Talk:Arsenic contamination of groundwater

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Wiki Education Foundation-supported course assignment[edit]

This article was the subject of a Wiki Education Foundation-supported course assignment, between 28 August 2021 and 10 December 2021. Further details are available on the course page. Student editor(s): Ethanndavid.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 17:33, 17 January 2022 (UTC)[reply]

Wiki Education Foundation-supported course assignment[edit]

This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Peer reviewers: Gmousalimas, JeshuaKJohn.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 14:45, 16 January 2022 (UTC)[reply]

Role of bacterial reduction[edit]

Bacterial reduction and high arsenic levels in groundwater is interesting, describing how bacteria can reduce adsorption (on metal oxides in the soil) and increase solubility of arsenic. However, I'm not sure if it's notable, and accepted, or speculative, so I won't put it in unless there's more info about this (citations elsewhere, other articles/pages...). --Singkong2005 09:49, 31 May 2006 (UTC)[reply]

Yes, the site you have is based on: Islam, FS, Gault, AG, Boothman, C, Polya, DA, Charnock, JM, Chatterjee, D, Lloyd, JR, Role of Metal-reducing Bacteria in Arsenic Release from Bengal Delta Sediments, Nature 430 (6995), p68-71, 2004. This paper has been cited 86 times in the web of science. it is apparent that quite few studies are being done now, reaching the conclusion that microbiological effects are significant.
This article about Michigan's groundwater arsenic problem provides insight into the significant role of biology. The most egregious arsenic contamination is being tied to anaerobic failure of soil resulting from improper (excessive loading of Biochemical oxygen demand) land treatment of high strength wastewater. This article says "The accumulation of juice wastes sprayed over more than 40 years on fields behin [sic?] the plant caused a condition in the soil that releases naturally occurring iron, manganese and arsenic particles into groundwater, according to the MDEQ. Monitoring wells near the former spray fields have shown levels of these heavy metals above current federal limits. There is a plume of heavy metals and contaminants that has tainted more than 20 wells east of the plant."
That "...condition in the soil..." is a reduced chemistry (see redox) produced when soil biology runs out of oxygen. The significance to the main article being that in wetlands, in the soil bottom of water storage lagoons, in cesspits, all common features worldwide, ionic forms of reduced iron, manganese and arsenic are soluble in water, allowing these metals to migrate with water, and to concentrate in groundwater. Although the Michigan articles refer to allegations and an unresolved lawsuit, the science is settled: arsenic contamination of groundwater, like iron contamination of groundwater is connected to biology and the redox chemistry produced by that biology. [1] My understanding of the science that I have as a soil scientist working with land application of wastewater is accurately stated by this 2009 article: "The spraying of the large amount of juice waste robs the soil of oxygen and causes natural-occurring metals in the soil, including arsenic, to collect in amounts that can be hazardous in drinking water." -- Paleorthid (talk) 19:08, 17 February 2019 (UTC)[reply]

Notes[edit]

  1. ^ Fendorf, Michael; van Geen (May 2010). "Spatial and Temporal Variations of Groundwater Arsenic in South and Southeast Asia" (PDF). Science. 328. pp. 1123–7. doi:10.1126/science.1172974. Retrieved 16 February 2019. When the biological oxygen demand from the decomposition of organic carbon exceeds the rate of oxygen infusion, anaerobic metabolism prevails and ... causes microbially mediated reduction of Fe(III) to Fe(II), as well as As(V) to As(III) ... The availability of labile organic carbon as a driver of microbial reduction is possibly the most prominent outstanding issue limiting our ability to predict the distribution of As in groundwater {{cite web}}: Cite has empty unknown parameter: |1= (help)

Testing arsenic levels?[edit]

Is there a practical low cost way to test water for arsenic? See also where the question is posed at Appropedia:Category:Water#Testing for arsenic? --Chriswaterguy talk 02:08, 15 February 2007 (UTC)[reply]

The most effective way is the colorimetric tests such as the Wagtech Arsenator. They use something like zinc powder or sodium borohydride to reduce the arsenic in water to arsine, which is volatile. The arsine gas is reacted on a mercuric bromide strip which changes colour. If a spectrometer is used to measure the colour change, the kit is quantitiative down to 2 - 5 ppb. The kit is quite expensive costing $ 1800 in 2004, which apparently left some people sceptical about its use in the third world (www.downtoearth.org.in/full6.asp?foldername=20040630&filename=news&sec_id=4&sid=37). The kit was reviewed by a group commission by UNICEF: it was given almost top marks, i.e. they reckon it works very well (www.wagtech.co.uk/UserFiles/File/Water%20Cat/ArsenatorEvaluation.pdf accessed 2008).

Research efforts are being pursued for electrochemical technique. Although it is cheap to implement and high sensitive (<0.1 ppb in some cases) some aspects need to be improved. With electrochemical techniques the electrode sensor needs to be carefully maintained to keep good performance. Which may involve some esoteric procedures which most people would find difficult. MTI produces the PVD6000 which detects arsenic and other metals, but it is large and more expensive than the Arsenator. (www.mtidiagnostics.com/pdv6000.html)

Effects of contamination[edit]

This section was misnamed and poorly written. If I were an English teacher, I would give the student an F.

  • The story of the arsenic contamination of the groundwater in Bangladesh is a tragic one. Diarrheal diseases have long plagued the developing world as a major cause of death, especially in children. Prior to the 1970s, Bangladesh had one of the highest infant mortality rates in the world.

