Editing River Mersey (section)

==Environment==
Water quality in the Mersey was severely affected by industrialisation, and in 1985, the [[Mersey Basin Campaign]] was established to improve water quality and encourage waterside regeneration. In 2002, oxygen levels that could support fish along the entire length were recorded for the first time since industry began on the Mersey.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/england/merseyside/3014655.stm|title=Mersey cleanest for 200 years|date=9 May 2003|publisher=BBC News}}</ref>

In 2009 it was announced that the river is "cleaner than at any time since the industrial revolution" and is "now considered one of the cleanest [rivers] in the UK".<ref>{{Cite news | last = Smith| first = Mark | date = 24 September 2009 | title = Mersey 'cleanest since industrial revolution' | periodical = Runcorn Weekly News | publisher = Trinity Mirror North West & North Wales | page = 7}}</ref>

===Sediment pollution===
Persistent organic and [[Mercury (element)|mercury]] (Hg) pollution contained within sediments of the Mersey estuary have been evaluated by [[British Geological Survey]].<ref name="Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediments from the Mersey Estuary, U.K.">{{cite journal |last1=Vane |first1=C. H. |last2=Harrison |first2=I. |last3=Kim |first3=A. W. |title=Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediments from the Mersey Estuary, U.K. |journal=Science of the Total Environment |date=March 2007 |volume=374 |issue=1 |pages=112–126 |doi=10.1016/j.scitotenv.2006.12.036 |pmid=17258286 |bibcode=2007ScTEn.374..112V |url=http://nora.nerc.ac.uk/id/eprint/992/ |language=en |issn=0048-9697}}</ref><ref name=" Mercury contamination in surface sediments and sediment cores of the Mersey Estuary, UK. ">{{cite journal |last1=Vane |first1=C. H. |last2=Jones |first2=D. G. |last3=Lister |first3=T. R. |title=Mercury contamination in surface sediments and sediment cores of the Mersey estuary, UK |journal=Marine Pollution Bulletin |date=2009 |volume=58 |issue=6 |pages=940–946 |doi=10.1016/j.marpolbul.2009.03.006 |pmid=19356771 |bibcode=2009MarPB..58..940V |url=http://nora.nerc.ac.uk/7405/ |language=en |issn=0025-326X}}</ref> Mersey river sediments from outer to inner estuary (Alfred Dock to Widnes) contain a variety of common organic pollutants, including [[polyaromatic hydrocarbons]] (PAH) with concentrations which fall in the middle of the range of similarly industrial-urban river-estuaries.<ref name="Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediments from the Mersey Estuary, U.K."/> The distribution of individual PAH compounds suggests that the Mersey has contaminants mainly derived from combustion sources such as vehicle exhaust as well as coal burning. The distribution of the toxic heavy metal Mercury (Hg) has been assessed by measuring 203 sediments taken from shallow cores (0.4  – 1.6 m) extracted from both the main river and adjacent salt marshes.<ref name=" Mercury contamination in surface sediments and sediment cores of the Mersey Estuary, UK. "/> The average amount of Hg in the Mersey was found to be 2&nbsp;mg/kg with the highest amounts of 5&nbsp;mg/kg occurring below the surface at concentrations harmful to sediment dwelling biota. The vertical rise and fall in Hg pollution observed at four Mersey salt marshes indicated a decline in metal pollution since the 1980s.<ref name=" Mercury contamination in surface sediments and sediment cores of the Mersey Estuary, UK. "/>

