Prevalence of pharmaceuticals and personal care products, microplastics and co-infecting microbes in the post-COVID-19 era and its implications on antimicrobial resistance and potential endocrine disruptive effects.

The COVID-19 (coronavirus disease 2019) pandemic's steady condition coupled with predominance of emerging contaminants in the environment and its synergistic implications in recent times has stoked interest in combating medical emergencies in this dynamic environment. In this context, high concentrations of pharmaceutical and personal care products (PPCPs), microplastics (MPs), antimicrobial resistance (AMR), and soaring coinfecting microbes, tied with potential endocrine disruptive (ED) are critical environmental concerns that requires a detailed documentation and analysis. During the pandemic, the identification, enumeration, and assessment of potential hazards of PPCPs and MPs and (used as anti-COVID-19 agents/applications) in aquatic habitats have been attempted globally. Albeit receding threats in the magnitude of COVID-19 infections, both these pollutants have still posed serious consequences to aquatic ecosystems and the very health and hygiene of the population in the vicinity. The surge in the contaminants post-COVID also renders them to be potent vectors to harbor and amplify AMR. Pertinently, the present work attempts to critically review such instances to understand the underlying mechanism, interactions swaying the current health of our environment during this post-COVID-19 era. During this juncture, although prevention of diseases, patient care, and self-hygiene have taken precedence, nevertheless antimicrobial stewardship (AMS) efforts have been overlooked. Unnecessary usage of PPCPs and plastics during the pandemic has resulted in increased emerging contaminants (i.e., active pharmaceutical ingredients and MPs) in various environmental matrices. It was also noticed that among COVID-19 patients, while the bacterial co-infection prevalence was 0.2-51%, the fungi, viral, protozoan and helminth were 0.3-49, 1-22, 2-15, 0.4-15% respectively, rendering them resistant to residual PPCPs. There are inevitable chances of ED effects from PPCPs and MPs applied previously, that could pose far-reaching health concerns. Furthermore, clinical and other experimental evidence for many newer compounds is very scarce and demands further research. Pro-active measures targeting effective waste management, evolved environmental policies aiding strict regulatory measures, and scientific research would be crucial in minimizing the impact and creating better preparedness towards such events among the masses fostering sustainability.

Scenario, perspectives and mechanism of arsenic and fluoride Co-occurrence in the groundwater: A review.

Arsenic (As) and fluoride (F-) are the two most conspicuous contaminants, in terms of distribution and menace, in aquifers around the world. While the majority of studies focus on the individual accounts of their hydro-geochemistry, the current work is an effort to bring together the past and contemporary works on As and F- co-occurrence. Co-occurrence in the context of As and F- is a broad umbrella term and necessarily does not imply a positive correlation between the two contaminants. In arid oxidized aquifers, healthy relationships between As and F- is reported owing desorption based release from the positively charged (hydr)oxides of metals like iron (Fe) under alkaline pH. In many instances, multiple pathways of release led to little or no correlation between the two, yet there were high concentrations of both at the same time. The key influencer of the strength of the co-occurrence is seasonality, environment, and climatic conditions. Besides, the existing primary ion and dissolved organic matter also affect the release and enrichment of As-F- in the aquifer system. Anthropogenic forcing in the form of mining, irrigation return flow, extraction, recharge, and agrochemicals remains the most significant contributing factor in the co-occurrence. The epidemiological indicate that the interface of these two interacting elements concerning public health is considerably complicated and can be affected by some uncertain factors. The existing explanations of interactions between As-F are indecisive, especially their antagonistic interactions that need further investigation. "Multi-contamination perspectives of groundwater" is an essential consideration for the overarching question of freshwater sustainability.

Multilayer arsenic mobilization and multimetal co-enrichment in the alluvium (Brahmaputra) plains of India: A tale of redox domination along the depth.