This section begins by saying there was a lot of suffering. Then it will go on to say that they dug wells, which was good (!) but then arsenic was found in the water.

It does not say how many people died or got sick as a result of the arsenic contamination. It only says that one mortality rate went down. Does this mean arsenic is good? I don't think that was the point. --Uncle Ed (talk) 02:15, 13 December 2007 (UTC)[reply]

Appears to be contradictory[edit]

"In West Bengal, water is mostly supplied from rivers. Groundwater comes from deep tubewells, which are few in number. Because of the low quantity of deep tubewells, the risk of arsenic patients in West Bengal is comparatively less.[11] " The section just above this mentions more than 8 million wells. It seems as if this is a new region, or there are two versions of the same section that have not been integrated into each other. As it reads, the section does not identify which well enough. Someone who knows needs to fix this.... On rereading I see my problem....The location is not assigned to India in its first mention, but somewhere in the middle of the paragraph. It should be assigned on the first mention of West Bengal. Never assume the reader has started at the first line of the section...making appropriate edits....OK... now I read the second section well. It is too stylistically different from the first one to imagine that they are talking about the same things. It seems to have a different purpose in mind. I question its usefulness the way it is written. It needs to be written so both sections work together.

This last paragraph appears to be a point of view. It does not contain any useful information about the topic. I suggest that it be removed...the paragraph above it is a nonsequitor to the section above it...


"One solution is “By using surface water and instituting effective withdrawal regulation. West Bengal and Bangladesh are flooded with surface water. We should first regulate proper watershed management. Treat and use available surface water, rain-water, and others. The way we're doing [it] at present is not advisable."[11]"


Avram Primack (talk) 04:24, 19 December 2011 (UTC)[reply]

Dubious Citations[edit]

The statement, "In addition, mining techniques such as hydraulic fracturing mobilize arsenic in groundwater and aquifers due to enhanced methane transportation and resulting changes in redox conditions,[1]" contains an inaccurate citation. The Brown et. al. 2010 paper deals with the mobilization of arsenic in the presence of petroleum hydrocarbon groundwater contamination. It does not reference or refer to hydraulic fracturing activities.

The statement, ". . . and inject fluid containing additional arsenic.[2]" is also a dubious citation. The database associated with that publication does not list hydraulic fracture injection fluids as the source of any contamination.[A] Also the website, FracFocus.org does not contain any arsenic compounds on the list of common fracture stimulation fluids.[B]

Additionally if any of these statements can be verified with other sources, this information would be more appropriately placed in Section 2 "Contamination specific nations and regions".

[A] http://www.iwapublishing.com/template.cfm?name=isbn9781780400389

[B] http://fracfocus.org/chemical-use/what-chemicals-are-used In-Fact-uation (talk) 23:08, 30 July 2013 (UTC) In-Fact-uation[reply]

Agree that the article had some comments that seemed inappropriate and unsubstantiated. I just removed a lot of them. The article was also tilted toward the US, whereas the issue is decidedly non-US. You further comments or contributions would be welcome since this topic is of global importance.--Smokefoot (talk) 01:51, 31 July 2013 (UTC)[reply]

Arsenic removal via solar water distillation?[edit]

I realize this is not a forum, but I am mystified why solar water distillation is apparently not mentioned as a method to remove arsenic. Is there some technical reason this specific technology is apparently not being used?

It has no moving parts, requires only sunlight to operate, and can be cleaned just by pouring enough new contaminated water into the evaporation basin to flush the concentrated waste out an overflow channel. Using only a sloped glass window with a silicone gasket and collection channel, the rest of it could be constructed locally.

The following website says that "4.9 kg of distilled water is produced per square meter of still surface", for solar stills operated in northern Chile.

Ref: http://www.solaqua.com/solstilbas.html

-- DMahalko (talk) 18:02, 7 January 2015 (UTC)[reply]

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Dietary Intake Suggestions[edit]

The two lines in the Dietary Intake section do not seem to contribute much to the overall article, it should either be supplemented with more facts or deleted altogether.

Veena.narashiman (talk) 04:32, 13 February 2018 (UTC)[reply]

Subterranean arsenic removal (SAR) technology.[edit]

You talked a lot about all of the advantages of SAR technology. Are there any disadvantages? Joey Stephenson 98 (talk) 01:15, 24 January 2019 (UTC)[reply]

Better graphic needed[edit]

This is the graphic being used by The United Nations Environment Programme (UNEP) (here). A comparison brings out the limitations of the current-but-now-14-years-old-graphic. The UNEP graphic was used with attribution to Schwarzenbach (2010) Global water pollution and human health. Looks like we editors need to dust off GIMP and craft a new graphic. -- Paleorthid (talk) 21:38, 17 February 2019 (UTC)[reply]


Removed further reading list[edit]

I've removed this further reading list as it's outdated and not overly useful:

Wiki Education assignment: Toxicology[edit]

This article was the subject of a Wiki Education Foundation-supported course assignment, between 29 August 2023 and 11 December 2023. Further details are available on the course page. Student editor(s): Biopsych13 (article contribs). Peer reviewers: Poisonpearl, Ash.cobbler, Idkwhattoputtt.

— Assignment last updated by Ash.cobbler (talk) 15:28, 15 November 2023 (UTC)[reply]

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