Permeability predictions for sand-clogged Portland cement pervious concrete pavement systems

Pervious concrete is an alternative paving surface that can be used to reduce the nonpoint source pollution effects of stormwater runoff from paved surfaces such as roadways and parking lots by allowing some of the rainfall to permeate into the ground below. This infiltration rate may be adversely affected by clogging of the system, particularly clogging or covering by sand in coastal areas. A theoretical relation was developed between the effective permeability of a sand-clogged pervious concrete block, the permeability of sand, and the porosity of the unclogged block. Permeabilities were then measured for Portland cement pervious concrete systems fully covered with extra fine sand in a flume using simulated rainfalls. The experimental results correlated well with the theoretical calculated permeability of the pervious concrete system for pervious concrete systems fully covered on the surface with sand. Two different slopes (2% and 10%) were used. Rainfall rates were simulated for the combination of direct rainfall (passive runoff) and for additional stormwater runoff from adjacent areas (active runoff). A typical pervious concrete block will allow water to pass through at flow rates greater than 0.2 cm/s and a typical extra fine sand will have a permeability of approximately 0.02 cm/s. The limit of the system with complete sand coverage resulted in an effective system permeability of approximately 0.004 cm/s which is similar to the rainfall intensity of a 30 min duration, 100-year frequency event in the southeastern United States. The results obtained are important in designing and evaluating pervious concrete as a paving surface within watershed management systems for controlling the quantity of runoff.     

Field comparison of three inhalable samplers (IOM, PGP-GSP 3.5 and Button) for welding fumes

Inhalable sampler efficiency depends on the aerodynamic size of the airborne particles to be sampled and the wind speed. The aim of this study was to compare the behaviour of three personal inhalable samplers for welding fumes generated by Manual Metal Arc (MMA) and Metal Active Gas (MAG) processes. The selected samplers were the ones available in Spain when the study began: IOM, PGP-GSP 3.5 (GSP) and Button. Sampling was carried out in a welding training center that provided a homogeneous workplace environment. The static sampling assembly used allowed the placement of 12 samplers and 2 cascade impactors simultaneously. 183 samples were collected throughout 2009 and 2010. The range of welding fumes' mass concentrations was from 2 mg m(-3) to 5 mg m(-3). The pooled variation coefficients for the three inhalable samplers were less than or equal to 3.0%. Welding particle size distribution was characterized by a bimodal log-normal distribution, with MMADs of 0.7 μm and 8.2 μm. For these welding aerosols, the Button and the GSP samplers showed a similar performance (P = 0.598). The mean mass concentration ratio was 1.00 ± 0.01. The IOM sampler showed a different performance (P < 0.001). The mean mass concentration ratios were 0.90 ± 0.01 for Button/IOM and 0.92 ± 0.02 for GSP/IOM. This information is useful to consider the measurements accomplished by the IOM, GSP or Button samplers together, in order to assess the exposure at workplaces over time or to study exposure levels in a specific industrial activity, as welding operations.     

Application of water quality indices and analysis of the surface water quality monitoring network in semiarid North-Central Chile

Surface water quality has increasing importance worldwide and is particularly relevant in the semiarid North-Central Chile, where agriculture and mining activities are imposing heavy pressure on limited water resources. The current study presents the application of a water quality index in four watersheds of the 29°-33°S realm for the period 1999-2008, based on the Canadian Council of Ministers for the Environment approach and the Chilean regulation for irrigation water quality. In addition, two modifications to the index are tested and a comprehensive characterization of the existing monitoring network is performed through cluster analysis. The basins studied show fairly good water quality in the overall, specially the Limarí basin. On the other hand, the lower index values were obtained for the headwaters of Elqui, associated with the El Indio mining district. The first modification of the indicator (i.e., to consider parameters differentially according to their effect on human health or the environment) did not produce major differences with respect to the original index, given the generally good water quality. The second modification (i.e., to consider as threshold values the more restrictive figures derived from a set of regulations) yielded important differences in the indicator values. Finally, an adequate characterization of the monitoring network was obtained. The results presented spatial coherence and the information can be used as a basis for the optimization of the monitoring network if required.     

Cadmium and lead in bovine milk in the mining area of the Caudal River (Spain)

The levels of cadmium and lead in 36 raw bovine milk samples were analysed. These samples come from seven farms with a semi-extensive grazing system and were collected between the autumn of 2007 and the winter of 2008. All the farms were located in Asturias (Spain), a zone of great industrial and mining activity in the proximities of the Caudal River. The samples were collected in sterile precleaned polypropylene tubes and frozen until the analysis. After a lyophilization process, the samples were treated with nitric acid and microwave treatment. Cadmium and lead determinations were carried out using inductively coupled plasma mass spectrometry with sensibility under 0.2 ppb for liquid matrix. The lead content was found to vary from 0.71 to 16.06 μg/kg wet weight (w.w.), and the cadmium was lower than 2 μg/kg w.w. The levels of lead in milk are higher in those farms near zones of storage of mining waste depots, thermal power and areas with high levels of traffic. All the values found are in concordance with research carried out at non-polluted areas, and those for the lead are well below the European Union limitations.     

Effects of spatial and temporal scales on cultural services valuation

The monetary valuation of ecosystem services has proved to be a powerful tool for influencing management decisions, as it can be used to quantify the relative importance of various ecosystem functions. However, these valuation methods are rarely implemented with adequate care; in particular, they do not consider spatial and temporal variations in the services offered and demanded. This paper examines the effect of heterogeneity on the valuation of cultural services offered by the Doñana natural protected area in Spain. We apply the zonal travel cost method at various spatial scales, and the individual travel cost method at various temporal scales. We conclude that economic valuation techniques must account for spatial and temporal heterogeneity if they are to provide accurate and realistic information.     

