Occupational risk assessment in construction industry – Overview and reflection

The construction industry is plagued by occupational risky situations and poor working conditions. Occupational risk assessment (ORA) on workplace sites is the first and key step to achieve adequate safety levels, particularly to support decision-making in safety programs. Most construction safety efforts are applied informally under the premise that simply allocating more resources to safety management will improve safety on site. Moreover, there are many traditional methods to address ORA, but few have been adapted and validated for use in the construction industry, particularly in the design stage, for which traditional approaches do not give adequate answers. This paper presents a state-of-the-art on ORA traditional methods, for the construction industry, discussing their limitations and pointing advantages of using fuzzy sets approaches to deal with ill-defined situations.     

Polymer coating of copper oxide nanoparticles increases nanoparticles uptake and toxicity in the green alga Chlamydomonas reinhardtii

Copper oxide nanoparticles (CuO NPs) are frequently used in a polymer-coated form, to be included in paints or fabrics for antimicrobial properties. Their application in antifouling paints may lead to the contamination of aquatic ecosystems. However, the toxicological risk of NPs in the environment is hard to evaluate due to a lack of knowledge on the mechanisms of NP interaction with biological systems. In this study, we investigated the effect of polymer coating on CuO NP toxicity in the green alga Chlamydomonas reinhardtii by comparing bare and polymer-coated CuO NPs prepared from the same CuO nanopowder. Both CuO NP suspensions were toxic to C. reinhardtii after 6 h treatment to concentrations of 0.005-0.04 g L⁻¹. Bare and polymer-coated CuO NPs induced a decrease of Photosystem II activity and the formation of reactive oxygen species. Polymer-coated CuO NP was found to be more toxic than the uncoated CuO NP. The higher toxicity of CS-CuO NP was mainly associated with the increased capacity of polymer-coated CuO NP to penetrate the cell compared to bare CuO NPs. These results indicates that the high toxicity of polymer-coated CuO NPs in algal cells results of intracellular interactions between NPs and the cellular system.     

Trophic and reproductive biochemistry of a deep-sea gelatinous octopus, Opisthoteuthis calypso

The present study provides a comprehensive analysis of the biochemical composition (proximate composition, amino acids and fatty acids in gonad, digestive gland and muscle) of the cirrate octopod, Opisthoteuthis calypso, collected off the coast of Portugal. Protein and energy contents of O. calypso were significantly lower (p < 0.05) than those observed for coastal octopods, suggesting that the gelatinous musculature of the cirrate octopus may not be a direct consequence of food limitation, but rather associated with reduced selective pressure for strong swimming ability in the deep sea. Moreover, principal component analyses of fatty acid (FA) data clearly separated coastal octopods from O. calypso. Saturated FA biomarkers (namely 16:0, 17:0, 18:0) and monounsaturated FA 22:1 suggest a higher phytodetrital influence on diet of O. calypso. A clear separation between groups was also observed with amino acid (AA) data. However, essential AA and non-essential AA designations (based on the flow of carbon through biochemical systems) do not necessarily provide an accurate picture of the origins of amino nitrogen in the deep-sea environment. Consequently, the interpretation of the present data is a challenging task but opens a new window of opportunity to unravel new trophic biomarkers in the deep sea.     

Population density and conservation status of the teiid lizard <Emphasis Type="Italic">Cnemidophorus littoralis</Emphasis>, an endangered species endemic to the sandy coastal plains (restinga habitats) of Rio de Janeiro state,Brazil

The threatened lizard Cnemidophorus littoralis occurs in only four restinga habitats of Brazilian coast and its current conservation status is “endangered”. Due to its restricted distribution, the effects of habitat degradation are especially harmful to them. To prevent a local or even total extinction, we analyzed changes in population density and in amount of disturbances of three restinga areas during a seven-year gap. This study took place in three restingas of Rio de Janeiro State, Brazil: Maricá, Jurubatiba and Grussaí. We compared C. littoralis current density with the one registered in 2005 by Menezes and Rocha (2013) with 2 ha transections in each restinga. We also made another group of transects to estimate population density along the entire extension of the restingas. Conservation index of each site was based on satellite images and field samplings. Data showed a decreasing trend of Cnemidophorus littoralis population density over the years. Grussaí had the lowest population density and the highest degradation index among the three sites, whereas Jurubatiba had the lowest degree of disturbance, the largest area and the highest lizard population density. Data showed an increase in the amount of disturbance in restingas over the years, which seemed to have a negative effect in C. littoralis population density. Improvement of surveillance and implementation of education programs in the protected areas and its surroundings, and periodic monitoring of C. littoralis populations to follow their density changes, are essential for the maintenance of the species.     

Optimal Space-time Coverage and Exploration Costs in Groundwater Monitoring Networks

A method to determine the optimal subset of stations from a reference level groundwater monitoring network is proposed. The method considers the redundancy of data from historical time series, the times associated with the total distance required to run through the entire monitoring network, and the sum of the times for each monitoring station. The method was applied to a hypothetical case-study consisting of a monitoring network with 32 stations. Cost-benefit analysis was performed to determine the number of stations to include in the new design versus loss of information. This optimisation problem was solved with simulated annealing. Results showed that the relative reduction in exploration costs more than compensates for the relative loss in data representativeness.     

Mill leaching: a viable substitute for mercury amalgamation in the artisanal gold mining sector?

