Impact of carbon,oxygen and sulfur content of microscale zerovalent iron particles on its reactivity towards chlorinated aliphatic hydrocarbons

Zerovalent iron (ZVI) abiotically degrades several chlorinated aliphatic hydrocarbons (CAHs) via reductive dechlorination, which offers perspectives for in situ groundwater remediation applications. The difference in reactivity between ZVI particles is often linked with their specific surface area. However, other parameters may influence the reactivity as well. Earlier, we reported for a set of microscale zerovalent iron (mZVI) particles the disappearance kinetic of different CAHs which were collected under consistent experimental conditions. In the present study, these kinetic data were correlated with the carbon, oxygen and sulfur content of mZVI particles. It was confirmed that not only the specific surface area affects the disappearance kinetic of CAHs, but also the chemical composition of the mZVI particles. The chemical composition, in addition, influences CAHs removal mechanism inducing sorption onto mZVI particles instead of dechlorination. Generally, high disappearance kinetic of CAHs was observed for particles containing less oxygen. A high carbon content, on the other hand, induced nonreactive sorption of the contaminants on the mZVI particles. To obtain efficient remediation of CAHs by mZVI particles, this study suggested that the carbon and oxygen content should not exceed 0.5% and 1% respectively. Finally, the efficiency of the mZVI particles may be improved to some extent by enriching them with sulfur. However, the impact of sulfur content on the reactivity of mZVI particles is less pronounced than that of the carbon and oxygen content.     

The influence of temperature on the territorial and mate locating behaviour of the small heath butterfly,Coenonympha pamphilus (L.) (Lepidoptera: Satyridae)

Summary Individual Coenonympha pamphilus males shifted mate locating behaviour depending on temperature. Under low temperature conditions males competed for territories, resulting in a high proportion of potential territories being occupied by stationary males and in long interactions between males in teritories. When temperatures became higher, stationary males tended to leave their territories and travel over a wider area, i.e. become vagrant. This resulted in a low proportion of territories being occupied by stationary males and inshort territorial interactions. Males could stay longer in flight without perching and hence also search a larger area for females within a given time span with increasing temperatures. This may explain why males adopt vagrant behaviour at higher temperatures. Al lower temperatures, on the other hand, when males cannot search effectively for females, waiting for them at a defended territory should be the most successful strategy.     

Occupational road trauma and permanent medical impairment

Medically impairing occupational injuries sustained in traffic in Sweden were analysed. More than half of the cases with a permanent medical impairment were caused by minor injuries. Soft tissue injuries to the neck (whiplash injuries) made up nearly half of all permanently impairing injuries, and half of these were caused by rear-end collisions. As a final result, just over one third (37%) of the total group had a permanent decreased work capacity, or needed to change jobs because of residual problems from their injuries. Professional drivers had the highest injury incidence per employed and they accounted for 28% of the total number of permanent impairment cases, and for 43% of the fatalities. Professional drivers also had a higher percentage of serious injuries and severe permanent impairments than other occupational groups. This might be associated with the low use of safety belts (16%) compared to other occupational groups, where usage was 4–5 times higher. This occupational injury problem ought to be handled in the same way as other occupational safety problems, i.e. protective equipment in a vehicle should be used and the use of safe vehicles should be encouraged.     

A source classification framework supporting pollutant source mapping,pollutant release prediction,transport and load forecasting,and source control planning for urban environments

Purpose

Implementation of current European environmental legislation such as the Water Framework Directive requires access to comprehensive, well-structured pollutant source and release inventories. The aim of this work was to develop a Source Classification Framework (SCF) ideally suited for this purpose.

Methods

Existing source classification systems were examined by a multidisciplinary research team, and an optimised SCF was developed. The performance and usability of the SCF were tested using a selection of 25 chemicals listed as priority pollutants in Europe.

Results

The SCF is structured in the form of a relational database and incorporates both qualitative and quantitative source classification and release data. The system supports a wide range of pollution monitoring and management applications. The SCF functioned well in the performance test, which also revealed important gaps in priority pollutant release data.

Conclusions

The SCF provides a well-structured approach for European pollutant source and release classification and management. With further optimisation and demonstration testing, the SCF has the potential to be fully implemented throughout Europe.