Nutrients and nonessential elements in soil after 11 years of wastewater irrigation

Irrigation of citrus (Citrus aurantium L. × Citrus paradise Macf.) with urban reclaimed wastewater (RWW) can be economical and conserve fresh water. However, concerns remain regarding its deleterious effects on soil quality. We investigated the ionic speciation (ISP) of RWW and potential impacts of 11 yr of irrigation with RWW on soil quality, compared with well-water (WW) irrigation. Most of nutrients (～53-99%) in RWW are free ionic species and readily available for plant uptake, such as: NH(4+), NO(3-), K(+), Ca(2+), Mg(2+), SO(4)(2-), H(3)BO(3), Cl(-), Fe(2+), Mn(2+), Zn(2+), Co(2+), and Ni(2+), whereas more than about 80% of Cu, Cr, Pb, and Al are complexed with CO(3-), OH(-), and/or organic matter. The RWW irrigation increased the availability and total concentrations of nutrients and nonessential elements, and soil salinity and sodicity by two to three times compared with WW-irrigated soils. Although RWW irrigation changed many soil parameters, no difference in citrus yield was observed. The risk of negative impacts from RWW irrigation on soil quality appears to be minimal because of: (i) adequate quality of RWW, according to USEPA limits; (ii) low concentrations of metals in soil after 11 yr of irrigation with RWW; and (iii) rapid leaching of salts in RWW-irrigated soil during the rainy season.     

Factors influencing local ecological knowledge maintenance in Mediterranean watersheds: Insights for environmental policies

Local ecological knowledge (LEK) has been found to be one of the main bridges to manage biocultural diversity. We analyzed the factors affecting LEK maintenance and transmission in a Mediterranean watershed. We used a mixed methods approach to evaluate the agricultural LEK in three different dimensions: biological, soil and water management, and forecasting. We found that the main factors for its maintenance were the respondent''s time living in the area and the social relationships established among farmers, which involved partner collaboration and farmer information exchanges. Protected areas also played a key role for maintaining the LEK associated with soil and water management. Finally, we found that outmigration and mechanization were the most important indirect drivers of change underlying LEK erosion. We suggest that environmental policies should focus on promoting this experiential knowledge, considering both intergenerational renewal and the gendered aspects of this knowledge.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0556-1) contains supplementary material, which is available to authorized users.     

Determining the Feasibility of Establishing New Multiple-Use Marine Protected Areas in Chile

This paper evaluates the feasibility of establishing a multiple-use marine protected area. The methodology was applied to evaluate three proposed sites in Chile with diverse conservation needs, social stress and poverty levels, and different economic activities (small-scale fishing, heavy industry, and mining activities). We use two broad categories for the evaluation: socio-economic and political–institutional. The methodology uses a combination of secondary data with personal interviews, workshops, and focus groups with stakeholders (e.g., fishermen, unions, politicians, social organizations) from different political, social, and economic backgrounds to characterize current and potential natural and social resources and to evaluate in an ordinal scale the feasibility of establishing the protected area. The methodology allows us to correctly identify the challenges faced in each site and can be used to develop appropriate strategies for balancing economic, social, and environmental objectives. This methodology can be replicated to evaluate the feasibility of other marine or terrestrial protected areas.     

Dioxin emissions from thermal waste management in Medellín, Colombia: present regulation status and preliminary results

Preliminary results of a study undertaken to characterize dioxin and furan releases from waste incineration plants operating in Medellín-Colombia are presented. Emission and fly ash samples were collected from representative plants burning medical and industrial residues to characterize PCDD/PCDF levels. Analyses were carried out following European standards for stationary gas emissions EN-1948:1996 and US EPA 1613 (fly ashes). Final extracts were analyzed by both high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC-HRMS) and high resolution gas chromatography coupled to ion trap tandem mass spectrometry (HRGC-ITMS/MS). Preliminary results revealed emission levels of 1-30.3 ng I-TEQ/Nm3 depending on whether or not an air pollution control system (APCS) was installed. Fly ashes contained 8.5-68 ng I-TEQ/g. Critical issues that should be addressed in an assessment and in developing waste management plans in Colombia are discussed.     

Eutrophication trends in forest soils in Galicia (NW Spain) caused by the atmospheric deposition of nitrogen compounds

We calculated the sensitivity of Galician forest soils to eutrophication caused by atmospheric deposition of nitrogen compounds, using the Simple Mass Balance (SMB) method as described by [Posch, M., de Vries, W., Hettelingh, J.-P., 1995. Critical loads of sulphur and nitrogen. In: Posch, M., de Smet, P.A.M., Hettelingh, J.-P., Downing, R.J. Calculation and Mapping of Critical Thresholds in Europe. Status Report 1995, Coordination Center for Effects, National Institute for Public Health and the Environment, Bilthoven, The Netherlands, pp. 31-42]. Deposition values were used to calculate critical loads exceedance. Galician natural forest ecosystems can support nitrogen deposition loads of more than 10 kg Nha (-1) yr (-1). The lowest critical loads (approximately 10 kg Nha (-1) yr (-1)) mainly occurred in forest stands in the interior zone, while highest critical load values (approximately 68 kg Nha (-1) yr (-1)) were observed in eucalyptus stands at low altitudes in the littoral area. Exceedances based on N deposition levels, calculated from data recorded in 2001, occurred in 40% of the forest soils, showing the need to control N emissions in these areas to prevent possible eutrophication of soils and waters. Analysis of rainfall bulk composition revealed that ammonium, probably derived from agricultural and cattle activities, was the main compound responsible for N deposition in Galicia.