Ecotoxicity Impact Research Articles

Ecotoxicological effect factors for calculating USEtox ecotoxicity characterization factors

BackgroundThis study aims to tackle the lack of freshwater ecotoxicological effect factors (EFs) crucial for determining freshwater ecotoxicity characterization factors (CFs) using the widely accepted scientific consensus USEtox model for ecotoxicity impact characterization. The objectives are: (1) to offer a collection of experimental EFs to support USEtox ecotoxicity characterization factor computations and (2) to contrast ecotoxicity data produced by various quantitative structure–activity relationship (QSAR) models against experimental data.ResultsExperimental ecotoxicity data were gathered from the REACH database and CompTox Version 2.1.1, which includes toxicity information from ToxValDB v9.4. QSAR-driven ecotoxicity data were extracted from ECOSAR v1.11 and T.E.S.T. v5.1.2. The experimental and estimated data underwent a harmonization process to ensure consistency. Subsequently, aquatic ecotoxicological EFs were determined. The merged REACH and CompTox databases list EFs for 11,295 substances, each identified by a unique CAS number. Among these, the USEtox database already catalogs 2426 substances with freshwater ecotoxicological EFs. This study expanded on that by calculating EFs for an additional 8869 substances. Using estimated data, EFs were determined for 6029 chemicals based on ECOSAR data and 6762 chemicals using TEST data.ConclusionsThis study calculated EFs for an additional 8869 substances, thereby broadening their inclusion in LCA evaluations. When integrated with the USEtox EFs database, this research encompasses 11,368 chemicals. The high correlation observed between experimental EFs and those in the USEtox database lends significant confidence to the calculations for chemicals not listed in USEtox. Conversely, the low correlation between estimated EFs and those in USEtox suggests limited confidence in calculations based on estimated data. Furthermore, the disparity in correlations between EFs calculated using ECOSAR and TEST indicates that different QSARs can yield varied results. This discrepancy underscores the need for caution when relying on estimated data. Given that EFs are contingent on data availability, it is imperative to periodically update EFs as new data emerges.

In Vitro Screening of Ecotoxic and Cytotoxic Activities of Ailanthus altissima Leaf Extract against Target and Non-Target Plant and Animal Cells.

Ailanthus altissima, an invasive plant species, exhibits pharmacological properties, but also some allergic effects on humans. This study aimed to evaluate the potential toxicity of A. altissima leaves, using a complex approach towards different organisms. The ecotoxic impact of a crude extract was investigated on seeds germination and brine shrimp lethality. Cytotoxicity was studied in vitro using non-target (haemolysis, liposomal model, fibroblast), and target (cancer cells) assays. Leaf extract at 1000 µg/mL significantly inhibited wheat and tomato germination, while no significant effects were found on parsley germination. A slight stimulatory effect on wheat and tomato germination was found at 125 µg/mL. In a brine shrimp-test, the extract showed a low toxicity at 24 h post-exposure (LC50 = 951.04 ± 28.26 μg/mL), the toxic effects increasing with the exposure time and extract concentration. Leaf extract caused low hematotoxicity. The extract was biocompatible with human gingival fibroblasts. No anti-proliferative effect was found within the concentration range of 10-500 µg/mL on malignant melanoma (MeWo) and hepatocellular carcinoma (HepG2). In a liposomal model-test, the extract proved to possess low capability to alter the eukaryotic cell-mimicking membranes within the tested concentration range. Given the low to moderate toxicity on tested organisms/cells, the A. altissima autumn leaves may find useful applications.

