Fate of β-blockers in aquifer material under nitrate reducing conditions: Batch experiments

The fate of the three environmentally relevant β-blockers atenolol, metoprolol and propranolol has been studied in batch experiments involving aquifer material and nitrate reducing conditions. Results from the about 90 d long tests indicate that abiotic processes, most likely sorption, jointly with biotransformation to atenololic acid were responsible for the 65% overall removal observed for atenolol. Zero order kinetics, typical of enzyme-limited reactions, controlled the transformation of this beta blocker to its corresponding carboxylic acid. The mass balance evidences that no mineralization of atenolol occurs in the biotic experiment and that atenololic acid is more stable than its parent compound under the studied conditions. This finding stresses the importance of considering atenololic acid as target compound in the environmental studies on the fate of atenolol. For metoprolol and propranolol the results from the experiment suggest a slower sorption to be the dominant removal process, which led to final decreases in concentrations of 25-30% and 40-45%, respectively. Overall, the removals observed in the experiments suggest that subsurface processes potentially constitute an alternative water treatment for the target beta-blockers, when compared to the removals reported for conventional wastewater treatment plants.     

Recent Cs deposition in sediments of Admiralty Bay, Antarctica

Cesium-137, radium-226 and lead-210 profiles of a 25 cm sediment core give an indication of recent changes in land-ocean interactions at a polar coastal environment (Admiralty Bay, King George Island, Antarctica). The linear sedimentation accumulation rate at the study site calculated from the unsupported ²¹⁰Pb profile was 6.7 mm/year from 1965 to 2005. A 3.5-fold increase in ¹³⁷Cs concentrations was observed in the top layer of this sediment core. This sharp increase seems to indicate a recent redistribution of fallout radionuclides previously deposited on soil, vegetation and snow. These results imply enhanced land-ocean interactions at this site likely as a result of climate change. Because our results are based on a single core, additional investigations are needed to confirm our observations.     

Experimental study of effectiveness of four radon mitigation solutions, based on underground depressurization, tested in prototype housing built in a high radon area in Spain

The present paper discusses the results of an empirical study of four approaches to reducing indoor radon concentrations based on depressurization techniques in underground sumps. The experiments were conducted in prototype housing built in an area of Spain where the average radon concentration at a depth of 1 m is 250 kBq m⁻³.Sump effectiveness was analysed in two locations: underneath the basement, which involved cutting openings into the foundation, ground storey and roof slabs, and outside the basement walls, which entailed digging a pit alongside the building exterior. The effectiveness of both sumps was likewise tested with passive and forced ventilation methods.The systems proved to be highly efficient, lowering radon levels by 91-99%, except in the solution involving passive ventilation and the outside sump, where radon levels were reduced by 53-55%. At wind speeds of over 8 m/s, however, passive ventilation across an outside sump lowered radon levels by 95% due to a Venturi effect induced drop in pressure.     

Serum levels of organochlorine pesticides in healthy adults from five regions of Spain

The aim of this study was to measure of serum levels of p,p′-dichlorodiphenyl trichloroethane (p,p′-DDT), p,p′-dichlorodiphenyl dichlorethylene (p,p′-DDE), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene (HCB) in healthy adults in Spain. Furthermore, we also analyzed these levels according to dietary, other lifestyle factors and anthropometric characteristics. We measured the concentrations of such organochlorine pesticides (OCPs) in serum samples collected during 1992–1996 from 953 subjects aged 35–64 years, they were residents of five Spanish regions, they were randomly selected from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. OCPs were determined by means of gas chromatography with electron-capture detection (GC-ECD). The most frequent compound found in serum was p,p′-DDE, present in 98% of the samples, followed by HCB and β-HCH, found in 89% and 77% of samples, respectively, while p,p′-DDT could be measured only in 26% of subjects. The geometric means of serum concentrations (ng/g lipid) were 822 for p,p′-DDE, 167 for β-HCH, and 379 for HCB. The concentrations of all OCPs were positively associated with age and body mass index, and decreased along the period of blood collection. No association was found between OCPs levels and dietary factors. The concentrations of p,p′-DDE and β-HCB were higher in Murcia, one of southern regions, most likely associated with intensive past use of pesticides related to agricultural practices, while higher levels of HCB were found in Navarra, located in the north, maybe due to industrial use rather than agricultural application.     

The analysis of pollutant profiles by means of compositional analysis. An application to PCDD/F data

Compositional analysis consists of a group of techniques used to manipulate closed (=compositional) data, i.e. multivariate data summing to a fixed quantity (proportions, percentages). It is based on the analysis of the relations among variables and the use of logarithmic transformations. It has been claimed that this group of techniques should be used to analyse profiles of pollutant sources because profiles themselves are proportions. We show in this paper that, for the exploratory analysis of these data, a good strategy is to combine the analysis done with and without transformation because they give different and complementary insights on the structure of the data. We discuss in particular the study of processes such as the mixing of pollutants produced by different sources and the exponential decay of concentrations with distance to the source found in many studies. The clr transformation is also appropriate for the study of the variables having small proportions, which remain concealed by the abundant variables when analysed without transformation. We present simulations to illustrate these ideas and we also apply these techniques to two data sets of PCDD/F content in moss tissues.     

