In addition, SCCPs perturbed nucleotide metabolism. The higher hypoxanthine levels observed in L02 cells after SCCP exposures indicate that SCCPs may induce several adverse effects, including hypoxia, reactive oxygen species production, and mutagenesis in L02 cells.

Chemical Space Covered by Applicability Domains of Quantitative Structure-Property Relationships and Semiempirical Relationships in Chemical Assessments.

A significant number of chemicals registered in national and regional chemical inventories require assessments of their potential "hazard" concerns posed to humans and ecological receptors. This warrants knowledge of their partitioning and reactivity properties, which are often predicted by quantitative structure-property relationships (QSPRs) and other semiempirical relationships. It is imperative to evaluate the applicability domain (AD) of these tools to ensure their suitability for assessment purpose. Here, we investigate the extent to which the ADs of commonly used QSPRs and semiempirical relationships cover seven partitioning and reactivity properties of a chemical "space" comprising 81,000+ organic chemicals registered in regulatory and academic chemical inventories. Our findings show that around or more than half of the chemicals studied are covered by at least one of the commonly used QSPRs. The investigated QSPRs demonstrate adequate AD coverage for organochlorides and organobromines but limited AD coverage for chemicals containing fluorine and phosphorus. These QSPRs exhibit limited AD coverage for atmospheric reactivity, biodegradation, and octanol-air partitioning, particularly for ionizable organic chemicals compared to nonionizable ones, challenging assessments of environmental persistence, bioaccumulation capability, and long-range transport potential. We also find that a predictive tool's AD coverage of chemicals depends on how the AD is defined, for example, by the distance of a predicted chemical from the centroid of the training chemicals or by the presence or absence of structural features.

First Evidence of Hindered Amine Light Stabilizers As Abundant, Ubiquitous, Emerging Pollutants in Dust and Air Particles: A New Concern for Human Health.

Hindered amine light stabilizers (HALSs) represent a crucial class of polymer additives that are extensively used in plastics and other polymeric materials. However, their environmental presence and related exposure risks have until now remained unexplored. This study addressed this critical knowledge by examining dust and air particles collected in South China, utilizing a comprehensive analytical approach to identify and quantify nine monomeric HALSs. A total of seven of the nine studied HALSs were detected in the samples, with bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (Tinuvin 770) and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (HS-508) identified as the most abundant and widespread pollutants. Median total concentrations of HALSs ranged from 417 to 8,830 ng/g in urban dust samples and from 28.6 to 70.9 pg/m3 in urban air particles. Notably, dust concentrations of HALSs significantly exceeded those of traditional well-known light stabilizers such as UV absorbers. Human exposure assessment indicated that in contrast to air inhalation dust ingestion represented a more substantial exposure pathway owing to the relatively low volatility of these newly identified chemicals. Predictive modeling suggests that many of the examined HALSs exhibited characteristics of persistence, high toxicity, or strong potential for long-range transport, underscoring their hazardous nature. This study represents the first comprehensive investigation into the prevalence of HALSs as a class of emerging pollutants widespread in the environment, necessitating heightened attention and further research in the future.

Assessment of Water Quality and Parasitofauna, and a Biometric Analysis of the Prussian Carp of the Romanian Lentic Ecosystem in Moara Domnească, Ilfov County

The aim of this study was to perform a morphometric analysis of Prussian carp individuals collected from the Moara Domnească pond in Ilfov County, Romania. This was accompanied by a physico-chemical characterization of the water, which was sampled from the same location. Consequently, we analyzed a total of 60 Prussian carp individuals that were caught in April (N = 32) and May 2023 (N = 28). For the Carassius gibelio in the study site, we provided, for the first time, data on the weight–length relationships (WLRs), the Fulton K condition factor and the biometric features, including the total length (TL), standard length (SL), head length (HL), snout length (SNL), body depth (BD), girth and ratios for the TL/HL, as well for the TL/BD and TL/SL. A negative growth type was estimated for both the samples of C. gibelio. Based on other studies and fishing reports, besides C. gibelio, there are another 11 species that belong to the Cypriniformes order, and there are two teleost members of the Perciformes order (Lepomis gibbosus and Perca fluviatilis)—these were also associated with this habitat. Water samples were collected from 12 sampling points (SP), which were subjected to physico-chemical characterizations that consisted of an assessment of the turbidity (T), pH, electrical conductivity (EC), chloride (Cl−), total hardness (TH), oxygen regime parameters, phosphate phosphorus (P-PO43−), nitrate nitrogen (N-NO3−), nitrite nitrogen (N-NO2−) and ammonium nitrogen (N-NH4+) levels. In addition, considering their characteristics (high toxicity, non-biodegradability, long-range atmospheric transport and bioaccumulation potential), a number of organochlorine pollutants (OCPs) were identified. The total hardness values presented a very significant correlation with conductivity (r = 0.5974 ***) and with pH (r = 0.5854 ***). The results allowed for the water samples to be placed into the quality classes established by legislation, and they were also discussed in relation to the fishes’ requirements.

