Emerging Organic Contaminants in the Third Pole Region: Sources, Transport, and Associated Risks.

Abstract. The presence of emerging organic contaminants (EOCs) in surface water bodies can cause adverse effects on non-target organisms. When these surface water bodies are used as drinking water sources, temporal variability in EOC concentrations can potentially impact drinking water quality and human health. To better understand the spatiotemporal variability of EOCs in drinking water sources in Central Pennsylvania, EOCs were evaluated in six drinking water sources during a two-year study (April 2016 – June 2018) in the Susquehanna River Basin (SRB). The study was conducted in two phases, whereby Phase I was a spatially distributed sampling within the SRB focusing on seven human pharmaceuticals while Phase II was a temporally intensive sampling regime at one site focusing on a broader range of EOCs including human and veterinary pharmaceuticals and a neonicotinoid insecticide. Concentration-discharge (C-Q) relationships were utilized to classify the transport dynamics exhibited by EOCs and understand the extent to which transport pathways such as surface runoff and wastewater effluent discharge may contribute to the presence of EOCs. Overall, EOCs were present at higher concentrations in colder seasons than warmer seasons. Concentrations of thiamethoxam, a neonicotinoid insecticide used in agricultural fields, and caffeine exhibited accretion dynamics in surface water during high flow periods consistent with higher transport during surface runoff events. Human pharmaceuticals known to persist in wastewater effluent were inversely correlated with discharge, indicating dilution characteristics consistent with diminished wastewater signals during surface runoff events. Acetaminophen exhibited episodic transport dynamics consistent with nonpoint source inputs during high flow periods.

The presence of numerous emerging organic contaminants (EOCs) and remobilization of legacy persistent organic pollutants (POPs) in polar regions have become significant concerns of the scientific communities, public groups and stakeholders. This work reviews the occurrences of EOCs and POPs and their long-range environmental transport (LRET) processes via atmosphere and ocean currents from continental sources to polar regions. Concentrations of classic POPs have been systematically monitored in air at several Arctic stations and showed seasonal variations and declining trends. These chemicals were also the major POPs reported in the Antarctica, while their concentrations were lower than those in the Arctic, illustrating the combination of remoteness and lack of potential local sources for the Antarctica. EOCs were investigated in air, water, snow, ice and organisms in the Arctic. Data in the Antarctica are rare. Reemission of legacy POPs and EOCs accumulated in glaciers, sea ice and snow may alter the concentrations and amplify their effects in polar regions. Thus, future research will need to understand the various biogeochemical and geophysical processes under climate change and anthropogenic pressures.

Emerging organic pollutants in the vadose zone of a soil aquifer treatment system: Pore water extraction using positive displacement

The Tibetan Plateau and its surrounding mountains have an average elevation of 4,400 m and a glaciated area of $$\sim $$ 100,000 $$\hbox {km}^{2}$$ giving it the name “Third Pole (TP) region”. The TP is the headwater of many major rivers in Asia that provide fresh water to hundreds of millions of people. Climate change is altering the energy and water cycle of the TP at a record pace but the future of this region is highly uncertain due to major challenges in simulating weather and climate processes in this complex area. The Convection-Permitting Third Pole (CPTP) project is a Coordinated Regional Downscaling Experiment (CORDEX) Flagship Pilot Study (FPS) that aims to revolutionize our understanding of climate change impacts on the TP through ensemble-based, kilometer-scale climate modeling. Here we present the experimental design and first results from multi-model, multi-physics ensemble simulations of three case studies. The five participating modeling systems show high performance across a range of meteorological situations and are close to having ”observational quality” in simulating precipitation and near-surface temperature. This is partly due to the large differences between observational datasets in this region, which are the leading source of uncertainty in model evaluations. However, a systematic cold bias above 2000 m exists in most modeling systems. Model physics sensitivity tests performed with the Weather Research and Forecasting (WRF) model show that planetary boundary layer (PBL) physics and microphysics contribute equally to model uncertainties. Additionally, larger domains result in better model performance. We conclude by describing high-priority research needs and the next steps in the CPTP project.