A sustainability assessment of the foundry production process in Italy

Sustainability has become an essential goal for companies to preserve their competitiveness; the metal cast industry is facing several challenges due stringent environmental regulations, resulting in sustainability performance issues. The evaluation of the cast iron environmental footprint has become a key point to drive the sector towards a more sustainable future.This study investigates the environmental performance of the cast iron manufactured by ten Italian foundries (named from A to J) by quantifying their product environmental footprint through the Life cycle assessment methodology. The scores of the surveyed foundries were compared with a benchmark value, that is representative of the average product manufactured by the Italian plants.The product environmental footprint of the casts of seven out of the ten surveyed plants is lower than the benchmark one. Raw materials acquisition is the most impacting in all sites; its contribution to the total product environmental footprint ranges from 59 % (foundry J) to 94 % (foundry D). Raw materials acquisition is followed by melting. The raw materials contributing more to the cast iron environmental footprint are pig iron and ferroalloys, together with electricity. The three elements on average accounts for the 60 % of the score of the casts of the surveyed plants.In all the considered plants climate change, particulate matter, resource, fossil fuels use and ecotoxicity are the most critical impact categories accounting for at least 70 % of the environmental footprint.The reduction of the cast iron environmental footprint is challenging because it requires to intervene on a well consolidated production process without altering the product quality. However, the substitution of pig iron and ferroalloys with recycled inputs, although not easy to achieve could be effective to enhance the sector sustainability since it would reduce the scores associated with the climate change, resource use and ecotoxicity impact categories.

Toward a comprehensive life cycle aquatic ecotoxicity assessment via machine learning: Application to coal power generation in China

Life cycle aquatic ecotoxicity assessments currently lack characterization factors due to the limited availability of experimental toxicity data. In this study, this problem was solved by designing a rapid and simplified approach using machine learning algorithms. The results were further tested and validated via a case study of coal power generation in China that has been implemented since 1990. Compared with the predicted characterization factors of life cycle aquatic ecotoxicity, the predicted average ecotoxicity values (logEC50) are clearly correlated (R2 = 0.597 and RMSE = 0.64) with the reported value in USEtox database based on chemicals' physicochemical properties, degradation rates, and bioaccumulation factors in fish. Approximately 13.6% of the ecotoxicity impact of China's coal power generation is underestimated due to the missing characterization factors of chemicals. In the case study, the predicted ecotoxicity value of the newly identified essential substance via the XGBoost algorithm for the case study was close to the actual value based on the experimental data. Intensifying atmospheric pyrene and chrysene control during the coal power generation stage, increasing the utilization rate of thermal power equipment, and optimizing coal consumption efficiency are efficient approaches for reducing the overall aquatic ecotoxicity from coal power generation in China. The proposed approach can rapidly predict ecotoxicity values and calculate missing characterization factors. Consequently, life cycle aquatic ecotoxicity assessments can be improved, and management strategies can be developed.

Reclaimed seawater discharge – Desalination brine treatment and resource recovery system

With the proliferation of reverse osmosis technology, seawater reverse osmosis desalination has been heralded as the solution to water scarcity for coastal regions. However, the large volume of desalination brine produced may pose an adverse environmental impact when directly discharged into the sea and result in energy wastage as the seawater pumped out is dumped back into the sea. Recently, zero liquid discharge has been extensively studied as a way to eliminate the aquatic ecotoxicity impact completely, despite being expensive and having a high carbon footprint. In this work, we propose a new strategy towards the treatment of brine to seawater level for disposal, dubbed reclaimed seawater discharge (RSD). This process is coupled with existing resource recovery techniques and waste alkali CO2 capture processes to produce an economically viable waste treatment process with minimal CO2 emissions. In this work, we placed significant focus on the electrolysis of brine, which simultaneously lowers the salinity of the desalination brine (56.0 ± 2.1 g/L) to seawater level (32.0 ± 1.4 g/L), generates alkali brine from seawater (pH 13.6) to remove impurities in brine (Mg2+ and Ca2+ to below ppm level), and recovers magnesium hydroxide, calcium carbonate, chlorine, bromine, and hydrogen gas as valuable resources. The RSD is further chemically dechlorinated and neutralised to pH 7.3 to be safe to discharge into the sea. The excess alkali brine is used to capture additional CO2 in the form of bicarbonates, achieving net abatement in climate change impact (9.90 CO2 e/m3) after product carbon abatements are accounted.