Impacts of a warming climate on concentrations of organochlorines in a fasting high arctic marine bird: Direct vs. indirect effects?

The present study examined how climate changes may impact the concentrations of lipophilic organochlorines (OCs) in the blood of fasting High Arctic common eiders (Somateria mollissima) during incubation. Polychlorinated biphenyls (PCBs), 1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p′-DDE), hexachlorobenzene (HCB) and four chlordane compounds (oxychlordane, trans-chlordane and trans- and cis-nonachlor) were measured in females at chick hatching (n = 223) over 11 years (2007–2017). Firstly, median HCB and p,p′-DDE concentrations increased ~75 % over the study period, whereas median chlordane concentrations doubled (except for oxychlordane). PCB concentrations, in contrast, remained stable over the study period. Secondly, both body mass and clutch size were negatively associated with OC levels, suggesting that females with high lipid metabolism redistributed more OCs from adipose tissue, and that egg production is an important elimination route for OCs. Thirdly, the direct climate effects were assessed using the mean effective temperature (ET: air temperature and wind speed) during incubation, and we hypothesized that a low ET would increase redistribution of OCs. Contrary to expectation, the ET was positively correlated to most OCs, suggesting that a warmer climate may lead to higher OCs levels, and that the impact of ET may not be direct. Finally, potential indirect impacts were examined using the Arctic Oscillation (AO) in the three preceding winters (AOwinter 1–3) as a proxy for potential long-range transport of OCs, and for local spring climate conditions. In addition, we used chlorophyll a (Chla) as a measure of spring primary production. There were negative associations between AOwinter 1 and HCB, trans-chlordane and trans-nonachlor, whereas oxychlordane and cis-chlordane were negatively associated with Chla. This suggests that potential indirect climate effects on eiders were manifested through the food chain and not through increased long-range transport, although these relationships were relatively weak.

Sources and environmental fate of halomethoxybenzenes.

Halomethoxybenzenes are pervasive in the atmosphere at concentration levels that exceed, often by an order of magnitude, those of the persistent organic pollutants with which they share the attributes of persistence and potential for long-range transport, bioaccumulation, and toxic effects. Long ignored by environmental chemists because of their predominantly natural origin-namely, synthesis by terrestrial wood-rotting fungi, marine algae, and invertebrates-knowledge of their environmental pathways remains limited. Through measuring the spatial and seasonal variability of four halomethoxybenzenes in air and precipitation and performing complementary environmental fate simulations, we present evidence that these compounds undergo continental-scale transport in the atmosphere, which they enter largely by evaporation from water. This also applies to halomethoxybenzenes originating in terrestrial environments, such as drosophilin A methyl ether, which reach aquatic environments with runoff, possibly in the form of their phenolic precursors. Our findings contribute substantially to the comprehension of sources and fate of halomethoxybenzenes, illuminating their widespread atmospheric dispersal.

Fingerprinting of chlorinated paraffins and their transformation products in plastic consumer products

