Pollutants, Volume 2, Issue 2 (June 2022) – 8 articles

Quantifying the sequestration in forest soils and watershed transport of Hg is key to reducing exposure of aquatic food chains to the toxic pollutant. We explored if forest soils, proximity in human developments, or watershed characteristics could shed light on sediment driven Hg transport in the Connecticut River, Merrimack River, and Thames River watersheds, in the northeastern USA. We sampled 48 upland forest soils and 32 riparian forest soils and collected bottled and trapped suspended sediments from April 2020 to November 2020 across the three watersheds. Forest soil Hg concentrations were greater in riparian forest soils (median = 153 ng g⁻¹) than in upland forest soils (median = 71 ng g⁻¹) across all three watersheds and developed sites near urbanization had higher Hg concentrations in the Merrimack River watershed (median = 407 ± 119 ng g⁻¹). The Connecticut River had the highest suspended sediment Hg export rate but when normalized by total area of the watershed, the Merrimack River had 0.19 kg km⁻² month⁻¹ while the Connecticut River had 0.13 kg km⁻² month⁻¹ and 0.04 km⁻² for the Thames River. Our findings suggest that riparian forest soils sequester while suspended sediments transport historical Hg pollution within the Merrimack River Watershed. Full article

This paper presents attempts to reduce the concentration of organic pollutants in oilfield produced wastewater before its discharge into natural water bodies or reinjection into the wells. The contaminant content was significantly decreased by wastewater treatment, based on solid phase adsorption, photocatalytic degradation of organic molecules and chemical oxidation of oily compounds. The study was conducted with real wastewater, which is in practice released in the environment. The produced water samples, taken from four sampling points in the oilfield site, were analyzed for physicochemical (temperature, redox potential (Eh), conductivity, pH, dissolved oxygen) and specific (chemical oxygen demand (COD), total oily hydrocarbons (TOH), phenols) parameters, cations (Ca²⁺, Mg²⁺, Na⁺, K⁺) and anions (Cl⁻, HCO₃⁻, SO₄²⁻, S²⁻), in order to determine the initial water status. The organic contaminants in oilfield produced water showed COD of 39–58 mg/L, TOH of 152–363 mg/L and phenols of 0.07–0.21 mg/L. The TOH was chosen as a suitable parameter for the evaluation of the treatment method efficiency. The adsorption on activated charcoal decreased the TOH levels up to 52 mg/L, which corresponds to 85% removal of oily compounds. Chemical oxidation, carried out with Ca(ClO)₂ in a concentration of 400 mg/L for 1 h at room temperature, showed TOH removal in the range of 80–94% for different wastewater samples. The use of 300 mg/L TiO₂ or ZnO under UV irradiation for 12 h led to TOH removal of 25–78% and 82–92%, respectively. Both photocatalysts were characterized by using X-ray diffraction, reflectance UV-vis spectroscopy and scanning electron microscopy. The crystal forms anatase and wurtzite for TiO₂ and ZnO, respectively, were found. The estimated band gap of 3.48 eV for direct transition in TiO₂ and 3.25 eV for ZnO agrees well with that reported in the literature. Higher photodegradation of organic compounds was observed for ZnO, indicating that it absorbed more light photons than TiO₂ did. A mechanism for photocatalytic degradation over a more efficient photocatalyst, ZnO, was proposed based on the GC-MS analysis of raw water and treated effluents produced for 6 and 12 h. Full article

This article focuses on the importance of a trans-disciplinary and participatory planning approach aiming at promoting a more resilient community. The COVID-19 outbreak is not just a health pandemic, but also a compound crisis in a globalized world, which emphasizes the need for, and urgency of, an ecological transition towards a new development model. This paper presents the outcomes of a research experience aimed at implementing a new development model inspired by integral sustainability for a transformative resilience of Basilicata region (Southern Italy). The research approach was implemented according to a participatory planning methodology to overcome the significant impacts of the pandemic and guide the transition towards real, sustainable development in all its dimensions (economic, social, environmental, and institutional). Community engagement in a research partnership allowed stakeholders to benefit from collective wisdom, creating more meaningful findings in preparing the regional community to face the challenges of the ecological transition. Scientific support of the research was fundamental in supporting political decision making in identifying strategic actions for a more sustainable and resilient Basilicata in this delicate historical moment of awareness, where the future will depend on today’s choices. Full article

