Search Results (81)

Heavy metal pollution is one of the major global issues arising from various anthropogenic activities. The natural habitat and human health may be at peril from heavy metal exposure since they are tenacious, bio-accumulative, and non-biodegradable. Therefore, eradicating heavy metals from the soil ecosystem is a crucial responsibility to create a secure, viable, and zero-waste ecosystem. There are numerous techniques for eliminating heavy metals from the environment, but each has its own benefits and drawbacks. When a biological agent is used to degrade pollutants, this process is called bioremediation. Nano-phytoremediation, an emerging bioremediation approach in the field of nanotechnology, uses biosynthesized nanoparticles and plant species for the removal of toxic heavy metals from the environment. It is an efficient, economical, and environmentally friendly technique. The adverse consequences of metal exposure on different plant species have been discovered to be greatly reduced by engineered nanomaterials. Because of their tiny dimensions and huge surface area, nanomaterials have an attraction towards metals and can thus quickly enter the contaminated zone of ecosystems that are metal-challenged. The current review provides an overview of various aspects of nano-phytoremediation for heavy metal remediation. Full article

Arsenic (As), a widely distributed metalloid in the Earth’s crust, constitutes one of the most significant environmental contaminants today. This study was carried out to determine As concentrations in the soils of a Castilla La Mancha (CLM; Spain) benchmark collection that represents all the soil orders (soil taxonomy) in this territory. It also examined vine plant tolerance to As in relation to soil concentration. For this purpose, soils and leaves from vineyards were collected from 10 locations in the CLM community. The bioconcentration factor (BCF) of As in vineyards was assessed. The results of the present study show that As content in soils is widely variable, and is fundamentally related to soil type and parent material. The most surprising point is that, although some vineyards have been treated with As derivatives, the vast majority of them do not accumulate any amount of As. This important finding must be used to enhance the quality of the final obtained product: wine. In other words, CLM wines are not at risk of As contamination and must, therefore, be clean wines. Our results suggest that CLM vineyards are clean of contamination by As because this element in leaves reveals null vine capacity to accumulate As, a process that derives from scarce As in soils and the traditional practices carried out by winegrowers. Full article

Analyses of mosses and lichens provide some information on the contents of both particulate and dissolved (from hydrometeors including snow and flooding) metal ions and other elements like As and Sb in the local environment. However, this information is compromised by rarity (and thus duly legal protection) of suitable species (particularly lichens) for regular sampling and also by poorly understood mechanisms of binding. Hence, it is crucial to find an alternative that does not harm or kill rare and/or protected organisms for sampling purposes while providing data that can be traced to environmental levels (e.g., metal ions in water) in a comprehensible way. Studying the coordination of aq. metal ions on some biogenic surface which can form ligating bonds to these ions provides such information. The most abundant and thus cheap such biopolymer acting as both a possible ligand and a water- (or environment-)biomass interface is chitin. Data from chitin exposed in either water, common sandy sediments, and ferric gels delivered by Fe-oxidizing bacteria are processed to understand adsorption in quantitative terms depending on local conditions, accounting for observed BCFs >> 1 for certain elements (Bi, V, LREEs). Slopes of functions that describe the increase of retention of some element upon increasing aq. concentrations allow us to construct (a) some function giving BCF by numerical integration, (b) predict the behavior of other elements for which certain parameters guiding complex formation are known as well. It turns out that top sensitivities (maximum BCF- or partition factor) values are reached with different elements depending on the environment the chitin sample was exposed to. PF can extend the detection and determination of many elements below levels directly observable in water or sediments. The detection of fallout radionuclides on chitin is even more sensitive (by a factor of 20–25) because of omitting dilution in workup by direct observation of γ radiation. Full article