     

Optimal monitoring and management of a water storage

The aim is to fill a water storage with potable water of a given quality, for subsequent treatment and distribution to a water conveying system. During a given period, a set of several pumping stations is working to deliver water from different sources at different locations. A multi-stage control process is considered whereby the total pumping time is divided into short sampling intervals. The intensity of pumping as a function of time is the control variable. It is assumed that there exists a reliable forecast of every pollutant as a function of time and water source. The amount of the pollutants are constrained in the final mass of water in the storage. The mass of water at the end of the operation period should be maximized. A linear programming (LP) model of the problem is described, and an algorithm of the reduction of its dimensionality is presented. An illustrative example is shown. A short conference version of this paper has been presented at 14th IEEE Mediterranean Conference on Control Automation, June 28–30 2006, Polytechnical University of Ancona, Ancona, Italy.     

An estimate of female mate searching costs in the lekking butterfly Coenonympha pamphilus

We estimated the cost to females of the lekking butterfly Coenonympha pamphilus of visiting males on leks instead of taking off and soliciting courtship from males passing them outside leks, as occurs in the non-lekking congener C. tullia. We followed released virgin females of C. pamphilus in the field until they mated. We estimated the time they lost by remaining perched and not approaching males that passed them, and observed how often and at what distance virgin females were passed by males in the field. We then calculated how much faster these females would have been detected if they had taken off and approached these males, using probabilities of detection as a function of passing distance derived from field observations on C. tullia females. C. pamphilus females on average lost 201 min by not approaching males on their way to leks. To estimate what this time loss meant in terms of fitness, we measured how the age at mating affected fecundity. Using field measures of fecundity and mortality, the time loss translated into an average 2.8% reduction in fecundity as a best estimate, and an average 1.3% reduction in fecundity as a lower estimate. This fitness cost is larger than has been reported earlier for a lekking bird, but is probably too small to eliminate the possibility of indirect benefits of mating with males on leks. Received: 15 August 1996 / Accepted after revision: 24 January 1997     

A Retrospective Isotopic Study of Spruce Decline in the Vosges Mountains (France)

The objective of this study was to assess the time variation of mineral and water stress levels across the life of a declining, Mg-deficient, spruce stand, in order to clarify the factors that caused the decline. Since 1985, strong soil acidification linked to a large leaching of nitrate and base cations was measured at the study site. In 1994, 5 trees were felled and tree rings were measured and analysed for Ca, Mg, K, Sr, ¹³C¹²C and ⁸⁷Sr/⁸⁶Sr isotopic ratios. Strontium pools and fluxes as well as root Sr isotope ratio in relation to depth were also measured. Wood chemical concentrations and isotope ratios were strongly related to the dominance status of each tree. On average during the study period, the ⁸⁷Sr/⁸⁶Sr ratio of spruce wood decreased. Using a mechanistic model computing long term variations of ⁸⁷Sr/⁸⁶Sr ratio in trees and soils, we reproduced the observed trend by simulating soil acidification – increasing Sr drainage from the whole profile, and particularly from the organic horizon –, and root uptake becoming more superficial with time. Between 1952 and 1976, tree ring ¹³C decreased strongly and continuously, which, in addition to other factors, might be related to an increase in water stress. Thus, a decrease in rooting depth, possibly related to soil acidification, appeared as a possible cause for the long term increase in water stress. The extreme drought event of 1976 appears to have revealed and triggered the decline.     

Latent effect of soil organic matter oxidation on mercury cycling within a southern boreal ecosystem

The focus of this study is to investigate processes causing the observed spatial variation of total mercury (THg) in the soil O horizon of watersheds within the Superior National Forest (Minnesota) and to determine if results have implications toward understanding long-term changes in THg concentrations for resident fish. Principal component analysis was used to evaluate the spatial relationships of 42 chemical elements in three soil horizons over 10 watersheds. Results indicate that soil organic carbon is the primary factor controlling the spatial variation of certain metals (Hg, Tl, Pb, Bi, Cd, Sn, Sb, Cu, and As) in the O and A soil horizons. In the B/E horizon, organic carbon appeared to play a minor role in metal spatial variation. These characteristics are consistent with the concentration of soil organic matter and carbon decreasing from the O to the B/E horizons. We also investigated the relationship between percent change in upland soil organic content and fish THg concentrations across all watersheds. Statistical regression analysis indicates that a 50% reduction in age-one and age-two fish THg concentration could result from an average 10% decrease in upland soil organic content. Disturbances that decrease the content of THg and organic matter in the O and A horizons (e.g., fire) may cause a short-term increase in atmospherically deposited mercury but, over the long term, may lead to decreased fish THg concentrations in affected watersheds.