Thermal decomposition of electronic wastes: mobile phone case and other parts

Pyrolysis and combustion runs at 850°C in a horizontal laboratory furnace were carried out on different parts of a mobile phone (printed circuit board, mobile case and a mixture of both materials). The analyses of the carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorodibenzo-p-dioxin, polychlorodibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, phenol, styrene, and its derivatives had the highest yields. In nearly all the runs the same PAHs were identified, naphthalene being the most common component obtained. Combustion of the printed circuit board produced the highest emission factor of PCDD/Fs, possibly due to the high copper content.     

Phytoremediation of 2,4-dichlorophenol using wild type and transgenic tobacco plants

Introduction

Transgenic plant strategies based on peroxidase expression or overexpression would be useful for phenolic compound removal since these enzymes play an important role in phenolic polymerizing reactions.

Material and methods

Thus, double transgenic (DT) plants for basic peroxidases were obtained and characterized in order to compare the tolerance and efficiency for 2,4-dichlorophenol (2,4-DCP) removal with WT and simple transgenic plants expressing TPX1 or TPX2 gene. Several DT plants showed the expression of both transgenes and proteins, as well as increased peroxidase activity.

Results

DT lines showed higher tolerance to 2,4-DCP at early stage of development since their germination index was higher than that of WT seedlings exposed to 25?mg/L of the pollutant. High 2,4-DCP removal efficiencies were found for WT tobacco plants. TPX1 transgenic plants and DT (line d) reached slightly higher removal efficiencies for 10?mg/L of 2,4-DCP than WT plants, while DT plants (line A) showed the highest removal efficiencies (98%). These plants showed an increase of 21% and 14% in 2,4-DCP removal efficiency for solutions containing 10 and 25?mg/L 2,4-DCP, respectively, compared with WT plants. In addition, an almost complete toxicity reduction of postremoval solutions using WT and DT plants was obtained through AMPHITOX test, which indicates that the 2,4-DCP degradation products would be similar for both plants.

Conclusion

These results are relevant in the field of phytoremediation application and, moreover, they highlight the safety of using DT tobacco plants because nontoxic products were formed after an efficient 2,4-DCP removal.     

Environmental and lifestyle factors affect benzene uptake biomonitoring of residents near a petrochemical plant

Background

We monitored urinary benzene excretion to examine factors affecting benzene uptake in a sample of the general population living near a petrochemical plant.

Methods

Our study population included 143 subjects: 33 petrochemical plant workers (W) with low level occupational benzene exposure; 30 residents in a small town 2 km from the plant (2kmR); 26 residents in a second small town located 2 to 4 km from the plant (4kmR); and 54 urban residents 25 km from the plant (25kmR). Exposure to benzene was evaluated by personal air sampling during one work-shift for the W group, and from 8.00 to 20:00 for general population subgroups, and by urinary benzene (BEN-U).

Results

Median airborne benzene exposure was 25, 9, 7 and 6 μg/m³ benzene among the W, 2kmR, 4kmR, and 25kmR subgroups, respectively; the highest level was found among the workers, while there was no significant difference among the other groups. Median BEN-U was 2 to 14-fold higher in smokers compared to non-smokers; among non-smokers BEN-U was the highest in W (median 236 ng/L), and lower in the 2kmR (48 ng/L) and 4kmR (63 ng/L) subgroups than in the 25kmR (120 ng/L) subgroup. A multiple linear regression analysis, explaining up to 73% of BEN-U variability, confirmed that active smoking and airborne benzene most strongly affected BEN-U. Among the non-smoking, non-occupationally exposed study subjects, a positive association was found between BEN-U and the distance of residence from the plant. This association was explained by increased exposure to urban traffic emissions in the study group residing at a greater distance from the plant. Environmental tobacco smoke had a marginally positive role.

Conclusion

Among factors affecting benzene uptake in non-occupationally exposed individuals, urban residence contributes to benzene exposure more than residing in close proximity to a petrochemical plant.     

