title: Direct Discharges of Domestic Wastewater are a Major Source of Phosphorus and Nitrogen to the Mediterranean Sea.
abstract: Direct discharges of treated and untreated wastewater are important sources of nutrients to coastal marine ecosystems and contribute to their eutrophication. Here, we estimate the spatially distributed annual inputs of phosphorus (P) and nitrogen (N) associated with direct domestic wastewater discharges from coastal cities to the Mediterranean Sea (MS). According to our best estimates, in 2003 these inputs amounted to 0.9 × 10(9) mol P yr(-1) and 15 × 10(9) mol N yr(-1), that is, values on the same order of magnitude as riverine inputs of P and N to the MS. By 2050, in the absence of any mitigation, population growth plus higher per capita protein intake and increased connectivity to the sewer system are projected to increase P inputs to the MS via direct wastewater discharges by 254, 163, and 32% for South, East, and North Mediterranean countries, respectively. Complete conversion to tertiary wastewater treatment would reduce the 2050 inputs to below their 2003 levels, but at an estimated additional cost of over €2 billion yr(-1). Management of coastal eutrophication may be best achieved by targeting tertiary treatment upgrades to the most affected near-shore areas, while simultaneously implementing legislation limiting P in detergents and increasing wastewater reuse across the entire basin.
authors.affiliation: Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Helen R
authors.initials: HR
authors.lastname: Powley
authors.affiliation: Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Dürr
authors.affiliation: Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.|Department of Environmental Engineering, Universidade Federal do Espírito Santo , Av. Fernando Ferrari 514, CEP 29075-910 - Vitória, Espírito Santo Brazil.
authors.forename: Ana T
authors.initials: AT
authors.lastname: Lima
authors.affiliation: Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.|School of Earth and Environment, University of Leeds , Leeds LS2 9JT, United Kingdom.|Department of Marine Biology, Haifa University , Mt Carmel, Haifa, Israel.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Krom
authors.affiliation: Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Van Cappellen
mesh_terms: D004784:Environmental Monitoring; D005068:Eutrophication; D008522:Mediterranean Sea; D009584:Nitrogen; D010758:Phosphorus; D045483:Rivers; D062065:Wastewater
chemical_list: D009584:Nitrogen; D010758:Phosphorus; D062065:Wastewater