The study attempts to understand arsenic (As) mobilization in a shallow aquifer with depth variation while focusing on the potential co-occurrence of As with priority metals (zinc and lead), using a pilot scale multilevel groundwater monitoring system (MGWS). Groundwater samples (n = 72) were collected bi-weekly (every 15 days) from the multilevel sampler (4.6, 9.2 and 13.8 m depths), installed at Tezpur, Sonitpur district of Brahmaputra floodplain (BFP), Assam, India, for a period of 1 year (August 2013-July 2014). Both geogenic and anthropogenic influences were found to affect the studied unconfined aquifer. At 4.6 m, weathering dominated due to interaction with CO2 and infiltrating water. Prevalent high pH (7.9-8.6) at all three depths in association with strong oxidizing condition (at 4.6 m) during the drier months seem to play a crucial role in desorption based As release. Multivariate analyses revealed that redox potential (ORP) remains the primary controller of As release at all three depths. With depth, stronger anoxic conditions resulted in the dominance of reductive hydrolysis leading to a co-occurrence scenario of As (max 4.6 µgL-1) with Zn (max 2514 µgL-1) and Pb (max 740 µL-1) with influences of anthropogenic modes of activities like agriculture and dry deposition from a brick kiln. Multi-element enrichment is an emerging concern but the bigger picture would be to understand the peculiarities of individual aquifers, as a generalization can lead to missing a ton of information. In this regard, long-term multilevel monitoring can help in the predictive understanding of the vertical stratification and co-occurrences of multi-metals that can subsequently be applied for water production at the safer depths.

Provenance, prevalence and health perspective of co-occurrences of arsenic, fluoride and uranium in the aquifers of the Brahmaputra River floodplain.

The present work focuses on understanding the provenance, prevalence and health perspective of As and F- along with possible co-occurrence of uranium (U) in the aquifers of the Brahmaputra floodplains (BFP), India. Groundwater (n = 164) and sediment samples (n = 5) were obtained from the upper, middle and lower BFP. Energy dispersive spectroscopy (EDX) revealed the presence of As, U and Fe in the sediment matrix. Regression analysis showed a weaker relationship between As and F- co-occurrence. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) suggested reductive dissolution of Fe (hydr)oxides responsible for As release in the BFP, especially in the upper and lower BFP. Bicarbonate appeared to compete with As oxyanions for adsorption on positively charged surfaces leading to As release. Arsenic desorption in presence of PO43-, F- and HCO3- at elevated pH appeared greatest in the upper BFP, suggesting the highest potential for co-occurrence. Co-occurrence, were mainly in isolated aquifers of the upper BFP owing to desorption of adsorbed As and F- from Fe (hydr)oxides at higher pH. Weathering and dissolution of clay minerals in the upper BFP, and competitive desorption in presence of HCO3- and PO43- in the middle and lower BFP, respectively, explain variabilities in F- release. Amorphous Fe (hydr)oxides like ferrihydrite act as sinks of U. Concentrations of As and F- will likely increase in the future as projected from the saturated levels of goethite and ferrihydrite. Hazard indices (HI) revealed that children (3-8 years) were at greater health risk than adults.

Simultaneous Semi-Coupled Dictionary Learning for Matching in Canonical Space.

Cross-modal recognition and matching with privileged information are important challenging problems in the field of computer vision. The cross-modal scenario deals with matching across different modalities and needs to take care of the large variations present across and within each modality. The privileged information scenario deals with the situation that all the information available during training may not be available during the testing stage, and hence, algorithms need to leverage the extra information from the training stage itself. We show that for multi-modal data, either one of the above situations may arise if one modality is absent during testing. Here, we propose a novel framework, which can handle both these scenarios seamlessly with applications to matching multi-modal data. The proposed approach jointly uses data from the two modalities to build a canonical representation, which encompasses information from both the modalities. We explore four different types of canonical representations for different types of data. The algorithm computes dictionaries and canonical representation for data from both the modalities, such that the transformed sparse coefficients of both the modalities are equal to that of the canonical representation. The sparse coefficients are finally matched using Mahalanobis metric. Extensive experiments on different data sets, involving RGBD, text-image, and audio-image data, show the effectiveness of the proposed framework.

Hydrogeochemical controls on mobilization of arsenic and associated health risk in Nagaon district of the central Brahmaputra Plain, India.

