Affiner votre recherche
Résultats 1-10 de 25
“Smart” nanosensors for early detection of corrosion: Environmental behavior and effects on marine organisms
2022
Martins, Roberto Borges | Figueiredo, Joana | Sushkova, Alesia | Wilhelm, Manon | Tedim, João | Loureiro, Susana
Corrosion is an environmental and economic global problem. “Smart” or stimuli-responsive colorimetric nanosensors for maritime coatings have been proposed as an asset to overcome the limitations of the current monitoring techniques by changing color in the presence of triggers associated with the early stages of corrosion. Layered double hydroxides (Zn–Al LDH; Mg–Al LDH) and silica mesoporous nanocapsules (SiNC) were used as precursor nanocarriers of active compounds: hexacyanoferrate ions ([Fe(CN)₆]³⁻) and phenolphthalein (PhPh), respectively. Additionally, the safer-by-design principles were employed to optimize the nanosensors in an eco-friendly perspective (e.g., regular vs. warm-washed SiNC-PhPh; immobilization using different carriers: Zn–Al LDH-[Fe(CN)₆]³⁻ vs. Mg–Al LDH-[Fe(CN)₆]³⁻). Therefore, the present study aims to assess the environmental behavior in saltwater and the toxic effects of the nanosensors, their nanocarriers, and the active compounds on the marine microalgae Tetraselmis chuii and the crustacean Artemia salina. Briefly, tested compounds exhibited no acute toxic effects towards A. salina (NOEC = 100 mg/L), apart from SiNC-PhPh (LC₅₀ = 2.96 mg/L) while tested active compounds and nanosensors caused significant growth inhibition on T. chuii (lowest IC₅₀ = 0.40 mg/L for SiNC-PhPh). The effects of [Fe(CN)₆]³⁻ were similar regardless of the nanocarrier choice. Regarding SiNC-PhPh, its toxicity can be decreased at least twice by simply reinforcing the nanocapsules washing, which contributes to the removal (at least partially) of the surfactants residues. Thus, implementing safe-by-design strategies in the early stages of research proved to be critical, although further progress is still needed towards the development of truly eco-friendly nanosensors.
Afficher plus [+] Moins [-]Bacterial community assemblages in sediments under high anthropogenic pressure at Ichkeul Lake/Bizerte Lagoon hydrological system, Tunisia
2019
Ben Salem, Fida | Ben Said, Olfa | Cravo-Laureau, Cristiana | Mahmoudi, Ezzeddine | Bru, Noëlle | Monperrus, Mathilde | Duran, Robert
Bacterial communities inhabiting sediments in coastal areas endure the effect of strong anthropogenic pressure characterized by the presence of multiple contaminants. Understanding the effect of pollutants on the organization of bacterial communities is of paramount importance in order to unravel bacterial assemblages colonizing specific ecological niches. Here, chemical and molecular approaches were combined to investigate the bacterial communities inhabiting the sediments of the Ichkeul Lake/Bizerte Lagoon, a hydrological system under anthropogenic pressure. Although the microbial community of the Ichkeul Lake sediment was different to that of the Bizerte Lagoon, common bacterial genera were identified suggesting a lake-lagoon continuum probably due to the hydrology of the system exchanging waters according to the season. These genera represent bacterial "generalists" maintaining probably general biogeochemical functions. Linear discriminant analysis effect size (LEfSe) showed significant differential abundance distribution of bacterial genera according to the habitat, the pollution type and level. Further, correlation analyses identified specific bacterial genera which abundance was linked with pesticides concentrations in the lake, while in the lagoon the abundance of specific bacterial genera was found linked with the concentrations of PAHs (Polycyclic aromatic hydrocarbons) and organic forms of Sn. As well, bacterial genera which abundance was not correlated with the concentrations of pollutants were identified in both lake and lagoon. These findings represent valuable information, pointing out specific bacterial genera associated with pollutants, which represent assets for developing bacterial tools for the implementation, the management, and monitoring of bioremediation processes to mitigate the effect of pollutants in aquatic ecosystems.
Afficher plus [+] Moins [-]Microbes from mined sites: Harnessing their potential for reclamation of derelict mine sites
2017
Thavamani, Palanisami | Samkumar, R Amos | Satheesh, Viswanathan | Subashchandrabose, Suresh R. | Ramadass, Kavitha | Naidu, R. | Venkateswarlu, Kadiyala | Megharaj, Mallavarapu
Derelict mines pose potential risks to environmental health. Several factors such as soil structure, organic matter, and nutrient content are the greatly affected qualities in mined soils. Soil microbial communities are an important element for successful reclamation because of their major role in nutrient cycling, plant establishment, geochemical transformations, and soil formation. Yet, microorganisms generally remain an undervalued asset in mined sites. The microbial diversity in derelict mine sites consists of diverse species belonging to four key phyla: Proteobacteria, Acidobacteria, Firmicutes, and Bacteroidetes. The activity of plant symbiotic microorganisms including root-colonizing rhizobacteria and ectomycorrhizal fungi of existing vegetation in the mined sites is very high since most of these microbes are extremophiles. This review outlines the importance of microorganisms to soil health and the rehabilitation of derelict mines and how microbial activity and diversity can be exploited to better plan the soil rehabilitation. Besides highlighting the major breakthroughs in the application of microorganisms for mined site reclamation, we provide a critical view on plant−microbiome interactions to improve revegetation at the mined sites. Also, the need has been emphasized for deciphering the molecular mechanisms of adaptation and resistance of rhizosphere and non-rhizosphere microbes in abandoned mine sites, understanding their role in remediation, and subsequent harnessing of their potential to pave the way in future rehabilitation strategies for mined sites.