===Fauna===
[[Atlantic salmon|Salmon]] have returned to the river<ref>{{cite journal|title=The origins of Atlantic salmon (Salmo salar L.) recolonizing the River Mersey in northwest England|doi=10.1002/ece3.353|pmid=23145338|volume=2|issue = 10|pages=2537–2548|journal=Ecology and Evolution|year=2012 | last1 = Ikediashi | first1 = Charles|pmc=3492779|bibcode=2012EcoEv...2.2537I |doi-access=free}}</ref> and have been seen jumping at [[Woolston, Cheshire|Woolston]] and Howley Weirs between September and November. Salmon [[Parr (fish)|parr]] and [[Spawn (biology)|smolt]] have been caught in the Mersey's tributaries, the River Goyt and the [[River Bollin]].<ref>{{cite web|url=http://www.environment-agency.gov.uk/static/documents/Leisure/Salmon_behaviour_in_the_Mersey_Catchment_FINAL.pdf|work=Environment Agency|title=Salmon behaviour in the Mersey Catchment|first=Sam|last=Billington|archive-url=http://webarchive.nationalarchives.gov.uk/20140328084622/http://www.environment-agency.gov.uk/static/documents/Leisure/Salmon_behaviour_in_the_Mersey_Catchment_FINAL.pdf|archive-date=28 March 2014|url-status=dead}}</ref> [[Gray seal|Atlantic grey seals]] from Liverpool Bay occasionally venture into the estuary<ref>{{citation | url= http://www.cheshire-biodiversity.org.uk/action-plans/listing.php?id=13 | title= Atlantic grey seal | publisher= Cheshire Region Biodiversity Project | access-date= 25 August 2012 | url-status= dead | archive-url= https://web.archive.org/web/20120806034427/http://www.cheshire-biodiversity.org.uk/action-plans/listing.php?id=13 | archive-date= 6 August 2012 }}</ref> along with [[bottlenose dolphin]] and [[harbour porpoise]]. [[Eurasian otter|Otter]] tracks have been observed near Fiddlers Ferry.<ref>{{citation | url=https://www.bbc.co.uk/news/uk-england-merseyside-15852705 | title=Otters return to once-polluted River Mersey | access-date=25 August 2012| publisher=BBC News | date=23 November 2011 }}</ref> Other fish in the estuary include [[Atlantic cod|cod]], [[Merlangius|whiting]], [[Common dab|dab]], [[European plaice|plaice]] and [[European flounder|flounder]].<ref name=LHU>{{cite web|url=http://www.hope.ac.uk/ebs/merseystrategy/EstGuide.pdf|title=Making the most of the Mersey|work=Liverpool Hope University|page=25|archive-url=https://web.archive.org/web/20030831124326/http://www.hope.ac.uk/ebs/merseystrategy/EstGuide.pdf|archive-date=31 August 2003}}</ref> [[Spiny dogfish]], [[Atlantic mackerel|mackerel]] and [[School shark|tope]] feed on [[shrimp]] and [[whitebait]] in the estuary.<ref name=LHU /> For ducks, the estuary is important to [[common shelduck]]s and [[Eurasian teal]].<ref>{{cite web|url=https://www.rspb.org.uk/whatwedo/campaigningfornature/casework/details.aspx?id=tcm:9-240075|title=Mersey Estuary|work=RSPB|access-date=5 March 2016}}</ref> Waders include [[Common redshank|redshank]], [[black-tailed godwit]], [[dunlin]], [[Northern pintail|pintail]] and [[Ruddy turnstone|turnstone]].<ref>{{cite web|url=http://www.merseybasin.org.uk/archive/assets/173/original/Flocking_To_The_Mersey.pdf|title=Flocking to the Mersey|work=Mersey Basin|access-date=5 March 2016}}</ref><ref>{{cite web|url=http://publications.naturalengland.org.uk/file/5942797565689856|title=Waterbird population trend analysis of the Mersey Estuary SPA, Mersey Narrows & North Wirral Foreshore pSPA and Ribble & Alt Estuaries SPA|work=Natural England|access-date=5 March 2016}}</ref>

===Environmental designations===
The section of the estuary between Runcorn Railway Bridge and [[Bromborough]], including [[Hale Duck Decoy]] and [[Mount Manisty]], is designated as a Site of Special Scientific Interest, the SSSI citation describing it as an "internationally important site for wildfowl".<ref>{{cite web | title=Mersey Estuary (SSSI citation) | url={{sssi link|1001398}} |author=Natural England |date=1985 |access-date=4 January 2022}}</ref> There are further SSSIs at New Ferry<ref>{{cite web | title=New Ferry (SSSI citation) | url={{sssi link|2000435}} |author=Natural England |date=2000 |access-date=4 January 2022}}</ref> and Mersey Narrows.<ref>{{cite web | title=Mersey Narrows (SSSI citation) | url={{sssi link|2000436}} |author=Natural England |date=2000 |access-date=4 January 2022}}</ref> The Mersey Estuary,<ref name="ramsar" /> and the Mersey Narrows and North Wirral Foreshore,<ref>{{cite web |url=https://rsis.ramsar.org/ris/2202 |title=The Mersey Narrows and North Wirral Foreshore |work=Ramsar Sites Information Service |publisher=Ramsar |date=7 May 2013 |access-date=4 January 2022}}</ref> are also [[Ramsar site]]s.