Characterisation of PM10 emissions from woodstove combustion of common woods grown in Portugal

A series of source tests was performed to evaluate the chemical composition of particle emissions from the woodstove combustion of four prevalent Portuguese species of woods: Pinus pinaster (maritime pine), Eucalyptus globulus (eucalyptus), Quercus suber (cork oak) and Acacia longifolia (golden wattle). Analyses included water-soluble ions, metals, radionuclides, organic and elemental carbon (OC and EC), humic-like substances (HULIS), cellulose and approximately l80 organic compounds. Particle (PM₁₀) emission factors from eucalyptus and oak were higher than those from pine and acacia. The carbonaceous matter represented 44–63% of the particulate mass emitted during the combustion process, regardless of species burned. The major organic components of smoke particles, for all the wood species studied, with the exception of the golden wattle (0.07–1.9% w/w), were anhydrosugars (0.2–17% w/w). Conflicting with what was expected, only small amounts of cellulose were found in wood smoke. As for HULIS, average particle mass concentrations ranged from 1.5% to 3.0%. The golden wattle wood smoke presented much higher concentrations of ions and metal species than the emissions from the other wood types. The results of the analysis of radionuclides revealed that the ²²⁶Ra was the naturally occurring radionuclide more enriched in PM₁₀. The chromatographically resolved organics included n-alkanes, n-alkenes, PAH, oxygenated PAH, n-alkanals, ketones, n-alkanols, terpenoids, triterpenoids, phenolic compounds, phytosterols, alcohols, n-alkanoic acids, n-di-acids, unsaturated acids and alkyl ester acids.     

Macrophage activity and histopathology of the lymphohematopoietic organs in male Wistar rats orally exposed to single or mixed pesticides

The noxious effects of low or effective dose exposure to single or mixed pesticides on macrophage activity and the lymphohematopoietic organs were investigated. Male Wistar rats were orally exposed to dichlorvos, dicofol, endosulfan, dieldrin and permethrin, either as single or combined mixtures during a 28-day study containing eight groups: one group received a semipurified diet (non-treated); two groups received a semipurified diet containing low dose mixture (dieldrin 0.025 mg/kg, endosulfan, 0.6 mg/kg, dicofol 0.22 mg/kg, dichlorvos 0.23 mg/kg, permethrin 5 mg/kg) or an effective dose mixture (dichlorvos 2.3 mg/kg, dicofol 2.5 mg/kg, endosulfan 2.9 mg/kg, dieldrin 0.05 mg/kg and permethrin 25.0 mg/kg), respectively; the other five groups received a semipurified diet containing each single pesticide in effective doses. At sacrifice, the thymus, spleen, mesenteric lymph nodes, Payer's patches and bone marrow were removed for histological analysis. Peritoneal macrophages were obtained to determine the phagocytosis and spreading indexes and tumoral necrosis factor alpha (TNF-α), nitric oxide (NO) and H₂O₂ production. Exposure to pesticide mixtures did not alter the percentage of macrophage phagocytosis and spreading, TNF-α production or the NO and H₂O₂ release when compared to the non-treated group. Neither was there any apparent evidence that a pesticide mixture at low or effective doses altered the histological structure of the lymphohematopoietic organs. The findings indicate that short-term treatment with pesticide mixtures did not induce an apparent immunotoxic effect in male Wistar rats.     

Biochemical effects of acetaminophen in aquatic species: edible clams Venerupis decussata and Venerupis philippinarum

Acetaminophen (paracetamol) is one of the most used pharmaceutical drugs, due to its antipyretic and analgesic properties that turn it into a primary choice in varied pathologies and conditions. However, and despite its massive use, acetaminophen is not exempt of adverse effects, especially when administered in over dosage, which are related to the formation of toxic metabolites by oxidative pathways. It is thus possible to observe that toxicity caused by acetaminophen is usually mediated by reactive oxygen species and can result in multiple effects, ranging from protein denaturation to lipid peroxidation and DNA damage. The occurrence of acetaminophen has been reported in the aquatic environment, being important to address the potential exertion of toxic effects on nontarget environmentally exposed organisms. The present study intended to characterize the effects of acute acetaminophen exposure on physiological traits (antioxidant defense, oxidative damage) of two species of bivalves, namely, the edible clams Venerupis decussata and Venerupis philippinarum. Results showed a significant increase in all oxidative stress biomarkers, evidencing the bioactivation of acetaminophen into a deleterious prooxidant, triggering the onset of deleterious effects. Furthermore, strong interspecific differences were observed among responses of the two tested species, which was a major issue due to intrinsic ecological implications when one considers that both species share the same habitat.     

