Exposure of workers in mineral processing industries in Brazil

The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. A preliminary survey pilot program, that included six mines in Brazil (two coal mines, one niobium mine, one nickel mine, one gold mine and one phosphate mine), was launched in order to determine the need to control the radioactive exposure of the mine-workers. Our survey consisted of the collection and analysis of urine samples, complemented by feces and air samples. The concentrations of uranium, thorium and polonium were measured in these samples and compared to background data from family members of the workers living in the same dwelling and from residents from the general population of Rio de Janeiro. The results from the coal mines indicated that the inhalation of radon progeny may be a source of occupational exposure. The workers from the nickel, gold and phosphate mines that were visited do not require a program to control internal radiological doses. The niobium mine results showed that in some areas of the industry exposure to thorium and uranium might occur.     

Forestry Mitigation Options for Mexico: Finding Synergies between National Sustainable Development Priorities and Global Concerns

We examine carbon (C) reference and mitigation scenarios for the Mexicanforest sector between the year 2000 and 2030. Estimates are presentedseparately for the period 2008–2012.Future C emissions and capture are estimated using a simulation modelthat: a) allocates the country land use/land cover classes among differentfuture uses and categories using demand-based scenarios for forestryproducts; b) estimates the total C densities associated to each land usecategory, and c) determines the net carbon implications of the process ofland use/cover change according to the different scenarios.The options analyzed include both afforestation/reforestation, such ascommercial, bionenergy and restoration plantations, and agroforestrysystems, and forest conservation, through the sustainable management ofnative forests and forest protection.The total mitigation potential, estimated as the difference between the totallong-term carbon stock in the reference and the mitigation scenario reaches300 × 10⁶ Mg C in the year 2012 and increases to 1,382 × 10⁶ Mg C in 2030. The average net sequestration in the 30 year period is 46 × 10⁶ Mg C yr^-1, or 12.5 × 10⁶ Mg C yr^-1 within the period 2008 to 2012. The costs of selected mitigation options range from 0.7–3.5 Mg C^-1 to 35 Mg C^-1. Some options are cost effective.     

Effect of surfactants on Fenton's reagent-mediated degradation of Kraft black liquor

One of the limitations of the biodegradation of hydrophobic chemical compounds, like lignins, is their low solubility in the aqueous solution where this process takes place. To resolve this problem, surfactants have been used to improve the solubility of these hydrophobic compounds. In this investigation, we studied the effect of surfactants (anionic, cationic, and non-ionic) on the treatment of Kraft black liquor with Fenton's reagent. In the Fenton reaction, H2O2 (two different concentrations, 10 mM and 20 mM), FeCl2 (1 mM) and surfactant solution (10%) were used. Black liquor degradation was determined by UV/Visible spectrophotometry and by measuring phenolic groups. In the presence of Fenton's reagent, the optimum conditions for the oxidative degradation of black liquor were 10 mM H2O2, 1 microL of 10% solution of anionic surfactant (SDS). The importance of the use of surfactants for preparing black liquor for subsequent Fenton's reagent-mediated degradation was discussed.     

Essential and non-essential trace element concentrations in muscle and liver of a pregnant Munk’s pygmy devil ray (Mobula munkiana) and its embryo

During gestation, essential and non-essential trace elements are transferred from the pregnant females to embryos. This study aimed to determine and compare the concentrations of seven essential trace elements (Fe, Zn, Se, Cu, Mn, Cr, Co) and six non-essential trace elements (As, Cd, V, U, Tl, Ag) in the muscle and the liver of a Munk’s pygmy devil ray pregnant female, Mobula munkiana, and its embryo. Transfer evidence of essential and non-essential trace elements was detected in M. munkiana tissues. Arsenic was found in elevated concentrations in the pregnant female and the embryo tissues. Elevated levels of Cd, V, U, and Ag were found in the pregnant female liver, but were minimal in the embryo tissue. This is the first study to investigate maternal transfer of essential and non-essential trace elements in these species and their reproductive strategy.

     

Emission factors from different burning stages of agriculture wastes in Mexico

Open-air burning of agricultural wastes from crops like corn, rice, sorghum, sugar cane, and wheat is common practice in Mexico, which in spite limiting regulations, is the method to eliminate such wastes, to clear the land for further harvesting, to control grasses, weeds, insects, and pests, and to facilitate nutrient absorption. However, this practice generates air pollution and contributes to the greenhouse effect. Burning of straws derived from the said crops was emulated in a controlled combustion chamber, hence determining emission factors for particles, black carbon, carbon dioxide, carbon monoxide, and nitric oxide throughout the process, which comprised three apparent stages: pre-ignition, flaming, and smoldering. In all cases, maximum particle concentrations were observed during the flaming stage, although the maximum final contributions to the particle emission factors corresponded to the smoldering stage. The comparison between particle size distributions (from laser spectrometer) and black carbon (from an aethalometer) confirmed that finest particles were emitted mainly during the flaming stage. Carbon dioxide emissions were also highest during the flaming stage whereas those of carbon monoxide were highest during the smoldering stage. Comparing the emission factors for each straw type with their chemical analyses (elemental, proximate, and biochemical), some correlations were found between lignin content and particle emissions and either particle emissions or duration of the pre-ignition stage. High ash or lignin containing-straw slowed down the pre-ignition and flaming stages, thus favoring CO oxidation to CO₂.

