Spatial distribution of illicit drugs in surface waters of the natural park of Pego-Oliva Marsh (Valencia,Spain)

Background, aim and scope  

The Pego-Oliva Marsh is the second most important wetland in the Valencian Community (Spain). It is included in the RAMSAR agreement and represents one key point for migratory birds. Emerging contaminants from the human pressure, such as pharmaceuticals, illicit drugs and personal care product, are not included in the list of priority contaminants of the Water Framework Directive yet, and are neither monitored nor controlled. However, pollution of emerging contaminants can threaten the environment and even human health. In order to understand the status of the emerging contamination and recommend future rationalization of countermeasures, the occurrence of illicit drugs was investigated.     

In situ experiments for element species-specific environmental reactivity of tin and mercury compounds using isotopic tracers and multiple linear regression

The fate of mercury (Hg) and tin (Sn) compounds in ecosystems is strongly determined by their alkylation/dealkylation pathways. However, the experimental determination of those transformations is still not straightforward and methodologies need to be refined. The purpose of this work is the development of a comprehensive and adaptable tool for an accurate experimental assessment of specific formation/degradation yields and half-lives of elemental species in different aquatic environments. The methodology combines field incubations of coastal waters and surface sediments with the addition of species-specific isotopically enriched tracers and a mathematical approach based on the deconvolution of isotopic patterns. The method has been applied to the study of the environmental reactivity of Hg and Sn compounds in coastal water and surface sediment samples collected in two different coastal ecosystems of the South French Atlantic Coast (Arcachon Bay and Adour Estuary). Both the level of isotopically enriched species and the spiking solution composition were found to alter dibutyltin and monomethylmercury degradation yields, while no significant changes were measurable for tributyltin and Hg(II). For butyltin species, the presence of light was found to be the main source of degradation and removal of these contaminants from surface coastal environments. In contrast, photomediated processes do not significantly influence either the methylation of mercury or the demethylation of methylmercury. The proposed method constitutes an advancement from the previous element-specific isotopic tracers’ approaches, which allows for instance to discriminate the extent of net and oxidative Hg demethylation and to identify which debutylation step is controlling the environmental persistence of butyltin compounds.     

The Influences of Ambient Particle Composition and Size on Particle Infiltration in Los Angeles,CA, Residences

Abstract

Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH₄NO₃). A comprehensive indoor monitoring study was conducted in 17 Los Angeles–area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (F_INF), for fine particles (PM_2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO₃ ^?]) components, and particle sizes ranging between 0.02 and 10 μm. F_INF was highest for BC (median = 0.84) and lowest for NO₃ ^? (median = 0.18). The low F_INF for NO₃ ^? was likely because of volatilization of NO₃ ^? particles once indoors, in addition to depositional losses upon building entry. The F_INF for PM_2.5 (median = 0.48) fell between those for BC and NO₃ ^?, reflecting the contributions of both particle components to PM_2.5. F_INF varied with particle size, air-exchange rate, and outdoor NO₃ ^? concentrations. The F_INF for particles between 0.7 and 2 μm in size was considerably lower during periods of high as compared with low outdoor NO₃ ^? concentrations, suggesting that outdoor NO₃ ^? particles were of this size. This study demonstrates that infiltration of PM_2.5 varies by particle component and is lowest for volatile species, such as NH₄NO₃. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM_2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas with high concentrations of NH₄NO₃ and other volatile particles.     

Costs of the electrochemical oxidation of wastewaters: a comparison with ozonation and Fenton oxidation processes

In the work described here the technical and economic feasibilities of three Advanced Oxidation Processes (AOPs) have been studied: Conductive-Diamond Electrochemical Oxidation (CDEO), Ozonation and Fenton oxidation. The comparison was made by assessing the three technologies with synthetic wastewaters polluted with different types of organic compounds and also with actual wastes (from olive oil mills and from a fine-chemical manufacturing plant). All three technologies were able to treat the wastes, but very different results were obtained in terms of efficiency and mineralization. Only CDEO could achieve complete mineralization of the pollutants for all the wastes. However, the efficiencies were found to depend on the concentration of pollutant (mass transfer control of the oxidation rate). Results obtained in the oxidation with ozone (at pH 12) or by Fenton's reagent were found to depend on the nature of the pollutants, and significant concentrations of oxidation-refractory compounds were usually accumulated during the treatment. Within the discharge limits that all of the technologies can reach, the economic analysis shows that the operating cost of Fenton oxidation is lower than either CDEO or ozonation, although CD\EO can compete satisfactorily with the Fenton process in the treatment of several kinds of wastes. Likewise, the investment cost for the ozonation process seems to be higher than either CDEO or Fenton oxidation, regardless of the pollutant treated.     