The scarcity of in situ observation stations and the unreliability of long-term satellite data necessitate the use of reanalysis datasets to study elevation-dependent climate change (EDCC) in the third pole (TP) region. We analyzed elevation-dependent temperature and precipitation patterns over TP using the ECMWF Atmospheric Reanalysis Fifth Generation (ERA5), a global reanalysis product with coarse resolution, along with three high-resolution regional reanalysis datasets that cover our study domain: Indian Monsoon Data Assimilation and Analysis (IMDAA), High Asia Refined Analysis—Version 2 (HAR-v2), and Tibetan Plateau Regional Reanalysis (TPRR). Comparing the performance of the four reanalysis datasets in capturing EDCC over TP is crucial, as these datasets provide spatially and temporally consistent data at an optimum resolution that greatly aids EDCC research. Our study results reveal the following: (1) A positive elevation-dependent warming trend is observed across all four datasets in winter and autumn, with varying magnitudes of warming across the datasets. (2) All four datasets exhibit positive elevation-dependent wetting trends in all seasons, except autumn. These are primarily driven by pronounced drying trends at lower elevations and relatively minimal changes in precipitation trends at higher elevations. (3) ERA5 and IMDAA exhibit similar results in capturing elevation-dependent climate change, whereas the TPRR dataset reveals more extreme and unique features in temperature trends compared to the other three datasets. HAR-v2 shows smaller variations in temperature and precipitation trends across different elevations and seasons, in contrast to the other three datasets. While all reanalysis datasets indicate EDCC in the TP, their varying degrees of seasonal and spatial differences underscore the need for a careful evaluation before using them as reference data. Comparison of reanalysis datasets with available observational records, such as in situ measurements and satellite data, over overlapping spatial and temporal domains is essential to assess their quality. This evaluation can help identify the most suitable reanalysis dataset, or combination of datasets, to serve as reliable a reference even in regions or periods without observational data.

Recent advances in the application of bismuth-based catalysts for degrading environmental emerging organic contaminants through photocatalysis: A review

The nexus between atmospheric moisture transport and basin‐scale flood response is still lacking over the Third Pole (TP) region, despite projected increases in extreme rainfall under a changing climate. Based on long‐term daily streamflow observations, we show that peaks‐over‐threshold floods over the Yarlung Zangbo River (YZR) basin show two temporal clusters, that is, July and late August, with the flood magnitudes of the second cluster larger than the first by 20%. These floods are resultant from a mixture of flood‐producing storms with contrasting storm motion and moisture transport pathways. A suite of coupled atmospheric‐hydrological modeling experiments further quantify the impacts of different moisture transport pathways on the space‐time rainfall structure and flood response. A 50% reduction of upper level moisture transport (i.e., through the upslope of the Himalayas) leads to decreased flood peak magnitudes by 30% at the basin outlet for the August 1998 floods over the YZR basin. Upper‐level moisture transport is associated with the notable low pressure over the central‐east India and westward extension of West Pacific Subtropical High that enhances convergence of water vapor fluxes from Bay of Bengal toward TP. The magnitude of impact can potentially alter the seasonal clustering of high‐flow events over TP. Our analyses contribute to improved characterization of flood risk over TP, and advances in flood frequency hydrology.

The Himalayas and Tibetan Plateau, identified as the Third Pole (TP), is a unique region because of its insertion into global environmental and climatic changes. Deposition of atmospheric nitrate in this region is one of the most important sources of reactive nitrogen to glacial‐hydrologic system and ecosystems. The isotopic composition of atmospherically deposited nitrate preserved in ice bodies plays a central role in delineating environmental and climatic changes, present, and past. Here, we provide an overview of the complete isotopic compositions (δ15N, δ18O, and Δ17O) of nitrate in aerosol, snow, ice, and water samples (n = 46) collected across the Southern, Southeastern, Central, and Northern TP to constrain complex nitrogen cycles of the atmosphere, cryosphere, hydrosphere, and, potentially, the biosphere. A large variability of snow nitrate isotopic compositions is observed across the TP at different spatial scales (from a single glacier to the entire plateau), likely due to the complex landscape and relevant physical and chemical processes across the TP. Large nitrate Δ17O values are observed in water samples collected from the Mt. Everest region, highlighting the considerable fraction (up to 45%) of atmospheric nitrate to the nitrate load in this Himalayan hydrologic system. Our work reveals the complex chemical, depositional, and postdepositional processes over the TP that are greater than previously thought and identifies further comprehensive investigations, which entail using nitrate isotopic compositions as an identifier for nitrate source apportionment in various ecosystems and understanding past atmospheric and climatic conditions in this region.

