Land cover along hiking trails in a nature tourism destination: the Azores as a case study

Environment, Development and Sustainability - Tourists have become increasingly interested in certain aspects of their destination, including landscape and biodiversity elements, thereby promoting...     

Toxicity testing of pesticides in zebrafish—a systematic review on chemicals and associated toxicological endpoints

The use of zebrafish (Danio rerio) has arisen as a promising biological platform for toxicity testing of pesticides such as herbicides, insecticides, and fungicides. Therefore, it is relevant to assess the use of zebrafish in models of exposure to investigate the diversity of pesticide-associated toxicity endpoints which have been reported. Thus, this review aimed to assess the recent literature on the use of zebrafish in pesticide toxicity studies to capture data on the types of pesticide used, classes of pesticides, and zebrafish life stages associated with toxicity endpoints and phenotypic observations. A total of 352 articles published between September 2012 and May 2019 were curated. The results show an increased trend in the use of zebrafish for testing the toxicity of pesticides, with a great diversity of pesticides (203) and chemical classes (58) with different applications (41) being used. Furthermore, experimental outcomes could be clustered in 13 toxicity endpoints, mainly developmental toxicity, oxidative stress, and neurotoxicity. Organophosphorus, pyrethroid, azole, and triazine were the most studied classes of pesticides and associated with various toxicity endpoints. Studies frequently opted for early life stages (embryos and larvae). Although there is an evident lack of standardization of nomenclatures and phenotypic alterations, the information gathered here highlights associations between (classes of) pesticides and endpoints, which can be used to relate mechanisms of action specific to certain classes of chemicals.     

Metal mixtures in pregnant women and umbilical cord blood at urban populations—Rio de Janeiro,Brazil

Environmental Science and Pollution Research - This study aims to assess interrelationships between serum lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) concentrations in pregnant women in...     

Need for recovery after emotional labor: Differential effects of daily deep and surface acting

This diary study examines the psychological processes that contribute to daily recovery from emotional labor by combining emotion regulation with work‐home resources theories. We hypothesized that overall perceptions of display rules relate positively to daily deep and surface acting. Daily surface acting was expected to relate positively to exhaustion and negatively to flow during work and consequently, to a higher need for recovery at the end of the workday. In contrast, daily deep acting was hypothesized to relate positively to flow and negatively to exhaustion and consequently, to a lower need for recovery at the end of the workday. In turn, need for recovery was expected to associate negatively to vigor at bedtime through reduced relaxation during leisure. Fifty Dutch and Polish employees first filled in a survey, and then a diary for five consecutive workdays, twice per day: at the end of the workday and before sleep. Multilevel path analyses largely supported these hypotheses suggesting that surface acting has unfavorable implications, whereas deep acting has favorable implications for daily well‐being at work and recovery after work.     

Tropical surface water quality studies: Implications for the aquatic fate of N-methyl carbamate pesticides

Water quality assessment was conducted on the Ruiru River, a tributary of an important tropical river system in Kenya, to determine baseline river conditions for studies on the aquatic fate of N-methyl carbamate (NMC) pesticides. Measurements were taken at the end of the long rainy season in early June 2013. Concentrations of copper (0.21–1.51 ppm), nitrates (2.28–4.89 ppm) and phosphates (0.01–0.50 ppm) were detected at higher values than in uncontaminated waters, and attributed to surface runoff from agricultural activity in the surrounding area. Concentrations of dissolved oxygen (8–10 ppm), ammonia (0.02–0.22 ppm) and phenols (0.19–0.83 ppm) were found to lie within normal ranges. The Ruiru River was found to be slightly basic (pH 7.08–7.70) with a temperature of 17.8–21.2°C. The half-life values for hydrolysis of three NMC pesticides (carbofuran, carbaryl and propoxur) used in the area were measured under laboratory conditions, revealing that rates of decay were influenced by the electronic nature of the NMCs. The hydrolysis half-lives at pH 9 and 18°C decreased in the order carbofuran (57.8 h) > propoxur (38.5 h) > carbaryl (19.3 h). In general, a decrease in the electron density of the NMC aromatic ring increases the acidity of the N-bound proton removed in the rate-limiting step of the hydrolysis mechanism. Our results are consistent with this prediction, and the most electron-poor NMC (carbaryl) hydrolyzed fastest, while the most electron-rich NMC (carbofuran) hydrolyzed slowest. Results from this study should provide baseline data for future studies on NMC pesticide chemical fate in the Ruiru River and similar tropical water systems.     

Degradation of Post-consumer PLA: Hydrolysis of Polymeric Matrix and Oligomers Stabilization in Aqueous Phase

Degradation of post-consumer PLA to lactic acid was analysed in order to assess the economic feasibility of the PLA chemical recycling process. Hydrolysis of PLA, in batch reactor, was analysed in the temperature range of 443–473 K, under autogenous pressure and a constant PLA to water ratio (equal to approximately 0.11 by weight), without the use of a catalyst. The experimental results suggest that the complete degradation of PLA can be obtained using relatively low reaction-times with the production of a mixture containing the monomer and traces of the dimer of lactic acid. The overall process was modelled using a two-step process: bulk degradation of PLA (in the solid or molten phase) with the solubilisation of low molecular weight oligomers, and their subsequent hydrolysis in water (stabilization). The model describes the trend of oligomer concentrations in the aqueous phase and PLA conversion as a function of time with both high accuracy and agreement with experimental results.     