Ecotoxicological assessment of waste-derived organic fertilizers and long-term monitoring of fertilized soils using a multi-matrix and multi-species approach

The present study investigates the ecotoxicity of 7 biofertilizers, including biowaste-derived organic matrices. Real-field tests were conducted to assess the impacts of soil fertilization with sewage sludge digestate from high-solid thermophilic anaerobic digestion (HSTAD) compared to those obtained on non-amended and urea-fertilized soils. The physical-chemical and ecotoxic impact of HSTAD digestate on soil was monitored for 12 months, at 5 time points and 2 soil depths, on a maize field divided in 3 portions (non-treated, fertilized with urea, amended with digestate). The chemical and physical characteristics of the soil were previously analyzed for 3 years to provide a long-term outlook of the impacts of biofertilizer application. Seven bioindicators were utilized for direct (on whole soil) and indirect (on soil elutriates) ecotoxicological tests on fertilizers and amended soils, including plant seeds (Lepidium sativum, Sorghum saccharatum, and Sinapsis alba), the aquatic organism Daphnia magna, the alga Raphidocelis subcapitata, the luminescent bacterium Aliivibrio fischeri, and the Nematode Caenorhabditis elegans. No serious negative effects on soil fertilized with HSTAD digestate were evidenced. Conversely, bioassays rather showed positive effects, encouraging the utilization of HSTAD digestate in agriculture, considering the proper concentrations of use. The obtained data were interpolated and a test battery integrated index was generated, confirming the absence of ecotoxicological risk for the soils amended with the applied fertilizers. The long-term evolution of the physical-chemical soil characteristics (including the concentrations of potential contaminants) was similar for both HSTAD digestate and urea application as well as for non-fertilized soil, indicating no negative effects due to digestate application on land. On the contrary, digestate application improved the content of stabilized organic matter and nutrients in soil. This study proposes a more correct approach to ecotoxicity assessment of fertilized soils for biofertilizer evaluation and demonstrates the long-term safe application of HSTAD digestate on agricultural soil.

Circular Bioeconomy Practices in the Greek Pig Sector: The Environmental Performance of Bakery Meal as Pig Feed Ingredient

Food systems and, to an extent, the pig sector are major contributors of greenhouse gas (GHG) emissions globally. At the same time, significant amounts of waste are produced from the food sector. The aim of this study is to examine the implementation of circular bio-economy practices in the Greek pig sector to improve its environmental performance. More specifically, in collaboration with a pig farm in Northern Greece and a waste management company, the collection and processing of bakery by-products was organized to produce bakery meal (BM) to integrate it in the diets of fattening and growing pigs. Using Life Cycle Assessment (LCA) methodology, the environmental performance of 20% BM inclusion in pig diets was examined in comparison with the conventional feedstock. BM experimentally replaced corn, wheat, barley, and soya bean from conventional feedstock. The Life Cycle Inventory (LCI) was based on the yearly average values of feed and energy consumption to produce 1 kg of living weight of pig on the pig farm. Life Cycle Impact Assessment (LCIA) was conducted with SimaPro v3.5, using Recipe Midpoint Hierarchical v1.6. The LCIA calculations exhibited that BM inclusion in pig diets can lead to significant land occupation decrease, approximately 30%, which is mostly related to reduced wheat and soya beans. The reduction of cultivated croplands also led to reduced fertilizer and pesticide application, which improved marine eutrophication and freshwater ecotoxicity impact by 20% while it significantly reduced risks of human carcinogenic toxicity by 25%. Moreover, the Greek pig sector exhibited a 5% capacity for overall improvement of its environmental performance, which relies on minimizing logistics when the pig farm conducted collection and processing of by-products. A basic assumption of this study is the assessment of bakery by-product quantities in the wider region of the pig farm. The availability of by-products, based on the reported experience, was limited, and the reliability of the supply was frequently disrupted. As such, the supply chain model of the central hub for the collection and processing of bakery by-products is proposed as more efficient for regulating logistic challenges and availability.