Afficher plus [+] Moins [-]Outdoor manufacture of UV-Cured plastic linings for storm water culvert repair: Chemical emissions and residual
2019
Li, Xianzhen | Ra, Kyungyeon | Nuruddin, Md | Teimouri Sendesi, Seyedeh Mahboobeh | Howarter, John A. | Youngblood, Jeffrey P. | Zyaykina, Nadya | Jafvert, Chad T. | Whelton, Andrew J.
Storm water culverts are integral for U.S. public safety and welfare, and their mechanical failure can cause roadways to collapse. To repair these buried assets, ultraviolet (UV) light cured-in-place-pipes (CIPP) are being installed. Chemical emission and residual material left behind from the installation process was investigated in New York and Virginia, USA. Samples of an uncured resin tube and field-cured styrene-based resin CIPPs were collected and analyzed. Also collected were air and water samples before, during, and after installations. Chemicals were emitted into air because of the installation and curing processes. Particulates emitted into the air, water, and soil contained fiberglass, polymer, and contaminants, some of which are regulated by state-level water quality standards. The uncured resin tube contained more than 70 chemical compounds, and 19 were confirmed with analytical standards. Compounds included known and suspected carcinogens, endocrine disrupting compounds, hazardous air pollutants, and other compounds with little aquatic toxicity data available. Compounds (14 of 19 confirmed) were extracted from the newly installed CIPPs, and 11 were found in water samples. Aqueous styrene (2.31 mg/L), dibutyl phthalate (12.5 μg/L), and phenol (16.7 μg/L) levels exceeded the most stringent state water quality standards chosen in this study. Styrene was the only compound that was found to have exceed a 48 h aquatic toxicity threshold. Newly installed CIPPs contained a significant amount volatile material (1.0 to > 9.0 wt%). Recommendations provided can reduce chemical emission, as well as improve worksite and environmental protection practices. Recommended future research is also described.
Afficher plus [+] Moins [-]Valuing the European ‘coastal blue carbon’ storage benefit
2013
Luisetti, T. | Jackson, E.L. | Turner, R.K.
‘Blue’ carbon ecosystems are important carbon storage providers that are currently not protected by any international mechanism, such as REDD. This study aims to contribute to raising awareness in the political domain about the ‘blue’ carbon issue. This analysis also provides guidance in terms of how to value stock and flows of ecosystem services adding to the debate begun by the Costanza et al. (1997) paper in Nature. Through scenario analysis we assess how human welfare benefits will be affected by changes in the European coastal blue carbon stock provision. The current extent of European coastal blue carbon has an accounting stock value of about US$180million. If EU Environmental Protection Directives continue to be implemented and effectively enforced, society will gain an appreciating asset over time. However, a future policy reversal resulting in extensive ecosystem loss could mean economic value losses as high as US$1billion by 2060.
Afficher plus [+] Moins [-]Heavy metal spatial and temporal trends (2008–2018) in clams and mussel from Adriatic Sea (Italy): Possible definition of forecasting models
2021
Tavoloni, Tamara | Miniero, Roberto | Bacchiocchi, Simone | Brambilla, Gianfranco | Ciriaci, Martina | Griffoni, Francesco | Palombo, Paolo | Stecconi, Tommaso | Stramenga, Arianna | Piersanti, Arianna
In 2008–2018, 1458 georeferenced samples of clams and 343 of mussels were harvested in Italy from classified areas along Marche coast and analyzed within food-safety monitoring plans. Pb, Cd, V, Ni, Cr, and As median levels (mg kg⁻¹) were 0.09, 0.08, 0.29, 0.77, 0.35, and 2.35 in clams and 0.16, 0.15, 0.46, 0.48, 0.25, and 3.34 in mussels. The reported levels were comparable with the published ones, and Hg always fell below LOQ (0.025 mg kg⁻¹). Pb and Cd datasets, based on quarterly results, show a decreasing trend in clams and constant baseline value for mussels. Time-trends and forecasting models represent an asset to predict emerging food safety/security risks. The metal levels in mussels and clams from the same area allow environmental safety assessment and thus enable the evaluation of contaminants in both water column and sediment. Monitoring of elements that are not regulated may help in preserving food and environmental safety.