Effect of Dursban 480 EC (chlorpyrifos) and Talstar 10 EC (bifenthrin) on the physiological and genetic diversity of microorganisms in soil

This investigation was undertaken to determine the impact of the insecticides Dursban 480 EC (with organophosphate compound chlorpyrifos as the active ingredient) and Talstar 10 EC (with pyrethroid bifenthrin as the active ingredient) on the respiration activity and microbial diversity in a sandy loam luvisol soil. The insecticides were applied in two doses: the maximum recommended dose for field application (15 mg kg^?1 for Dursban 480 EC and 6 mg kg^?1 for Talstar 10 EC) and a 100-fold higher dose for extrapolation of their effect. Bacterial and fungal genetic diversity was analysed in soil samples using PCR DGGE and the functional diversity (catabolic potential) was studied using BIOLOG EcoPlates at 1, 3, 7, 14, 28, 56 and 112 days after insecticide application. Five bacterial groups (α, β, γ proteobacteria, firmibacteria and actinomycetes) and five groups of fungi or fungus-like microorganisms (Ascomycota, Basidiomycota, Chytridiomycota, Oomycota and Zygomycota) were analysed using specific primer sets. This approach provides high resolution of the analysis covering majority of microorganisms in the soil. Only the high-dose Dursban 480 EC significantly changed the community of microorganisms. We observed its negative effect on α- and γ-proteobacteria, as the number of OTUs (operational taxonomic units) decreased until the end of incubation. In the β-proteobacteria group, initial increase of OTUs was followed by strong decrease. Diversity in the firmibacteria, actinomycetes and Zygomycota groups was minimally disturbed by the insecticide application. Dursban 480 EC, however, both positively and negatively affected certain species. Among negatively affected species Sphingomonas, Flavobacterium or Penicillium were detected, but Achromobacter, Luteibacter or Aspergillus were supported by applied insecticide. The analysis of BIOLOG plates using AWCD values indicated a significant increase in metabolic potential of microorganisms in the soil after the high-dose Dursban application. Analysis of respiration demonstrated high microbial activity after insecticide treatments; thus, microbial degradation was relatively fast. The half-life of the active insecticide compounds were estimated within the range of 25 to 27 days for Talstar and 6 to 11 days for Dursban and higher doses stimulated degradation. The recommended dose levels of both insecticides can be considered as safe for microbial community in the soil.     

Degradation of atrazine using solar driven fenton-like advanced oxidation processes

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was degraded using cobalt-peroximonosulfate (Co/PMS) advanced oxidation process (AOP). Three Co concentrations (0.00, 0.25 and 0.50 mM) and five peroximonosulfate (PMS) concentrations (0, 5, 8, 16 and 32 mM) were tested. Maximum degradation reached was 88% using dark Co/PMS in 126 minutes when 0.25 mM of cobalt and 32 mM of PMS were used. Complete atrazine degradation was achieved when the samples were irradiated by the sun under the same experimental conditions described. Tests for identification of intermediate products allowed identification and quantification of deethylatrazine in both dark and radiated conditions. Kinetic data for both processes was calculated fitting a pseudo-first order reaction rate approach to the experimental data. Having kinetic parameters enabled comparison between both conditions. It was found that the kinetic approach describes data behavior appropriately (R² ≥ 0.95). Pseudo-kinetic constants determined for both Co/PMS processes, show k value of 10^?4 for Co/PMS and a k value of 10^?3 for Co/PMS/ultraviolet (UV). This means, that, with the same Co/PMS concentrations, UV light increases the reaction rate by around one order of magnitude than performing the reaction under dark conditions.     

Leaching of heavy metals and alkylphenolic compounds from fresh and dried sewage sludge

Reusing sewage sludge as a soil fertiliser has become a common alternative to disposal. Although this practice has a few benefits, it may contribute to the medium- and long-term contamination of the trophic chain because sewage sludge may contain heavy metals and organic contaminants. As the leaching of contaminants may depend on the sludge pre-treatment, the leaching of heavy metals (Cu, Ni, Pb, Zn and Cr) and alkylphenolic compounds (APCs) (octylphenol (OP), nonylphenol (NP), nonylphenol-mono-ethoxylate (NP₁EO)) was investigated in five fresh and 40 °C dried sewage sludge samples from north-eastern Spain. FT-IR analyses and full-scan GC-MS chromatograms showed that sludge drying changed the nature of organic compounds leading to changes in their solubility. Moreover, sludge drying led to a higher relative contribution of dissolved organic carbon than the particulate organic carbon in the leachates. Leaching of Pb, Zn and Cr was below 5 % in both fresh and dried sludge samples, whereas Cu and Ni leached at rates up to 12 and 43 %, respectively, in some of the dried sludge samples. The leaching yields of OP, NP and NP₁EO ranged from 1.3 to 35 % for fresh samples, but they decreased from 0.8 to 3.4 % in dried samples. The decrease in the leachability of APCs observed in dried sludge samples might be attributed to the fact that these compounds are associated with particulate organic matter, with significantly lower concentration or even absent in dried sludge than in fresh sludge samples. Therefore, it is recommended to dry the sludge before its disposal.     

