Pollutants, Volume 4, Issue 3 (September 2024) – 10 articles

This work aims to assess the bioavailability and bioaccumulation of Cr, Cu, Pb, and Zn in the soil–plant system (Erigeron canadensis L.) in the zone of anthropogenic impact in Dnipro city, a significant industrial and economic centre of Ukraine. Sampling was carried out at three locations at distances of 1.0 km, 5.5 km, and 12.02 km from the main emission sources associated with battery production and processing plants in Dnipro. The concentrations of heavy metals such as Cr, Cu, Pb, and Zn were analysed using atomic emission spectrometry from soil and parts of Erigeron canadensis L. The highest concentrations of elements in the soil, both for the mobile form and the total form, were determined to be 48.96 mg kg⁻¹ and 7830.0 mg kg⁻¹, respectively, for Pb in experimental plot 1. The general ranking of accumulation of elements in all experimental plots, both for the plant as a whole and for its parts, was as follows: Zn > Cu > Cr > Pb. Zn for plants was the most available heavy metal among all studied sites and had the highest metal content in the plant (339.58 mg kg⁻¹), plant uptake index (PUI-506.84), bioabsorption coefficient (BAC-314.9), and bioconcentration coefficient (BCF-191.94). According to the results of the study, it is possible to evaluate Erigeron canadensis L. as a hyperaccumulator of Zn, Cu, and Cr and recommend it for phytoextraction of soils contaminated with Zn, Cu, and Cr and phytostabilization of soils contaminated with Pb. Full article

The emergence of infectious disease outbreaks and ‘superbugs’ related to pollution combined with climate change is a current problem, not just a future threat. In May 2024, an extreme flood hit the Rio Grando Sul State, southern Brazil, triggering an important leptospirosis outbreak in urban settings with deficient sanitation systems. This and other cases discussed in this article exemplify how extreme weather events exacerbate the consequences of environmental pollution by multiple classes of pathogens in the global scenario of increasing anthropogenic pressures on the environment. A combination of actions to combat climate change and improvements in sanitation systems is essential to mitigate this problem. Full article

Aquaculture and waste valorization have the potential to show solid achievements toward food security and improvements in the circularity of resources, which are crucial aspects of achieving a sustainable lifestyle in agreeance with Agenda 2030 goals. This study aims to optimize and simplify the decision-making processes for the valorization of marine wastes (natural and from aquaculture) as secondary raw materials to produce high-value-added market goods. However, significant concentrations of pollutants may be present within wastes, compromising overall quality, and social dynamics can hinder their usage further. Goro’s lagoon was chosen as a case study, where the relations between the ecosystem services, a thriving bivalve economy, and social dynamics are deeply rooted and intertwined. Therefore, in the manuscript cost–benefit and foresight analyses are conducted to determine the best usage for algal biomass considering pollution, social acceptance, and profitability. These analyses are virtually conducted on bio-refineries that could be operating in the case study’s area: briefly, for a thirty-year running bio-plant, the CBA indicates the two best alternatives with an income of 5 billion euros (NPV, with a 5% discount rate) for a biofuel-only production facility, and a half for a multiproduct one, leading to the conclusion that the first is the best alternative. The foresight, instead, suggests a more cautious approach by considering external factors such as the environment and local inhabitants. Hence, the main innovation of this work consists of the decision-maker’s holistic enlightenment toward the complexities and the hidden threats bound to this kind of closed-loop efficiency-boosting process, which eventually leads to optimized decision-making processes. Full article

Application of hydraulic fracturing to produce “unconventional” oil and gas from shale formations and other low-permeability geological units has raised concerns about the potential environmental impacts, including potential adverse effects of fracturing fluids (FF) on groundwater. In this study, laboratory batch test experiments and new analytical methods were developed to analyze FF chemicals as potential indicators (tracers) to detect impacts of fracturing fluids on groundwater. The tests, conducted over 101–196 days, included FF with synthetic chemicals (~40,000–4,000,000 µg/L), placed in batches with groundwater and sediment at 5° and 25 °C, along with sterile controls. Using the new methods, measurable concentrations of the FF chemicals were many orders in magnitude lower (~3000 to 3,000,000 X) compared to their concentrations in synthetic fracturing fluids, indicating that these chemicals are excellent candidates as indicators of FF contamination in groundwater, if they are relatively persistent, and not prone to extensive loss by sorption during migration in the subsurface. Variable sorption and degradation of the chemicals was observed in both batch and column tests. Sorption was negligible (sorption coefficient, K_d~0.0) for some synthetic chemicals (polyethylene glycol, ethanolamines, isopropanol, and ethyl hexanol) in some tests. At the other extreme, strong sorption was observed for some of the higher molecular weight cocamido propyl betaine (max K_d = 1.17) and polyethylene glycol (max K_d = 1.12) components, and triethanolamine (max K_d = 0.47) in other tests. Apparent loss by degradation was observed for each chemical in some tests, but negligible in others. The shortest apparent half-lives were for isopropanol and ethyl hexanol at 25 °C (t^½ < 11 days), and the most persistent synthetic chemicals were polyethylene glycols (t^½ ≥ 182 d) and the ethanolamines (t^½ ≥ 212 d). Of the potentially diagnostic FF chemicals investigated, the relatively hydrophilic and persistent lower molecular weight polyethylene glycols are some of the most promising as potential indicators of contamination of groundwater by FF. Full article

