Investigation of sequential and enzymatic extraction of arsenic from drinking water distribution solids using ICP-MS

A sequential extraction approach was utilized to estimate the distribution of arsenite [As(iii)] and arsenate [As(v)] on iron oxide/hydroxide solids obtained from drinking water distribution systems. The arsenic (As) associated with these solids can be segregated into three operationally defined categories (exchangeable, amorphous and crystalline) according to the sequential extraction literature. The exchangeable As, for the six drinking water solids evaluated, was estimated using 10 mM MgCl(2) and 10 mM NaH(2)PO(4) and represented between 5-34% of the total As available from the solid. The amorphously bound As was estimated using 10 mM (NH(4))(2)C(2)O(4) and represented between 57-124% of the As available from the respective solid. Finally, the crystalline bound As was estimated using titanium citrate and this represented less than 1.5% of the As associated with the solids. A synthetic stomach/intestine extraction approach was also applied to the distribution solids. The stomach fluid was found to extract between 0.5-33.3 microg g(-1) As and 120-2,360 microg g(-1) iron (Fe). The As concentrations in the intestine fluid were between 0.02-0.04 microg g(-1) while the Fe concentration ranged from 0.06-0.7 microg g(-1) for the first six drinking water distribution solids. The elevated Fe levels associated with the stomach fluid were found to produce Fe based precipitates when the intestinal treatment was applied. Preliminary observations indicate that most of the aqueous Fe in the stomach fluid is ferric ion and the observed precipitate produced in the intestine fluid is consistent with the decreased solubility of ferric ion at the pH associated with the intestine.     

Links among nitrification, nitrifier communities, and edaphic properties in contrasting soils receiving dairy slurry

Soil biotic and abiotic factors strongly influence nitrogen (N) availability and increases in nitrification rates associated with the application of manure. In this study, we examine the effects of edaphic properties and a dairy (Bos taurus) slurry amendment on N availability, nitrification rates and nitrifier communities. Soils of variable texture and clay mineralogy were collected from six USDA-ARS research sites and incubated for 28 d with and without dairy slurry applied at a rate of ~300 kg N ha(-1). Periodically, subsamples were removed for analyses of 2 M KCl extractable N and nitrification potential, as well as gene copy numbers of ammonia-oxidizing bacteria (AOB) and archaea (AOA). Spearman coefficients for nitrification potentials and AOB copy number were positively correlated with total soil C, total soil N, cation exchange capacity, and clay mineralogy in treatments with and without slurry application. Our data show that the quantity and type of clay minerals present in a soil affect nitrifier populations, nitrification rates, and the release of inorganic N. Nitrogen mineralization, nitrification potentials, and edaphic properties were positively correlated with AOB gene copy numbers. On average, AOA gene copy numbers were an order of magnitude lower than those of AOB across the six soils and did not increase with slurry application. Our research suggests that the two nitrifier communities overlap but have different optimum environmental conditions for growth and activity that are partly determined by the interaction of manure-derived ammonium with soil properties.     

Development and Validation of an Aquatic Fine Sediment Biotic Index

The Fine Sediment Biotic Index (FSBI) is a regional, stressor-specific biomonitoring index to assess fine sediment (<2 mm) impacts on macroinvertebrate communities in northwestern US streams. We examined previously collected data of benthic macroinvertebrate assemblages and substrate particle sizes for 1,139 streams spanning 16 western US Level III Ecoregions to determine macroinvertebrate sensitivity (mostly at species level) to fine sediment. We developed FSBI for four ecoregion groupings that include nine of the ecoregions. The grouping were: the Coast (Coast Range ecoregion) (136 streams), Northern Mountains (Cascades, N. Rockies, ID Batholith ecoregions) (428 streams), Rockies (Middle Rockies, Southern Rockies ecoregions) (199 streams), and Basin and Plains (Columbia Plateau, Snake River Basin, Northern Basin and Range ecoregions) (262 streams). We excluded rare taxa and taxa identified at coarse taxonomic levels, including Chironomidae. This reduced the 685 taxa from all data sets to 206. Of these 93 exhibited some sensitivity to fine sediment which we classified into four categories: extremely, very, moderately, and slightly sensitive; containing 11, 22, 30, and 30 taxa, respectively. Categories were weighted and a FSBI score calculated by summing the sensitive taxa found in a stream. There were no orders or families that were solely sensitive or resistant to fine sediment. Although, among the three orders commonly regarded as indicators of high water quality, the Plecoptera (5), Trichoptera (3), and Ephemeroptera (2) contained all but one of the species or species groups classified as extremely sensitive. Index validation with an independent data set of 255 streams found FSBI scores to accurately predict both high and low levels of measured fine sediment.     

