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“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 [-]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 [-]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 [-]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 [-]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 [-]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 [-]A Comparison of In Situ Constant and Falling Head Permeameter Tests to Assess the Distribution of Clogging Within Horizontal Subsurface Flow Constructed Wetlands
2012
Pedescoll, A. | Knowles, P. R. | Davies, P. | Garcia, J. | Puigagut, J.
Clogging is the main operational problem associated with horizontal subsurface flow constructed wetlands (HSSF CWs). The measurement of saturated hydraulic conductivity has proven to be a suitable technique to assess clogging within HSSF CWs. The vertical and horizontal distribution of hydraulic conductivity was assessed in two full-scale HSSF CWs by using two different in situ permeameter methods (falling head (FH) and constant head (CH) methods). Horizontal hydraulic conductivity profiles showed that both methods are correlated by a power function (FH = CH0.7821, r 2 = 0.76) within the recorded range of hydraulic conductivities (0–70 m/day). However, the FH method provided lower values of hydraulic conductivity than the CH method (one to three times lower). Despite discrepancies between the magnitudes of reported readings, the relative distribution of clogging obtained via both methods was similar. Therefore, both methods are useful when exploring the general distribution of clogging and, specially, the assessment of clogged areas originated from preferential flow paths within full-scale HSSF CWs. Discrepancy between methods (either in magnitude and pattern) aroused from the vertical hydraulic conductivity profiles under highly clogged conditions. It is believed this can be attributed to procedural differences between the methods, such as the method of permeameter insertion (twisting versus hammering). Results from both methods suggest that clogging develops along the shortest distance between water input and output. Results also evidence that the design and maintenance of inlet distributors and outlet collectors appear to have a great influence on the pattern of clogging, and hence the asset lifetime of HSSF CWs.
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 [-]Economic growth target and environmental regulation intensity: evidence from 284 cities in China
2022
Li, Feiyang | Wang, Zhen | Huang, Liangxiong
Management of economic growth targets is a universal measure employed by worldwide governments for macroeconomic regulation. This paper aims to empirically investigate the impact of economic growth targets set by governments of prefecture-level cities on the environmental regulation intensity. We extracted panel data on annual economic growth targets and environmental regulation indicators from the government work reports (2009–2016) of 284 China’s prefecture-level cities. The study concludes that an increase in economic growth target significantly weakens the intensity of environmental regulation. The conclusion still holds true after robustness tests, including changing measurement variables, regression samples, and conducting endogenous tests. The underlying reason for the inhibitory effect may be that in order to achieve economic growth targets, local governments prefer less stringent environmental regulations. They subsequently expand outputs in the short term by increasing the proportion of secondary industry in GDP, land transfer area, and fixed asset investment. Further research in this paper also finds that only cities with low economic development levels and low openness to the outside world experience the negative effect of a local government’s annual economic growth target on environmental regulation intensity.
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