Healthy indoor environments influence the comfort, health and wellbeing of the occupants. Monitoring the indoor temperature, relative humidity and CO₂ levels in primary schools during the COVID-19 pandemic was mandated by a local authority in Scotland. The aim was to investigate the comfort and safety of the teachers and their pupils. This paper presents the measurements of indoor climate in 20 classrooms in four different primary schools in Scotland. The schools were of different architypes. The classrooms were of different sizes, orientations and occupancy, and had different ventilation systems. Ventilation was achieved either by manually opening the windows, or by a mechanical ventilation system. Indoor air temperature, relative humidity and carbon dioxide (CO₂) concentrations were continuously monitored for one week during the heating season 2020/21. Occupancy and opening of the windows were logged in by the teachers. The ventilation rates in the classrooms were estimated by measuring the CO₂ concentrations. On the 20 classrooms of the study, data of 19 were analysed. The results show that four of the five mechanically ventilated classrooms performed better than natural ventilation, which indicates that opening the windows depended on the customs and habits. Classrooms in naturally ventilated Victorian buildings have the worst average ventilation rate (4.38 L/s per person) compared to the other classrooms (5.8 L/s per person for the more recent naturally ventilated ones, and 6.08 L/s per person for the mechanically ventilated ones). The results of this preliminary study will be used as the basis to find ways to ensure adequate ventilation in natural ventilated classrooms. Full article

Sustainability is a paradigm of generative action if combined with the principle of antifragility. This contribution, adhering to a transdisciplinary approach, proposes a reinterpretation of the principles of the 2030 Agenda, orienting them towards a community-building model. Sustainability can be seen as passive (care) and active (custody), determining paths to be activated at the territorial level. Sustainability is a communitarian learning path measured by one’s antifragility capacity. The effectiveness of the Agenda is linked to the dissemination and accountability of the challenges contained in the 17 objectives. The local scale is perhaps the most suitable for activating this process. However, this requires a strengthening of the anti-fragility of communities and organizations, which must be more capable of recognizing and reducing vulnerabilities and weaknesses. A promising field of application is that of impact assessment, to be reworked in the light of the antifragility approach. Full article

The first case of COVID-19 in Iran was reported on 19 February 2020, 1 month before the Nowruz holidays coincided with the global pandemic, leading to quarantine and lockdown. Many studies have shown that environmental pollutants were drastically reduced with the spread of this disease and the decline in industrial activities. Among these pollutants, nitrogen dioxide (NO₂) and carbon monoxide (CO) are widely caused by anthropogenic and industrial activities. In this study, the changes in these pollutants in Iran and its four metropolises (i.e., Tehran, Mashhad, Isfahan, and Tabriz) in three periods from 11 March to 8 April 2019, 2020, and 2021 were investigated. To this end, timeseries of the Sentinel-5P TROPOMI and in situ data within the Google Earth Engine (GEE) cloud-based platform were employed. It was observed that the results of the NO₂ derived from Sentinel-5P were in agreement with the in situ data acquired from ground-based stations (average correlation coefficient = 0.7). Moreover, the results showed that the concentration of NO₂ and CO pollutants in 2020 (the first year of the COVID-19 pandemic) was 5% lower than in 2019, indicating the observance of quarantine rules, as well as people’s initial fear of the coronavirus. Contrarily, these pollutants in 2021 (the second year of the COVID-19 pandemic) were higher than those in 2020 by 5%, which could have been due to high vehicle traffic and a lack of serious policy- and law-making by the government to ban urban and interurban traffic. These findings are essential criteria that might be used to guide future manufacturing logistics, traffic planning and management, and environmental sustainability policies and plans. Furthermore, using the COVID-19 scenario and free satellite-derived data, it is now possible to investigate how harmful gas emissions influence air quality. These findings may also be helpful in making future strategic decisions on how to cope with the virus spread and lessen its negative social and economic consequences. Full article