Observations of particle growth at a remote,Arctic site

Observations of particle size distributions suggest that particles grow significantly just above the snow surface at a remote, Arctic site. Measurements were made at Summit, Greenland (71.38°N and 31.98°W) at approximately 3200 m above sea level. No new particle formation was observed locally, but growth of ultrafine particles was identified by continuous evolution of the geometric mean diameter (GMD) during four events. The duration of the growth during events was between 24 and 115 h, and calculated event-average growth rates (GR) were 0.09, 0.30, 0.27, and 0.18 nm h^?1 during each event, respectively. Four-hour GR up to 0.96 nm h^?1 were observed. Events occurred during below- and above-average temperatures and were independent of wind direction. Correlation analysis of hourly-calculated GR suggested that particle growth was limited by the availability of photochemically produced precursor gases. Sulfuric acid played a very minor role in particle growth, which was likely dominated by condensation of organic compounds, the source of which was presumably the snow surface. The role of boundary layer dynamics is not definite, although some mixing at the surface is necessary for the observation of particle growth. Due to the potentially large geographic extent of events, observations described here may provide a link between long-range transport of mid-latitude pollutants and climate regulation in the remote Arctic.     

Environmental and Socio-economic Aspects of the Operation of Industrial Regions: The Case Study of the Industrial Area of Alexandroupolis (Greece)

The paper summarizes the results of a study concerning the operation of industrial plants and their effects to the environment. It also addresses, shortly, the consequences to the quality of human life and proposes potential measures that may contribute to the reduction of the negative environmental impacts. The relatively small organized Industrial Area of Alexandroupolis (Greece) is examined as a case study. In particular, the activities of its major industrial facilities are presented and their emissions to the environment are examined. In addition, the socio-economic aspects of the operation of the Industrial Area are studied. The results of the study showed that the operation of the Industrial Area has specific negative effects in the natural environment of the region and in the quality of life of the residents. Methodological and legislative tools, such as control systems for the environmental pollution, the green chemistry, and the environmental management systems, may be employed to assist the prevention and confrontation of environmental problems.     

Organic Agriculture’s Approach towards Sustainability; Its Relationship with the Agro-Industrial Complex, A Case Study in Central Macedonia, Greece

Up to now, several scientific works have noted that the organic sector resembles more and more conventional farming’s structures, what is widely known as the “conventionalization” thesis. This phenomenon constitutes an area of conflict between organic farming’s original vision and its current reality and raises ethical and social questions concerning the structure of agricultural systems of production and their interactions with the socio-economic and natural environment. The main issue of this dialogue is the concept of sustainable agriculture, which for scientists and policymakers is a means to express their vision of a better agriculture. In this article we focus on agricultural sustainability in the context of capitalist production as conducted by the two subsystems of agro-industrial system. As we have proposed in this article, the relationship between organic agriculture, defined by two essential components (prevention and direct marketing), and the agro-industrial complex, defined by two subsystems, indicates the degree of agricultural sustainability. The investigation of this relationship can be extremely useful as it may lead those involved in the discussion of sustainability to identify the key aspects of sustainable agriculture. In order to investigate the interaction of organic farming with the agro-industrial complex, a survey was conducted in Central Macedonia, Northern Greece, involving local organic farms. The results of our study indicate that a large proportion of organic producers did not differ substantially from their counterparts in conventional agriculture in so far as their relationship with the agro-industrial complex is concerned. Finally, this research highlights two scenarios for the evolution of organic farming. The first is the full absorption of organic farming to the existing economic system and the second one is the development of organic farming in a radically opposite direction to conventional farming.     

Dissolution kinetics of sub-millimeter Composition B detonation residues: role of particle size and particle wetting

