Editing Eutrophication (section)

===Chemical removal of phosphorus===
{{Further|Chemical phosphorus removal}}
Removing [[phosphorus cycle|phosphorus]] can remediate eutrophication.<ref>{{Cite journal|doi=10.1021/es5036267|pmid=25137490|title=Geo-Engineering in Lakes: A Crisis of Confidence?|journal=Environmental Science & Technology|volume=48|issue=17|pages=9977–9979|year=2014|last1=Spears|first1=Bryan M.|last2=Maberly|first2=Stephen C.|last3=Pan|first3=Gang|last4=MacKay|first4=Ellie|last5=Bruere|first5=Andy|last6=Corker|first6=Nicholas|last7=Douglas|first7=Grant|last8=Egemose|first8=Sara|last9=Hamilton|first9=David|last10=Hatton-Ellis|first10=Tristan|last11=Huser|first11=Brian|last12=Li|first12=Wei|last13=Meis|first13=Sebastian|last14=Moss|first14=Brian|last15=Lürling|first15=Miquel|last16=Phillips|first16=Geoff|last17=Yasseri|first17=Said|last18=Reitzel|first18=Kasper|bibcode=2014EnST...48.9977S|url=http://ir.rcees.ac.cn/handle/311016/9551|access-date=September 8, 2020|archive-date=October 21, 2021|archive-url=https://web.archive.org/web/20211021121418/http://ir.rcees.ac.cn/handle/311016/9551|url-status=live}}</ref><ref>{{Cite journal |doi=10.5268/IW-4.4.769|title=Geoengineering in lakes: Welcome attraction or fatal distraction?|journal=Inland Waters|volume=4|issue=4|pages=349–356|year=2014|last1=MacKay|first1=Eleanor|last2=Maberly|first2=Stephen|last3=Pan|first3=Gang|last4=Reitzel|first4=Kasper|last5=Bruere|first5=Andy|last6=Corker|first6=Nicholas|last7=Douglas|first7=Grant|last8=Egemose|first8=Sara|last9=Hamilton|first9=David|last10=Hatton-Ellis|first10=Tristan|last11=Huser|first11=Brian|last12=Li|first12=Wei|last13=Meis|first13=Sebastian|last14=Moss|first14=Brian|last15=Lürling|first15=Miquel|last16=Phillips|first16=Geoff|last17=Yasseri|first17=Said|last18=Spears|first18=Bryan|bibcode=2014InWat...4..349M |hdl=10072/337267|s2cid=55610343|hdl-access=free}}</ref> Of the several phosphate sorbents, [[alum]] ([[aluminium sulfate]]) is of practical interest.<ref>{{cite web|url=http://www.dnr.state.wi.us/org/water/fhp/papers/alum_brochure.pdf |title=Wisconsin Department of Natural Resources |access-date=August 3, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20091128030217/http://www.dnr.state.wi.us/org/water/fhp/papers/alum_brochure.pdf |archive-date=November 28, 2009 }}</ref>)   Many materials have been investigated.<ref>{{Cite journal|doi=10.1007/s10452-016-9575-2|title=Guiding principles for the development and application of solid-phase phosphorus adsorbents for freshwater ecosystems|journal=Aquatic Ecology|volume=50|issue=3|pages=385–405|year=2016|last1=Douglas|first1=G. B.|last2=Hamilton|first2=D. P.|last3=Robb|first3=M. S.|last4=Pan|first4=G.|last5=Spears|first5=B. M.|last6=Lurling|first6=M.|bibcode=2016AqEco..50..385D |hdl=10072/406333 |s2cid=18154662|url=http://irep.ntu.ac.uk/id/eprint/27767/1/PubSub5337_Pan.pdf|access-date=December 15, 2019|archive-date=September 19, 2020|archive-url=https://web.archive.org/web/20200919184710/http://irep.ntu.ac.uk/id/eprint/27767/1/PubSub5337_Pan.pdf|url-status=live}}</ref><ref>{{Cite journal|doi=10.1016/J.WATRES.2016.03.035|pmid=27039034|title=Editorial – A critical perspective on geo-engineering for eutrophication management in lakes|journal=Water Research|volume=97|pages=1–10|year=2016|last1=Lürling|first1=Miquel|last2=MacKay|first2=Eleanor|last3=Reitzel|first3=Kasper|last4=Spears|first4=Bryan M.|bibcode=2016WatRe..97....1L |url=http://nora.nerc.ac.uk/id/eprint/513724/1/N513724PP.pdf|access-date=December 15, 2019|archive-date=July 31, 2020|archive-url=https://web.archive.org/web/20200731023813/http://nora.nerc.ac.uk/id/eprint/513724/1/N513724PP.pdf|url-status=live}}</ref>  The phosphate sorbent is commonly applied in the surface of the water body and it sinks to the bottom of the lake reducing phosphate, such sorbents have been applied worldwide to manage eutrophication and algal bloom (for example under the commercial name [[Phoslock]]).