Soil contamination

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Soil contamination, soil pollution, or land pollution as a part of

GIS in Environmental Contamination, as well as an appreciation of the history of industrial chemistry.[2]

In North America and Western Europe the extent of contaminated land is best known, with many of countries in these areas having a legal framework to identify and deal with this environmental problem. Developing countries tend to be less tightly regulated despite some of them having undergone significant industrialization.

Causes

Soil pollution can be caused by the following (non-exhaustive list):

The most common chemicals involved are

solvents, pesticides, lead, and other heavy metals
.

Any activity that leads to other forms of

soil remediation
becomes more tedious.

E-waste processing in Agbogbloshie, Ghana. Improper disposal of manufactured goods and industrial wastes, often means that communities in the global south have to process goods. Especially without proper protections, heavy metals and other contaminates can seep into the soil, and create water pollution and air pollution.

Historical deposition of

polynuclear aromatic hydrocarbons (PAHs; e.g., benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(cd)pyrene, phenanthrene, anthracene, and others). These PAHs are known human carcinogens
and the acceptable concentrations of them in soil are typically around 1 mg/kg. Coal ash and slag can be recognised by the presence of off-white grains in soil, gray heterogeneous soil, or (coal slag) bubbly, vesicular pebble-sized grains.

Treated

controversial as a "fertilizer". As it is the byproduct of sewage treatment, it generally contains more contaminants such as organisms, pesticides, and heavy metals than other soil.[3]

In the European Union, the

pathogenic microorganisms do not get into water courses and to ensure that there is no accumulation of heavy metals in the top soil.[4]

Pesticides and herbicides

A pesticide is a substance used to kill a pest. A pesticide may be a chemical substance, biological agent (such as a virus or bacteria), antimicrobial, disinfectant or device used against any pest. Pests include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes (roundworms) and microbes that compete with humans for food, destroy property, spread or are a vector for disease or cause a nuisance. Although there are benefits to the use of pesticides, there are also drawbacks, such as potential toxicity to humans and other organisms.[5][6]

trinitrotoluene (2:4 D and 2:4:5 T) have the impurity dioxin, which is very toxic and causes fatality even in low concentrations. Another herbicide is Paraquat. It is highly toxic but it rapidly degrades in soil due to the action of bacteria and does not kill soil fauna.[7]

Insecticides are used to rid farms of pests which damage crops. The insects damage not only standing crops but also stored ones and in the tropics it is reckoned that one third of the total production is lost during food storage. As with

Paris Green and other compounds of arsenic. Nicotine has also been used since 1690.[8]

There are now two main groups of synthetic insecticides:

1.

environmental effects were realized. It was found worldwide in fish and birds and was even discovered in the snow in the Antarctic. It is only slightly soluble in water but is very soluble in the bloodstream. It affects the nervous and endocrine systems and causes the eggshells of birds to lack calcium causing them to be easily breakable. It is thought to be responsible for the decline of the numbers of birds of prey like ospreys and peregrine falcons in the 1950s – they are now recovering.[9] As well as increased concentration via the food chain, it is known to enter via permeable membranes, so fish get it through their gills. As it has low water solubility, it tends to stay at the water surface, so organisms that live there are most affected. DDT found in fish that formed part of the human food chain caused concern, but the levels found in the liver, kidney and brain tissues was less than 1 ppm and in fat was 10 ppm, which was below the level likely to cause harm. However, DDT was banned in the UK and the United States to stop the further buildup of it in the food chain. U.S. manufacturers continued to sell DDT to developing countries, who could not afford the expensive replacement chemicals and who did not have such stringent regulations governing the use of pesticides.[10]

2. Organophosphates, e.g. parathion, methyl parathion and about 40 other insecticides are available nationally. Parathion is highly toxic, methyl-parathion is less so and Malathion is generally considered safe as it has low toxicity and is rapidly broken down in the mammalian liver. This group works by preventing normal nerve transmission as cholinesterase is prevented from breaking down the transmitter substance acetylcholine, resulting in uncontrolled muscle movements.[11]

