Multi-decadal trajectories of phosphorus loading, export, and instream retention along a catchment gradient

Archetypes and Controls of Riverine Nutrient Export Across German Catchments

“…Mean PO 4 -P concentrations were positively linked to direct anthropogenic input from point sources, although the overall explained variance in the PLSR and RF models was surprisingly low (R 2 CrossVal = 0.34 and 0.40). Previous studies have also demonstrated the strong control of point sources on average riverine total P concentrations (Minaudo et al, 2019;Westphal et al, 2019;Withers & Jarvie, 2008), with their contributions remaining high even after significant reductions of inputs from point sources (Behrendt et al, 1999;Westphal et al, 2019). However, even in a densely populated catchments (about 460 inhabitants km −2 ), contributions of point sources to total P can be similar to diffuse sources, for example about 60% at load peak and 40% with modern wastewater treatment (Westphal et al, 2019).…”

“…Out of the initial pool of 6,000 sites of the newly assembled Germany-wide data base, water quality time series were selected based on the following criteria concerning the quality and availability of concentration and spatial data: 1) Data availability of at least three years in the target period from 2000 to 2015. This time period excludes major changes in the 1990s when major improvements of wastewater treatment were put into place (Westphal et al, 2019) 2) Minimum of 70 concentration samples after outlier removal. As the large number of sites demanded a cost-effective method, only extreme outliers likely to be typographical errors were removed (following Oelsner et al, 2017).…”

Chemometric Assessment of Bulgarian Wastewater Treatment Plants’ Effluents

“…The relative contribution of N and P loads discharged from WWTPs in Europe decreased continuously in the last 40 years because stringent regulations for wastewater treatment had been introduced [ 28 , 29 , 30 , 31 , 32 , 33 ]. The role of advanced P removal technologies (e.g., coagulation, flocculation, and decantation) in increasing P sorption onto suspended colloidal matter is the probable reason for altering the bioavailable P in the river downstream [ 34 ].…”

Modified Biochar—A Tool for Wastewater Treatment

“…Because of this, eutrophication is a global problem causing a decline in the quality of both fresh and marine water worldwide [12]. The continuing high levels of phosphorus leeching into water ecosystems will accelerate harmful processes such as algal blooms or hypoxia in aquatic ecosystems [13], which will lead to significant ecosystem changes and to endangerment of a significant number of species [14]. This is one of the most visible examples of biosphere changes due to human activities [15].…”