Seafood constitutes the primary source of exposure to the organic form of mercury in the general population, and the Trieste Gulf is considered a hotspot of mercury contamination. We used a newly developed quantitative food frequency questionnaire to obtain an estimation of the intake of mercury through seafood consumption in a sample of 32 individuals from Trieste. Then, we validated the results obtained from the questionnaire against those of the analysis of total mercury measured in the hair of the same individuals through Spearman rank correlation coefficients, Cohen’s weighted Kappa statistic, and a Bland–Altman plot. The Spearman rank correlation coefficient and Cohen’s weighted Kappa statistic were 0.76 and 0.69, respectively. In the Bland–Altman plot, 93.75% of the data points lay within the acceptability range. The plot revealed an ever-increasing overestimation of mercury intake by the questionnaires as the hair mercury increased. By applying a standardized filtering procedure to the results of the questionnaires, we obtained a Spearman rank correlation coefficient and Cohen’s weighted Kappa statistic of 0.69 and 0.57, respectively. In this Bland–Altman plot, 93.75% of the data points lay within the acceptability range. In this latter plot, the proportionality between the mean difference and the magnitude of the measurement was more subtle compared to that observed in the plot built upon the non-filtered questionnaires. This preliminary study shows the high accuracy of the reported questionnaire in the estimation of habitual mercury intake, similar to the one measured through the analysis of hair. Full article

This state-of-the-art review is designed to provide a factual analysis of indoor air pollution in Pakistan. Primarily, the main sources of indoor air pollution and related air pollutants were analyzed. Key sources of indoor air pollution include household energy sources (biomass, wood, coal, tobacco, and low temperatures) producing particulate matter (PM), dust particles, smoke, COx, noxious gases, bioaerosols, airborne microflora, and flame retardants. According to the literature, rural regions of Pakistan using biomass indoor fuels have a high indoor PM concentration in the range of 4000–9000 μg/m³. In rural/urban regions, indoor smoking also leads to high PM_2.5 levels of ~1800 μg/m³, which can cause pulmonary infections. In hospitals, PM concentrations were detected up to 1000 μg/m³, causing repeated infections in patients. Indoor ingestion of dust containing polychlorinated biphenyl concentrations was observed at high levels (~8.79–34.39 ng/g) in cities; this can cause serious health effects such as cancer risks and a loss of working productivity. Moreover, indoor microflora and bacteria (~10,000–15,000 cfu m⁻³) in urban/rural regions cause respiratory/cancer risks. In this context, indoor air quality (IAQ) monitoring and management strategies have been somewhat developed; however, their implementation in Pakistan’s rural/urban indoor environments is still needed. Various challenges were identified for monitoring/regulating IAQ. There is a firm need for industry–academia–research cooperation and for the involvement of government/agencies to support indoor air pollution control/management and for intervention strategies. Full article

The Brazilian Pampa biome covers half of Rio Grande do Sul state, in the extreme south of Brazil, creating an ecotone zone with the Atlantic Forest and bordering Pampa’s territory belonging to Uruguay and Argentina. Pampa is a non-forest biome mainly composed of grasslands and mosaics of grassland-forest vegetation. This biome shows significant animal and plant diversity, contributing to the maintenance of important ecosystem services, including CO₂ capture, pollination, and water cycle regulation. However, forestry plantations, inappropriate cattle ranching, mining activities, unplanned urbanization, and the cultivation of monocultures (soy, rice, tobacco, and other cash crops) significantly threaten the conservation of the Pampa biome. A major problem observed in the Pampa, due to the great connection of this biome with agricultural areas, is pesticide pollution, which significantly affects the health of humans and animals that occupy the region. A robust body of evidence indicates that aquatic and terrestrial ecosystems in the Brazilian Pampa are extensively contaminated with pesticides, as indicated by studies involving animal biomarkers and pesticide analyses performed on water and soil samples. Human studies also suggest that pesticides affect different body systems, facilitating the onset of various chronic diseases. Brazil’s conservation actions and policies have a special focus on forest ecosystems, neglecting non-forest biomes and thus aggravating the problems related to Pampa’s conservation. In this article, we discuss some problems caused by pesticide pollution in the Brazilian Pampa, drawing attention to the need for intensification of policies focused on the promotion of human and environmental health. Finally, we suggest the bioecological bioeconomy as an alternative for Rio Grande do Sul to progress its economic development but with less dependency on detrimental activities to the Pampa biome. Full article