Multilingual education of students on a global scale and perspective—international networking on the example of bioindication and biomonitoring (B&B technologies)

Living or formerly living organisms are being used to obtain information on the quality of the general health status of our environment by bioindication and biomonitoring methods for many decades. Thus, different roads toward this common scientific goal were developed by a lot of different international research groups. Global cooperation in between various scientific teams throughout the world has produced common ideas, scientific definitions, and highly innovative results of this extremely attractive working field. The transdisciplinary approach of different and multifaceted scientific areas—starting from biology, analytical chemistry, via health physics, up to social and economic issues—have surpassed mental barriers of individual scientists, so that “production” of straightforward common results related to the influence of material and immaterial environmental factors to the well-being of organisms and human life has now reached the forefront of international thinking. For the further sustainable development of our common scientific “hobby” of bioindication and biomonitoring, highest personal energy has to be given by us, being teachers to our students and to convince strategically decision makers as politicians to invest (financially) into the development of education and research of this innovative technique. Young people have to be intensively convinced on the “meaning” of our scientific doing, e.g., by extended forms of education. One example of multilingual education of students on a global scale and perspective is given here, which we started about 3 years ago.     

Assessment of nitrous oxide emission from cement plants: Real data measured with both Fourier transform infrared and nondispersive infrared techniques

Nitrous oxide (N₂O) is the third most important greenhouse gas after carbon dioxide and methane, and contributes about 6% to the greenhouse effect. Nitrous oxide is a minor component of the atmosphere, and it is a thousand times less than carbon dioxide (CO₂). Nevertheless, it is much more potent than CO₂ and methane, owing to its long stay in the atmosphere of approximately 120 yr and the high global warming potential (GWP) of 298 times that of CO₂. Although greenhouse gases are natural in the atmosphere, human activities have changed the atmospheric concentrations. Most of the values of emission of nitrous oxide are still obtained by means of emission factors and not actually measured; the lack of real data may result in an underestimation of current emissions. The emission factors used for the calculation of N₂O can be obtained from the “Guidelines for the implementation of the national inventory of emissions” of the Intergovernmental Panel on Climate Change, which refer to all nations for the realization of their inventory. This study will present real data, measured in several Italian cement plants with different characteristics. The work also shows a comparison between N₂O concentration measured with in situ Fourier transform IR (FTIR) and the reference method EN ISO 21258 based on nondispersive IR (NDIR), in order to investigate the interfering compounds in the measurement with NDIR.

Implications:N₂O may arise as an unwanted by-product of nitrogen oxide (NO_x) abatement systems, in particular selective noncatalytic reduction (SNCR). Since it is applied in the cement plants, N₂O emission from cement industry is evaluated, with both FTIR and NDIR instrument. Several considerations emerged from the results. First of all, the emission from this industrial sector is not negligible, and for that reason N₂O concentration should be regulated; another observation is that the reference method based on the NDIR technique is not as selective as FTIR could be.     

Haneş and Valea Vinului (Romania) closed mines Acid Mine Drainages (AMDs) – Actual condition and passive treatment remediation proposal

Acid Mine Drainages (AMDs) from Hane? and Valea Vinului (Romania) closed mines were considered for characterization and treatment using a local zeolitic volcanic tuff, ZVT, (M?cica?, Cluj County, Romania). Water samples were collected from two locations, before and after discharging point in case of Hane? mine, and on three horizons in case of Valea Vinului mine. Physico-chemical (pH, total solid, heavy metal ions concentration) analyses showed that the environment is strongly affected by these AMD discharges even if the mines were closed years ago. Iron, manganese and zinc were the main pollutants identified in Hane? mine AMD, while zinc is the one mainly present in case of Valea Vinului AMD. A batch technique (no stirring) in which the ZVT was put in contact with the AMD sample was proposed as a passive remediation technique. ZVT successfully remove heavy metal ion from AMD. According to heavy metal ion concentrations, removal efficiencies are reaching 100%, varying as follows, Fe²⁺ > Zn²⁺ > Mn²⁺. When the ZVT was compared with two cationic resins (strong, SAR and weak acid, WAR) the following series was depicted, SAR > ZVT > WAR.