Preciseness, rather than simplicity, is required to assess pesticide reduction strategies: Findings from rice production in Japan

Pesticide reduction is given high priority in the worldwide sustainability agenda. The reduction of pesticide impacts, rather than the reduction of application rates, has become a common criterion for monitoring policy progress. However, simplicity—an essential requirement in improving the applicability of pesticide impact assessment—may distort the accuracy of the evaluation and therefore prevent effective pesticide reduction. Here, we present contrasting results that underscore how the selection of evaluation methods that differ in simplicity affects the assessment results of pesticide reduction strategies. Briefly, we analysed the impact of conversion from conventional to low-input management adopting both a simplified linear-based method and a precise method that includes newly calculated nonlinear approach-based characterization factors for 109 active ingredients (AIs). The two methods were then used to estimate the freshwater ecotoxicity impact of eight rice farms in Japan where both conventional pesticide application and pesticide reduction strategies are practiced. The results show that the simplified method generated anomalies at the farm level through overestimation and underestimation of the individual AI impacts. Patterns that contributed to extreme changes of impact at the farm level were also identified. These findings suggest a strong need for a precise evaluation method for effectively monitoring policy progress at the farm level.

Evaluating Environmental Impact of Natural and Synthetic Fibers: A Life Cycle Assessment Approach

This research aims to analyze the environmental impact of six fibers in the textile industry: conventional and organic cotton, silk, jute, flax, and polyester. The study used a life cycle assessment (LCA) methodology with a cradle-to-gate system boundary and analyzed the stages of agriculture, spinning, weaving, and dyeing. In agriculture production, five impact categories (i.e., fossil resource scarcity, global warming, land use, terrestrial ecotoxicity, and water consumption) have the most significant differences across these fibers. Polyester production significantly impacted the terrestrial ecotoxicity impact category, while stratospheric ozone depletion had a minor impact. In yarn preparation and spinning, silk has the most significant impact in most categories, followed by conventional cotton, while jute had the most minimal impact. In weaving, the most visible differences were in fossil resource scarcity, global warming, land use, terrestrial ecotoxicity, and water consumption. Conventional cotton dyeing showed significant impacts on global warming potential and terrestrial ecotoxicity. This study contributes to the limited literature on existing LCA research in the textile industry. Adding updated information will help increase the comprehension of LCA research and guide stakeholders in transitioning fashion supply chains more sustainably.

Mitigating Ecotoxicity Risks of Pesticides on Ornamental Plants Based on Life Cycle Assessment.

Ornamental plants such as floriculture and nurseries, have become increasingly popular, but their growth relies heavily on the use of many different types of pesticides. The widespread and inefficient use of these pesticides causes environmental pollution and damage to non-target organisms. Despite these impacts, there has been little research conducted on potential agrochemical pollution in the ornamental plant industry. To address this gap, a life cycle assessment (LCA) was conducted to evaluate the pesticide-related freshwater ecotoxicity impact of the US ornamental plant industry in comparison to that of major field crops. The study analyzed 195 pesticide active ingredients used in 15 major ornamental plant and four field crops. Results showed that the freshwater ecotoxicity per area (PAF m3 d/ha) of ornamental plants was significantly higher than that of field crops due to the high pesticide intensity (kg/ha) and ecotoxicity of insecticides and fungicides used in floriculture and nurseries. To mitigate environmental stress, minimizing the use of highly toxic pesticides is recommended. A ban on low-dose, high-toxicity pesticides could reduce pesticide-driven ecotoxicity by 34% and 49% for floriculture and nursery plants, respectively. This study is among the first to quantify the pesticide-driven ecotoxicity impacts of horticultural ornamental plants and proposes feasible ways to reduce these impacts, thus making the world more sustainable while still preserving its beauty.