Afficher plus [+] Moins [-]Analysis of influencing factors of carbon emissions in resource-based cities in the Yellow River basin under carbon neutrality target
2022
Sun, Xiumei | Zhang, Haotian | Ahmad, Mahmood | Xue, Chaokai
In 2020, China promised to achieve carbon peaking by 2030 and carbon neutrality by 2060, and these targets are famous as “Goal 3060” in China. Chinese resource-based cities are concerned about the realization of Goal 3060 to practice national action against environmental change. In this paper, this study evaluates the impact of population, economic growth, energy intensity, industrial structure, fixed asset investment, and urbanization level on carbon emissions in Chinese cities. To do so, the paper divides 36 Chinese cities into four types (growing city, mature city, recessionary city, and regenerative city) from 2003 to 2017 by factor investigation according to the diverse development stages. The extended STIRPAT model is used to assess the impact of various factors on CO₂ emissions in the Yellow River basin and diverse city levels. The panel regression analysis was conducted for the basin as a whole and cities at different development stages through a fixed-effects model and a linear regression model with Driscoll-Kraay standard errors. The results show that (1) the total carbon emissions in the Yellow River basin continued to climb during the study period. However, the growth rate slowed down significantly after 2012. In addition, there are differences in the total carbon emissions and growth rate of different cities. (2) Population, real GDP, energy intensity, industrial structure, and fixed asset investment all have a significant positive impact on carbon emissions in the overall basin except the urbanization level which has a significant negative influence on carbon emissions. (3) There is heterogeneity in the influencing factors of carbon emissions in resource-based cities at various development stages. Based on these results, corresponding policies are proposed for different types of cities to help resource-based cities achieve the 3060 dual carbon goal.
Afficher plus [+] Moins [-]Influencing factors and decoupling analysis of carbon emissions in China’s manufacturing industry
2021
Jin, Baoling | Han, Ying
The manufacturing industry directly reflects national productivity, and it is also an industry with high energy consumption and severe carbon emissions. This study decomposes the influential factors on carbon emissions in China’s manufacturing industry from 1995 to 2018 into industry value added, energy consumption, fixed asset investment, carbon productivity, energy structure, energy intensity, investment carbon intensity, and investment efficiency by Generalized Divisia Index Model. The decoupling analysis of carbon emissions and industry value added is carried out to investigate the states of the manufacturing industry under the pressure of “low carbon” and “economy.” Results show that first, fixed asset investment is the driving force of carbon emissions, followed by industry value added; investment carbon intensity, carbon productivity, investment efficiency, and energy intensity are the mitigating factors; simultaneously, the impacts of energy consumption and energy structure are fluctuating. Second, the decoupling of manufacturing has improved, especially in the light industry. Third, the decoupling of carbon emissions and economic development is mainly dominated by the decoupling of energy consumption and industry added value. Therefore, reducing the proportion of coal consumption and optimizing the energy structure are significant ways to promote the low-carbon development of the manufacturing industry.
Afficher plus [+] Moins [-]Sewerage infrastructure asset management based on a consumer-centric approach
2022
Jo, Hanseul | Ryu, Jaena | Shin, Jungwoo
In most developed countries, such as the USA, the E.U., and East Asia, the importance of public infrastructure asset management has been stressed for a long time. Among the various types of public infrastructure, sewerage systems are one of the most cost-intensive facilities to manage. Sewerage systems are considered highly difficult to manage due to the undetermined level of service needed, different standards of user satisfaction, and the large gap of service understanding between experts and users. To address these issues, this study aims to define the appropriate target level of service improvement by combining consumers’ expected level of service and complaint data. In this study, the case of the inland flood management project in South Korea is investigated because of the global trend of increasing flood damage. The complaint data represent the frequency of flood damage in the area. Using the contingent valuation method, we found that people want to use 25% of their current monthly sewage bill on the management project. In addition, the results of this study demonstrate that people prefer to deal with the problems caused by old service infrastructure when it can be handled at a lower cost during early stages.
Afficher plus [+] Moins [-]Heterogeneous choices of environmental strategies for heavily polluting firms under institutional pressure in China
2022
Wang, Sen | Yin, Jianhua | Zhu, Xiaomei
The question of how organisations choose their environmental strategy remains an unsolved problem in institutional theory. We argue that institutional pressure and the characteristics of the firm affect choices around environmental strategies. An empirical analysis of 597 heavily polluting firms indicates that more firms choose environmental leadership strategies, which means that they actively work with upstream and downstream firms to reduce emissions, when government pressure is the greatest; however, more companies are likely to choose pollution prevention strategies, which implies recycling materials in the production process is implemented, when public pressure is the greatest. Finally, organisations with more redundant resources and strong asset specificity are more prone to choose environmental leadership strategies as policy pressure or public pressure increases. The findings offer a decision-making framework to promote environmental measures related to government policy formulation and public participation. The results can also provide empirical evidence to guide environmental strategic choices for heavily polluting enterprises.
Afficher plus [+] Moins [-]