A combined GIS-MCDA approach to prioritize stream water quality interventions, based on the contamination risk and intervention complexity.

Water management decisions are complex ever since they are dependent on adopted politics, social objectives, environmental impacts, and economic determinants. To adequately address hydric resources issues, it is crucial to rely on scientific data and models guiding decision-makers. The present study brings a new methodology, consisting of a combined GIS-MCDA, to prioritize catchments that require environmental interventions to improve surface water quality. A Portuguese catchment, Ave River Basin, was selected to test this methodology due to the low water quality. First, it was calculated the contamination risk of each catchment, based on a GIS-MCDA using point source pressures, landscape metrics, and diffuse emissions as criteria. This analysis was compared to local data of ecological and chemical status through ANOVA and the Tukey test. The results showed the efficiency of the method since the contamination risk was lower for catchments under a good status and higher in catchments with a lower classification. In a second task, it was calculated the intervention complexity using a different GIS-MCDA. For this approach, it was chosen five criteria that condition environmental interventions, population density, slope, percentage of burned areas, Strahler order, and the number of effluent discharge sites. Both multicriteria methods were combined in a graphical analysis to rank the catchments intervention priority, subdividing the prioritization into four categories from 1st to 4th, giving a higher preference for catchments with high contamination risk and low intervention complexity. As a result, catchments with a good status were dominantly placed under low intervention priority, and catchments with a lower ecological status were classified as a high priority, 1st and 2nd. In total, 248 catchments were spatially ranked, which is an essential finding for decision-makers, that are willing to safeguard the catchment water quality.

A structural equation model to predict macroinvertebrate-based ecological status in catchments influenced by anthropogenic pressures.

A Partial Least Squares-Path Model (PLS-PM) was developed for the Ave River Basin (North of Portugal), and the results used in a scenario analysis. The data for PLS-PM comprised a set of anthropogenic pressures, water quality parameters, and a macroinvertebrate-based biodiversity index (IPtIN) used to assess the ecological status of streams. These groups of measured parameters (called latent variables) were given the names "Pressures", "Contamination" and "Ecological Integrity". Besides, latent variables were connected through path coefficients representing potential causal effects among them. In a large portion of Ave the ecological status of streams is currently bad or poor. Nitrate and coliforms were the most weighted measured variables of latent variable "Contamination", with w ≈ 0.7 and w ≈ 0.2, respectively. The highest "Pressures" weights were ascribed to livestock farming (0.7) and population density (0.4). The connections "Pressures"-"Contamination" and "Contamination" - "Ecological Integrity" exposed a sequence of direct negative effects between the three variables, expressed in the corresponding path coefficients (pc = 0.87 and pc = -1.11). Paradoxically, a direct negative effect of "Pressures" over "Ecological Integrity" was absent (pc = 0.29). Therefore, the poor ecological status of local stream waters might not be directly related to the presence of potentially threatening contaminant sources (the "Pressures"), but to ineffective monitoring of livestock farming and wastewater treatment activities that potentiate (accidental) releases of contaminants into the streams. The lack of a direct link "Pressures" - "Ecological Integrity" supported the results of pressure change versus IPtIN change scenarios. Regardless of some significant reductions of anthropogenic activity and population density until 2027, announced by the Portuguese Environmental Agency, the scenarios could not predict improvement of ecological status beyond the "moderate" category. The study recommendations were therefore to prevent contamination through proper implementation and monitoring of existing watershed management plans. The adequate treatment of domestic effluents and the control of livestock farming residues are urgent.

Electron scattering from 1-butanol at intermediate impact energies: Total cross sections.

We report experimental measurements of the absolute total cross sections (TCSs) for electron scattering from 1-butanol at impact energies in the range 80-400 eV. Those measurements were conducted by considering the attenuation of a collimated electron beam, at a given energy, through a gas cell containing 1-butanol, at a given pressure, and through application of the Beer-Lambert law to derive the required TCS. We also report theoretical results using the Independent-Atom Model with Screening Corrected Additivity Rule and Interference approach. Those results include the TCS, the elastic integral cross section (ICS), the ionization total ICS, and the sum over all excitation process ICSs with agreement at the TCS level between our measured and calculated results being encouraging.

A partial least squares - Path modeling analysis for the understanding of biodiversity loss in rural and urban watersheds in Portugal.

The main purpose of this study was to use Partial Least Squares - Path Modeling (PLS-PM) to quantify the contributions of natural and human-induced threats to biodiversity loss in rural and urban watersheds. The study area comprised the Sabor and Ave river basins, located in northern Portugal. The Sabor is rural and sparsely populated while the Ave is urbanized, industrialized and densely populated. Within PLS-PM, threats are called exogenous latent variables while the ultimate environmental consequence (biodiversity loss) is termed endogenous latent variable. Latent variables are concepts represented by numerical parameters called formative variables. The selected latent variables were given the names "pressures", "contamination" and "ecological integrity". The most important "pressures" were the wildfire risk, the percentage of urban area in sub-catchments, the diffuse emissions of livestock nitrogen (N) and agriculture/forest phosphorus (P), and the point source emissions of urban N, P and biochemical oxygen demand, as well as of industrial N. The latent variable called "contamination" was primarily represented by stream water concentrations of phosphate, suspended solids and dissolved oxygen. And finally, the "ecological integrity" was represented by the he North Invertebrate Portuguese Index. The results unequivocally showed that point source emissions in the Sabor (except industrial N) and stream water contamination in the Ave determine biodiversity loss. These contrasting influences suggest that Ave basin has evolved from a catchment where man once produced localized negative effects on stream ecological integrity (a condition still observed in the Sabor basin) to a catchment where the dense human occupation has covered the entire area with urban contaminant sources, somewhat generalizing the local effects. The attribution of local effects to biodiversity loss in the rural catchment and of regional effects in the urban catchment is confirmed by the results of a study covering the entire planet.