     

Contamination levels of polychlorinated biphenyls in wild versus cultivated samples of female and male mussels (Mytilus sp.) from the Northwest Coast of Iberian Peninsula—new application for QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology

A newly analytical method based on QuEChERS extraction followed by gas chromatography with mass spectrometry (GC-MS) analysis was developed and validated for the quantification of 18 PCBs in wild (from Matosinhos Beach, Portugal) and cultivated (from Ria de Arousa, Spain) mussel samples, pooled by sex. Wild animals showed higher PCB levels than cultivated mussels, with males from both origins, presenting an upper contamination profile comparing with females. This fact seems to be correlated with few biometric parameters, but other interdependencies, not addressed herein, such as distinct lipid contents between sexes, as a consequence of the gametogenic stage, may also explain this data. Overall, data reiterate the importance of investigating the presence of PCBs in marine biological samples, which can act both as bioindicators of environmental contamination, either as food quality controls for human health.     

Spatiotemporal Associations of Reservoir Nutrient Characteristics and the Invasive,Harmful Alga Prymnesium parvum in West Texas

Golden alga (Prymnesium parvum) is a harmful alga that has caused ecological and economic harm in freshwater and marine systems worldwide. In inland systems of North America, toxic blooms have nearly eliminated fish populations in some systems. Modifying nutrient profiles through alterations to land or water use may be a viable alternative for golden alga control in reservoirs. The main objective of this study was to improve our understanding of the nutrient dynamics that influence golden alga bloom formation and toxicity in west Texas reservoirs. We examined eight sites in the Upper Colorado River basin, Texas: three impacted reservoirs that have experienced repeated golden alga blooms; two reference reservoirs where golden alga is present but nontoxic; and three confluence sites downstream of the impacted and reference sites. Total, inorganic, and organic nitrogen and phosphorus and their ratios were quantified monthly along with golden alga abundance and ichthyotoxicity between December 2010 and July 2011. Blooms persisted for several months at the impacted sites, which were characterized by high organic nitrogen and low inorganic nitrogen. At impacted sites, abundance was positively associated with inorganic phosphorus and bloom termination coincided with increases in inorganic nitrogen and decreases in inorganic phosphorus in late spring. Management of both inorganic and organic forms of nutrients may create conditions in reservoirs unfavorable to golden alga.     

Foraminiferal biotopes and their distribution control in Ria de Aveiro (Portugal): a multiproxy approach

Ria de Aveiro, which is located in the centre of Portugal (40° 38′ N, 8° 45′ W), is a well-mixed and complex coastal lagoon that is separated from the sea by a sandy barrier and connects with the Atlantic through an artificial inlet. Tidal currents are the main factor controlling the lagoon’s hydrodynamics and, to a great extent, the sedimentary dynamic. The inner lagoonal zones receive input from several rivers and experience the pressure caused by the accumulation of organic matter and pollutants (namely, trace metals) from diverse anthropic activities. This paper is the first piece of work aiming to recognize, characterize and explain the main benthic foraminiferal biotopes in Ria de Aveiro. To provide a broad overview of this kind of setting, our results are compared to those of previous published studies conducted in similar transitional environments. The research is based on an investigation of 225 sites spread throughout this ecosystem. Utilizing a statistical approach, this study analyses the details of dead benthic foraminiferal assemblages composed of 260 taxa, the texture and composition (mineralogical and geochemical) of the sediment and physicochemical data. On the basis of the results of R-mode and Q-mode cluster analyses, several different biotopes can be defined as marsh biotope/near-marsh biotope; marginal urban/marginal urban mixing biotope; inner-outer lagoon biotope or enclosed lagoon; outer lagoon biotope, mixed sub-biotope; and outer lagoon, marine sub-biotope. These biotopes are related to foraminifera assemblages and substrate type and are influenced by local currents, water depth, chemical and physicochemical conditions, river or oceanic proximity, and anthropogenic impact, as evidenced by the mapping of the six factor loadings of the principal component analysis conducted herein. Based on a similar methodology of analysis as that applied in previous studies in the Lagoon of Venice, comparable biotypes were identified in Lagoon of Aveiro.     

Enhanced activated persulfate oxidation of ciprofloxacin using a low-grade titanium ore under sunlight: influence of the irradiation source on its transformation products

Environmental Science and Pollution Research - In this work, the activated persulfate oxidation of ciprofloxacin (CIP) using a low-grade titanium ore under sunlight or simulated sunlight were...