Artisanal small-scale gold miners (ASM) occasionally employ whole ore amalgamation by adding mercury into ball mills to recover gold. In this process, 25–30% of the mercury added is lost to the environment. It is also inefficient less than 30% of gold is recovered. Amalgamation, followed by cyanidation, has been observed at many artisanal mining sites. This combination poses additional environmental and health consequences. Tests with ore samples from Talawaan, North Sulawesi, Indonesia indicate the possibility of replacing mercury by cyanidation in the ball mill, reaching gold extraction of 93% in 6 h of leaching. The gold in the Indonesian ore sample is fine and less than 8% of gold recovery was obtained with gravity concentration of the ore ground 80% below 0.25 mm, which is a reasonably fine grain size for artisanal gold operations. Replacing mercury addition with cyanidation in ball mills was implemented in one artisanal gold mining operation in Portovelo, Ecuador, achieving 95% of gold extraction in 8 h of mill leaching. This technique demonstrated a drastic improvement in gold recovery. It was found to be a simple, inexpensive technique well accepted by local miners. The results from laboratory and field tests are promising; however a thorough investigation into the socio-economic and environmental aspects of this presented alternative must be conducted prior to introduction.     

Multiple resistance of acetolactate synthase and protoporphyrinogen oxidase inhibitors in Euphorbia heterophylla biotypes

Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX.     

The gastropod statolith: a tool for determining the age of<Emphasis Type="Italic"> Nassarius reticulatus</Emphasis>

The microstructure, shape and appearance of the growth rings in statoliths of Nassarius reticulatus (L.) were investigated. This species possesses two statocysts, each containing a single spherical statolith of calcium carbonate of up to 0.22 mm in diameter in the largest animals. The relationship between statolith diameter (SD) and total shell height (TSH) is exponential [ln(TSH)=26.3SD–0.842], although the function is site specific. Statoliths of the largest whelks (>29 mm) contained three or four clearly defined rings, corresponding to TSH values of ~1.1, 4.6–5.3, 12.0–13.5 and 18.5 mm, respectively. The first ring likely represents the metamorphic ring that was deposited at the time of larval metamorphosis when the post-larval whelk adopted a benthic lifestyle. The estimated size of the whelks at formation of the second, third and fourth statolith rings closely matched the TSH inferred from the shell rings. It is concluded that the patterns of growth rings present in statoliths can provide information about the age and growth of N. reticulatus.Communicated by O. Kinne, Oldendorf/Luhe     

Seasonal changes in nucleic acids,amino acids and protein content in juvenile Norway lobster (<Emphasis Type="Italic">Nephrops norvegicus</Emphasis>)

The objective of this study was to describe the seasonal variations in nucleic acid contents and amino acid profiles in the muscle of juvenile Nephrops norvegicus. RNA and protein contents, and RNA:protein and RNA:DNA ratios varied significantly between seasons, being highest in spring and lowest in autumn/winter ( P<0.05). Though DNA content increased significantly from autumn to summer ( P<0.05), protein:DNA ratio did not show significant seasonal variations ( P=0.05). In respect to protein-bound amino acid content (BAA), a significant increase was observed from winter to summer ( P<0.05). Both essential (EAA) and non-essential amino acids (NEAA) increased significantly (27.6% and 27.8%, respectively; P<0.05), mainly due to the considerable increase in arginine and proline (59.1% and 225.2%, respectively; P<0.05). A significant decrease was observed in the free amino acid content (FAA) from winter to summer ( P<0.05); and a higher percentage decrease occurred in free non-essential (FNEAA; 27.9%) in comparison to free essential amino acids (FEAA; 21.8%). The significant increase in RNA and BAA contents from winter to spring may be related to protein synthesis. On the other hand, the lowest values obtained in winter may be due to a reduction in feeding activity; in this period the muscle protein must be progressively hydrolysed, which is evident with the higher FAA content. The liberated amino acids enter the FAA pool and become available for energy production.     

Emissions from the combustion of eucalypt and pine chips in a fluidized bed reactor

Interest in renewable energy sources has increased in recent years due to environmental concerns about global warming and air pollution,reduced costs and improved efficiency of technologies.Under the European Union(EU)energy directive,biomass is a suitable renewable source.The aim of this study was to experimentally quantify and characterize the emission of particulate matter(PM_(2.5))resulting from the combustion of two biomass fuels(chipped residual biomass from pine and eucalypt),in a pilot-scale bubbling fluidized bed(BFB)combustor under distinct operating conditions.The variables evaluated were the stoichiometry and,in the case of eucalypt,the leaching of the fuel.The CO and PM_(2.5)emission factors were lower when the stoichiometry used in the experiments was higher(0.33±0.1 g CO/kg and 16.8±1.0 mg PM_(2.5)/kg,dry gases).The treatment of the fuel by leaching before its combustion has shown to promote higher PM_(2.5)emissions(55.2±2.5 mg/kg,as burned).Organic and elemental carbon represented 3.1 to 30 wt.% of the particle mass,while carbonate(CO_3~(2-))accounted for between 2.3 and 8.5 wt.%.The particulate mass was mainly composed of inorganic matter(71% to 86% of the PM_(2.5)mass).Compared to residential stoves,BFB combustion generated very high mass fractions of inorganic elements.Chloride was the water soluble ion in higher concentration in the PM_(2.5)emitted by the combustion of eucalypt,while calcium was the dominant water soluble ion in the case of pine.