In the present study, the toxicity of nicosulfuron to Danio rerio embryos was evaluated in three experiments through standardized toxicity tests according to OECD TG236 guidelines. In the first experiment, six concentrations of nicosulfuron (0, 0.1, 1, 10, 100, 1000 mg/L) were tested under optimal conditions (26 °C, pH 7.0) to assess the general sensitivity of zebrafish embryos to nicosulfuron. The second and third experiment examined the effects of different pH levels (5.0 and 9.0) and temperatures (21 °C and 31 °C) on the toxicity at four nicosulfuron concentrations (0, 10, 100, 1000 mg/L). Additionally, the sub-organismic effects of nicosulfuron on stress protein levels (Hsp70) of fish embryos were analyzed. Throughout the embryo experiments, no malformations were observed in all experiments. The survival rate exceeded 80% in all groups except for the 21 °C (pH 7.0) treatment groups. No significant effect of nicosulfuron on the survival rate was found at the same temperature or pH (p > 0.05). No significant difference in the heart rate was found among all nicosulfuron groups (p > 0.05) at 21 °C. The heart rate of fish embryos at 31 °C, pH 5.0 and pH 9.0 increased with nicosulfuron concentrations. Except for the pH 5.0 (26 °C) and 21 °C (pH 7.0) treatment groups, nicosulfuron was found to increase the hatching rate of embryos in other treatments; however, the corresponding times of action were different. At 21 °C (pH 7.0), the embryos did not hatch until 144 h post-fertilization. In terms of proteotoxicity, nicosulfuron was found to be more toxic to zebrafish embryos in the 21 °C, pH 5.0 and pH 9.0 treatment groups. However, at 31 °C, no significant difference in Hsp70 levels was found among all the different nicosulfuron concentrations (p > 0.05). Our results show that nicosulfuron exerts a weak toxicity to zebrafish embryos; however, this toxicity is amplified by inappropriate pH or temperature conditions. Full article

While many sources of contamination in chemical and biological laboratories are well understood and known, some are less so. To quantify the magnitude of the potential contamination of solutions by zinc in common laboratory syringes, a study was conducted on solutions stored in rubber-containing syringes in which the rubber was catalyzed by zinc. This study identified specific factors contributing to contamination from laboratory syringes, including the syringe brand, time, solution type, and pH. Two common syringe brands, Covidien and BD, were tested, and three time durations, 0 days, 1 day, and 14 days, were examined. The solutions tested included sucrose and tartaric acid, representing both covalent and ionic species. Additionally, this study employed a pH range of 2 to 13 to further explore zinc contamination across a wide range of conditions and factors. The zinc concentration from the syringes was measured using inductively coupled plasma mass spectrometry (ICP-MS). The results, which ranged from less than 20 to over 600 μg L⁻¹, revealed increased zinc concentration at both extreme pH values, while remaining lower but measurable at neutral pH levels. Zinc contamination is important to study because its contamination in laboratory syringes could interfere with the detection of other elements, further skew laboratory data, unexpectedly catalyze reactions, and lead to inconsistencies in experimental conditions. This study further emphasizes the broader significance of understanding pollutants within laboratory settings. The findings highlight the intricate dynamics of zinc contamination, stressing the need for the control of environmental factors and the broad dissemination of lesser-known sources. Recognizing the potential impact of contaminants like zinc is crucial, as it not only influences analytical accuracy, but also mirrors the wider concern of pollutants compromising scientific integrity in diverse experimental conditions. Full article

Cadmium accumulation in wheat as a daily food, even in low concentrations, is a serious threat to human health. Previous studies have reported conflicting results on the impact of calcium treatments on cadmium uptake and translocation in plants due to the complex soil conditions. Our hydroponic study offers clearer insights into how specific calcium treatment parameters influence cadmium uptake and translocation in wheat. The hydroponic medium was contaminated by cadmium (CdCl₂) and the following treatments were applied: CaCO₃, CaSO₄, CaCl₂, CaCO₃ + CaSO₄, CaCO₃ + CaCl₂, and CaSO₄ + CaCl₂. After harvesting, the wheat was analyzed for Cd²⁺ uptake characteristics including translocation factor, bioconcentration factor, and uptake. Furthermore, physiological growth parameters and plant nutrients were also determined. Applying CaCO₃ significantly decreased wheat Cd²⁺ concentration by about three times in CaCO₃ and two times in CaCO₃ + CaSO₄ and CaCO₃ + CaCl₂ treatments than in Cd-control. This study clearly elucidates that pH and CO₃²⁻ were crucial in reducing Cd²⁺ concentration in wheat. SO₄²⁻, Cl⁻, and Ca²⁺ showed no effect on Cd²⁺ concentration. Ca²⁺ only reduced the translocation factor (TF) of Cd²⁺ in plants. CaCO₃ also declined cadmium interference in the Mg²⁺, Mn²⁺, and Cu²⁺ uptake. Therefore, this study provides novel insight into the pure effects of calcium treatments on controlling cadmium contamination in plants, independent of soil effect. Full article