Chlorinated paraffins (CPs) can be classified according to their length as short-chain (SC, C10–C13), medium-chain (MC, C14–C17) and long-chain (LC, C ≥ 18) CPs. Technical CP-mixtures can contain a wide range of carbon- (C-, nC = 10–30) and chlorine- (Cl-, nCl = 3–19) homologues. CPs are high-production volume chemicals (>106 t/y). They are used as flame-retardants, plasticizers and coolant fluids. Due to the persistence, bioaccumulation, long-range environmental transport potential and adverse effects, SCCPs are regulated as persistent organic pollutants (POPs) by the Stockholm Convention. Transformation of CPs can lead to the formation of unsaturated compounds such as chlorinated mono- (CO), di- (CdiO) and tri-olefins (CtriO). Such transformation reactions can occur at different stages of CP manipulation providing characteristic C-/Cl-homologue distributions. All this results in unique patterns that collectively create a fingerprint, which can be distinguished from CP-containing samples. Therefore, CP-fingerprinting can develop into a promising tool for future source apportionment studies and with it, the reduction of environmental burden of CPs and hazards to humans. Herein, CP-containing plastics were studied to establish fingerprints and develop this method. We analyzed four household items by reverse-phase liquid-chromatography coupled with a mass spectrometer with an atmospheric pressure chemical ionization source and an Orbitrap mass analyzer (RP-LC-APCI-Orbitrap-MS) operated at a resolution of 120000 (FWHM at m/z 200). MS-data of different CP-, CO-, CdiO- and CtriO-homologues were efficiently processed with an R-based automatic mass spectra evaluation routine (RASER). From the 16720 ions searched for, up to 4300 ions per sample were assigned to 340 C-/Cl-homologues of CPs and their transformation products. Specific fingerprints were deduced from the C-/Cl-homologues distributions, the carbon- (nC) and chlorine- (nCl) numbers and saturation degree. These fingerprints were compared with the ones obtained by a GC-ECNI-Orbitrap-MS method.

Physical and chemical processes driving remote seasonal atmospheric exposure to cyclic volatile methysiloxanes and short-chain chlorinated paraffins

Cyclic volatile methylsiloxanes (cVMS) and short-chain chlorinated paraffins (SCCPs) use has been restricted in recent years due to environmental health concerns. Both of these classes of emerging contaminants possess long range transport potential (LRTP), highlighting the need for continuous monitoring to assess effectiveness of implemented regulations. However, emission source elucidation and understanding processes affecting atmospheric transport remain challenging. Atmospheric levels of cVMSs and SCCPs were simultaneously monitored at a background monitoring site in Norway from January–July 2020. Concentrations obtained from active air samplers ranged from 49.9 to 845 (mean: 208) pg/m3 for ƩSCCPs and from 0.4 to 3.5 (mean: 1.5), 1.1–15 (mean: 5.6) and 0.1–0.9 (mean: 0.4) ng/m3 for octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), respectively. As SCCPs pose several challenges to analysts, different quantification methodologies and blank handling procedures were investigated to ensure reliable environmental measurements. Simulations using a Lagrangian atmospheric transport model (FLEXPART) revealed air masses impacting sampling measurements were of Oceanic origin, but periodic emission events from Europe and Russia were also observed. Seasonal pattern in cVMS concentrations was mainly driven by atmospheric degradation via hydroxyl radical reaction, whereas SCCP concentrations were more influenced by periodic anthropogenic inputs from local and continental Europe. No clear correlation could be observed with SCCP atmospheric concentrations and temperature over the entire sampling campaign. However, increased volatilization at elevated temperatures may be important with emissions originating from local sources. Higher chlorinated homologue groups dominated during the winter season and declined towards spring and summer, whereas reverse was found for the lower and more volatile chlorinated homologue groups.

Spatial distribution of Dechlorane Plus and dechlorane related compounds in European background air

The highly chlorinated chemical Dechlorane Plus (DP) was introduced as a replacement flame retardant for Mirex, which is banned through the Stockholm Convention (SC) for its toxicity (T), environmental persistence (P), potential for bioaccumulation (B) and long-range environmental transport potential (LRETP). Currently, Dechlorane Plus is under consideration for listing under the Stockholm Convention and by the European Chemical Agency as it is suspected to also have potential for P, B, T and LRET. Knowledge of atmospheric concentrations of chemicals in background regions is vital to understand their persistence and long-range atmospheric transport but such knowledge is still limited for Dechlorane Plus. Also, knowledge on environmental occurrence of the less described Dechlorane Related Compounds (DRCs), with similar properties and uses as Dechlorane Plus, is limited. Hence, the main objective of this study was to carry out a spatial mapping of atmospheric concentrations of Dechlorane Plus and Dechlorane Related Compounds at background sites in Europe. Polyurethane foam passive air samplers were deployed at 99 sites across 33 European countries for 3 months in summer 2016 and analyzed for dechloranes. The study showed that syn- and anti-DP are present across the European continent (&amp;lt;MDL-2.6 pg/m3 and &amp;lt;MDL-12.3 pg/m3, respectively), including parts of the Arctic. This supports that these compounds have potential for long-range atmospheric transport to remote regions. The highest concentrations of Dechlorane Plus were observed in central continental Europe, with anti-DP fractions close to the commercial mixture of Dechlorane Plus. The only detected Dechlorane Related Compounds was Dechlorane-602, which was found in 27% of the samples (&amp;lt;MDL-0.33 pg/m3). The measured concentrations and spatial patterns of Dechlorane Plus and Dechlorane-602 in air across Europe indicate the influence of primary sources of these compounds on background concentrations in European air. Future air monitoring efforts targeting dechloranes is needed in both background and source areas, including consistent temporal trends.