The dissolution of the 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from microscale particles (<250 μm) of the explosive formulation Composition B was examined and compared to dissolution from macroscopic particles (>0.5 mm). The dissolution of explosives from detonation soot was also examined. The measured mass transfer coefficients for the microscale particles were one to two orders of magnitude greater than the macroscopic particles. When normalized to particle surface area, mass transfer coefficients of microscale and macroscale particles were similar, indicating that the bulk dissolution processes were similar throughout the examined size range. However, an inverse relationship was observed between the particle diameter and the RDX:TNT mass transfer rate coefficient ratio for dry-attritted particles, which suggests that RDX may be more readily dissolved (relative to TNT) in microscale particles compared to macroscale particles. Aqueous weathering of larger Composition B residues generated particles that possessed mass transfer coefficients that were on the order of 5- to 20-fold higher than dry-attritted particles of all sizes, even when normalized to particle surface area. These aqueous weathered particles also possessed a fourfold lower absolute zeta-potential than dry-attritted particles, which is indicative that they were less hydrophobic (and hence, more wettable) than dry-attritted particles. The increased wettability of these particles provides a plausible explanation for the observed enhanced dissolution. The wetting history and the processes by which particles are produced (e.g., dry physical attrition vs. aqueous weathering) of Composition B residues should be considered when calculating mass transfer rates for fate and transport modeling.     

Mercury Balance on a Large Pulverized Coal-Fired Furnace

This paper presents results of a survey of mercury concentrations in coal, ash, water, fly ash, and flue gas discharges from a 5.5 × 10⁶ Ib/hr steam generator serving a 775 MW (net) turbine-generator set. Representative composite or grab samples were obtained for inlet coal and outlet ash and water. Stack samples were obtained for fly ash and mercury vapor emissions while the unit was operated at 660 MW (net) (85% of full load). Samples were analyzed by anodic stripping voltammetry, plasma emission spectroscopy, and neutron activation analysis to determine mercury concentration entering the furnace in the coal and leaving the furnace in the flue gas, fly ash, bottom and hopper ash, and water. Method inter-comparisons are discussed. A material balance for mercury has been calculated from fuel, ash, and stack gas flow rates. About 90% of the mercury in the coal is released and appears as vapor discharged in the stack gas while 10% remains in the residual ash. For a 700 MW (net) unit, about 5 lb/day of mercury vapor is released to the atmosphere.     

PFAS profiles in three North Sea top predators: metabolic differences among species?

Profiles of seven compounds of perfluoro-alkyl substances (PFASs) were compared among three species of top predators from the Danish North Sea: the white-beaked dolphin (Lagenorhynchus albirostris), the harbor porpoise (Phocoena phocoena), and the harbor seal (Phoca vitulina). The seals had higher total burdens (757.8 ng g^?1 ww) than the dolphins (439.9 ng g^?1 ww) and the porpoises (355.8 ng g^?1 ww), probably a reflection of feeding closer to the shore and thus contamination sources. The most striking difference among the species was the relative contribution of perfluorooctanesulfonamide (PFOSA) to the profiles; the seals (0.1 %) had much lower levels than porpoises (8.3 %) and dolphins (26.0 %). In combination with the values obtained from the literature, this result indicates that Carnivora species including Pinnipedia have a much higher capacity of transforming PFOSA to perfluorooctane sulfonic acid (PFOS) than cetacean species. Another notable difference among the species was that the two smaller species (seals and porpoises) with supposedly higher metabolic rates had lower concentrations of the perfluorinated carboxylic acids, which are generally more easily excreted than perfluorinated sulfonamides. Species-specific characteristics should be recognized when PFAS contamination in marine mammals is investigated, for example, several previous studies of PFASs in cetaceans have not quantified PFOSA.     

Integrated landscape planning and remuneration of agri-environmental services. Results of a case study in the Fuhrberg region of Germany

Until now, existing remuneration of environmental services has not sufficiently supported the goals of spending money more effectively on the environment and of motivating farmers. Only a small share of the budgets for agriculture in the EU, as well as in US and other countries, is available for buying environmental goods and services beyond the level of good farming practice (GFP). This combined with the insufficient targeting of compensation payments to areas where special measures are needed leads to an unsatisfactorily low impact of agri-environment measures compared to other driving forces that stimulate the intensification of farming. The goal of this paper is to propose a management concept that enhances the ecological and cost efficiency of agri-environment measures. Components of the concept are a comprehensive environmental information base with prioritised goals and targets (available in Germany from landscape planning) and new remuneration models, which complement conventional compensation payments that are based upon predetermined measures and cost. Comprehensive landscape planning locates and prioritises areas which require environmental action. It contains the information that authorities need to prioritise funding for environmental services and direct measures to sites which need environmental services beyond the level of GFP.Also appropriate remuneration models, which can enhance the cost efficiency of public spending and the motivation of the farmers, can be applied on the base of landscape planning.Testing of the planning methodology and of one of the remuneration models (success-oriented remuneration) in a case study area (“Fuhrberger Feld” north of Hanover, Germany) demonstrated the usability of the concept and led to proposals for future development of the methodology and its application in combination with other approaches.