Air pollution (AP) is a significant risk factor for public health, and its impact is becoming increasingly concerning in developing countries where it is causing a growing number of health issues. It is therefore essential to map and monitor AP sources in order to facilitate local action against them. This study aims at assessing the suitability of Sentinel-5 AP products based on Google Earth Engine (GEE) to monitor air pollutants, including CO, NO₂, SO₂, and O₃ in Arak city, Iran from 2018 to 2019. Our process involved feeding satellite images to a cloud-free GEE platform that identified pollutant-affected areas monthly, seasonally, and annually. By coding in the JavaScript language in the GEE, four pollution parameters of Sentinel-5 satellite images were obtained. Following that, images with clouds were filtered by defining cloud filters, and average maps were extracted by defining average filters for both years. The employed model, which solely used Sentinel-5 AP products, was tested and assessed using ground data collected from the Environmental Organization of Central Province. Our findings revealed that annual CO, NO₂, SO₂, and O₃ were estimated with RMSE of 0.13, 2.58, 4.62, and 2.36, respectively, for the year 2018. The annual CO, NO₂, SO₂, and O₃ for the year 2019 were also calculated with RMSE of 0.17, 2.41, 4.31, and 4.6, respectively. The results demonstrated that seasonal AP was estimated with RMSE of 0.09, 5.39, 0.70, and 7.81 for CO, NO₂, SO₂, and O₃, respectively, for the year 2018. Seasonal AP was also estimated with RMSE of 0.12, 4.99, 1.33, and 1.27 for CO, NO₂, SO₂, and O₃, respectively, for the year 2019. The results of this study revealed that Sentinel-5 data combined with automated-based approaches, such as GEE, can perform better than traditional approaches (e.g., pollution measuring stations) for AP mapping and monitoring since they are capable of providing spatially distributed data that is sufficiently accurate. Full article

Beaches are major sites of microbiological pollution. Assessment of the abundance of resistant forms of enteric protozoa on these recreational waters is important for the prevention and management of health risks. Based on sedimentation and flotation methods, this study found that Kribi beach waters concentrate considerable amounts of enteric protozoa, which are potentially pathogenic. They include Coccidia (Cryptosporidium sp. and Cyclospora cayetanensis), Amoebae (Endolimax nana, Entamoeba histolytica and Entamoeba coli) and Flagellates (Giardia intestinalis). In general, seasonal changes and tidal cycles have significantly impacted the spread of these parasites along Kribi beaches. Thus, at all sites surveyed (Mpalla, Ngoyè and Mboamanga), maximum protozoan abundances were recorded at low tide and during the rainy seasons. It should also be noted that at each sampling site, significant correlations were recorded between certain protozoa and certain physico-chemical variables (p < 0.05). At Mboamanga, for example, Cryptosporidium sp. and Endolimax nana were positively correlated during the Short Rainy Season with temperature (r = 0.601, p = 0.044 and r = 0.632, p = 0.042). At Mpalla, a positive and significant correlation was observed during the Short Rainy Season between Entamoeba coli and pH (r = 0.605, p = 0.033). The high concentration of resistant forms of these enteric protozoa at Kribi beaches is a real public health threat for bathers. Therefore, in this tourist town, it is urgent to put in place an effective plan for the collection and sustainable treatment of solid and liquid waste, which are the main sources of contamination. Full article

The current study aimed to determine the acute and sub-chronic toxicity of ammonia to juvenile surf clams (Mactra chinensis Philippi). Acute toxicity tests were conducted with seven concentrations of ammonium chloride using a 96 h static-renewal approach. Sub-chronic ammonia exposure tests (20 d exposures) were conducted with 6 concentrations at 20 °C. The 96 h median lethal concentration (96 h LC₅₀) was 11.1 (10.0; 12.0) mg/L total ammonia nitrogen (TAN) and 0.56 (0.50; 0.60) mg/L unionized ammonia (NH₃). The relative growth rate was significantly reduced at concentrations higher than 1.6 mg/L TAN (0.075 mg/L NH₃) in the 20 d tests. The estimated maximum acceptable toxicant concentration (MATC) based on the reduced growth of juvenile M. chinensis was between 0.8 and1.6 mg/L TAN (0.038–0.075 mg/L NH₃). Histopathological changes were evaluated in the surviving clams after 20 days of exposure. Exposure to 14.1 mg/L TAN (0.661 mg/L NH₃) resulted in changes in the mantle, foot and digestive diverticulum. We also examined the antioxidant enzyme activities of superoxide dismutase (SOD) and catalase (CAT) in 10 d and 20 d at 6 different levels (plus a control) of ammonia from 0.8 mg/L to 14.1 mg/L TAN. Ammonia exposure at 0.8 mg/L TAN (0.038 mg/L NH₃) significantly affected SOD and CAT activities. The level of enzymic activity decreased with the increasing concentration of TAN. The results improved our understanding of oxidative damage under ammonia exposure and provided data for the aquaculture of sunray surf clams. Full article