Microplastics in agricultural soil: Polystyrene fragments inhibit soil microbial and enzymatic activities but promote nutrient concentration of Cowpea (Vigna unguiculata)

The disintegration and fragmentation of plastics into microplastics (MPs) and their transport from aquatic and terrestrial ecosystems into agricultural soils have been reported to be hazardous to soil health and crop growth. However, it is unknown how biological soil quality indicators and agronomic indices of a C3 plant respond to MPs' ecotoxicity after short-term exposure. Here, we conducted two experiments to define the eco-toxicity impact of polystyrene-MPs (PS-MPs) exposure at concentrations of (i) non-amended control, (ii) 0.5% PS-MP (w/w), (iii) 1% PS-MP (w/w), (iv) 2% PS-MP (w/w), and (v) 4% PS-MP (w/w) on the soil microbial biomass, respiration, and enzymatic activity—indicators of soil quality, and cowpea (model C3 plant) growth and nutrient concentrations. Our results demonstrate that PS-MPs, generally considered nontoxic, negatively inhibit microbial biomass and extracellular enzymatic activities after 30 days of soil incubation. On the other hand, increasing concentrations of PS-MPs increased soil basal respiration and the microbial metabolic quotient (qCO2), indicating microbial stress. Cowpea growth, irrespective of PS-MPs concentration and exposure time, showed neutral or non-inhibitory responses after 60 days. However, PS-MPs at low concentration (0.5% w/w) promoted an increase in cowpea leghemoglobin content, total chlorophyll pigment, and shoot and root nutrient concentrations (N, P, Zn, and Fe) over the control. Overall, our findings affirm the short-term ecotoxicity effect of PS-MPs on soil biological indicators of soil quality but also indicate that PS-MP exposure may not always have negative impacts on the agronomic performance of certain C3 plant species, such as cowpea.

Environmental ranking of European industrial facilities by toxicity and global warming potentials

We present a methodology to develop the integrated toxicity and climate change risk assessment of Europe based facilities, industries and regions. There is an increasingly important need for large scale sustainability measurement solutions for company reporting with high granularity. In this paper we measure key aspects of Sustainable Development Goals in terms of human, cancer and non-cancer toxicity, ecotoxicity together with global warming impact potentials from point source pollutant releases of more than 10,000 companies and their 33,000 facilities in Europe from 2001 to 2017, by using the European Pollutant Release and Transfer Register. For our assessment, we deploy a scientific consensus model, USEtox for characterizing human and ecotoxicological impacts of chemicals and the global warming potential values from the Intergovernmental Panel on Climate Change. We discuss water and air emissions of dozens of pollutants in urban, rural, coastal and inland areas. Companies in the electricity production sector are estimated to have the largest human toxicity impact potential (46% of total) and the largest global warming impact potential (50%), while companies in the sewerage sector have the largest ecotoxicity impact potential (50%). In the overall economy, the correlation between facilities’ global warming and toxicity impact potentials is positive, however, not very strong. Therefore, we argue that carbon footprint of industrial organizations can be only used as a climate change risk indicator, but not as an overall environmental performance indicator. We confirm impact potentials of major pollutants in previous research papers (Hg accounting for 76% of the total human toxicity and Zn accounting for 68% of total ecotoxicity), although we draw the attention to the limitations of USEtox in case of metals. From 2001 to 2017 total human toxicity dropped by 28%, although the downward trend reversed in 2016. Ecotoxicity and global warming impact potentials remained unchanged in the same period. Finally, we show that the European pollutant release monitoring data quality could be further improved, as only three quarters of the toxic releases are measured in the Member States of the European Union, and a high share of toxic pollutant releases are only estimated in some countries. Of the measured or calculated toxic releases, only one third is reported according to the most robust CEN/ISO standards and about one fifth according to the least preferred other methods, like engineering judgements.

Increasing Biowaste and Manure in Biogas Feedstock Composition in Luxembourg: Insights from an Agent-Based Model

