Sequential Extraction Versus Comprehensive Characterization of Heavy Metal Species in Brownfield Soils

The applicability of sequential extraction as a means to determine species of heavy-metals was examined by a study on soil samples from two Superfund sites: the National Lead Company site in Pedricktown, NJ, and the Roebling Steel, Inc., site in Florence, NJ. Data from a standard sequential extraction procedure were compared to those from a comprehensive study that combined optical- and scanning-electron microscopy, X-ray diffraction, and chemical analyses. The study shows that larger particles of contaminants, encapsulated contaminants, and/or man-made materials such as slags, coke, metals, and plastics are subject to incasement, non-selectivity, and redistribution in the sequential extraction process. The results indicate that standard sequential extraction procedures that were developed for characterizing species of contaminants in river sediments may be unsuitable for stand-alone determinative evaluations of contaminant species in industrial-site materials. However, if employed as part of a comprehensive, site-specific characterization study, sequential extraction could be a very useful tool.     

Possibilities for improving nitrogen use from organic materials in agricultural cropping systems

Nitrogen release from organic nutrient sources in soil is influenced by a range of factors such as soil temperature and moisture, and chemical composition of the organic material. Chemical composition can, to a certain degree, be controlled to increase the synchronization of nitrogen (N) release with plant N demand, whereas climatic factors cannot be controlled and so must be taken into account when planning management measures. In this paper, we discuss different ways to affect N release through manipulation of the chemical composition of fresh or pretreated plant materials and animal manures, timing of incorporation, and intentional distribution during application. We conclude by giving an overview of off-farm options that may need to be implemented to achieve improved use of N, especially in agricultural systems with surplus N.     

Economic assessment of the negative impacts of ozone on crop yields and forest production. A case study of the estate Ostads Säteri in southwestern Sweden

Ground level ozone concentrations, in combination with the prevailing climate, at the estate Ostads S?teri in southwestern Sweden were estimated to reduce the yield of wheat and potato ranging between 5% and 10%. Occasionally, in years with the highest ozone concentrations and/or climatic conditions favoring high rates of ozone uptake to the leaves, yield loss levels above 10% may occur. Based on simple extrapolation, these ozone-induced reductions of crop yields at Ostads S?teri represent a potential total annual yield loss in Sweden in the range of 24.5 million Euro for wheat and 7.3 million Euro for potato, respectively. A simulation of forest growth at Ostad S?teri predicted that prevailing mean ozone exposure during 1993-2003 had the potential to reduce forest growth by 2.2% and the economic return of forest production by 2.6%. Using this value for extrapolation to the national level, the potential annual economic loss for Sweden due to negative impacts of ozone on forest production would be in the range of 56 million Euro (2004 prices).     

Effects of Sorbent Injection on Participate Properties: Part I. Low-Temperature Sorbent Injection

Abstract

This article is the first of a two-part series dealing with the effects of sorbent injection processes on particulate properties. Part I reviews the effects on particulate properties of low-temperature sorbent injection processes (those processes that treat flue gas at temperatures near 300 °F). Part II reviews the effects on particulate properties of high-temperature sorbent injection processes (those processes that involve sorbent injection into the combustion or economizer sections of a boiler). In this article, we review what is currently known about the effects of the low-temperature sorbent injection processes on electrical resistivity, particulate mass loading, particulate size distribution, particulate morphology and cohesivity.

Mixtures of ash and sorbent produced by low-temperature sorbent injection processes are typically less cohesive than most types of fly ash. At temperatures within 30 °F of the water dew point, the combination of low cohesivity and low electrical resistivity of the ash and sorbent mixtures can cause electrical reentrainment in electrostatic precipitators. Deliquescent additives such as calcium chloride cause the water to be retained on the particle surface, thereby increasing cohesivity.

Sorbent injection has been reported to increase the particulate mass loading by a factor of 1.8 to 10, depending upon the reagent ratio and the coal sulfur content. Conventional and in-duct spray drying processes tend to shift the particle size distribution toward larger particles, while dry injection processes tend to shift the particle size distribution toward smaller particles.     

Dense resistivity and induced polarization profiling for a landfill restoration project at H?rl?v, Southern Sweden.

A resistivity and time-domain induced polarization (IP) survey was conducted at a landfill site under restoration at H?rl?v in Southern Sweden. The covering of the landfill had begun some years ago, without keeping precise records of the work done, as is usual in such procedures. The survey was conducted in two steps, on two adjacent areas. First, a number of geoelectrical sections were made on a partly covered area that had been investigated earlier by auger drilling, in order to assist restoration. Then, a second area that should have received its final cover was imaged, and some defects in the cover could be detected and repaired. The resistivity and time-domain IP results were consistent with the results of the geotechnical drillings, and they enabled quasi-continuous mapping along the profiles. Three-dimensional visualization showed the overall consistency of the two-dimensional lines, and helped to generate a global view of the site. In spite of some ambiguities, cover and waste could be distinguished in most cases. In particular, fine-grained cover materials could be clearly distinguished from other cover materials.     