Understanding the Environmental Distribution and Potential Health Risks of Pollutants from Deodorant Products: A Review

Deodorants are frequently used personal care products; however, questions have been raised concerning their possible toxicity to cause air and water pollution, and their potential impact on human health. The degree to which deodorant ingredients, such as fragrance chemicals, antibacterial compounds, aluminium compounds, and preservatives, are toxic depends on their chemical composition. Many of these chemicals have been connected to adverse health effects, such as skin rashes, allergic reactions, endocrine disruption, and respiratory problems. Understanding these chemicals’ toxicity is crucial for determining any potential risks to human health. Spray formulations have the potential to release volatile organic compounds into the air, such as propellants and fragrance chemicals, which can be harmful to human respiratory health and lead to indoor and outdoor air pollution. Improper disposal and wastewater treatment can lead to the contamination of water bodies, potentially impacting aquatic ecosystems and human water supplies. This review provides an overview of the toxicity of deodorant ingredients in various formulations, including sprays, roll-ons, and sticks. The partition coefficients Log Kaw (air-water partition coefficient), Log Koa (airorganic carbon partition coefficient), and Log Kow (octanol-water partition coefficient), values of deodorant ingredients were summarized for assessing their potential for long-range transport, persistence in the environment, and bioaccumulation in organisms.

Biomonitoring Atmospheric Pollution of Polycyclic Aromatic Hydrocarbons Using Mosses

Polycyclic aromatic hydrocarbons (PAHs), as the main components of petroleum hydrocarbons (PHCs), are carcinogenic organic pollutants that occur widely in the atmospheric environment with increasing concentration. Moreover, PAHs are widespread all over the world due to their high volatility and long-range transport potential. The monitoring of atmospheric PAHs is often limited by working conditions, especially around oil field operation areas and other industrial areas. Mosses (Bryophyta), the most sensitive atmosphere pollution indicators, can be easily collected and have been used to monitor atmospheric pollutants including PAHs. Thus, characteristics and influencing factors of mosses’ absorption and accumulation of PAHs in the atmosphere were discussed, and the application of mosses in the biomonitoring of atmospheric PAHs were summarized. Biomonitoring mosses include Dicranum scoparium, Hypnum cupressiforme, Thamnobryum alopecurum, Thuidium tamariscinum, Hylocomium splendens, Pleurozium scheberi, etc. Currently, the main methods for monitoring PAHs by mosses are biomonitoring with the chemical analysis method, the index of atmospheric purity (IAP) method, the ecological survey method, and the Moss-bag technique. Biomonitoring of atmospheric PAHs using mosses has a relatively wide range of prospects.

Research progress of the POP fugacity model: a bibliometrics-based analysis.

With the emergence of environmental issues regarding persistent organic pollutants (POPs), fugacity models have been widely used in the concentration prediction and exposure assessment of POPs. Based on 778 relevant research articles published between 1979 and 2020 in the Web of Science Core Collection (WOSCC), the current research progress of the fugacity model on predicting the fate and transportation of POPs in the environment was analyzed by CiteSpace software. The results showed that the research subject has low interdisciplinarity, mainly involving environmental science and environmental engineering. The USA was the most paper-published country, followed by Canada and China. The publications of the Chinese Academy of Sciences, Lancaster University, and Environment Canada were leading. Collaboration between institutions was inactive and low intensity. Keyword co-occurrence analysis showed that polychlorinated biphenyls, organochlorine pesticides, and polycyclic aromatic hydrocarbons were the most concerning compounds, while air, water, soil, and sediment were the most concerning environmental media. Through co-citation cluster analysis, in addition to the in-depth exploration of traditional POPs, research on emerging POPs such as cyclic volatile methyl siloxane and dechlorane plus were new research frontiers. The distribution and transfer of POPs in the soil-air environment have attracted the most attention, and the regional grid model based on fugacity has been gradually improved and developed. The co-citation high-burst detection showed that the research hotspots gradually shifted from pollutant persistence and long-range transport potential to pollutant distribution rules among the different environmental media and the long-distance transmission simulation.