Biowaste and manure are resources readily available as feedstock for biogas production. Possible scenarios with increased use of biowaste and manure for biogas production in the Grand Duchy of Luxembourg are investigated in this study using an Agent-Based Model (ABM) coupled with Life Cycle Assessment (LCA). ABMs are particularly suitable to simulate human-natural systems, since they allow modelers to consider behavioral aspects of individuals. On the other hand, when it comes to the assessment of a system’s environmental sustainability, LCA is largely recognized as a sound methodology and widely used in research, industry, and policy making. The paper simulates three different scenarios that reproduce 10 years and can help policymakers building emission mitigation strategies. The aim is to increase the number of biogas plants or change the feedstock composition for anaerobic digestion in Luxembourg whilst observing the expected environmental impacts generated by these changes. The first scenario (Scenario A) is the baseline scenario, which simulates the current situation, with 24 operating biogas plants. The results of Scenario A show that, on average, 63.02 GWh of electricity production per year is possible from biogas. The second scenario (Scenario B) foresees an increase in the manure share (which is initially 63%) in the biogas feedstock composition along with an increase in the number of biogas production plants. The third scenario (Scenario C) only concerns increasing the amount of manure in the feedstock composition without the introduction of new plants. The results of Scenario C show that an 11% increase in electricity production is possible if more farms contribute to the production by bringing their excess manure to the biogas plant. This value is even higher (14%) in Scenario D where more biowaste is made available. The aggregated life-cycle impact assessment (LCIA) single scores, calculated with the ReCiPe method, show that Scenario C has the lowest impacts (although by only around 7% compared to the worst performing scenario, i.e., Scenario D), while Scenario D allows the highest electricity production (71.87 GWh in the last year of the simulation). As a result, the inclusion of more livestock farms into already established biogas cooperatives (as in Scenario C) can pave the way for an increase in electricity production from renewables and can bring a reduction in environmental impacts (more than 35% for the Terrestrial Ecotoxicity impact category and more than 27% in categories such as Agricultural Land Occupation, Marine Eutrophication and Water Depletion), thanks to the exploitation of manure for biogas production.

Heavy Metal Accumulation in Sediments of Small Retention Reservoirs—Ecological Risk and the Impact of Humic Substances Distribution

Anthropogenic pollutants that accumulate in bottom sediments may pose a serious threat to the aquatic environment and humans. The aim of the study was to determine the ecological risk related to the contamination of sediment with heavy metals and the relationship between the accumulation of heavy metals and various granulometric fractions and humic substances in the bottom sediments of small retention reservoirs located in catchments of varying anthropopressure. The research objects were five small dam reservoirs located in south-eastern Poland. The sediments of the reservoir exposed to the greatest anthropopressure from the catchment area posed a serious threat to aquatic organisms feeding at the bottom. The bottom sediments of the remaining reservoirs showed a low level of potential toxicity (or non-toxicity). The observed relationship between the enrichment of sediments with organic matter (OM) and the increased risk of their ecotoxic impact on aquatic organisms was determined by excessive exposure to heavy metal contamination. The sand content did not appear to have a clear effect on the metal accumulation, although it was associated with enrichment in OM. Due to diverse environmental conditions, it was not possible to unequivocally confirm that the accumulation of heavy metals in the sediments of small retention reservoirs directly depends on the content of organic matter and humic substances, but such relationships were observed in most of the objects.

Life cycle environmental impacts of using food waste liquid fodder as an alternative for pig feeding in a conventional Cuban farm

This work aimed to compare cleaner production alternatives for pig production in the Cuban context through the Life Cycle Assessment (LCA) approach emphasizing the utilization of food waste (FW) as a substitute for traditional grain-based pig feeding. A conventional waste management method (lagooning) was assessed, including more environmentally friendly approaches (use of anaerobic digestion (AD) process); including the substitution of a fraction of solid fodder with food waste liquid fodder (LF), obtained from food waste. The analysis was based on one porcine equivalent livestock unit. The environmental impact categories assessed were global warming, terrestrial ecotoxicity, human carcinogenic toxicity, freshwater ecotoxicity, terrestrial acidification, and freshwater eutrophication. The major environmental benefits for pig production were observed when the maximum capacity of pigs was considered. In addition, favorable environmental performance was achieved by considering the substitution of solid fodder by LF, the AD as a waste management process, and the valorization of the solid and liquid effluents. The avoided products-related activities were the main contributor to freshwater ecotoxicity, human carcinogenic toxicity, and terrestrial ecotoxicity impact categories (up to 71 %). The sensitivity analysis showed that the variation in LF composition (protein concentration) could have a remarkable impact in all impact categories. Climate change performed as the more sensible impact category, suggesting that greenhouse gas (GHG) emissions, such as CO2 and N2O, are important drivers to change the environmental impact and need more attention. This research demonstrates that the environmental profile of the process can be improved by applying a cleaner production approach (AD as a waste management alternative and LF substituting solid fodder).