End-of-life vehicle (ELV) forecasting constitutes a crucial aspect of sustainable waste management and resource allocation strategies. While the existing literature predominantly employs time-series forecasting and machine learning methodologies, a dearth of studies leveraging deep learning techniques, particularly Long Short-Term Memory (LSTM) networks, is evident. Moreover, the focus on localized contexts within national or municipal boundaries overlooks the imperative of addressing ELV generation dynamics at an international scale, particularly within entities such as the EU-27. Furthermore, the absence of methodologies to reconcile missing historical data presents a significant limitation in forecasting accuracy. In response to these critical gaps, this study proposes a pioneering framework that integrates grey systems theory (GST)-based backcasting with LSTM-based deep learning methodologies for forecasting ELV generation within the EU until 2040. By introducing this innovative approach, this study not only extends the methodological repertoire within the field but also enhances the applicability of findings to supranational regulatory frameworks. Moreover, the incorporation of backcasting techniques addresses data limitations, ensuring more robust and accurate forecasting outcomes. The results indicate an anticipated decline in the recovery and recycling of ELVs, underscoring the urgent need for intervention by policymakers and stakeholders in the waste management sector. Through these contributions, this study enriches our understanding of ELV generation dynamics and facilitates informed decision-making processes in environmental sustainability and resource management domains. Full article

The use of stable isotopes, specifically δ¹⁸O_PO4 ratios, in differentiating potential sources of inorganic phosphorus (e.g., wastewater, septic, wild animals, domesticated animals, livestock, substrates, or commercial fertilizers) to watersheds is a growing field. This method produces data that, used in conjunction with statistical mixing models, enables a better understanding of contributing sources of runoff. However, given the recent development of this research area there are obvious limitations that have arisen, due in large part to the limited available reference data to compare water samples. Here, we attempt to expand the availability of reference samples by applying stable isotope methods to three types of common agricultural manures: poultry, dairy, and swine. We also aim to concatenate the organic waste literature on this topic, creating a more robust comparison database for future study and application in phosphorus source partitioning research. Among our samples, δ¹⁸O_PO4 ratios for poultry were considerably elevated compared to dairy and swine manures (values of 18.5‰, 16.5‰, and 17.9‰, respectively). Extending this to other published ratios of δ¹⁸O_PO4 from various types of waste products (e.g., septic, wastewater, livestock, other animals), a total range from 8.7‰ to 23.1‰ emerged (with existing poultry manure samples also ranking among the highest overall). Variation among samples in the larger dataset demonstrates the need for a further compilation of δ¹⁸O_PO4 ratios for various types of waste, especially specific to geographic regions and watershed scales. With an increased sample size, the statistical strength associated with these methods would greatly improve. Full article

A 2018 report from the Water Quality for Human Consumption Vigilance Information System (SISÁGUA, Brazil) showed the presence of 27 pesticides in Brazilian drinking water, of which 11 have carcinogenic potential. We assessed the data for 27 municipalities in Paraná state southwest, a rural landscape with high cancer rates. We selected data from the carcinogenic potential of 11 pesticides provided by international agencies (alachlor, aldrin-diheldrin, atrazine, chlordane, DDT, diuron, glyphosate, lindane, mancozeb, molinate, and trifluralin) and estimated the number of cancer cases attributable to drinking water contamination by pesticides. Also, we correlated such findings with incidence and mortality cancer rates for ten topographies obtained from the Brazilian National Cancer Institute (INCA) database. A total of 9 cities were selected, corresponding to about 81,000 people. All towns had all pesticides quantified in the drinking water. About ten cancer cases were attributed to drinking water contamination by pesticides in 2014–2017, mainly linked to diuron and mancozeb. Concerning the consolidated incidence of cancer cases reported by the INCA, significant correlations were found regarding aldrin-diheldrin, alachlor, and atrazine for breast cancer, atrazine for prostate cancer, and mancozeb and diuron for colon cancer, among others. Regarding the consolidated mortality rates, some correlations were found between DDT and trifluralin for the breast, DDT and lindane for the prostate, and glyphosate for lung cancer. Moderate correlations were found between the estimated and consolidated cancer cases for several topographies. Our findings highlight the correlation between drinking water contamination in Paraná state southwest and its increased incidence of cancers with poor prognosis. Full article