Zinc is an essential plant and human nutrient and its primary source is Zn-rich food consumption. The only way to enrich plants with Zn is through the application of Zn fertilizers including various chemical and organic sources of ZnO nanoparticles (NPs). The Zn bioavailability from ZnO NPs must be considered for their recommendation as a fertilizer, and very little is known about the efficacy of such fertilizers in the Hungarian soil environment. In the present investigation, we prepared ZnO NPs of different sizes and applied them in two distinct textures of soils (sandy loam (SL) and silty clay (SC)) in an incubation experiment. The prepared ZnO NPs were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). ZnO NPs were applied in both soil types at 500 mg L⁻¹ in the form of a suspension, and ZnSO₄ was applied in the form of a solution. The soils were incubated for 7 and 14 days. Column leaching was performed to analyze the dissolved Zn. Retained Zn in the soil matrix was extracted using 0.05 M EDTA. The results showed that approximately 21–23% and 10–13% higher Zn was observed in the pore water of SL and SC soils, respectively, when spiked with small-sized NPs compared to large-sized NPs, while 14–26% higher dissolved Zn was observed in SL soil compared to SC soil. It is concluded that the size of NPs and the soil texture are the main factors that play important roles in deciding the fate of NPs under an alkaline soil environment. Full article

Agricultural stubble burning is the third largest source of air pollution after vehicular and industrial emissions. Fine particulate matter (PM_2.5), volatile organic compounds (VOCs), carbon monoxide (CO), nitrogen dioxide (NO₂), and black carbon (BC) are some of the pollutants emitted during such burning events. The Lower Rio Grande Valley (RGV) region of South Texas is a major hub of agricultural activity, and sugarcane farming is one of them. Unfortunately, this activity results in episodic events of high air pollution in this low-resourced, Hispanic/Latino majority region of the U.S.–Mexico border. This study presents results from a sugarcane site in La Feria, South Texas, where the air quality was monitored before, during, and after the sugarcane stubble burning. Various parameters were monitored on an hourly basis from 24 February 2022 to 4 April 2022. Our results demonstrate high levels of all the monitored pollutants during the burning phase in contrast to the pre- and post-burning period. The black carbon levels went up to 6.43 µg m⁻³ on the day of burning activity. An increase of 10%, 11.6%, 25.29%, 55%, and 67.57% was recorded in the PM₁, PM_2.5, PM₁₀, Black Carbon, and CO levels, respectively, during the burning period in comparison with the total study period. The absorption Ångström exponent value reached a maximum value of 2.03 during the burning activity. ThePM_2.5/PM₁₀ ratio was 0.87 during the burning activity. This study also highlights the importance for continuous monitoring of air quality levels due to stubble burning in the Lower Rio Grande Valley Region of South Texas. Full article

Mercury (Hg) has been used for millennia in artisanal and small-scale gold mining (ASGM) to extract gold from ore as an amalgam that is heated to recover gold. Since there is hardly any sustainable technology that can be used to recover it, the vast percentage of released Hg finds its way into the environment. Currently, ASGM is the largest source of mercury pollution on Earth. Mercury (Hg) is listed among the top 10 most harmful metals by the World Health Organization (WHO), and it is known to cause several neurological disorders in humans. Thus, Hg levels in environmental systems surrounding pollution hotspots such as ASGM mines need to be monitored to ensure their proper management and protect vulnerable ecosystems and human health. This work was aimed to study the level of Hg pollution in soils and plants thriving around ASGM mines in Eastern Uganda and to evaluate the Hg phytoremediation potential of the plants. The total Hg contents were determined for soils, food crops and wild plants growing around ASGM mines. The results for the pH, organic carbon (OC) and electric conductivity (EC) of the soils in the study area were comparable to those of the control soils. The soils in the studied ASGM areas exhibited high Hg concentrations ranging between 723 and 2067 folds more than those of the control soils. All soils were moderately to heavily contaminated according to geoaccumulation (Igeo) index values that ranged between 1.16 and 3.31. The results of this study also showed that the food crops and wild plants accumulated Hg levels that were above the 20 ng/g (0.02 ppm) permissible limit. This study revealed relatively higher levels of Hg in the aerial parts of the plants compared with the underground organs, which can be attributed to Hg deposition, entry through stomata and foliar adsorption. Mercury levels in 47% of the food crop samples were above the FAO/WHO permissible mercury limit of 0.5 µg/g. Similarly, medicinal plants accumulated Hg to levels that were several folds higher than the 0.2 ppm permissible limit of mercury in herbal materials of Canada. Interestingly, this study showed that some wild plant species, especially sedges, exhibited relatively higher levels of mercury accumulation than others thriving in the same environment, an indication that such plants could be utilized in the phytoremediation of Hg-contaminated sites. Full article