To weigh or not to weigh. Recommendations for communicating aggregated results of buildings LCA

Interpreting contradictory results of multiple midpoint environmental indicators is challenging task. Hence, partial or full aggregation into building single scores has gained ground for the clear message they convey. This paper helps to improve understanding of the possibilities and limitations of such practice. Partial aggregated scores of five buildings were explored, limited to the environmental indicators shared by the methods examined and inventoried for the case studies. In general, the buildings’ single score ranking was maintained regardless of the aggregation approach, but rank reversal is possible if e.g., ecotoxicity impact indicators are considered. Such indicators are directly influenced by the mass of metals used in a building. Furthermore, uncertainties on their results, in LCI data and in impact and damage assessment are high, and experience with them is still limited. No single best aggregation stands out per se. All of them can play their part if officially supported to ensure that coherent weights/factors are built upon solid, up-to-date data and fair intergenerational and income equity valuation procedures. In such cases, LCA practitioners are encouraged to use single scores in addition to environmental profiles or selected indicators. Overall aggregation procedures shall be transparently described, and zero pure time preference rate and equity weighting applied and explicitly declared. Sensitivity/uncertainty analysis shall be performed to assess results robustness, potential ranking reversal risks, and the effect of different discount rates. When partial aggregation is alternatively pursued, it shall be based on endpoint categories.

Environmental assessment model for scrubbers versus alternative mitigation systems for feeder vessels in liner shipping

Implementation of the Global Sulphur Cap (GSC), in January 2020, boosted scrubber installation in vessels to fulfill the new air emission limitations. This increase in scrubbers' use has intensified concern about its environmental performance. Even though achievement of GSC requirements through this mitigation system has been widely proven, the impact of wash water discharge on the marine environment remains under discussion. In this paper, an assessment environmental model is introduced to quantify in monetary terms the performance of feeder vessels that operate with several mitigation systems. This model attempts to improve traditional air emission evaluations by including the impact of scrubbers' discharges on the marine environmental. In this way, the analysis not only allows different mitigations systems to be ranked by considering their capacity to reduce air emissions, but also provides further information about the marine eutrophication and ecotoxicity impact from scrubbers' discharge. Through the model's application to a regular shipping line between the Canary Islands and the Iberian Peninsula, it was found that, the scrubber, regardless of its operation mode (open- or closed loop), is the most efficient mitigation option after the Liquefied Natural Gas (LNG) fuel shift. The impact of scrubbers' discharge was not as significant as expected on the feeder vessel's total pollution since this provides similar relative weight to the methane emissions from a dual-engine option by operating with LNG. The results also show the need to more closely research the marine eutrophication impact of closed-loop scrubbers.Finally, this paper warns about a significant dispersion on the monetary values of marine ecotoxicity and eutrophication, due to a high dependence of the results on the frameworks’ localization. Consequently, further research is needed on the homogenization of pollution monetization in the marine environment.

Antifouling Marine Coatings with a Potentially Safer and Sustainable Synthetic Polyphenolic Derivative.

