Contamination from agricultural sources and, in particular, nitrate pollution, is one of the main concerns in groundwater management. However, this type of pollution entails the entrance of other substances into the aquifer, as well as it may promote other processes. In this study, we deal with hydrochemical and isotopic analysis of groundwater samples from four distinct zones in Catalonia (NE Spain), which include 5 different aquifer types, to investigate the influence of fertilization on the overall hydrochemical composition of groundwater. Results indicate that intense fertilizer application, causing high nitrate pollution in aquifers, also homogenize the contents of the major dissolved ions (i.e.; Cl(-), SO4(2-), Ca(2+), Na(+), K(+), and Mg(2+)). Thus, when groundwater in igneous and sedimentary aquifers is compared, significant differences are observed under natural conditions for Cl(-), Na(+) and Ca(2+) (with p-values ranging from <0.001 to 0.038), and when high nitrate concentrations occur, these differences are reduced (most p-values ranged between 0.054 and 0.978). Moreover, positive linear relationships between nitrate and some ions are found indicating the magnitude of the fertilization impact on groundwater hydrochemistry (with R(2) values of 0.490, 0.609 and 0.470, for SO4(2-), Ca(2+) and Cl(-), respectively). Nevertheless, the increasing concentration of specific ions is not only attributed to agricultural pollution, but to their enhancing effect upon the biogeochemical processes that control water-rock interactions. Such results raise awareness that these processes should be evaluated in advance in order to assess an adequate groundwater resources management.Peer ReviewedPostprint (author's final draft

The aim of this study is to develop and validate a brief measure of self-efficacy specifically for use with people with multiple sclerosis (MS). Self-efficacy is the subjective belief that one can overcome challenges that one is faced with. In order to incorporate the subjective experiences of individuals with MS, a 'patient-focused' methodology has been adopted. Open-ended interviews were used to generate potential scale items. Items were piloted on an initial sample of individuals with MS and reduced to 14 items on the basis of their perceived relevance to this patient group. The final 14-item scale was then used with a further 142 individuals in order to assess its psychometric properties. The scale demonstrated high internal consistency (Cronbach's alpha = 0.81) and test-retest reliability (r = 0.81, P < 0.001) and acceptable validity. Issues concerning the assessment of validity are discussed in terms of the scale's relevancy to individuals with MS and the theoretical issues around the construct of self-efficacy. The scale has shown sensitivity to detect change following a brief therapeutic intervention, with an effect size of 0.502. This MS Self-efficacy Scale could, therefore, be a useful tool in the assessment of psychological adjustment and quality-of-life of individuals with MS.

To use compound-specific isotope analysis for confidently assessing organic contaminant attenuation in the environment, isotope fractionation patterns associated with different transformation mechanisms must first be explored in laboratory experiments. To deliver this information for the common groundwater contaminant chloroform (CF), this study investigated for the first time both carbon and chlorine isotope fractionation for three different engineered reactions: oxidative C-H bond cleavage using heat-activated persulfate, transformation under alkaline conditions (pH ∼ 12) and reductive C-Cl bond cleavage by cast zerovalent iron, Fe(0). Carbon and chlorine isotope fractionation values were -8 ± 1‰ and -0.44 ± 0.06‰ for oxidation, -57 ± 5‰ and -4.4 ± 0.4‰ for alkaline hydrolysis (pH 11.84 ± 0.03), and -33 ± 11‰ and -3 ± 1‰ for dechlorination, respectively. Carbon and chlorine apparent kinetic isotope effects (AKIEs) were in general agreement with expected mechanisms (C-H bond cleavage in oxidation by persulfate, C-Cl bond cleavage in Fe(0)-mediated reductive dechlorination and E1 elimination mechanism during alkaline hydrolysis) where a secondary AKIE (1.00045 ± 0.00004) was observed for oxidation. The different dual carbon-chlorine (ΔδC vs ΔδCl) isotope patterns for oxidation by thermally activated persulfate and alkaline hydrolysis (17 ± 2 and 13.0 ± 0.8, respectively) vs reductive dechlorination by Fe(0) (8 ± 2) establish a base to identify and quantify these CF degradation mechanisms in the field.

No abstract

No abstract