Carla S. S. Ferreira

Dynamics of surface water quality driven by distinct urbanization patterns and storms in a Portuguese peri-urban catchment

PurposeAlthough the influences of urban land use on water quality have been widely investigated, the impacts of different urbanization patterns, particularly in Mediterranean environments, are not well understood. Focussing on a Portuguese peri-urban catchment with 40 % urban cover, this paper explores (1) the impact of areas with differing urban extent and storm drainage system on streamwater quality and (2) temporal variations driven by season and storm events of differing magnitude, intensity and antecedent weather.Materials and methodsWater quality was assessed at the catchment outlet (E) and for three upstream tributaries: (1) Porto Bordalo (PB), 39 % urban with a new major road and piping of some overland flow from impervious surfaces directly into the stream; (2) Espírito Santo (ES), 49 % urban, mostly comprising detached houses surrounded by gardens, and with overland flow infiltrating into downslope pervious soils; and (3) Quinta (Q), 22 % urban with partial piping of overland flow from a recent enterprise park area. Water samples were collected at different stages in storm hydrograph responses to ten rainfall events from October 2011 to March 2013. The water quality variables analysed included chemical oxygen demand (COD), nutrients (Kjeldahl nitrogen [Nk-N], ammonium [NH4–N], nitrate [NO3–N] and total dissolved phosphorus (TDP) and heavy metals (Zn and Cu).Results and discussionUrban areas had great impact on COD, with the highest median concentrations in ES and the lowest in Q. In ES, fertilizing lawns and gardens may have been responsible for its higher median NO3–N concentrations. High concentrations of heavy metals were recorded in PB and Q, probably due to the piping of road runoff directly into the stream. Generally, higher pollutant concentrations were recorded in the first storm events after the summer drought due to the flushing of accumulated solutes and a lower dilution effect, with Nk-N and NH4–N exceeding water quality standards. Over the wet season, increasing soil moisture favoured greater flow connectivity between runoff processes from pollutant sources and the stream network, leading to a higher proportion of samples exceeding pollution thresholds.ConclusionsNo direct relationship was identified between urban extent and water quality, possibly due to the overriding impact of different storm drainage systems and flow connectivities of different urban patterns. Hydrological regime, linked to seasonal changes, also exerted a major influence on the water quality dynamics. Information on the spatiotemporal dynamics of pollutants, linked to different urban patterns and storm drainage systems, should help enable urban planners to minimize the adverse impacts of urbanization on aquatic ecosystems.

Assessment of promising agricultural management practices

iSQAPER project - Interactive Soil Quality Assessment in Europe and China for Agricultural Productivity and Environmental Resilience - aims to develop an app to advise farmers on selecting the best Agriculture Management Practice (AMPs) to improve soil quality. For this purpose, a soil quality index has to be developed to account for the changes in soil quality as impacted by the implementation of the AMPs. Some promising AMPs have been suggested over the time to prevent soil degradation. These practices have been randomly adopted by farmers but which practices are most used by farmers and where they are mostly adopted remains unclear. This study is part of the iSQAPER project with the specific aims: 1) map the current distribution of previously selected 18 promising AMPs in several pedo-climatic regions and farming systems located in ten and four study site areas (SSA) along Europe and China, respectively; and 2) identify the soil threats occurring in those areas. In each SSA, farmers using promising AMPs were identified and questionnaires were used to assess farmers perception on soil threats significance in the area. 138 plots/farms using 18 promising AMPs, were identified in Europe (112) and China (26).Results show that promising AMPs used in Europe are Crop rotation (15%), Manuring & Composting (15%) and Min-till (14%), whereas in China are Manuring & Composting (18%), Residue maintenance (18%) and Integrated pest and disease management (12%). In Europe, soil erosion is the main threat in agricultural Mediterranean areas while soil-borne pests and diseases is more frequent in the SSAs from France and The Netherlands. In China, soil erosion, SOM decline, compaction and poor soil structure are among the most significant. This work provides important information for policy makers and the development of strategies to support and promote agricultural management practices with benefits for soil quality.

Determination of Soluble/Exchangeable Metals in Peri-urban Farmland (Ribeira dos Covões) of Central Portugal

Heavy metal contamination of soil is widespread, and there is a potential risk of transferring toxic metals to agricultural crops, animals and humans. The total heavy metals content can indicate the extent of contamination, but this measure is not usually an accurate indication of the phyto-toxicity; therefore, a number of recent studies have investigated the bioavailable heavy metal fractions in soils and evaluated the phyto-toxic risks for humans. Soluble and exchangeable forms of metals in the soil are the fractions available for plants. The main purpose of the present study is to quantify the total and soluble/exchangeable fractions of heavy metals (Pb, Cr, Cu and Zn) in soils of peri-urban farmland in Portugal (Ribeira dos Covões). The results show that the total heavy metals content is greater than the soluble/exchangeable content, but no clear correlations were recorded: Pb ‒ 70.8 mg/kg vs. 16.7 mg/kg, Cr ‒ 25.0 mg/kg vs. 0.0 mg/kg, Zn ‒ 383.3 mg/kg vs. 0.0 mg/kg, Cu ‒ 183.3 mg/kg vs. 0.0 mg/kg in a horticultural garden (site 10), and; Pb ‒ 270.8 mg/kg vs. 79.0 mg/kg, Cr ‒ 25.0 mg/kg vs. 0.0 mg/kg, Zn ‒ 12.5 mg/kg vs. 0.0 mg/kg, Cu ‒ 33.3 mg/kg vs. 29.2 mg/kg in a backyard (site 18). It is possible that the use of a single extraction procedure, in the laboratory, may not provide a proper assessment of heavy metal forms, and it is therefore advisable to combine different extraction methods in order to correctly perform a risk-based evaluation.

Innovative Soil Management Practices (SMP) Assessment in Europe and China

(1) Instituto das Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), University of Évora, Núcleo da Mitra Apartado 94 7006-554 Évora, Portugal (lbarao@uevora.pt), (2) 2 Centre for Development and Environment (CDE), University of Bern, Hallerstrasse 10, 2012 Bern, Switzerland, (3) University of Pannonia (UP), Deák F. u. 16., H-8360 Keszthely, Hungary, (4) Wageningen University (WU), The Netherlands, (5) Stichting Dienst Landbouwkundig Onderzoek (DLO), The Netherlands, (6) Gaec de la Branchette (GB), France, (7) Research Centre for Natural Resources, Environment and Society (CERNAS), College of Agriculture, Polytechnic Institute of Coimbra, Coimbra, Portugal, (8) University of Miguel Hernández (UMH), Spain, (9) Agricultural University Athens (AUA), Greece, (10) University of Ljubljana, Biotechnical Faculty, Jamnikarjeva 101, 1000 Ljubljana, Slovenia, (11) Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út. 15., H-1022 Budapest, Hungary, (12) National Research and Development Institute for Soil Science, Agrochemistry and Environmental Protection (ICPA), Romania, (13) Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland, (14) Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, Estonia, (15) 15 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences (IARRP, CAAS), China, (16) Soil and Fertilizer Institute of the Sichuan Academy of Agricultural Sciences (SFI), China, (17) Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources (ISWC), China