<ref>{{Cite journal |doi=10.1016/j.watres.2015.06.051|pmid=26250754|title=Longevity and effectiveness of aluminum addition to reduce sediment phosphorus release and restore lake water quality|journal=Water Research|volume=97|pages=122–132|year=2016|last1=Huser|first1=Brian J.|last2=Egemose|first2=Sara|last3=Harper|first3=Harvey|last4=Hupfer|first4=Michael|last5=Jensen|first5=Henning|last6=Pilgrim|first6=Keith M.|last7=Reitzel|first7=Kasper|last8=Rydin|first8=Emil|last9=Futter|first9=Martyn|bibcode=2016WatRe..97..122H |doi-access=free}}</ref><ref>{{Cite journal |doi=10.1016/j.watres.2013.08.019|pmid=24041525|title=Controlling eutrophication by combined bloom precipitation and sediment phosphorus inactivation|journal=Water Research|volume=47|issue=17|pages=6527–6537|year=2013|last1=Lürling|first1=Miquel|last2=Oosterhout|first2=Frank van|bibcode=2013WatRe..47.6527L }}</ref><ref>{{Cite journal |doi=10.1080/10402381.2016.1265618|title=Attempted management of cyanobacteria by Phoslock (Lanthanum-modified clay) in Canadian lakes: Water quality results and predictions|journal=Lake and Reservoir Management|volume=33|issue=2|pages=163–170|year=2017|last1=Nürnberg|first1=Gertrud K.|bibcode=2017LRMan..33..163N |s2cid=89762486}}</ref><ref>{{Cite journal |doi=10.1080/10402381.2016.1263693|title=Nine years of phosphorus management with lanthanum modified bentonite (Phoslock) in a eutrophic, shallow swimming lake in Germany|journal=Lake and Reservoir Management|volume=33|issue=2|pages=119–129|year=2017|last1=Epe|first1=Tim Sebastian|last2=Finsterle|first2=Karin|last3=Yasseri|first3=Said|bibcode=2017LRMan..33..119E |s2cid=90314146}}</ref><ref name=":110">{{Cite journal |last1=Kennedy |first1=Robert H. |last2=Cook |first2=G. Dennis |title=Control of Lake Phosphorus with Aluminum Sulfate: Dose Determination and Application Techniques |date=June 1982 |url=https://doi.org/10.1111/j.1752-1688.1982.tb00005.x |journal=Journal of the American Water Resources Association |volume=18 |issue=3 |pages=389–395 |doi=10.1111/j.1752-1688.1982.tb00005.x |bibcode=1982JAWRA..18..389K |issn=1093-474X}}</ref> In a large-scale study, 114 lakes were monitored for the effectiveness of alum at phosphorus reduction. Across all lakes, alum effectively reduced the phosphorus for 11 years. While there was variety in longevity (21 years in deep lakes and 5.7 years in shallow lakes), the results express the effectiveness of alum at controlling phosphorus within lakes.<ref>{{Cite book |last1=Huser |first1=Brian J. |last2=Egemose |first2=Sara |last3=Harper |first3=Harvey |last4=Hupfer |first4=Michael |last5=Jensen |first5=Henning |last6=Pilgrim |first6=Keith M. |last7=Reitzel |first7=Kasper |last8=Rydin |first8=Emil |last9=Futter |first9=Martyn |date=2016 |title=Longevity and effectiveness of aluminum addition to reduce sediment phosphorus release and restore lake water quality |location=[[Fjärdingen]] |publisher=Uppsala universitet, Limnologi Uppsala universitet |oclc=1233676585 }}</ref> Alum treatment is less effective in deep lakes, as well as lakes with substantial external phosphorus loading.<ref name=":22">Cooke, G. D., Welch, E. B., Martin, A. B., Fulmer, D. G., Hyde, J. B., & Schrieve, G. D. (1993). Effectiveness of Al, Ca, and Fe salts for control of internal phosphorus loading in shallow and deep lakes. ''Hydrobiologia'', ''253''(1), 323-335.</ref>

Finnish phosphorus removal measures started in the mid-1970s and have targeted rivers and lakes polluted by industrial and municipal discharges. These efforts have had a 90% removal efficiency.<ref name="Raike 2003">{{Cite journal|last1=Räike|first1=A.|last2=Pietiläinen|first2=O. -P.|last3=Rekolainen|first3=S.|last4=Kauppila|first4=P.|last5=Pitkänen|first5=H.|last6=Niemi|first6=J.|last7=Raateland|first7=A.|last8=Vuorenmaa|first8=J.|year=2003|title=Trends of phosphorus, nitrogen and chlorophyll a concentrations in Finnish rivers and lakes in 1975–2000|journal=Science of the Total Environment|volume=310|issue=1–3|pages=47–59|bibcode=2003ScTEn.310...47R|doi=10.1016/S0048-9697(02)00622-8|pmid=12812730}}</ref> Still, some targeted point sources did not show a decrease in runoff despite reduction efforts.