Blood nickel and chromium levels in association with smoking and occupational exposure among head and neck cancer patients in Tunisia

Chronic exposure to chromium (Cr) and nickel (Ni) has long been recognized as being capable to increase head and neck cancer (HNC) incidence among exposed human populations. This study represents the first biomonitoring of Cr and Ni exposure in Tunisia and focuses on a possible association with HNC risk. The aim of the present study was to evaluate the concentrations of Cr and Ni in the blood of HNC patients and controls. Metals blood levels of 169 HNC patients and 351 controls were determined using a Perkin-Elmer Analyst 800 Atomic Absorption Spectrometer. Mean blood levels of Cr and Ni in HNC cases (52.15 and 111.60 μg/L, respectively) were significantly higher than those of controls (37.04 and 30.50 μg/L, respectively). Cases’ blood levels of Cr and Ni were significantly higher than those of controls after controlling for the other risk factors of HNC, including smoking, shisha consumption, occupational exposure, and nearby environment (P?<?0.05). Among these risk factors, smoking and occupational exposure presented the most significant association with HNC (odds ratio (OR)?=?6.54 and 7.66, respectively, P?<?0.001). Cr and Ni levels in blood sample of cases and controls that are smoker/occupationally exposed were higher than that of non-smoker/non-occupationally exposed (P?<?0.05). Smokers who are occupationally exposed present the most significant association with HNC (OR?=?25.08, P?<?0.0001). High levels of blood Cr (OR?=?2.09) and high levels of blood Ni (OR?=?8.87) were strongly associated with HNC after other potential confounders were controlled (P?=?0.004 and P?<?0.0001, respectively). This study suggested a potential role of Cr and Ni in the mechanism of HNC development.     

Development of the concept of spatial–temporal mask for testing effects of discharge from well-drilling activities on biological communities

This paper describes the use of Bayesian spatial models to develop the concept of a spatial–temporal mask for the purpose of identifying regions in which before and after drilling effects are most clearly defined and from which the consequences of exposure of macrofauna and meiofauna to the release of drilling discharges can be evaluated over time. To determine the effects of drilling fluids and drill-cuttings on the marine benthic community, it is essential to know not only where discharged materials ended up within the possible impact area, but also the chemical concentrations to which biota were exposed during and after drilling. Barium and light hydrocarbons were used as chemical tracers for water-based and non-aqueous-based fluids in a shallow water site in the Campos Basin, off the coast of Brazil. Since the site showed evidence of exposure to waste material from earlier drilling, the analysis needed to take into account the background concentrations of these compounds. Using the Bayesian models, concentrations at unsampled sites were predicted and regions altered and previously contaminated were identified.     

Study of the presence of fluorine in the recycled fractions during carbothermal treatment of EAF dust

Carbothermal treatment tests of electric arc furnace dusts (EAFD) using the Waelz kiln process were carried out in pilot-scale for the production of zinc oxide. The association of halides in the EAFD, and the recycled products, such as zinc oxide fumes and high-grade iron contents fractions were examined by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. XRD reveals the presence of chlorine and fluorine in the dusts in the form of KCl, NaCl and CaF2. An ultra-pure fraction of zinc was obtained after the Double Leaching Waelz Oxide (DLWO) process was performed on the zinc oxide fumes. The halide contents were reduced to approximately 100 ppm Cl and 700 ppm F. The rest of these elements are in the form of CaF2. About 65% F is volatilised as lead and zinc fluorides, 15% is expected in the magnetic fractions and 20% in non-magnetic fractions as CaF2 and MnF2, respectively.     