Intake of phthalates and di(2-ethylhexyl)adipate: results of the Integrated Exposure Assessment Survey based on duplicate diet samples and biomonitoring data

Phthalates are ubiquitous environmental chemicals with potential detrimental health effects. The purpose of our study was to quantify dietary intake of phthalates and of DEHA (Di-ethylhexyl adipate) using duplicate diet samples and to compare these data with the calculated data based on urinary levels of primary and secondary phthalate metabolites. 27 female and 23 male healthy subjects aged 14-60 years collected daily duplicate diet samples over 7 consecutive days. Overall, 11 phthalates were measured in the duplicates by GC/MS and LC/MS methods. Urinary levels of primary and secondary phthalate metabolites are also available. The median (95th percentile) daily intake via food was 2.4 (4.0) microg/kg b.w. (Di-2-ethylhexyl phthalate, DEHP), 0.3 (1.4) microg/kg b.w. (Di-n-butyl phthalate, DnBP), 0.6 (2.1) microg/kg b.w. (Di-isobutyl phthalate, DiBP) and 0.7 (2.2) microg/kg b.w. for DEHA. MEPH (Mono-2-ethylhexyl phthalate) was detectable only in minor concentrations in the samples, thus conversion of DEHP to MEHP and dietary intake of MEHP were negligible. When comparing back-calculated intake data of the DEHP metabolites with dietary DEHP intake from the day before significant correlations were observed for most of the metabolites. No correlation was found for DnBP and only a weak but significant correlation for DiBP. The median and 95th percentile daily dietary intake of all target analytes did not exceed the recommended tolerable daily intake. Our data indicated that food was the predominant intake source of DEHP, whilst other sources considerably contributed to the daily intake of DnBP and DiBP in an adult population.     

Environmental filtering and land-use history drive patterns in biomass accumulation in a mediterranean-type landscape

Aboveground biomass (AGB) reflects multiple and often undetermined ecological and land-use processes, yet detailed landscape-level studies of AGB are uncommon due to the difficulty in making consistent measurements at ecologically relevant scales. Working in a protected mediterranean-type landscape (Jasper Ridge Biological Preserve, California, USA), we combined field measurements with remotely sensed data from the Carnegie Airborne Observatory's light detection and ranging (lidar) system to create a detailed AGB map. We then developed a predictive model using a maximum of 56 explanatory variables derived from geologic and historic-ownership maps, a digital elevation model, and geographic coordinates to evaluate possible controls over currently observed AGB patterns. We tested both ordinary least-squares regression (OLS) and autoregressive approaches. OLS explained 44% of the variation in AGB, and simultaneous autoregression with a 100-m neighborhood improved the fit to an r2 = 0.72, while reducing the number of significant predictor variables from 27 variables in the OLS model to 11 variables in the autoregressive model. We also compared the results from these approaches to a more typical field-derived data set; we randomly sampled 5% of the data 1000 times and used the same OLS approach each time. Environmental filters including incident solar radiation, substrate type, and topographic position were significant predictors of AGB in all models. Past ownership was a minor but significant predictor, despite the long history of conservation at the site. The weak predictive power of these environmental variables, and the significant improvement when spatial autocorrelation was incorporated, highlight the importance of land-use history, disturbance regime, and population dynamics as controllers of AGB.     

提高农业种植体系有机物质中氮利用的可能性研究

土壤有机养分源中的氮释放受许多因子的影响,如土壤温度和水分、有机物质的化学组成.在某种程度上,控制有机物质的化学组成可以增加氮释放和植物需求的同步性,而气候因子是不能控制的,因此在计划管理措施时要考虑这些因素.本文通过调节新鲜或预处理过的植物材料和牲畜粪肥的化学组成、施用时间以及有意分配,来探讨影响氮释放的不同途径.最后阐述提高氮利用率需要实施的农场外的(off-farm)的选择,尤其是对氮过剩的农业体系.     

Assessing the Restoration Success of River Widenings: A Landscape Approach

During the last 200 years, many rivers in industrialized countries have been modified by canalization. In the last two decades, the philosophy of river management has changed considerably, and restoration of ecological integrity has become an important management goal. One appealing restoration approach is to create “river widenings” that permit braiding within a limited area. This study presents a new and efficient framework for rapidly assessing such widening projects and offers a novel method to comparing restored sites with near-natural stretches (stencil technique). The proposed framework evaluates spatial patterns of riparian habitat types using landscape metrics as indicators. Three case studies from river restoration (river widening) in Switzerland are presented for demonstration purposes.The method compares restored sites with prerestoration conditions and near-natural conditions, which are assumed to represent the worst and best case states of a river system. To take into account the limited spatial extent of the restored sites, the so-called “stencil technique” was developed, where the landscape metrics of the near-natural reference sites are calculated for both the entire study area and smaller sections (clips). The clips are created by using a stencil that has the exact shape and size of the restored area (random window-sampling technique). Subsequently, the calculated metrics for the restored sites are compared to the range of values calculated for the near-natural data subset. Our studies show that the proposed method is easy to apply andprovides a valid way to assess the restoration success of river widenings. We found that river widenings offer real opportunities for establishing riparian habitats. However, they promote mainly pioneer successional stages and the habitat mosaic of the restored section is more complex than at the near-natural reference sites.