Crop residue burning emits a variety of air pollutants that drastically affect air quality, both locally and regionally. To study the impact of crop residue burning, in the present study, concentrations of particulate matter (PM_2.5), trace gases (tropospheric ozone (O₃), nitrogen oxides (NO_x), carbon monoxide (CO), and volatile organic compounds (VOCs)) were recorded in Agra, a suburban downwind site. The study was conducted during the pre-harvest (15 September to 5 October 2021) and post-harvest periods (6 October to 10 November 2021). During the post-harvest period, PM_2.5 concentrations were recorded to be three to four times higher than the NAAQ Standards (35 µg/m³), while O₃ and VOC concentrations showed an increment of 16% and 30.4%, respectively. NO_x and CO concentrations also showed higher levels (19.7 ± 7.5 ppb and 1498.5 ± 1077.5 ppb) during this period. Moderate resolution imaging spectroradiometer (MODIS), along with air mass backward trajectory analysis (HYSPLIT Model), were used to detect fire hotspots that suggested that the enhanced pollutant levels may be due to the burning of crop residue in agricultural fields over the northwest Indo-Gangetic Plain (NW-IGP). Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX) analysis showed high K concentrations during the post-harvest period, which may be attributed to crop residue burning or biomass combustion. Full article

The densest network for measuring air pollutant concentrations in Colombia is in Medellin, where most sensors are located in the heavily polluted lower parts of the valley. Measuring stations in the higher elevations on the mountains surrounding the valley are not available, which limits our understanding of the valley’s pollutant dynamics and hinders the effectiveness of data assimilation studies using chemical transport models such as LOTOS-EUROS. To address this gap in measurements, we have designed a new network of low-cost sensors to be installed at altitudes above 2000 m.a.s.l. The network consists of custom-built, solar-powered, and remotely connected sensors. Locations were strategically selected using the LOTOS-EUROS model driven by diverse meteorology-simulated fields to explore the effects of the valley wind representation on the transport of pollutants. The sensors transmit collected data to internet gateways for posterior analysis. Various tests to verify the critical characteristics of the equipment, such as long-range transmission modeling and experiments with an R score of 0.96 for the best propagation model, energy power system autonomy, and sensor calibration procedures, besides case exposure to dust and water experiments, to ensure IP certifications. An inter-calibration procedure was performed to characterize the sensors against reference sensors and describe the observation error to provide acceptable ranges for the data assimilation algorithm (<10% nominal). The design, installation, testing, and implementation of this air quality network, oriented towards data assimilation over the Aburrá Valley, constitute an initial experience for the simulation capabilities toward the system’s operative capabilities. Our solution approach adds value by removing the disadvantages of low-cost devices and offers a viable solution from a developing country’s perspective, employing hardware explicitly designed for the situation. Full article

Due to increasing health and environmental issues, indoor air quality (IAQ) has garnered much research attention with regard to incorporating advanced clean air technologies. Various physicochemical air treatments have been used to monitor, control, and manage air contaminants, such as monitoring devices (gas sensors and internet of things-based systems), filtration (mechanical and electrical), adsorption, UV disinfection, UV photocatalysts, a non-thermal plasma approach, air conditioning systems, and green technologies (green plants and algae). This article reviews presently viable technologies for cleaning indoor air and enhancing IAQ. However, regarding the integration of each technology, there are certain limitations to these methods, including the types of pollutants released. As a result, advanced nanomaterials have been applied to monitoring sensors, filtration and adsorption media, and UV photocatalysts to improve IAQ values. The most important nanomaterials used in this regard include polymeric nanofibrous membranes, nanoporous nanomaterials, nanocomposite hydrogels, polymer/nanocarbon nanocomposite, polymer/metal oxide nanocomposite, polymeric nanohybrids, etc. Accordingly, through the use of nanotechnology, optimal solutions linking IAQ regulation techniques to novel nanomaterials can be achieved to attain safe IAQ levels. Full article