Editing Turbidity (section)

==Causes and effects==
Turbidity in open water may be caused by growth of [[phytoplankton]]. Human activities that disturb land, such as [[construction]], [[mining]] and [[agriculture]], can lead to high [[sediment]] levels entering water bodies during rain storms due to [[storm water]] [[surface runoff|runoff]]. Areas prone to high bank erosion rates as well as [[urbanized area]]s also contribute large amounts of turbidity to nearby waters, through stormwater [[water pollution|pollution]] from [[Pavement (material)|paved]] surfaces such as roads, bridges, parking lots and airports.<ref>{{cite report |title=National Management Measures to Control Nonpoint Source Pollution from Urban Areas |url=https://www.epa.gov/nps/urban-runoff-national-management-measures |date=November 2005 |publisher=U.S. Environmental Protection Agency (EPA) |location=Washington, D.C. |id=EPA 841-B-05-004. Chapters 7-8.}}</ref> Some industries such as [[quarry]]ing, mining, and coal recovery can generate very high levels of turbidity from colloidal rock particles.

In drinking water, the higher the turbidity level, the higher the risk that people may develop [[gastrointestinal diseases]].<ref>{{cite journal |last1=Mann |first1=A.G. |last2=Tam |first2=C.C. |last3=Higgins |first3=C.D. |last4=Lodrigues |first4=L.L. |title=The association between drinking water turbidity and gastrointestinal illness: a systematic review |date=2007-09-21 |journal=BMC Public Health |publisher=Springer Nature |volume=7 |issue=256 |page=256 |doi=10.1186/1471-2458-7-256|pmid=17888154 |pmc=2174477 |doi-access=free }}</ref> This is especially problematic for immunocompromised people, because contaminants like [[virus]]es or [[bacteria]] can become attached to the suspended solids. The suspended solids interfere with water disinfection with [[chlorine]]<ref>{{Cite journal |last1=LeChevallier |first1=M W |last2=Evans |first2=T M |last3=Seidler |first3=R J |date=July 1981 |title=Effect of turbidity on chlorination efficiency and bacterial persistence in drinking water |journal=Applied and Environmental Microbiology |volume=42 |issue=1 |pages=159–167 |doi=10.1128/aem.42.1.159-167.1981 |pmc=243978 |pmid=7259162 |bibcode=1981ApEnM..42..159L }}</ref> because the particles act as shields for viruses and bacteria. Similarly, suspended solids can protect bacteria from [[Ultraviolet germicidal irradiation|ultraviolet (UV) sterilization]] of water.<ref>{{cite report |title=Guidelines for Ultraviolet Disinfection of Drinking Water |url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/waterquality/dwog_part_b_-_16_ultraviolet_disinfection_of_drinking_water.pdf |date=January 2022 |publisher=British Columbia Ministry of Health |location=Victoria, BC |pages=6–7}}</ref>

In water bodies such as [[lake]]s, rivers and [[reservoirs]], high turbidity levels can reduce the amount of light reaching lower depths, which can inhibit growth of submerged [[aquatic plants]] and consequently affect species which are dependent on them, such as [[fish]] and [[shellfish]]. High turbidity levels can also affect the ability of [[fish gill]]s to absorb dissolved oxygen. This phenomenon has been regularly observed throughout the [[Chesapeake Bay]] in the eastern United States.<ref>{{cite web |last1=Stevenson |first1=J. Court |last2=Piper |first2=Catherine B. |last3=Confer |first3=Nedra |title=Decline of Submerged Plants in Chesapeake Bay |date=1979 |url=http://www.fws.gov/chesapeakebay/savpage.htm |publisher=U.S. Fish and Wildlife Service |location=Annapolis, MD |archive-url=https://web.archive.org/web/20190428081405/http://www.fws.gov/chesapeakebay/savpage.htm |archive-date=2019-04-28}}</ref><ref>{{cite web |title=Sediments |url=http://www.chesapeakebay.net/sediments.aspx |date=2009-08-06 |publisher=[[Chesapeake Bay Program]] |location=Annapolis, MD |archive-url=https://web.archive.org/web/20110927073649/http://www.chesapeakebay.net/sediments.aspx |archive-date=2011-09-27}}</ref>

For many [[mangrove]] areas, high turbidity is needed in order to support certain species, such as to protect juvenile fish from predators. For most mangroves along the eastern coast of [[Australia]], in particular [[Moreton Bay]], turbidity levels as high as 600 [[Nephelometer|Nephelometric]] Turbidity Units (NTU) are needed for proper [[ecosystem]] health.{{Citation needed|date=August 2022}}