Count, identification and antimicrobial susceptibility of bacteria recovered from dental solid waste in Brazil

In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.     

Trends in the use of psychoactive substances by truck drivers in São Paulo State,Brazil: A time-series cross sectional roadside survey (2009–2016)

Objective: Truck drivers represent a group that is susceptible to the use of stimulant substances to reduce the symptoms of fatigue, which may be caused by a stressful and exhausting work environment. The use of psychoactive substances may increase the risk for involvement in road traffic crashes. Previous studies have demonstrated that amphetamine, cocaine, and cannabis are the 3 main drugs used by Brazilian truck drivers. We studied the prevalence of amphetamine, benzoylecgonine (indicating use of cocaine), and Δ-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH; indicating use of cannabis) in urine samples from truck drivers in the state of São Paulo, Brazil, using the same methodology during 8 years (2009–2016).

Methods: Samples were collected during a health program supported by the Federal Highway Police. Toxicological analyses were performed using immunoassays and gas chromatography–mass spectrometry.

Results: The total prevalence of illicit drugs was 7.8%. Benzoylecgonine was the most prevalent substance (3.6%), followed by amphetamine (3.4%) and THC-COOH (1.6%). We found the highest drug prevalence in 2010 (11.3%) and the lowest in 2011 (6.1%). We could detect a slight change in the pattern of stimulant use: until 2010, amphetamine was the most prevalent substance; however, in 2011 benzoylecgonine became the most frequently detected substance. This lasted until 2015, probably due to changes in Brazilian legislation regarding appetite suppressants; the most common one is metabolized to amphetamine.

Conclusion: These data show that the use of psychoactive substances by truck drivers in Brazil did not decrease during the study period. This reinforces the need for further preventive measures to reduce drug use among drivers, which could lead to a decrease in traffic crashes in Brazil.     

Evaluation of chelating and cytoprotective activity of vanillin against the toxic action of mercuric chloride as an alternative for phytoremediation

Environmental Geochemistry and Health - Mercury is widely found in nature, however, in low concentrations, but anthropological activities have increased its concentration considerably. This causes...     

Methylmercury in a predatory fish (Cichla spp.) inhabiting the Brazilian Amazon

This research tested whether limnological conditions, biological characteristics of fish and anthropogenic impacts influenced the assimilation of methylmercury into the muscle of a sedentary piscivorous fish, Cichla spp., from three rivers (Negro, Madeira, Tapajós) and two hydroelectric reservoirs (Balbina, Tucuruí) within the Brazilian Amazon. Methylmercury in this fish ranged from 0.04 to 1.43microgg(-1) w.w. across sites. No significant differences were observed in the methylmercury concentrations between males and females, or for different morphotypes of this species. Positive correlations were found between methylmercury and fish body weight. No differences were found between the weight normalized methylmercury (MeHg) concentrations or its percent of total mercury in fish from the three rivers; weight normalized MeHg was highest in one of the two reservoirs. In Rio Tapajós, where gold mining and deforestation cause high water turbidity, fish showed the highest MeHg and concentrations were different across the four sites examined. In all sampling areas, the %MeHg was found to be higher than 70.     

Functional group influences on the reactive azo dye decolorization performance by electrochemical oxidation and electro-Fenton technologies

Electrochemical water treatment technologies are highly promising to achieve complete decolorization of dyebath effluents, as demonstrated by several studies reported in the literature. However, these works are focused on the treatment of one model pollutant and generalize the performances of the processes which are not transposable since they depend on the pollutant treated. Thus, in the present study, we evaluate, for the first time, the influence of different functional groups that modify the dye structure on the electrochemical process decolorization performance. The textile azo dyes Reactive Orange 16, Reactive Violet 4, Reactive Red 228, and Reactive Black 5 have been selected because they present the same molecular basis structure with different functional groups. The results demonstrate that the functional groups that reduce the nucleophilicity of the pollutant hinder the electrophilic attack of electrogenerated hydroxyl radical. Thereby, the overall decolorization efficiency is consequently reduced as well as the decolorization rate. Moreover, the presence of an additional chromophore azo bond in the molecule enhances the recalcitrant character of the azo dyes as pollutants. The formation of a larger and more stable conjugated π system increases the activation energy required for the electrophyilic attack of ^?OH, affecting the performance of electrochemical technologies on effluent decolorization.     

Method of median semi-variance for the analysis of left-censored data: Comparison with other techniques using environmental data

In environmental monitoring, variables with analytically non-detected values are commonly encountered. For the statistical evaluation of these data, most of the methods that produce a less biased performance require specific computer programs. In this paper, a statistical method based on the median semi-variance (SemiV) is proposed to estimate the position and spread statistics in a dataset with single left-censoring. The performances of the SemiV method and 12 other statistical methods are evaluated using real and complete datasets. The performances of all the methods are influenced by the percentage of censored data. In general, the simple substitution and deletion methods showed biased performance, with exceptions for L/2, Inter and L/√2 methods that can be used with caution under specific conditions. In general, the SemiV method and other parametric methods showed similar performances and were less biased than other methods. The SemiV method is a simple and accurate procedure that can be used in the analysis of datasets with less than 50% of left-censored data.     

Unraveling the water and land nexus through inter- and transdisciplinary research: sustainable land management in a semi-arid watershed in Brazil’s Northeast

For decades, large reservoirs have been built for hydropower plants in Brazil’s São Francisco River Basin. Rural development has been a simultaneous goal with a primary focus on irrigation. Irrigated agriculture, however, has suffered from poor soils, insufficient water management strategies, and a disregard for integrating grazing-based smallholdings outside of the irrigation schemes. Recurrent droughts are distressing all sectors. This synthesis assessed sustainable land management options by investigating the aquatic and terrestrial land use systems alongside their underlying ecosystem functions and services. Decisions about the allocation of scarce water proved to be both the major issue of land use discourses and driver of practices. The primarily hydroelectricity-focused water management practice cannot be maintained at the same level in the long run, as it has become ever more adverse towards competing water usages. The increasing use of the water and adjacent land also constitutes a major potential threat to water quality. Managed water level fluctuations should generally mimic natural patterns. Wind and solar power generation are suitable complements to agricultural land use. Cycling scarce nutrients between aquatic and terrestrial sectors is ambitious but promising, ultimately improving the generally poor soils in the area. Smart management of biodiversity can foster intensively-irrigated cropping, although the non-irrigated Caatinga ecosystem needs better management of its conflicting uses. Aims and responsibilities of multi-level planning and management require clarification and coordination between sectors, while practices of public participation should be revised in order to better support a comprehensive and transparent transition towards sustainability.     

Mean sea-level rise impacts on Santos Bay, Southeastern Brazil – physical modelling study

The greenhouse effect and resulting increase in the Earth’s temperature may accelerate the mean sea-level rise. The natural response of bays and estuaries to this rise, such as this case study of Santos Bay (Brazil), will include change in shoreline position, land flooding and wetlands impacts. The main impacts of this scenario were studied in a physical model built in the Coastal and Harbour Division of Hydraulic Laboratory, University of São Paulo, and the main conclusions are presented in this paper. The model reproduces near 1,000 km² of the study area, including Santos, São Vicente, Praia Grande, Cubatão, Guarujá and Bertioga cities.