Thimerosal in childhood vaccines contributes to accumulating mercury toxicity in the kidney

Mercury (Hg) is a hazardous chemical that accumulates in many cells and tissues, thereby producing toxicity. The kidney is a key target organ for Hg accumulation and toxicity. The contributing factors to Hg accumulation in humans include: (1) elemental and inorganic Hg exposure, often occurring by inhalation of Hg vapors; (2) exposure to methyl Hg (meHg), for example, through contaminated seafood; and (3) exposure to ethyl mercury (etHg) via thimerosal-containing vaccines. Systematic investigations on the toxic effects of etHg/thimerosal on the nervous system were carried out, and etHg/thimerosal emerged as a possible risk factor for autism and other neurodevelopmental disorders. There is, however, little known about the mechanisms and molecular interactions underlying toxicity of etHg/thimerosal in the kidney, which is the focus of the current review. Susceptible populations such as infants, pregnant women, and the elderly are exposed to etHg through thimerosal-containing vaccines, and in-depth study of the potential adverse effects on the kidney is needed. In general, toxicity occurring in association with different forms of Hg is related to: intracellular thiol metabolism and oxidative stress reactions; mitochondrial function; intracellular distribution and build-up of calcium; apoptosis; expression of stress proteins; and also interaction with the cytoskeleton. Available evidence for the etHg-induced toxicity in the kidney was examined, and the main mechanisms and molecular interactions of cytotoxicity of etHg/thimerosal exposure in kidney described. Such accumulating knowledge may help to indicate molecular pathways that, if modulated, may better handle Hg-mediated toxicity.     

Concrete made with recycled tire rubber: Effect of alkaline activation and silica fume addition

The present work deals with the investigation of the potential use of recycled tire rubbers in cement matrices. This facilitates the development of concrete with a lesser environmental impact. Thus, it contributes to developing construction in a sustainable way. Concrete formulations were produced with the replacement of 10% sand aggregate by recycled tire rubber using conventional rubber and rubber modified with alkaline activation and silica fume addition to improve the mechanical properties. The water/cement ratio (or composition) and the testing age were used as additional variables. The concrete characterization was performed by testing the compressive strength, elastic modulus, density and microstructure (SEM). The recycled tire rubber proved to be an excellent aggregate to use in the concrete. It was observed that its compressive strength was reduced by only 14% (28 days), in comparison to the conventional concrete, reaching 48 MPa for the mixture with higher resistance. The concrete compositions were found to be lighter and a reduced interface was observed between the rubber and cement matrix after the chemical treatment. The rubberized concrete can support construction sustainability, minimize the consumption of natural resources by using an industrial residue and produce a material with special features.     

Seasonal rhythm in a Mediterranean coastal fish community as monitored by a cabled observatory

To adequately describe seasonal rhythms in habitat utilization by fish communities, observations are needed that occur at a relatively high frequency and over large temporal windows. For the first time, images collected from a cabled video-observatory (the western Mediterranean expandable SEAfloor OBservatory; OBSEA) were utilized to examine habitat utilization by coastal fishes. Over the course of a year, hourly digital images of the water column and an artificial reef were obtained during daylight hours. For each image, the total number of species, an estimate of the abundance of individuals, and the Shannon Diversity Index were quantified. A total of 22 fish species commonly associated with nearshore western Mediterranean habitats were identified, and significant spatial (water column vs. artificial reef), seasonal (spring, summer, autumn, and winter), and daily (morning, midday, and sunset) differences in habitat utilization occurred. Four species (Diplodus vulgaris, Diplodus cervinus, Diplodus sargus, and Scorpaena porcus) were associated with the artificial reef, while one species (Pagrus pagrus) chiefly occurred in the water column. Chromis chromis and Diplodus annularis occurred at the site more frequently in the winter and autumn, respectively, while 14 other species utilized the site more frequently in either the spring (8 spp) or summer (6 spp). In addition, Dentex dentex and Spicara maena occurred more frequently at sunset, while D. cervinus displayed a crepuscular rhythm (occurring more frequently in the morning and at sunset). Species diversity was highest in the summer and lowest in the winter. If not taken into account when planning in situ sampling, such seasonal and/or diel differences may lead to spurious estimates of population sizes and biodiversity. We suggest that cabled video-observatories offer a non-invasive and reliable technology for faunistic sampling and population assessment in coastal water of the Mediterranean and likely elsewhere.