The influence of Sarcocornia fruticosa on retention of PAHs in salt marsh sediments (Sado estuary, Portugal)

Depth concentration profiles of PAHs, organic carbon and dissolved oxygen in non-colonised sediments and sediments colonised by Sarcocornia fruticosa from Mitrena salt marsh (Sado, Portugal) were determined in November 2004 and April 2005. Belowground biomass and PAH levels in below and aboveground material were also determined. In both periods, colonised sediments were oxygenated until 15-cm, rich in organic carbon (max 4.4%) and presented much higher PAH concentrations (max. 7.1 microg g(-1)) than non-colonised sediments (max. 0.55 microg g(-1)). Rooting sediments contained the highest PAH concentrations. The five- and six-ring compounds accounted to 50-75% of the total PAHs in colonised sediments, while only to 30% in non-colonised sediments. The elevated concentrations of PAHs in colonised sediments may be attributed to the transfer of dissolved PAH compounds towards the roots as plant uptake water and subsequent sequestration onto organically rich particles. A phase-partitioning mechanism probably explains the higher retention of the heavier PAHs. In addition oxygenated conditions of the rooting sediments favour the degradation of the lighter PAHs and explain the elevated proportion of the heavier compounds. Below and aboveground materials presented lower PAH concentrations (0.18-0.38 microg g(-1)) than colonised sediments. Only 3- and 4-PAHs were quantified in aboveground material, reflecting either preferential translocation of lighter compounds from roots or atmospheric deposition.     

Methane balance of a bioreactor landfill in Latin America

This paper presents results from a methane (CH4) gas emission characterization survey conducted at the Loma Los Colorados landfill located 60 km from Santiago, Chile. The landfill receives approximately 1 million metric tons (t) of waste annually, and is equipped with leachate control systems and landfill gas collection systems. The collected leachate is recirculated to enable operation of the landfill as a bioreactor. For this study, conducted between April and July 2000, a total of 232 surface emission measurements were made over the 23-ha surface area of the landfill. The average surface flux rate of CH4 emissions over the landfill surface was 167 g x m(-2) x day(-1), and the total quantity of surface emissions was 13,320 t/yr. These values do not include the contribution made by "hot spots," originating from leachate pools caused by "daylighting" of leachate, that were identified on the landfill surface and had very high CH4 emission rates. Other point sources of CH4 emissions at this landfill include 20 disconnected gas wells that vent directly to the atmosphere. Additionally, there are 13 gas wells connected to an incinerator responsible for destroying 84 t/yr of CH4. The balance also includes CH4 that is being oxidized on the surface of the landfill by meth-anotrophic bacteria. Including all sources, except leachate pool emissions, the emissions were estimated to be 14,584 t/yr CH4. It was estimated that less than 1% of the gas produced by the decomposition of waste was captured by the gas collection system and 38% of CH4 generated was emitted to the atmosphere through the soil cover.     

Assessing pollution levels in sediments of a harbour with two opposing entrances: environmental implications

The harbour of Ceuta, North Africa, differs substantially from conventional harbours with only one entrance since it has two opposing entrances and a channel which increases water renewal and local currents, with implications for sedimentary processes, levels of pollution and oxygen concentration. The distribution of heavy metals, nutrients and total hydrocarbons was investigated in sediment samples from this particular harbour. The grain size effect, a normalization technique using Fe concentrations and different sediment quality guidelines are discussed, and the data from the harbour of Ceuta are compared with other harbours worldwide. In spite of the water renewal, sediments inside the harbour of Ceuta were characterised by moderate levels of pollution, mainly hydrocarbons (496--6972 microg/g), P (282--1350 microg/g), N (100--2600 microg/g) and heavy metals Cu (5--865 microg/g), Pb (10--516 microg/g), Zn (296--695 microg/g), Cr (13--381 microg/g) and Ni (8--671 microg/g). Taking into account that there is no industrial activity around the harbour of Ceuta, the major sources of contamination are the sewage effluents of urban influence, anti-fouling paints and accidental oil spills during loading and dumping involved in shipping operations. The design of Ceuta harbour should be taken into consideration in the design, construction and management of future harbours.     

Effect of hydrocarbon pollution on the microbial properties of a sandy and a clay soil

The aim of this work was to ascertain the effects of different types of hydrocarbon pollution on soil microbial properties and the influence of a soil's characteristics on these effects. For this, toxicity bioassays and microbiological and biochemical parameters were studied in two soils (one sandy and one clayey) contaminated at a loading rate of 5% and 10% with three types of hydrocarbon (diesel oil, gasoline and crude petroleum) differing in their volatilisation potential and toxic substance content. Soils were maintained under controlled conditions (50-70% water holding capacity, and room temperature) for six months and several microbiological and toxicity parameters were monitored 1, 60, 120 and 180 days after contamination. The toxic effects of hydrocarbon contamination were greater in the sandy soil. Hydrocarbons inhibited microbial biomass, the greatest negative effect being observed in the gasoline-polluted sandy soil. In both soils crude petroleum and diesel oil contamination increased microbial respiration, while gasoline had little effect on this parameter, especially in the sandy soil. In general, gasoline had the highest inhibitory effect on the hydrolase activities involved in N, P or C cycles in both soils. All contaminants inhibited hydrolase activities in the sandy soil, while in the clayey soil diesel oil stimulated enzyme activity, particularly at the higher concentration. In both soils, a phytotoxic effect on barley and ryegrass seed germination was observed in the contaminated soils, particularly in those contaminated with diesel or petroleum.