Occurrence of the UV-filter 2-Ethylhexyl 4-methoxycinnimate (EHMC) in Antarctic snow: First results

The distribution of Personal Care Products in Antarctica is still far from being well documented. A pilot study was conducted to evaluate the presence of organic UV filters in Antarctica using GC–MS/MS. The 2-Ethylhexyl 4-methoxycinnimate (EHMC), also known as octinoxate, was detected for the first time in Antarctic surface snow, and also in snowmelt and ponds with concentrations from 0.4 ng/L up to 3.1 ng/L. In this pristine environment, human activities in scientific bases and facilities are a potential primary local source of EHMC. However, the results presented in this study suggest that long-range sources might also be responsible for the presence of EHMC in Antarctica. Considering the physicochemical properties of EHMC, long-range atmospheric transport is plausibly a relevant process involved in its deposition and accumulation in Antarctic snow. Two modelling studies on contaminants' long-range transport potential are compared to investigate the behaviour of EHMC in polar environments and its transport potential.

Priority pesticides in Chile: Predicting their environmental distribution, bioaccumulation, and transport potential.

Agriculture is one of the main economic activities in Chile and is associated with extensive use of pesticides, which can represent a risk to the environment and to human health. Currently, there are over 400 pesticides approved for commerce in Chile, including chemicals banned in other countries (e.g., flocoumafen and chlorfenapyr). An empirical analysis of their potential environmental effects is difficult due to this large number, thus opening the doors for the use of computational tools for prioritization efforts based on their persistence, bioaccumulation, and transport potential in the environment. The main objectives of this study were to estimate the properties and environmental distribution of pesticides approved for commerce in Chile and to generate a priority list for further evaluation in local environments. We used the Estimation Program Interface Suite interface to estimate the distribution coefficients, half-lives, and bioaccumulation potential of all pesticides registered in the Chilean Agriculture and Livestock Services. Additionally, the Pov & LRTP Screening Tool was used to estimate their overall persistence and long-range transport potential in the environment. The results were used to develop a P-B-lon range transport (LRT) score, which considered persistence, bioaccumulation, and long-range transport potential. All pesticides were compared to a group of polychlorinated biphenyls (PCBs), used as reference compounds, to generate a list of priority pesticides with persistent organic pollutants characteristics. The results showed that most pesticides were distributed between the organic phase and water, where they also showed the longest half-lives and bioaccumulation potential. A group of 21 pesticides showed relatively high P-B-LRT scores, compared to PCBs, and were classified as priority compounds. The list was further refined based on the volume of sales for each pesticide.Integr Environ Assess Manag 2023;19:676-683. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Reducing mercury emissions from coal-fired power plants in India: Possibilities and challenges.

Coal combustion is the largest source of power in India at the moment. This combustion also emits trace amounts of hazardous substances such as mercury. Mercury is a global pollutant with the potential for long-range transport and ability to persist in the environment, bioaccumulate and cause toxicity. Controlling emissions of mercury from coal-fired power plants (CFPPs) is recognized by the Minamata Convention on Mercury as an important step in curbing the harmful effects of mercury to the environment and humans. India has been identified as one of the top emitters of mercury to the atmosphere, and coal combustion contributes to more than half of these emissions. Here, we discuss the current state of regulations on mercury emissions from CFPPs in India, the current information on mercury from CFPP stacks, and the possible way forward. Present data suggest that mercury specific emission control technologies are not required to comply with the regulatory requirements. As such, any reduction in mercury emissions will rely on co-benefits obtained from technologies to control emissions of other pollutants such as flue gas desulphurization, or methods to increase the efficiencies of CFPP such as coal washing. Additional reductions may be made from a business-as-usual scenario if the energy mix of India changes to renewable non-fossil fuel-based energy at an accelerated pace. Quantitative studies assessing the role of such climate change policies on mercury emissions reduction are recommended.

The Emissions Fractions Approach to Assessing the Long-Range Transport Potential of Organic Chemicals.

