The fluvial flux of total reactive and total phosphorus from the UK in the context of a national phosphorus budget: comparing UK river fluxes with phosphorus trade imports and exports

Abstract

A national river water quality database of total reactive phosphorus (TRP) and total phosphorus (TP) and flow was used, together with catchment characteristic datasets (soils, land use and hydroclimatic properties), to derive national fluvial phosphorus (P) flux estimates for Great Britain (England, Wales and Scotland) from 1974 to 2012. These fluvial P fluxes were compared with P imports and exports, in fertilizer, food, feedstuffs, and industrial products, along with coastal direct discharge of wastes, at the British national boundary from 1990 to 2012. The results showed that: (i) Average annual river TP concentrations in Great Britain have declined from a peak of 0.27-0.1 mg P/l and annual river TP flux has declined from 120 to 16 ktonnes P/year (0.49-0.06 tonnes P/km 2 /year); (ii) Average river TRP concentration has declined from a peak of 0.19-0.05 mg P/l and annual river TRP flux has declined from 71 to 10 ktonnes P/year (0.29-0.05 tonnes P/km 2 ); (iii) Over the period 2003-2012, even after the introduction of the Urban Waste Water Directive, 60 % of UK's TP flux was still from urban areas; and (iv) In 1990, the fluvial flux of TP from the UK was equivalent to 41 % of imports; by 2012 this had decreased to 15 %. The UK (relative to its boundary) continues to accumulate P and, over the last 15 years, this accumulation has increased at an average rate of 0.6 ktonnes P/year 2 . Enhanced removal of P in waste water treatment has shifted the environmental pathway of sewage P from discharge to rivers to accumulation in sewage sludge, which is largely disposed of on agricultural land, and which could eventually provide a sustained legacy source of P to rivers for decades. However, a substantial proportion of P accumulation is via food waste into landfills.

Fixing the Broken Phosphorus Cycle: Wastewater Remediation by Microalgal Polyphosphates

“…In the UK, nutrient losses to surface waters are estimated at 980 kt N year −1 of total dissolved N and 16 kt P year −1 of total phosphorus, with a 60% contribution from urban areas despite the introduction of the EU Urban Waste Water Directive in 1991 (Worrall et al, 2009;Worrall et al, 2016). Current STWs efficiently remove organic matter using heterotrophic bacteria but rely on nitrification/denitrification to remove N compounds, a process that is energy intensive and wastefully returns N 2 (and greenhouses gases, e.g., N 2 O) to the atmosphere.…”

Multidecadal Trajectory of Riverine Nitrogen and Phosphorus Dynamics in Rural Catchments

“…Human activities have substantially altered riverine exports of nitrogen (N) and phosphorus (P) in the Anthropocene (Galloway et al, 2004;Seitzinger et al, 2010;Worrall et al, 2016), causing major alterations of freshwater and marine ecosystems worldwide (Sardans et al, 2012;Steffen et al, 2015). Documenting anthropogenic alterations of nutrient cycles in aquatic ecosystems is a challenge as industrialization in western countries began in the eighteenth century and agricultural intensification in the midtwentieth century, while river monitoring became widespread only since the 1990s, with few noticeable exceptions of multidecadal data sets starting earlier (Billen et al, 2007;Howden et al, 2010;Kopacek et al, 2017;Pinay et al, 2017;Romero et al, 2016;Stets et al, 2015;Viaroli et al, 2018;Worrall et al, 2016).…”

Global Opportunities to Increase Agricultural Independence Through Phosphorus Recycling

“…Meanwhile, recent trajectories for subnational P use are understood for subsets of the globe, while research on the full global heterogeneity and dynamics remains a challenge, particularly for recycled P flows and social factors (e.g., cultural norms, regulations) that affect of P use. The fact remains that prior P research was dominated by biophysical studies of fluvial transport (e.g., Mayorga et al, 2010;Seitzinger et al, 2010) and soil pools (e.g., Ringeval et al, 2017;Sattari et al, 2012;Zhang et al, 2017), substance flow and mass balance studies at coarse national or continental resolution (Bai et al, 2016;Mihelcic et al, 2011;Morée et al, 2013;Seyhan, 2009;Van Dijk et al, 2016), and finer-scale budgets of catchments and regions that lack global completeness (e.g., Powers et al, 2016;Worrall et al, 2016). Future global and subnationally resolved analyses of P, recycling fluxes, and options and constraints linked to economics, policies, land management, and regulatory complexities (e.g., legality of transport across jurisdictions and transfer permits) could accelerate development of spatially prioritized plans for P use and food security.…”