Environmental consideration in procurement of construction contracts: current practice,problems and opportunities in green procurement in the Swedish construction industry

Research and initiatives concerning green procurement have to a great extent focused on products. This article, however, explores the current practice, problems and opportunities of green procurement of construction contracts. In particular, the application of environmental criteria for contract awarding is targeted. The findings of the study indicate that both public and private clients in the Swedish construction industry take environmental issues into consideration in their procurements. The environmental preferences are often formulated as environmental requirements. However, environmental criteria in tender evaluation are less common and seldom affect the award decisions. The environmental evaluation criteria that do occur often relate to the contractors' capabilities of managing the environmental work in the project.     

Estimating catchment nutrient flow with the HBV-NP model: sensitivity to input data

The dynamic catchment model HBV-N has been further developed by adding routines for phosphorus transport and is now called the HBV-NP model. The model was shown to satisfactorily simulate nutrient dynamics in the R?nne? catchment (1,900 km2). Its sensitivity to input data was tested, and results demonstrated the increased sensitivity to the selection of input data on a subcatchment scale when compared with the catchment scale. Selection of soil and land use databases was found to be critical in some subcatchments but did not have a significant impact on a catchment scale. Although acceptable on a catchment scale, using templates and generalization, with regards to emissions from point sources and rural households, significantly decreased model performance in certain subcatchments when compared with using more detailed local information. A division into 64 subcatchments resulted in similar model performance at the catchment outlet when compared with a lumped approach. Adjusting the imported matrixes of the regional leaching of nitrogen, from agricultural land, against mean subcatchment water percolation did not have a significant impact on the model performance.     

Modeling the response of eutrophication control measures in a Swedish lake

The response of a biogeochemical lake model (BIOLA) to different eutrophication management actions has been studied in a eutrophic lake. Management actions included in the study were nutrient load reduction, sediment manipulation, biomanipulation, and herbicide application. The model was used to simulate nutrient and biomass concentrations in the lake during the 1990s. During the same period, management scenarios were also simulated. Several ecological parameters were calibrated to better simulate the behavior of the chosen lake, but there were still some difficulties with phosphate. This indicated that further model development is necessary. The most favorable development within the lake was found for scenarios with nutrient load reduction and biomanipulation through planktivorous fish reduction. Reducing both the nitrogen and phosphorus loads had a greater effect on the lake's water quality than simply reducing just one of the nutrients.     

Variance in female quality, operational sex ratio and male mate choice in a bushcricket

Male bushcrickets, Kawanaphila nartee, exercise mate choice when nutrients are limited. Male mate choice is associated with a female-biased operational sex ratio (OSR) that arises from an increased relative paternal investment under nutrient limitation. However, increased male choosiness could be attributable to the fact that females vary more in fecundity, and consequently in mate quality, when nutrient limited. Our objective was to experimentally partition the influences of OSR (male or female bias) and variance in mate quality (high or low) and to assess their relative influence on the intensity of mate choice by male bushcrickets. Female quality was manipulated by controlled feeding regimes that directly affected female fecundity. We found that males and females engaged in sexual interactions sooner under a male-biased than a female-biased OSR. Males were more likely to reject females on their first encounter when variance in female quality was high. However, the effect of quality variance on the total number of rejections during a 4-h observation period was dependent on the perceived OSR. A male's prior experience of variance in female quality did not influence male choosiness. Our observed rates of mate rejection conformed well with those predicted from recent theoretical models of sexual differences in choosiness. In conclusion, our results show that the opportunity for selection via male mate choice is influenced by an interaction between OSR and the variance in mate quality that arises within nutrient-limited populations of females. Received: 5 January 1998 / Accepted after revision: 25 October 1998     

EIA and green procurement: Opportunities for strengthening their coordination

EIA plays an important role in enhancing the environmental performance of the construction sector. In recent years, the construction sector has been developing green procurement practices. Green procurement is a process that involves the incorporation of environmental requirements during the procurement of services and products. However, discussion on green procurement is rarely seen during the EIA phase. This paper addresses possible opportunities for improving the coordination between EIA and green procurement within the construction sector. The linking of EIA and green procurement has been postulated in the paper as an aid to strengthen the coordination between project planning and implementation. The paper is based on a literature review and is an outcome of an on-going research project concerning EIA and green procurement. This study indicated that it would be appropriate to introduce green procurement during the pre-decision phase of an EIA. In the present study, the opportunities for integrating green procurement at the stage of EIA are associated with the integration of project planning and EIA. Future research should investigate the mechanism through which the link can be established.     

Modelling Dissolved Organic Carbon Turnover in Humic Lake Örträsket, Sweden

The organic carbon balance of a lake with high input of allochthonous organic carbon is modelled integrating physical, chemical and biological processes. The physical model captures the behaviour of real thermal stratification in the lake for different flow situations during the period 1993–1997. The dissolved organic carbon model is based on simulated trajectories of water parcels. By tracking parcels, account is kept of environmental factors such as temperature and radiation as well as DOC quality for each parcel. The DOC concentration shows seasonal variations primarily dependent on inflow. The organic matter degradation (bacterial- and photodegradation) in the lake amounts to 1.5–2.5 mg C l^–1 yr^–1, where photooxidation is responsible for approximately 10%. The estimated DIC production in the lake is large compared to sediment mineralisation and primary production. The main conclusion is that the model with the selected parameterisations of the degradation processes reasonably well describes the DOC dynamics in a forest lake.