In recent years, elevated concentration of arsenic (As) in groundwater in the northeastern states of India has become a major cause of concern. Since many regions of the Brahmaputra plains are reported with groundwater As contamination, an attempt was made to study the As contamination and factors governing its release in the Nagaon district in Brahmaputra floodplain, based on various water types, relation of As with other major ions and with various depth profiles. The origin of groundwater mineralization and the processes responsible for As enrichment in groundwater was determined by calculating saturation index using PHREEQC code. Multivariate statistical analysis was carried out for identification of As-releasing mechanism based on rock-water interaction. Principle component analysis of physicochemical parameters revealed the association of As with SiO2 and Cl- in pre-monsoon and the fact that alkaline condition favors release of As. The relation between As and Fe shows that reductive dissolution of solid Fe oxide and hydroxide phases could be the source of As in Nagaon district. The result of hierarchical cluster analysis indicates that As release could also be associated with the agrochemicals application. Health risk assessment revealed that children are more susceptible to carcinogenic as well as non-carcinogenic health impact with consumption of As-contaminated drinking water. The male population is more susceptible to cancer as compared to females as the average water consumption is higher in case of male. Overall, the study highlights the health risk assessment is a matter of chief concern in this study as the younger generation are at higher risk.

Coupling fractionation and batch desorption to understand arsenic and fluoride co-contamination in the aquifer system.

The present work is an attempt to study As and F+ coevality using laboratory based assays which couples fractionation and batch dissolution experiments. Sequential extraction procedure (SEP) resulting into five "operationally defined phases", was performed on sediment and soil samples collected from the Brahmaputra flood plains, Assam, India. High correlation between the Fe (hydr)oxide fraction and total As content of the soil/sediment sample indicates the involvement of Fe (hydr)oxides as the principal source of As. F- being an anion has high potential to be sorbed onto positively charged surfaces. Findings of the SEP were used to design the batch desorption experiments by controlling the Fe (hydr)oxide content of the soil/sediment. Desorption of As and F- was observed under acidic, neutral and alkaline pH from untreated and Fe (hydr)oxide removed samples. Highest amount of As and F- were found to be released from untreated samples under alkaline pH, while the amount leached from samples with no Fe (hydr)oxide was low. The study showed that the Fe (hydr)oxide fraction commonly found in the soils and sediments, had high affinity for negatively charged species like F- oxyanions of As, AsO43- (arsenate) and AsO33- (arsenite). Fe (hydr)oxide fraction was found to play the major role in co-evolution of As and F-. Two sorption coefficients were proposed based on easily leachable fraction and As present in the groundwater of sampling location for understanding of contamination vulnerability from the leaching.

Co-occurrence perspective of arsenic and fluoride in the groundwater of Diphu, Assam, Northeastern India.

Considerable lacunae exists in As and F(-) co-contamination investigation in the Brahmaputra and Gangetic floodplains. Therefore we selected Diphu a township in the Karbi Plateau rising from the Brahmaputra floodplains for evaluation of As and F co-occurrence, correlation with coexisting ions of the aquifer system and elucidation of potential processes for releasing As and F(-) in the groundwater. Our initial appraisal used generic plots for identification of hydro geochemical processes and major water types. Subsequently, As and F(-) co-occurrence with pH, depth, HCO3(-), SO4(2-), Ca(2+) and Fe were probed for possible correlation followed by hierarchical cluster analyses to identify key processes for co-occurrence. Finally, saturation indices of groundwater minerals were calculated using MINTEQA2 to elucidate prospective As and F(-) release into groundwater. Results indicate F(-) and As presence in Ca-HCO3 rich water along with positive correlation between Ca(2+) and F(-) possibly due to limestone reserves in adjoining areas. Multivariate analyses suggest the presence of high concentrations of PO4(3-), and H4SiO4 either individually or in combination can enhance the mobility of both As and F(-) and possibly abet conditions conducive for co-contamination of aquifers. Initial release of As and F(-) from the parent rock seems driven by the anthropogenic activities while mobilization depends on chemical interactions and individual affinities of the elements. The results of speciation highlight further mobilization of As and F(-) into the groundwater which in turn require regular attention for sustainable management of scarce water resource present in the area.