Comparison of static and mineralogical ARD prediction methods in the Nordic environment

Acid rock drainage (ARD) is a major problem related to the management of mining wastes, especially concerning deposits containing sulphide minerals. Commonly used tests for ARD prediction include acid–base accounting (ABA) tests and the net acid generation (NAG) test. Since drainage quality largely depends on the ratio and quality of acid-producing and neutralising minerals, mineralogical calculations could also be used for ARD prediction. In this study, several Finnish waste rock sites were investigated and the performance of different static ARD test methods was evaluated and compared. At the target mine sites, pyrrhotite was the main mineral contributing to acid production (AP). Silicate minerals were the main contributors to the neutralisation potential (NP) at 60% of the investigated mine sites. Since silicate minerals appear to have a significant role in ARD generation at Finnish mine waste sites, the behaviour of these minerals should be more thoroughly investigated, especially in relation to the acid produced by pyrrhotite oxidation. In general, the NP of silicate minerals appears to be underestimated by laboratory measurements. For example, in the NAG test, the slower-reacting NP-contributing minerals might require a longer time to react than is specified in the currently used method. The results suggest that ARD prediction based on SEM mineralogical calculations is at least as accurate as the commonly used static laboratory methods.     

Emergent publics and affects in environmental governance

Drawing on the wide social scientific literature on emotions and affects, we highlight the value and potential contribution of the affect theory for understanding public engagement in environmental policy and planning. We suggest that such theorization complements political ontologies that envision concerned publics to arise as citizens are attached to objects and other beings in their everyday life. Focus on emotions and affects enables in-depth exploration of the corporeality of these attachments, increasing understanding about how affected publics get driven for action and how new sensibilities and horizons for action are created. Based on the discussion of affect theory and case examples, we argue that emotions and affects should be treated as crucial carriers of knowledge about transformation of political subjects and their concerns. They also direct analytic gaze beyond public participation procedures and encourage the development of novel, more inclusive settings for public engagement.     

Degradation of 1,2-dichloroethane from wash water of ion-exchange resin using Fenton’s oxidation

Background, aim, and scope  

Chlorinated volatile organic compounds (CVOCs), widely used in industry as solvents and chemical intermediates in the production of synthetic resins, plastics, and pharmaceuticals, are highly toxic to the environment and public health. Various studies reported that Fenton’s oxidation could degrade a variety of chlorinated VOCs in aqueous solutions. In acidic conditions, ferrous ion catalyzes the decomposition of H₂O₂ to form a powerful ^•OH radical. In this study, wastewater from wash of ion-exchange resin containing typical CVOC, 1,2-dichloroethane, was treated using Fenton’s oxidation. To reduce environmental load and processing costs of wastewater, Fenton process as a simple and efficient treatment method was applied to degrade 1,2-dichloroethane of wash water.     

Bleached kraft pulp mill discharged organic matter in recipient lake sediment

Environmental properties of organic matter contained halogen and sulfur were studied in sediments of bleached kraft pulp mill effluent (BKME) recipient lakes and 2 m³ outdoor enclosures (mesocosms). The BKME contributed to 1% (v/v) of the total water flow in the lake downstream of the pulp mill where the sediments contained 1.7 to 4 mg of tetrahydrofuran extractable organic halogen (EOX-Cl) and 0.6 to 0.8 mg of tetrahydrofuran extractable organic sulfur (EOS-S) g⁻¹ of organic matter. Upstream sediment contained 0.03 mg of EOXCl and 0.7 mg of EOS-S g⁻¹ of organic matter. EOX was a better indicator for the influence of BKME in the recipient sediment than EOS. The polarity of BKME contained EOX corresponded to log K^ow of < 1, and that of the downstream sediment contained EOX to > 4.5. HP-SEC analysis of the molecular weight distribution (MWD) of the EOX showed a peak between 300 to 600 g mol⁻¹ for the BKME and between 1000 to 2000 g mol⁻¹ for the downstream sediment. The MWD of the BKME contained EOS peaked at 300 to 1000 g mol⁻¹, and that of the downstream sediment contained EOS at 1000 to 5000 g mol⁻¹. These results indicate that BKME contained organic halogen and sulfur undergo major structural transformations when incorporated into sediment. The biota-to-sediment accumulation factor (BSAF) of EOX from sediments formed downstream of the mill and in the mesocosms to the lipids ofLumbriculus variegatus was 0.4 to 0.7. This is of a similar order of magnitude to the BSAF reported for 2,3,7,8-tetrachlorodibenzop-dioxin and 2,3,7,8-tetrachlorodibenzofuran.     

Managing Biodiversity in a Forestry Environment

In forest management and other land-use planning, ecological, social, and economical demands often conflict. Forest planning in particular has been biased towards maximizing economic output while disregarding the ecological effects of forestry practices. In this paper we present an approach for taking biological diversity into account in strategic forest management planning. We used the Analytic Hierarchy Process (AHP) method for resource allocation and priority setting. We carried out a case study, whereby a set of management strategies was evaluated in order to identify the strategy which best fulfills the requirement of maintaining biological diversity while at the same time yielding a reasonable income from timber production. We discuss applicability of the approach in solving different forest management and conservation planning problems, as well as in assessment of ecological impacts.     

Geographical variability in the bioenergetic characteristics of Monoporeia/Pontoporeia spp. populations from the northern Baltic Sea,and their potential contribution to benthic nitrogen mineralization

The physiological condition, determined as the ammonia excretion rate (V NH ₄ ⁺ ), total lipid level and lipid class composition, of two deposit-feeding benthic amphipods, Monoporeia (=Pontoporeia) affinis and Pontoporeia femorata, was studied from 12 opensea stations in the northern Baltic Sea between 24 May and 11 June 1993. The M. affinis populations can be geographically grouped according to their physiological condition: (1) eastern Gulf of Finland, with moderate lipid level (mean 24.4% of dry wt) and high V NH ₄ ⁺ (45.2 mol NH ₄ ⁺ g^-1 dry wt d^-1); (2) Bothnian Sea, wigh high lipid level (34.5%) and low V NH ₄ ⁺ (24.6 mol NH ₄ ⁺ g^-1 dry wt d^-1); and (3) Bothnian Bay, with low lipid level (15.2%) and high V NH ₄ ⁺ (44.3 mol NH ₄ ⁺ dry wt d^-1). A similar pattern could be observed also in the level of triacylglycerols and the neutral-to-polar lipid ratio. P. femorata, the dominating species in the western Gulf of Finland, showed variable station-specific excretion rates (22.3 to 43.0 mol NH ₄ ⁺ g^-1 dry wt d^-1) and lipid levels (23.4 to 30.4%). The spatial variability in the weight-specific V NH ₄ ⁺ of M. affinis could not be explained by the differences in the size of individuals, lipid level or lipid class composition; this emphasizes the significance of the effects of spatially differing nutritional conditions, which manifest themselves as different modes of metabolic energy production and different intensities of energy storage. In addition, the potential contribution of the amphipod populations to benthic nitrogen mineralization was estimated; in May to June, the NH ₄ ⁺ release of different populations ranged from 12 to 237 mol NH ₄ ⁺ m^-2d^-1. In general, populations with high abundance and/or biomass release the greatest amounts of NH ₄ ⁺ , but the values are modified by the physiological condition of the individuals.