Abstract. Altitudinal precipitation gradient plays an important role in the interpolation of precipitation in the Third Pole (TP) region, where the topography is very complex but in situ data are very sparse. This study proves that the altitude dependence of precipitation in the TP can be reasonably reproduced by a high-resolution atmospheric simulation-based dataset called ERA5_CNN. The precipitation gradients, including both absolute (APGs) and relative gradients (RPGs), for 388 sub-basins of the TP above 2500 m a.s.l. are calculated based on the ERA5_CNN. Results show that most sub-basins have positive precipitation gradients, and negative gradients are mainly found along the Himalayas, the Hengduan Mountains and the western Kunlun. The annual APG and RPG averaged across all sub-basins of the TP are 0.05 mm d−1 × 100 m−1 and 4.25 % × 100 m−1, respectively. The values of the APG are large in wet seasons but small in dry seasons, while the RPG shows opposite variations. Further analyses demonstrate that the RPGs have negative correlations with relative humidity but positive correlations with wind speed, likely because dry air tends to reach saturation at high altitudes, while stronger wind can bring more humid air to high altitudes. In addition, we find that precipitation gradients tend to be positive at small spatial scales compared to those at large scales, mainly because local topography plays a vital role in determining precipitation distribution at small scales. These findings on the spatiotemporal variations of precipitation gradients provide useful information for interpolating precipitation in the TP region.

The presence of emerging organic contaminants (EOCs) and potentially toxic elements in groundwater is a global concern. In Nigeria, however, monitoring and risk assessment data for EOCs such as Methylparaben (MeP), Ethylparaben (EtP), Propylparaben (PrP), Butylparaben (BuP), and antibiotics like ampicillin, chloramphenicol, ciprofloxacin (CIP), and metronidazole (MET) are scarce, especially in rural areas. This study quantified EOCs and metals in groundwater from two rural Nigerian communities using high-performance liquid chromatography-UV and inductively coupled plasma optical emission spectroscopy, with validation through recovery (99.6%-101%) and linearity (R2>0.999). Health risks were assessed via target hazard quotient (THQ), target carcinogenic risk (TCR), and risk quotient (RQH). The groundwater samples followed the decreasing order: Ca > Mg > Na > K > Co > Al > Fe > Cr > Mn > Zn > Cd > Ni > Pb > B > Cu > Se for metals and MET > CIP > BuP > MeP > PrP > EtP for EOCs. Groundwater EOC concentrations were as high as 7,846 (MET), 1,137 (CIP), 342 (MeP), 295 (EtP), 299 (PrP), and 400 μgL-1 (BuP) while Fe, Zn, Al, Cr, Ni, and Pb in all groundwater samples investigated were higher than the permissible limit recommended by the World Health Organization. The human risk assessment revealed both noncarcinogenic and carcinogenic hazards from Cd, Cr, Ni, and Pb, with Cr contributing approximately 90% of the cumulative THQ and TCR. Additionally, CIP exhibited high RQH ( > 1) across all age groups, ranging from 1.142 to 49.174. Findings from this study indicate that groundwater consumption in these communities poses significant health risks.