The pulp and paper industry is a major contributor to water and air pollution globally. Pulp and paper processing is an intensive energy consuming process that produces multiple contaminants that pollute water, air, and affect ecological and human health. In Canada, the National Pollutant Release Inventory (NPRI) is used to assess the release of air pollutants into the atmosphere from industrial facilities (including pulp and paper mills) and provides a repository of annual emissions reported by individual facilities. This study compared annual air emissions of carbon monoxide, nitrogen oxides, total particulate matter (TPM), PM_2.5, PM₁₀, sulphur dioxide, and volatile organic compounds from nine different pulp and/or paper mills in Atlantic Canada from three provinces (Nova Scotia, New Brunswick, and Newfoundland and Labrador) between 2002 and 2019. Results revealed that annual releases were several orders of magnitude higher than federal reporting thresholds suggested by Environment and Climate Change Canada. Pulp mills emit higher pollutant loads than those producing paper. The highest exceedance of a reporting threshold was for particulate matter (PM_2.5) at Northern Pulp in Nova Scotia. The emissions of PM_2.5 were on average (over a 17-year period) about 100,000% above the reporting threshold of 0.3 tonnes per year. Full article

Electronic air cleaning (EAC) technologies have garnered significant attention for use in buildings. Many EAC technologies rely on the addition of reactive constituents to indoor air to react with gas-phase compounds, enhance particle deposition, and/or inactivate microorganisms. However, limited data are available on the efficacy of many EAC technologies and their potential to form chemical byproducts during operation. Here we experimentally evaluate the indoor air quality impacts, specifically targeting particles and gases but not microbial constituents, of a commercially available additive oxidizing EAC that generates positive and negative ions and hydrogen peroxide (H₂O₂). Tests were conducted in a large unoccupied test chamber in Chicago, IL and an unoccupied laboratory in Portland, OR under a combination of natural conditions (i.e., without pollutant injection) and perturbation conditions (i.e., with pollutant injection and decay). A combination of integrated and time-resolved measurements was used across both test locations. Chamber tests at lower airflow rates demonstrated that operation of the EAC: (i) had no discernible impact on particle concentrations or particle loss rates, with estimated clean air delivery rates (CADRs) for various particle measures less than ±10 m³/h, (ii) was associated with apparent decreases in some volatile organic compounds (VOCs) and increases in other VOCs and aldehydes, especially acetaldehyde, although a combination of high propagated uncertainty, limitations in test methods (e.g., lack of replicates), and variability between repeated tests limit what quantitative conclusions can be drawn regarding gas-phase organics; (iii) did generate H₂O₂, assessed using a crude measure, and (iv) did not generate ozone (O₃). Laboratory tests at higher airflow rates, which involved injection and decay of particles and a single VOC (limonene), both simultaneously and separately, demonstrated that: (i) pollutant loss rates for both particles and limonene were slightly lower with the EAC on compared to off, yielding slightly negative pollutant removal efficiencies (albeit largely within propagated uncertainty) and (ii) there was a change in observed concentrations of one potential limonene degradation product, m/z 59 (putatively identified as acetone), with steady-state levels increasing from 10 ppb (air cleaner off) to 15 ppb (air cleaner on). No increases or decreases beyond measurement uncertainty were observed for other analyzed gaseous limonene degradation products. Overall, both chamber and laboratory tests demonstrated negligible effectiveness of this device at the test conditions described herein for removing particles and mixed results for VOCs, including decreases in some VOCs, no discernible differences in other VOCs, and apparent increases in other compounds, especially lower molecular weight aldehydes including acetaldehyde. Full article