Photoelectrocatalytic degradation of camphor on TiO2/RuO2 electrodes

The degradation of camphor using titanium/ruthenium dioxide (TiO₂/RuO₂; 70:30) electrodes was investigated in a photoelectrochemical thin-film reactor under near UV light irradiation. Two different electrolytes (Na₂SO₄ and NaCl) were used in this work. Camphor degradation was monitored by solvent extraction methods and gas chromatography (GC) analysis. Comparative studies between photoelectrochemical, electrochemical, photolytic, and heterogeneous photocatalytical process were carried out. When NaCl was used, the degradation efficiency of camphor was improved, probably on account of electrochemical generation of active chlorine species and their photochemical conversion to chlorine radicals. Under these conditions camphor was completely mineralized at reaction times of 30 min.     

Seasonal evaluation of outdoor/indoor air quality in primary schools in Lisbon

The aim of this study was to evaluate the indoor (I) and outdoor (O) levels of NO?, speciated volatile organic compounds (VOCs) and carbonyls at fourteen primary schools in Lisbon (Portugal) during spring, autumn and winter. Three of these schools were also selected to be monitored for comfort parameters, such as temperature and relative humidity, carbon dioxide (CO?), carbon monoxide (CO), total VOCs, and both bacterial and fungal colony-forming units per cubic metre. The concentration of CO? and bioaerosols greatly exceeded the acceptable maximum values of 1800 mg m?3 and 500 CFU m?3, respectively, in all seasons. Most of the assessed VOCs and carbonyls occurred at I/O ratios above unity in all seasons, thus showing the importance of indoor sources and building conditions in indoor air quality. However, it has been observed that higher indoor VOC concentrations occurred more often in the colder months, while carbonyl concentrations were higher in the warm months. In general, the I/O NO? ratios ranged between 0.35 and 1, never exceeding the unity. Some actions are suggested to improve the indoor air quality in Lisbon primary schools.     

Ecotoxicity and genotoxicity assessment of losartan after UV/H2O2 and UVC/photolysis treatments

Environmental Science and Pollution Research - Losartan potassium (LOS) is one of the most antihypertensives used in the world, and its presence in environmental matrices can cause impacts to...     

From farming families to scavengers: a case study in the outskirts of Belém in the state of Pará

 In the middle of the 1970s, the introduction of large industrial and agricultural projects in Brazilian Amazonia created a situation of violence and loss of land used by farming families. In this context, the process of migration to the metropolitan region of Belém, which is principally in the interior of the state of Pará, was intensified. Excluded by the formal labor market, these families started to collect disposed material as scavengers. The material collected is found in landfills, streets, and open dumping areas. The main purpose of this research is to understand the social and environmental relations inherent in collection and recycling activities in the Amazon Region. Received: August 19, 2001 / Accepted: November 21, 2001     

Transformation of progesterone by marine bacteria

The progesterone transforming ability of marine bacteria has been determined. 20 of the 53 marine cultures tested were found capable of transforming progesterone to 6-hydroxyprogesterone and/or to 11,17-dihydroxyprogesterone.     

Plant community tolerant to trace elements growing on the degraded soils of São Domingos mine in the south east of Portugal: environmental implications

The selection of trace element tolerant species is a key factor to the success of remediation of degraded mine soils. Mining activities generate a large amount of waste rocks and tailings, which get deposited at the surface. The degraded soils, the waste rocks and tailings are often very unstable and will become sources of pollution. The direct effects will be the loss of cultivated land, forest or grazing land, and the overall loss of production. The indirect effects will include air and water pollution and siltation of rivers. These will eventually lead to the loss of biodiversity, amenity and economic wealth. Restoration of a vegetation cover can fulfil the objectives of stabilization, pollution control, visual improvement and removal of threats to human beings. Thus, remediation of mine spoils/tailings and biogeochemical prospecting would rely on the appropriate selection of plant species. Plant community responds differently on their ability to uptake or exclude a variety of metals. In this work, plant species were sampled from all populations established in an abandoned copper mine of S?o Domingos, SE Portugal. Plants belonging to 24 species, 16 genera and 13 families were collected from the degraded copper mine of S?o Domingos. Plant samples were analysed for total Ag, As, Cu, Ni, Pb, and Zn. The highest concentrations of metals in soils dry matter were 11217.5 mg Pb kg(-1), 1829 mg Cu kg(-1), 1291 mg As kg(-1), 713.7 mg Zn kg(-1), 84.6 mg Cr kg(-1), 54.3 mg Co kg(-1), 52.9 mg Ni kg(-1) and 16.6 mg Ag kg(-1). With respect to plants, the higher concentrations of Pb and As were recorded in the semi-aquatic species Juncus conglomeratus with 84.8 and 23.5 mg kg(-1) dry weight (DW), Juncus efusus with 22.4 and 8.5 mg kg(-1) DW, and Scirpus holoschoenus with 51.7 and 8.0 mg kg(-1) DW, respectively. Thymus mastichina also showed high content of As in the aboveground parts, 13.6 mg kg(-1) DW. Overall, the results indicate accumulation of various metals by different plant species, with some of these metals being partitioned to the shoots. Environmental implications of these observations are discussed.     

Gamma dose rates and distribution of natural radionuclides in sand beaches--Ilha Grande, Southeastern Brazil

In order to study the process of dispersion and the activity concentration of 232Th and 238U series and 40K radionuclides in two island beaches in southeastern Brazil, analyses was made of sand samples of 0-10 cm profile, during a 12-month period. Moreover, the monthly variations of gamma dose rates were studied to determine the local environment absorbed dose rate. The average activity concentration of primordial radionuclides 232Th, 238U and 40K at Preta beach, they were 239, 121 and 110 Bq kg(-1), while at Dois Rios beach they were 48, 39 and 412 Bq kg(-1), respectively. The absorbed dose rate in air, observed at 1 m above the ground, ranged from 54 to 228 nGy h(-1) at Preta beach and from 39 to 110 nGy h(-1) at Dois Rios beach. The annual effective dose equivalent corresponding to Preta beach is 0.15 mSv a(-1) and to Dois Rios 0.08 mSv a(-1).