The development of harmless substances to replace biocide-based coatings used to prevent or manage marine biofouling and its unwanted consequences is urgent. The formation of biofilms on submerged marine surfaces is one of the first steps in the marine biofouling process, which facilitates the further settlement of macrofoulers. Anti-biofilm properties of a synthetic polyphenolic compound, with previously described anti-settlement activity against macrofoulers, were explored in this work. In solution this new compound was able to prevent biofilm formation and reduce a pre-formed biofilm produced by the marine bacterium, Pseudoalteromonas tunicata. Then, this compound was applied to a marine coating and the formation of P. tunicata biofilms was assessed under hydrodynamic conditions to mimic the marine environment. For this purpose, polyurethane (PU)-based coating formulations containing 1 and 2 wt.% of the compound were prepared based on a prior developed methodology. The most effective formulation in reducing the biofilm cell number, biovolume, and thickness was the PU-based coating containing an aziridine-based crosslinker and 2 wt.% of the compound. To assess the marine ecotoxicity impact of this compound, its potential to disrupt endocrine processes was evaluated through the modulation of two nuclear receptors (NRs), peroxisome proliferator-activated receptor γ (PPARγ), and pregnane X receptor (PXR). Transcriptional activation of the selected NRs upon exposure to the polyphenolic compound (10 µM) was not observed, thus highlighting the eco-friendliness towards the addressed NRs of this new dual-acting anti-macro- and anti-microfouling agent towards the addressed NRs.

Environmental and economic sustainability of crack mitigation in reinforced concrete with SuperAbsorbent polymers (SAPs)

Due to the increasing awareness and sensitivity towards the environmental and economic sustainability issues, the concrete industry has to deliver innovative solutions, in terms of materials, products and structural concepts, to achieve higher durability of engineering feats in real service scenarios. The inclusion of SuperAbsorbent Polymers (SAPs) into the concrete mix, can not only stimulate the autogenous crack healing, but is also able to reduce the shrinkage cracking through internal curing. In this paper, Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) analysis have been performed to assess both the ecological and economic profile, in real scale, of conventional reinforced concrete structures , made with concrete containing SAPs, in comparison to a reference solution without any addition. For this purpose, the corrosion of reinforcement has been regarded as the main degradation mechanism and different corrosion models have been considered and combined with the structural analysis principles to obtain reliable Service Life (SL) estimations. Four different scenarios, with a SL ranging from 50 up to 100 years, have been analyzed to assess the potential benefits of a wall, cast with SAP-containing concrete (Wall_SAP). Both Wall_SAP and a reference wall without SAP (Wall_Ref) are subjected to the concrete cover replacement as main maintenance activity while for the Wall_Ref also the crack filling by means of polyurethane resin is considered as an option (Wall_Resin). The adopted CML impact-assessment method, developed by the Center of Environmental Science of Leiden University, shows the advantage of using SAPs, since the environmental burdens were reduced up to 20% in the case of Fresh Water Aquatic Ecotoxicity impact category in comparison to the reference for the fourth scenario. In this scenario a hemispherical corrosion pit model for the steel bars and a service life of 100 years were taken into account. Furthermore, the economic assessment developed for the same scenario, pointed out for the SAPs based solution, there identified as Wall_SAP_M2_100, a consistent reduction in terms of costs up to 14% if compared to the reference, there named as Wall_Ref_M2_100. The outcomes definitely highlight the potential of the analyzed technology that can fulfil the future needs of the stakeholders involved in the construction sector.

Environmental performance evaluation of warm mix asphalt with recycled concrete aggregate for road pavements

ABSTRACT A Life Cycle Assessment (LCA) was undertaken to compare the potential environmental impacts associated with the use of Recycled Concrete Aggregate (RCA) as a partial replacement of natural aggregates in the production of Warm Mix Asphalt (WMA), with those of a conventional Hot Mix Asphalt (HMA). The LCA was conducted according to the ‘cradle-to-laid’ approach, including four pavement LCA phases. Three percentages of RCA replacement for natural coarse aggregates in WMA were considered: 15, 30 and 45%. The results of laboratory tests were used as inputs in the design of pavement structures with different percentages of RCA for typical Colombian pavement design conditions. Primary data and SimaPro 8.4.0 software were used in modelling the processes analysed in the case study. All the life cycle inputs and outputs related to the functional unit were characterised according to the impact assessment methodology TRACI v.2.1. The results show that the potential environmental benefits arising from the combined effect of reducing the consumption of natural aggregates and reduced mixing temperature are offset by the reduced performance and the increased optimum asphalt content when incorporating RCA in WMA. The highest relative increase in the environmental impacts, at 29%, was observed in the Ecotoxicity impact category.