Pollutants, Volume 2, Issue 1 (March 2022) – 9 articles

Although there is mounting evidence that suggests that air pollution is impactful to human health and educational outcomes, this is especially problematic in schools with higher air pollution levels. To understand whether all schools in an urban area are exposed to similar outdoor air quality and whether school infrastructure protects children equally indoors, we installed research-grade sensors to observe PM_2.5 concentrations in indoor and outdoor settings to understand how unequal exposure to indoor and outdoor air pollution impacts indoor air quality among high- and low-income schools in Salt Lake City, Utah. These data and resulting analysis show that poor air quality may impact school settings and the potential implications with respect to environmental inequality. Based on this approach, we found that during atmospheric inversions and dust events, there was a lag ranging between 35 and 73 min for the outdoor PM_2.5 concentrations to follow a similar temporal pattern as the indoor PM_2.5. This lag has policy and health implications and may help to explain rising concerns regarding reduced educational outcomes related to air pollution in urban areas. Full article

Sewage pollution leads to the contamination of bivalve shellfish by pathogenic microorganisms. Bacterial indicators support the management of risks associated with the consumption of shellfish; however, they often fail to indicate adequately the potential hazard to human health posed by certain human enteric viruses. Bacteriophages have been proposed as alternative indicators that may more effectively predict the presence of enteric viral pathogens. This study explored the relationships between bacterial indicators (Escherichia coli (E. coli), faecal coliforms (FC) and intestinal enterococci (IE)), phages (somatic (SOMPH), F-specific RNA (F + PH) and human-specific Bacteroides GB-124 phages (GB124PH)) and Norovirus (NoV) (GI/GII) in mussels (Mytilus edulis) and their overlying waters. The bioaccumulation of these indicators and Norovirus in shellfish matrices (e.g., flesh, digestive gland) was investigated bimonthly over a 12-month period in an English estuary. The findings revealed a marked seasonality in the distribution of all organisms, with the highest levels occurring during the autumn/winter months. The levels of all phages in shellfish and their overlying waters correlated better with the levels of Norovirus than with those of bacterial indicators. Somatic coliphages were the indicator that exhibited the strongest correlations with NoV (rho = 0.929). This study suggests that relatively low-cost culture-based phage enumeration appears to offer a more accurate indication of the likely presence of Norovirus in mussels than traditional bacterial indicators. Full article

Copper is a frequently used heavy metal worldwide and known to be an essential micronutrient for most living organisms including plants. However, excessive levels of copper in soil may adversely affect plant growth and survival. The continuing introduction of copper to soil, e.g., through excessive utilization of agrochemicals has raised serious environmental concerns throughout the world. A variety of plants have the capability to eliminate pollutants from soil through different mechanisms; however, limited information is reported on phytoremediation potential of maize (Zea mays L.) and its uptake and the accumulation potential in copper-containing soils. The effects of additions of 0, 50, 100, 200 and 300 mg kg⁻¹ of copper to soil on growth parameters of Z. mays, copper uptake from soil and accumulation in roots and shoots, and phytoremediation potential of Z. mays were investigated in this research. Copper content in soil and plant samples were determined using atomic absorption spectrophotometry. The addition of 50 mg kg⁻¹ Cu stimulated Z. mays growth parameters, while higher content of Cu exhibited inhibitory effects of plant growth. Results indicated that roots accumulated significantly higher levels of Cu than shoots in all treatments, suggesting dominancy of phytostabilization mechanism in remediation of Cu-polluted soil by Z. mays. However, translocation of Cu from the roots to the aerial parts enhanced to some extent with copper level in soil. The greatest Cu accumulation capacity of 5210 µg per pot was gained in Z. mays cultivated in soil treated with 200 mg kg⁻¹ copper. Results demonstrated that Z. mays can promisingly remediate low to moderately copper-contaminated soils. Full article

The aim of the present work was to evaluate the influence of two different pharmaceutical compounds (bezafibrate and paroxetine) on the phytoremediation potential of Phragmites australis in an estuarine medium contaminated by copper. Plants were exposed for seven days to a simplified estuarine medium, elutriate solution, with or without sediment. The medium was doped with copper and bezafibrate or paroxetine. P. australis plants were able to accumulate a significant amount of Cu, particularly in their roots (600 and 250 times increase in copper levels in the absence and presence of sediment, respectively), corroborating the phytostabilization potential of salt marsh plants. Metal uptake and translocation was significantly lower in the presence of sediment (Cu in leaves increased 20 times in the absence and only 4 times in the presence of sediment). An effect of either pharmaceutical compound on metal accumulation was not observed (levels of Cu in plants tissues were in general identical) but, in the presence of sediment, both bezafibrate and paroxetine changed Cu solubility in elutriate solution, either decreasing or increasing it. The current study highlights the possible influence the presence of contaminants of different characteristics (inorganic and organic contaminants) can have on salt marsh phytoremediation potential in the long run, and the effects pollutants might have in the environment. Full article

