Voluntary environmental management systems (EMS) based on the international standard ISO 14001 have become widespread globally in recent years. The purpose of this study is to assess the impact of voluntary management systems on energy efficiency in the Swedish manufacturing industry by means of objective industrial energy data derived from mandatory annual environmental reports. The study focuses on changes in energy efficiency over a period of 12 years and includes both ISO 14001-certified companies and non-certified companies. Consideration is given to energy improvement efforts in the companies before the adoption of ISO 14001. The analysis has been carried out using statistical methods for two different industrial energy parameters: electricity and fossil fuel consumption. The results indicate that ISO 14001 adoption and certification has increased energy efficiency regarding the use of fossil fuel. In contrast, no effect of the management systems has been found concerning the use of electricity. The mixed results of this study are only partly in line with the results of previous studies based on perceptions of company representatives

Voluntary industrial environmental management initiatives such as management systems based on the international standard ISO 14001has been widely spread over the world in recent years. Previous research on the influence of these systems relies heavily on how the benefits of the systems are perceived by companies’ representatives. Additionally, most studies tend to focus on the impact on the overall environmental performance of the companies, not identifying differences in different environmental aspects. The purpose of this paper is to explore the impact of voluntary environmental management systems on energy efficiency in Swedish manufacturing industry by means of objective industrial waste data derived from mandatory annual environmental reports. The study focuses on changes in energy efficiency over a period of 12 years and includes both ISO 14001-certified companies (66 companies) and non-certified firms (50 companies). Consideration is given to energy improvement efforts in the companies before ISO 14001 adoption. Analysis has been carried out using statistical methods for two different industrial energy parameters: electricity and fossil fuel consumption. The results indicate that ISO 14001 adoption has an impact on the energy efficiency regarding the use of fossil fuel. In contrast no impact has been found concerning the use of electricity.

Purpose: Stormwater discharges include contaminated sediments that accumulate in the receiving water body. It is thus important to investigate sediment and pollutant processes and pathways from the catchment to, and within, the receiving water. These processes may be influenced by seasonal changes. The objective of this study was to investigate the stormwater impact on receiving waters in the Luleå area, Northern Sweden; seasonal changes in contamination loads in the receiving waters due to snowmelt; and factors influencing the pollutant pathways in the receiving waters.

Materials and methods: In front of three storm sewer outlets in Luleå, samples of bottom sediment (surface layer 0-2 cm) were collected from the connecting ditches and the downstream water body in autumn and spring (before and after the snow season 2009/2010). The characteristics of the receiving waters differed in geomorphology and vegetation. The sediment was analyzed for loss-on-ignition (LOI), grain size, and bulk concentrations of SiO 2, Al 2O 3, CaO, Fe 2O 3, MnO, Na 2O, P 2O 5, TiO 2, As, Cd, Co, Cr, Cu, Hg, Ni, Pb, S, V, and Zn. The sediment contamination was compared to concentrations at a reference point in Luleå where the bottom sediment was not affected by stormwater discharges and with Swedish environmental quality guidelines. Pearson's correlation and a principal component analysis were used to further evaluate the results.

Results and discussion: Relative to the reference point, elevated trace metal concentrations were detected in sediments at all three sampling stations. At two of the stations, seasonal variations in ditch sediment grain size, LOI, and contaminant concentrations were observed, originating from stormwater sediment. Snowmelt runoff caused an increased proportion of fine-grained sediment fractions (<0.063 mm) in spring, mainly due to changes in runoff intensity and high sediment loads in the snowmelt runoff. The retention of metals appeared to be due to low turbulence in the water and the presence of organic material.

Conclusions: Stormwater discharge affected the contaminant concentrations in the bottom sediments. The observed seasonal variation of contaminants indicated that relatively high amounts of contaminants are discharged during snowmelt and then reallocated within the receiving water body, either directly or after some temporal retention, depending on the characteristics of the receiving water. A calm water column and the presence of organic material in the receiving water body were crucial for the retention of metals.

In this paper, preliminary results of a study investigating the impact of stormwater discharges on the bottom sediment of stormwater recipients in Luleå, northern Sweden are presented. The aim was to evaluate sediment metal concentrations taken in front of stormwater sewer discharge points from two ditches/recipients, their seasonal variation and the influence of geomorphology and vegetation on the metal distribution. Compared with northern Sweden background values, the Cd, Cu, Pb and Zn concentrations in the sediment samples were elevated. However, besides stormwater discharges, local sulphide soils in the catchment areas can affect the metal concentrations. Partly, seasonal variations in the metal concentrations were noticed; higher metal concentrations were observed in spring associated with a high LOI content and large fractions of fine grain size particles (<0.125 mm). Low/no runoff in winter and metal accumulation in snow followed by continuous snow melt runoff transports mostly fine grain sizes and therewith associated metals, which then settle and accumulate in the ditches/recipients. Dense reed vegetation can retain coarse grain sizes and supplies the sediment with decomposing organic material. Decomposition processes affect the redox conditions in the sediment through oxygen consumption. In the reduced sediment metals can be trapped in combination with sulphide formation.