Evaluation of GC-ion trap-MS/MS methodology for monitoring PCDD/Fs in infant formulas

The application of high resolution gas chromatography in combination with low resolution mass spectrometry with electron ionization and MS/MS detection (HRGC-MS/MS) is tested for its use in the analysis of PCDD/Fs in infant formulas. Development of the analytical method was based upon EPA directrices and international recommendations. Calibration linearity was tested and average relative response for any native and labelled compound over the five-point calibration range below 14% was found. The precision and accuracy of the proposed analytical procedure are also presented. Results obtained are in agreement with EPA criteria. The method is applied to the analysis of a number of initial and follow-on milk based infant formulas. In general, HRGC-MS/MS constitutes an interesting method for the analysis of dioxins in such matrices.     

Monitoring PCDD/Fs and other organic substances in workers of a hazardous waste incinerator: a case study

The aim of this study was to measure, 6 years after regular operations, the concentrations of a number of organic substances in blood and urine of 19 workers employed at a hazardous waste incinerator (HWI) in Spain, and to establish the temporal variation with respect to baseline data and previously performed surveys. This facility was the first, and so far the only HWI in that country. The levels of hexachlorobenzene (HCB), polychlorinated biphenyls (PCB 28, 52, 101, 138, 153 and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in six composite plasma samples, while concentrations of di-, tri, and pentachlorophenols, as well those of 1-hydroxypyrene were measured in the urine of these workers. The current mean PCDD/F concentration, 10.4 ng I-TEQ/kg lipid, was significantly lower than that found in the baseline survey, 26.7 ng I-TEQ/kg lipid and similar to that found in the previous (2004) study (7.7 ng I-TEQ/kg lipid). PCDD/F levels in plasma were similar or even lower than those recently reported for various non-exposed populations. For the remaining analyzed substances in plasma and urine, there was not any significant increase in comparison with the levels found in the baseline survey. On the other hand, no marked differences between the concentrations of organic substances in plasma or urine were found according to the respective workplace (plant, laboratory and administration). The results of the present survey indicate that after 6 years of regular operation, the workers at the HWI are not occupationally exposed to PCDD/Fs and other organic substances in their workplaces.     

Simulation of stomatal conductance for Aleppo pine to estimate its ozone uptake

The data from a previous experiment carried out in open-top chambers to assess the effects of ozone (O3) exposure on growth and physiology of Aleppo pine (Pinus halepensis Mill.) were re-assessed to test the performance of the EMEP O3 stomatal conductance model used to estimate tree O3 uptake at a European scale. Aleppo pine seedlings were exposed during three consecutive years to three different O3 treatments: charcoal filtered air, non-filtered air and non-filtered air supplemented with 40 nl l(-1). The results of the model using the default parameterisation already published for Mediterranean conifers showed a poor performance when compared to measured data. Therefore, modifications of g(max), f(min), and new f(VPD), f(temp) and f(phen) functions were developed according to the observed data. This re-parameterisation resulted in a significant improvement of the performance of the model when compared to its original version.     

Accelerated carbonation of municipal solid waste incineration fly ashes

As a result of the EU Landfill Directive, the disposal of municipal solid waste incineration (MSWI) fly ash is restricted to only a few landfill sites in the UK. Alternative options for the management of fly ash, such as sintering, vitrification or stabilization/solidification, are either costly or not fully developed. In this paper an accelerated carbonation step is investigated for use with fly ash. The carbonation reaction involving fly ash was found to be optimum at a water/solid ratio of 0.3 under ambient temperature conditions. The study of ash mineralogy showed the disappearance of lime/portlandite/calcium chloride hydroxide and the formation of calcite as carbonation proceeded. The leaching properties of carbonated ash were examined. Release of soluble salts, such as SO4, Cl, was reduced after carbonation, but is still higher than the landfill acceptance limits for hazardous waste. It was also found that carbonation had a significant influence on lead leachability. The lead release from carbonated ash, with the exception of one of the fly ashes studied, was reduced by 2-3 orders of magnitude.     

Levels of metals, PCBs, PCNs and PAHs in soils of a highly industrialized chemical/petrochemical area: temporal trend

In 2005, the concentrations of various metals and organic pollutants were analyzed in soils collected in different areas of Tarragona (Catalonia, Spain), where an important chemical/petrochemical complex is located. The levels of seven elements (As, Cd, Cr, Hg, Mn, Pb and V), as well as those of polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polycyclic aromatic hydrocarbons (PAHs) were determined in soils, and compared with those obtained in a background study carried out in 2002. Only Cd and Pb showed significant higher concentrations in the petrochemical zone, while no significant differences were found for the remaining elements. In turn, vanadium was the only element showing a significant increase in the concentration between 2002 and 2005. With regard to the organic pollutants, no significant differences were found according to the area of sampling. However, an increase in naphthalene levels was observed during the period 2002-2005 in soils of the chemical and petrochemical areas. According to the present results, it is suggested that the levels of vanadium must be periodically monitored to assure that the important industrialization of Tarragona does not mean health risks for the population living near the complex.     