Effects of sex on the levels of metals and metalloids in the hair of a group of healthy Spanish adolescents (13 to 16 years old)

Human biomonitoring can be a reliable tool to protect the health of the citizens of major urban environments. Human hair may be an invaluable specimen to determine chronic exposure to any environmental contaminant in an individual, especially in the young population. However, different factors including a lack of studies that have established reference values for metals and metalloids (trace elements) in human scalp hair make the use of this matrix controversial. A monitoring study was performed to establish possible normal or tentative reference values of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Pb, Sn, Ti, Tl and Zn in adolescents’ (aged 13–16) hair who have lived since birth in Alcalá de Henares, Madrid region (Spain). Strict inclusion criteria were followed to study the effect of sex on the hair metal content, and the levels of the above contaminants were also studied in park topsoils from Alcalá de Henares. Scalp hair samples were collected from 96 healthy adolescents (28 boys and 68 girls), and reference values were calculated following the recommendations of the International Union of Pure and Applied Chemistry. The levels of Cd, Cu, Pb, Sn and Zn in hair of adolescents from Alcalá de Henares show a sex dependency, being significantly higher in female participants. Sex should be a factor taken into account when developing future reference values and hair metal content. Soil metal contamination was not correlated with the levels found in hair. To conclude, the values of metals and metalloids here analysed and discussed could be considered as tentative reference values for Spanish adolescents aged 13–16 years living in the Madrid region, and may be used to identify the level of exposure of adolescents in this Spanish region to the various metals and metalloids.

     

Evaluation of concrete production with solid residues obtained from fluidized-bed incineration of MSW-derived solid recovered fuel (SRF)

The aim of this work was to evaluate the use of solid residues derived from municipal solid waste-derived solid recovered fuel incinerated in a circulating fluidized-bed boiler for concrete production. The concrete mixtures casted by partially replacing the natural aggregates with bottom ash (27 %) and exhausted sand (13 %), according to the European standards for concrete, may be classified in the C16/20 class. The leaching tests performed on monolithic concrete samples showed that the concentrations measured in the leachates were lower than limit values for waste recovery, with the only exception of nickel for the mixture made with the exhausted sand.     

Characterization of atmospheric aerosols in the city of S?o Paulo, Brazil: comparisons between polluted and unpolluted periods

The objective of this study was to determine the size and composition of atmospheric aerosols in the downtown area of the city of S?o Paulo, Brazil, for a polluted and an unpolluted period. Aerosols were sampled with a portable air sampler (PAS), Micro-Orifice Uniform Deposit Impactor (MOUDI), and Scanning Mobility Particle Sizer. At the study site, air quality is poor, especially during the winter, high concentrations of pollutants being emitted primarily by the light- and heavy-duty vehicle fleet. We analyzed mass, black carbon (BC), Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sn, Zr, and Pb. During the polluted period, diurnal PM₁₀ was higher than nocturnal PM₁₀, whereas the inverse was true during the unpolluted period. The FPM was rich in BC, S, and Pb, whereas CPM was rich in Al, Si, Ca, Ti, and Fe. Mass balance was performed by category: ammonium sulfate, sodium chloride, crustal material, BC, and other. The PAS-determined FPM was mainly BC. The MOUDI-determined FPM crustal material explained more mass than did ammonium sulfate and BC during the polluted period, whereas ammonium sulfate had the largest mass during the unpolluted period. Crustal material was the major CPM component, followed by ammonium sulfate and BC. During the unpolluted period, FPM concentrations were lower, whereas those of ammonium sulfate were relatively higher, especially at night, and particle number was inversely proportional to particle size. Aerosol growth was more intense during the polluted period.     

Impact of agglomeration and different dispersions of titanium dioxide nanoparticles on the human related in vitro cytotoxicity and genotoxicity

The published results on nanoparticles cytotoxicity and genotoxicity such as titanium dioxide nanoparticles (TiO(2) NPs) are inconsistent, and often conflicting and insufficient. Since different parameters may have impact on the toxicity results, there is need to lay stress on detailed characterization of NPs and the use of different testing conditions for assessment of NPs toxicity. In order to investigate whether dispersion procedures influence NP cytotoxicity and genotoxicity, we compared two protocols giving TiO(2) NP dispersions with different stability and agglomeration states. Detailed primary and secondary characteristics of both TiO(2) NP dispersions in culture media were carried out before toxicological testing; TK6 human lymphoblast cells, EUE human embryonic epithelial cells and Cos-1 monkey kidney fibroblasts were used to assess cytotoxicity (by trypan blue exclusion, proliferation activity and plating efficiency assays) and genotoxicity (by the comet assay). DNA strand breaks were detected by the alkaline comet assay. DNA oxidation lesions (especially 8-oxo-7,8-dihydroguanine, 8-oxoG) were measured with a modified comet assay including incubation with specific repair enzyme formamidopyrimidine DNA glycosylase (FPG). The TiO(2) NPs dispersion with large agglomerates (3 min sonication and no serum in stock solution) induced DNA damage in all three cell lines, while the TiO(2) NPs dispersed with agglomerates less than 200 nm (foetal serum in stock solution and sonication 15 min) had no effect on genotoxicity. An increased level of DNA oxidation lesions detected in Cos-1 and TK6 cells indicates that the leading mechanism by which TiO(2) NPs trigger genotoxicity is most likely oxidative stress. Our results show that the dispersion method used can influence the results of toxicity studies. Therefore at least two different dispersion procedures should be incorporated into assessment of cyto- and genotoxic effects of NPs. It is important, when assessing the hazard associated with NPs, to establish standard testing procedures and thorough strategies to consider the diverse conditions relevant to possible exposures.