Farming dynamics and social capital: A case study in the urban fringe of Mexico City

Urban development has important implications for farmland preservation and natural resource management in local peri-urban communities. Social science research on recent changes in rural landscape of mega-cities tends to be limited to case studies in Latin-American nations. This study analyses the socioecomic dynamics of farming land use and the interactions between multiple cultural variables and the environment. Fieldwork was carried out during the 2002–2003 period in rural livelihoods of the five high mountain towns of south Mexico City. Data obtained from participatory survey and ethnographic techniques were integrated to assess changes in rural landscape and resource management and how urbanization, deforestation and market oriented agricultural production result in different livelihoods within a similar urban fringe context. The dynamic of mixture of urban and rural landscapes is based on farm productivity and social capital factors. The study concludes that policy support for regional agricultural production systems through enhancing ecosystems services, environmental protection and economic development is needed for sustainable development of local communities. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue     

Effective monitoring of agriculture: a response

The development of effective agricultural monitoring networks is essential to track, anticipate and manage changes in the social, economic and environmental aspects of agriculture. We welcome the perspective of Lindenmayer and Likens (J. Environ. Monit., 2011, 13, 1559) as published in the Journal of Environmental Monitoring on our earlier paper, "Monitoring the World's Agriculture" (Sachs et al., Nature, 2010, 466, 558-560). In this response, we address their three main critiques labeled as 'the passive approach', 'the problem with uniform metrics' and 'the problem with composite metrics'. We expand on specific research questions at the core of the network design, on the distinction between key universal and site-specific metrics to detect change over time and across scales, and on the need for composite metrics in decision-making. We believe that simultaneously measuring indicators of the three pillars of sustainability (environmentally sound, social responsible and economically viable) in an effectively integrated monitoring system will ultimately allow scientists and land managers alike to find solutions to the most pressing problems facing global food security.     

Uranium speciation in river sediments contaminated by phosphate ores

Large amounts of phosphate ores with high concentrations of uranium were dumped by a phosphate plant into the Flix water reservoir in the Ebre River, Catalonia, NE Spain. These phosphate wastes have been mixed over the years with effluents from other industries as well as with the sediments of the river, resulting in a complex mixture of solid wastes and sediments. No investigations on uranium speciation in such sediments were made because of the complexity of the sediments composition as well as the relatively low uranium content. However, these studies are necessary in order to predict the release of the uranium to the river waters. Here, we studied uranium speciation in sediments from two sampling points of the Flix water reservoir and at depths from 5 to 113 cm. We used room temperature time-resolved laser fluorescence spectroscopy and a three-step sequential extraction procedure described by the Standards, Measurements, and Testing Programme of the European Union. We found that uranium was mainly present in the sediment samples as meta-autunite [Ca(UO₂)₂(PO₄)₂·10–12H₂O], whose low solubility will result in a low release of uranium to the river waters. In addition, we found that some uranium was linked to sediments by forming surface complexes. We therefore made the first study of uranium speciation in the sediments of the Flix water reservoir.     

Obtaining polycyclic aromatic hydrocarbon concentration ratios and molecular markers for residential wood combustion: Temuco, a case study

It is known that residential wood combustion (RWC) is an important source of fine particle emissions. The purpose of this work was to characterize the chemical composition of the particulate matter present in the Temuco urban atmosphere during winter, specifically the polycyclic aromatic hydrocarbon (PAH) profile, because PAHs are considered to be among the key compounds in particulate matter toxicity. During the 2008 winter monitoring campaign, samples of particulate matter with aerodynamic diameters of < or = 10 (PM10) and < or = 2.5 (PM2.5) microm were taken on days with contamination episodes. Sixteen U.S. Environmental Protection Agency (EPA) PAH compounds were extracted with toluene and determined by gas chromatography-mass spectrometry (GC-MS). The results show that phenantrene was the predominant compound associated with particulate matter at a concentration range between 300 and 600 ng m(-3), 18 times higher than the second most abundant PAH compound. High-molecular-mass compounds such as dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3,c,d]pyrene were also found, but they were minorities in the set. It was recognized from the PAH concentration ratios of the Temuco atmospheric aerosol that the main contamination source was in fact residential wood combustion; although not all the concentration ratios evaluated match the reported reference values, probably due to the kind of biomass used, the characteristics of Chilean heating appliances and climate.     

Levels of glyphosate in surface waters, sediments and soils associated with direct sowing soybean cultivation in north pampasic region of Argentina

Levels of glyphosate were determined in water, soil and sediment samples from a transgenic soybean cultivation area located near to tributaries streams of the Pergamino-Arrecifes system in the north of the Province of Buenos Aires, Argentina. Field work took into account both the pesticide application and the rains occurring after applications. The pesticide was analysed by HPLC-UV detection, previous derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). In addition, SoilFug multimedia model was used to analyse the environmental distribution of the pesticides. In the field, levels of glyphosate in waters ranged from 0.10 to 0.70mg/L, while in sediments and soils values were between 0.5 and 5.0mg/Kg. Temporal variation of glyphosate levels depended directly on the time of application and the rain events. The results obtained from the application of the model are in accordance with the values found in the field.