A neural-fuzzy approach to classify the ecological status in surface waters

A methodology based on a hybrid approach that combines fuzzy inference systems and artificial neural networks has been used to classify ecological status in surface waters. This methodology has been proposed to deal efficiently with the non-linearity and highly subjective nature of variables involved in this serious problem. Ecological status has been assessed with biological, hydro-morphological, and physicochemical indicators. A data set collected from 378 sampling sites in the Ebro river basin has been used to train and validate the hybrid model. Up to 97.6% of sampling sites have been correctly classified with neural-fuzzy models. Such performance resulted very competitive when compared with other classification algorithms. With non-parametric classification-regression trees and probabilistic neural networks, the predictive capacities were 90.7% and 97.0%, respectively. The proposed methodology can support decision-makers in evaluation and classification of ecological status, as required by the EU Water Framework Directive.     

Evaluation of exposure to fluoride in child population of North Argentina

Fluoride is an important element for humans. It inhibits initiation and progression of dental caries and stimulates bone formation. However, excessive intake may lead to the appearance of dental and/or skeletal fluorosis and a decrease in intellectual coefficient in child populations. This study evaluates exposure to fluoride in the child population of Chaco province (Argentina) by analysis of drinking water, food and its bioaccessible fraction (quantity of fluoride solubilised by gastrointestinal digestion and available for intestinal absorption) and urine as a biomarker of internal dose. The concentration of fluoride in drinking water varied between 0.050 and 4.6 mg L^?1, and 80% of the samples exceeded the WHO drinking-water guideline value (1.5 mg L^?1). Fluoride concentrations in food ranged between 0.80 and 3.0 mg kg^?1 fresh weight (fw), being lower in bioaccessible fraction (0.43–1.9 mg kg^?1, fw). On the basis of the consumption data declared for the young child population, fluoride intake varies between 4.1 and 6.5 mg day^?1, greater than the level recommended for this age group. Moreover, in some cases, concentrations of fluoride found in urine (0.62–8.9 mg L^?1) exceeded those reported in areas with declared fluorosis. All data obtained show the worrying situation of child population in this area of Argentina.

     

Altered physiology, cell structure, and gene expression of Theobroma cacao seedlings subjected to Cu toxicity

Seedlings of Theobroma cacao CCN 51 genotype were grown under greenhouse conditions and exposed to increasing concentrations of Cu (0.005, 1, 2, 4, 8, 16, and 32 mg Cu L^?1) in nutrient solution. When doses were equal or higher than 8 mg Cu L^?1, after 24 h of treatment application, leaf gas exchange was highly affected and changes in chloroplasts thylakoids of leaf mesophyll cells and plasmolysis of cells from the root cortical region were observed. In addition, cell membranes of roots and leaves were damaged. In leaves, 96 h after treatments started, increases in the percentage of electrolyte leakage through membranes were observed with increases of Cu in the nutrient solution. Moreover, there was an increase in the concentration of thiobarbituric acid-reactive substances in roots due to lipid peroxidation of membranes. Chemical analysis showed that increases in Cu concentrations in vegetative organs of T. cacao increased with the increase of the metal in the nutrient solution, but there was a greater accumulation of Cu in roots than in shoots. The excess of Cu interfered in the levels of Mn, Zn, Fe, Mg, K, and Ca in different organs of T. cacao. Analysis of gene expression via RTq-PCR showed increased levels of MT2b, SODCyt, and PER-1 expression in roots and of MT2b, PSBA, PSBO, SODCyt, and SODChI in leaves. Hence, it was concluded that Cu in nutrient solution at doses equal or above 8 mg L^?1 significantly affected leaf gas exchange, cell ultrastructure, and transport of mineral nutrients in seedlings of this T. cacao genotype.     

Restoration of areas degraded by alluvial sand mining: use of soil microbiological activity and plant biomass growth to assess evolution of restored riparian vegetation

River or alluvial sand mining is causing a variety of environmental problems in the Itajaí-açú river basin in Santa Catarina State (south of Brazil). When this type of commercial activity degrades areas around rivers, environmental restoration programs need to be executed. In this context, the aim of this study was to assess the evolution of a restored riparian forest based on data on the soil microbial activity and plant biomass growth. A reference site and three sites with soil degradation were studied over a 3-year period. Five campaigns were performed to determine the hydrolysis of the soil enzyme fluorescein diacetate (FDA), and the biomass productivity was determined at the end of the studied period. The variation in the enzyme activity for the different campaigns at each site was low, but this parameter did differ significantly according to the site. Well-managed sites showed the highest biomass productivity, and this, in turn, showed a strong positive correlation with soil enzyme activity. In conclusion, soil enzyme activity could form the basis for monitoring and the early prediction of the success of vegetal restoration programs, since responses at the higher level of biological organization take longer, inhibiting the assessment of the project within an acceptable time frame.