The assessment of long-range transport potential (LRTP) is enshrined in several frameworks for chemical regulation such as the Stockholm Convention. Screening for LRTP is commonly done with the OECD Pov and LRTP Screening Tool employing two metrics, characteristic travel distance (CTD) and transfer efficiency (TE). Here we introduce a set of three alternative metrics and implement them in the Tool’s model. Each metric is expressed as a fraction of the emissions in a source region. The three metrics quantify the extent to which the chemical (i) reaches a remote region (dispersion, ϕ1), (ii) is transferred to surface media in the remote region (transfer, ϕ2), and (iii) accumulates in these surface media (accumulation, ϕ3). In contrast to CTD and TE, the emissions fractions metrics can integrate transport via water and air, enabling comprehensive LRTP assessment. Furthermore, since there is a coherent relationship between the three metrics, the new approach provides quantitative mechanistic insight into different phenomena determining LRTP. Finally, the accumulation metric, ϕ3, allows assessment of LRTP in the context of the Stockholm Convention, where the ability of a chemical to elicit adverse effects in surface media is decisive. We conclude that the emission fractions approach has the potential to reduce the risk of false positives/negatives in LRTP assessments.

Insights into Variations and Potential Long-Range Transport of Atmospheric Aerosols from the Aral Sea Basin in Central Asia

The dramatic shrinkage of the Aral Sea in the past decades has inevitably led to an environmental calamity. Existing knowledge on the variations and potential transport of atmospheric aerosols from the Aral Sea Basin (ASB) is limited. To bridge this knowledge gap, this study tried to identify the variations and long-range transport of atmospheric aerosols from the ASB in recent years. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data were used to gain new insight into the types, variation and long-range transport of atmospheric aerosols from the ASB. The results showed five types of tropospheric aerosols and one type of stratospheric aerosol were observed over the ASB. Polluted dust and dust were the dominant subtypes through the year. Sulfate/other was the only stratospheric aerosol detected. The occurrence frequency of aerosols over the ASB showed obvious seasonal variation. Maximum occurrence frequency of dust appeared in spring (MAM) and that of polluted dust peaked in summer (JJA). The monthly occurrence frequency of dust and polluted dust exhibited unimodal distribution. Polluted dust and dust were distributed over wide ranges from 1 km to 5 km vertically. The multi-year average thickness of polluted dust and dust layers was around 1.3 km. Their potential long-range transport in different directions mainly impacts Uzbekistan, Turkmenistan, Kazakhstan and eastern Iran, and may reach as far as the Caucasus region, part of China, Mongolia and Russia. Combining aerosol lidar, atmospheric climate models and geochemical methods is strongly suggested to gain clarity on the variations and long-range transport of atmospheric aerosols from the Aral Sea Basin.

Suspect Screening of Liquid Crystal Monomers (LCMs) in Sediment Using an Established Database Covering 1173 LCMs.

Recent studies have suggested that liquid crystal monomers (LCMs) are emerging contaminants in the environment, and knowledge of this class of substances is very rare. Here, we reviewed existing LCM-related documents, i.e., publications and patents, and established a database involving 1173 LCMs. These 1173 LCMs were further calculated for their physicochemical properties, i.e., persistence (P), bioaccumulation (B), long-range transport potential (LRTP), and Arctic contamination and bioaccumulation potential (ACBAP). We found that 476 out of them were P&B chemicals (99% of them were halogenated), and 320 of them could have ACBAP properties (67% of them were halogenated). This LCM database was further applied for suspect screening of LCMs in n = 33 sediment samples by use of gas chromatography coupled to quadrupole time-of-flight mass spectrometry (GC-QTOF/MS). We tentatively identified 26 LCM formulas, which could have 43 chemical structures. Two out of these 43 suspect LCM candidates, 1-butoxy-2,3-difluoro-4-(4-propylcyclohexyl) benzene (3cH4OdFP) and 1-ethoxy-2,3-difluoro-4-(4-pentyl cyclohexyl) benzene (5cH2OdFP), were fully confirmed by a comparison of unique GC and MS characteristics with their authentic standards. Overall, our present study expanded the previous LCM database from 362 to 1173, and 1173 LCMs in this database were calculated for their physicochemical properties. Meanwhile, taking n = 33 sediment samples as an exercise, we successfully developed a suspect screening strategy tailored for LCMs, and this strategy could have promising potential to be extended to other environmental matrices.