Distribution, source identification, and health risk of emerging organic contaminants in groundwater of Xiong'an New Area, Northern China

<p>Groundwater is a vital resource for the development of urban areas where the problem focuses on the quantity as well on the quality, which constituted a challenge to be faced, an example of this is the case of Barcelona. Currently, Barcelona groundwater is used for irrigation of parks and gardens and street cleaning due to its poor quality as a source of drinking water, in addition, there are numerous pumping in the city to prevent flooding of underground structures (e.g. subway). Barcelona is a developed city with a high population density. Due to the socio economic, industrial activities and lifestyle of its inhabitants, as is common in urban areas, there has been a progressive deterioration on the quality of its water. Among the pollutants found in these waters, of special interest are the emerging organic contaminants (EOCs), which present a high risk to the aquatic environment and human health. The behavior, spatial distribution and processes that control them in the aquatic environment are still uncertain and most of them are unregulated.</p><p>In this work, the use of classical hydrogeochemical techniques, GIS, univariate, bivariate and multivariate statistical analysis and geostatistical techniques allow to assess, identify and locate the main physicochemical processes that control the composition of this waters considering the inorganic and organic (EOCs) parameters and the correlations between them.</p><p>isotopic analysis of the SO<sub>4</sub><sup>2-</sup> molecule, , corroborated the significant contribution of wastewater in the composition of these waters. The analysis of the EOCs showed that the highest concentration of these compounds is located towards the Besòs River. This fact indicate that this would be the main source and of greater magnitude of input of EOCs into the aquifer, while towards the urban area of Barcelona the abundance of EOCs would originate from sewage filtrations, where the input is of a lesser magnitude, this was corroborated with the factorial analysis of the EOCs. The areas with reducing conditions in general showed a higher concentration of these compounds, indicating that most of them would degrade more easily in oxidizing environments.</p><p>The processes and/or contributions identified are: water-rock interaction, water mixing, redox processes, aquifer-river interaction, sewage seepage and infiltration of urban runoff. The high heterogeneity found in the physicochemical parameters and EOCs would denote the complex hydrogeological situation of the system. the abundance of EOCs found in these waters together with the isotopic analysis, would indicate that the main source of recharge for most of this samples should be anthropogenic, mostly wastewater (sewage seepage or aquifer-river interaction).</p>

Although there is a growing interest in emerging organic contaminants (EOCs), most research is focused on wastewater treatment, the occurrence of EOCs, and their fate in the aquatic environment. There is limited information about their behavior in agricultural soils, where they can be introduced via irrigation with treated wastewater (TWW). In this study, the degradation in an agricultural soil of eight EOCs (bisphenol A, carbamazepine, diethyl phthalate, ethyl paraben, 5-methyl-1H-benzotriazole, primidone, Surfynol 104, and tris(2-chloroethyl) phosphate) with a broad range of physical-chemical properties was monitored for 40 days. Two types of soil treatments were performed: non-sterilization and sterilization. In the non-sterilized soil, by the end of the incubation period, degradation was greater than 70% for all the target compounds except carbamazepine, Surfynol 104, and primidone ( 70%). These findings indicate that soil sterilization reduces overall degradation rates, which suggests that microbial activity plays an important role in the degradation of most of the EOCs studied in soil.

The photochemically generated oxidative organic radicals (POORs) in dissolved black carbon (DBC) was investigated and compared with that in dissolved organic matter (DOM). POORs generated in DBC solutions exhibited higher one-electron reduction potential values (1.38-1.56 V) than those in DOM solutions (1.22-1.38 V). We found that the photogeneration of POORs from DBC is enhanced with dissolved oxygen (DO) increasing, while the inhibition of POORs is observed in reference to DOM solution. The behavior of the one-electron reducing species (DBC•-/DOM•-) was employed to explain this phenomenon. The experimental results revealed that the DO concentration had a greater effect on DBC•- than on DOM•-. Low DO levels led to a substantial increase in the steady-state concentration of DBC•-, which quenched the POORs via back-electron reactions. Moreover, the contribution of POORs to the degradation of 19 emerging organic contaminants (EOCs) in sunlight-exposed DBC and DOM solutions was estimated. The findings indicate that POORs play an important role in the photodegradation of EOCs previously known to react with triplets, especially in DBC solutions. Compared to DOM solutions, POOR exhibits a lower but considerable contribution to EOC attenuation. This study enhances the understanding of pollutant fate in aquatic environments by highlighting the role of DBC in photochemical pollutant degradation and providing insights into pollutant transformation mechanisms involving POORs.

Multi-residue analysis of legacy POPs and emerging organic contaminants in Singapore's coastal waters using gas chromatography–triple quadrupole tandem mass spectrometry