The use of conventional techniques for physico-chemical remediation of hydrocarbon such non-aqueous phase liquids (NAPL)-polluted sites may disturb the natural biotic settings of the (sub)-surface. However, natural attenuation has been reported very slow and sometime results as incomplete removal under prevailing site conditions. In particular, microbial growth is quite slow in cold regions, which reduces the applicability of bioremediation in treating NAPL-polluted soil-water. Thus, this study aims to evaluate the thermally enhanced bioremediation techniques to treat NAPL-polluted soil-water using practical experiments. A one-dimensional large column setup was designed and fabricated for this purpose. The column was integrated with automatic temperature controlling baths to maintain different soil-water temperatures (4 °C, 20 °C, 28 °C, and 36 °C), which was circulated through the porous media filled in the column setup. Results show a high dissolution rate of toluene, the selected light NAPL, at an elevated temperature of 28–36 °C. The biodegradation rates of the NAPL were found to be 0.002 mg L/h, 0.008 mg L/h, 0.012 mg L/h, and 0.015 mg L/h at soil-water temperature levels of 4 °C, 20 °C, 28 °C, and 36 °C, respectively. It was found that at high soil-water temperature (28 °C and 36 °C), a significant increment in microbial actions accelerates the biodegradation rate of NAPL in the subsurface system. The outcomes of this study may help in treating NAPL-polluted sites using solar or geo-thermal based heating systems for thermally enhanced bioremediation. Full article

Organic UV filters are continuously released in aquatic ecosystems due to their widespread use, especially in touristic coastal environments. Generally, organic UV filters are poorly soluble in water and tend to accumulate in the sediment compartment. This represents a conceivable risk for sediment-dwelling organisms and a potential for transfer of the UV filters up the food chain. This study aimed to assess the potential transfer of seven UV filters including benzophenone-3 (BP3), bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), butyl methoxydibenzoylmethane (BM), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT), 2-ethylhexyl salicylate (ES), diethylhexyl butamido triazone (DBT), and octocrylene (OC) from artificial spiked sediment (10 µg.g⁻¹ dry weight) to sediment-dwelling worms. All UV filters were detected in the worms after 28 days of exposure, but only BP3 was apparently bioaccumulated, with a biota sediment accumulation factor (BSAF) of 12.38 ± 4.65. However, metabolomic profiling revealed that OC was metabolized by the worms into 11 fatty acid conjugates, demonstrating that OC did also accumulate in the worms in the form of OC–fatty acid conjugates. Here, the sole quantification of the parent organic UV filter underestimated the accumulation factor and the exposure of organisms. In general, it is therefore important to pair the conventional method (BSAF calculus) with other techniques, such as metabolomics, to assess the actual potential for bioaccumulation of xenobiotics including transformed xenobiotics. Full article

Carbon adsorbents for use in the removal of gaseous toluene from the air were prepared from buckwheat (Fagopyrum esculentum Moench) hull. A chemically-activated adsorbent was prepared via the impregnation of raw hull powder with potassium carbonate, followed by thermal decomposition. The chemically-activated adsorbent exhibited improved adsorption capacity for toluene compared to the adsorbent prepared without chemical activation. Toluene concentration in the air decreased from 220 ppm to 160 ppm during 24 h of adsorption using unactivated adsorbent. Only a trace amount of toluene remained after the adsorption under the same conditions using K₂CO₃-activated adsorbent. This improvement was explained based on experimental results, specifically, iodine adsorption tests, methylene blue adsorption tests, and microscopic observations. Chemical activation dramatically increased the specific surface area of the adsorbent and created mesopores capable of adsorbing toluene. This study revealed that a mesoporous adsorbent for use in volatile toluene removal can be prepared from waste biomass (buckwheat hull) by chemical activation using potassium carbonate. Full article

The proposed approach based on compositional data analysis was applied on simultaneous measurements of the mineral element concentrations of PM₁₀ and PM_2.5 from a typical suburban site with and without a Saharan event. The suburban site is located in the city of Rome. The selected mineral elements were Al, Si, Ca, Fe, Ti, Mg, and Sr. The data relating to these elements are reported in a previous study. The considered elements are mainly related to mineral matter. The proposed approach allows statistically validating that the mineral element concentrations of PM during days with a Saharan event differ from those without a Saharan event in terms of mineral element composition and size distribution. In particular, the results showed that the compositional data analysis applied to simultaneous measurements of mineral element concentrations of PM₁₀ and PM_2.5 is a helpful technique that can be used to study environmental sites affected by natural sources such as Saharan events. Moreover, the presented technique can be handy in all those conditions where it is important to discriminate whether the occurrence of an exceedance or a violation of the daily limit value established for PM could also be due to natural sources. Full article