Agents of war

The disposal of munitions, and a lack of care in manufacture of munitions caused by the urgency of production, can contaminate soil for extended periods. There is little published evidence on this type of contamination largely because of restrictions placed by governments of many countries on the publication of material related to war effort. However,

biological weapon contaminated the whole island of Gruinard.[13]

Human health

Exposure pathways

Contaminated or polluted soil directly affects human health through direct contact with soil or via inhalation of soil contaminants that have vaporized; potentially greater threats are posed by the infiltration of soil contamination into groundwater

aquifers used for human consumption, sometimes in areas apparently far removed from any apparent source of above-ground contamination. Toxic metals can also make their way up the food chain through plants that reside in soils containing high concentrations of heavy metals.[14] This tends to result in the development of pollution-related diseases
.

Most exposure is accidental, and exposure can happen through:[15]

  • Ingesting dust or soil directly
  • Ingesting food or vegetables grown in contaminated soil or with foods in contact with contaminants
  • Skin contact with dust or soil
  • Vapors from the soil
  • Inhaling clouds of dust while working in soils or windy environments

However, some studies estimate that 90% of exposure is through eating contaminated food.[15]

Consequences

Health consequences from exposure to soil contamination vary greatly depending on pollutant type, the pathway of attack, and the vulnerability of the exposed population. Researchers suggest that pesticides and heavy metals in soil may harm cardiovascular health, including inflammation and change in the body's internal clock.[16]

Chronic exposure to

health hazards in soil and groundwater.[17]

Chronic exposure to benzene at sufficient concentrations is known to be associated with a higher incidence of leukemia. Mercury and

groundwater contaminated through soil.[18]

The Scottish Government has commissioned the Institute of Occupational Medicine to undertake a review of methods to assess risk to human health from contaminated land. The overall aim of the project is to work up guidance that should be useful to Scottish Local Authorities in assessing whether sites represent a significant possibility of significant harm (SPOSH) to human health. It is envisaged that the output of the project will be a short document providing high level guidance on health risk assessment with reference to existing published guidance and methodologies that have been identified as being particularly relevant and helpful. The project will examine how policy guidelines have been developed for determining the acceptability of risks to human health and propose an approach for assessing what constitutes unacceptable risk in line with the criteria for SPOSH as defined in the legislation and the Scottish Statutory Guidance.[citation needed]

Ecosystem effects

This area is contaminated with stagnant water and refuse, making the environment unhygienic.

Not unexpectedly, soil contaminants can have significant deleterious consequences for ecosystems.

predator or consumer species. Even if the chemical effect on lower life forms is small, the lower pyramid levels of the food chain may ingest alien chemicals, which normally become more concentrated for each consuming rung of the food chain. Many of these effects are now well known, such as the concentration of persistent DDT materials for avian consumers, leading to weakening of egg shells, increased chick mortality and potential extinction of species.[20]

Effects occur to

agricultural lands which have certain types of soil contamination. Contaminants typically alter plant metabolism, often causing a reduction in crop yields. This has a secondary effect upon soil conservation, since the languishing crops cannot shield the Earth's soil from erosion. Some of these chemical contaminants have long half-lives and in other cases derivative chemicals are formed from decay of primary soil contaminants.[21]

Potential effects of contaminants to soil functions

Heavy metals and other soil contaminants can adversely affect the activity, species composition and abundance of soil microorganisms, thereby threatening soil functions such as biochemical cycling of carbon and nitrogen.[22] However, soil contaminants can also become less bioavailable by time, and microorganisms and ecosystems can adapt to altered conditions. Soil properties such as pH, organic matter content and texture are very important and modify mobility, bioavailability and toxicity of pollutants in contaminated soils.[23] The same amount of contaminant can be toxic in one soil but totally harmless in another soil. This stresses the need for soil-specific risks assessment and measures.

Cleanup options

Cleanup or

GIS in Environmental Contamination) for analyzing transport[24] and fate of soil chemicals. Various technologies have been developed for remediation of oil-contaminated soil and sediments [25]
There are several principal strategies for remediation:

By country

Various national standards for concentrations of particular contaminants include the United States EPA Region 9 Preliminary Remediation Goals (U.S. PRGs), the U.S. EPA Region 3 Risk Based Concentrations (U.S. EPA RBCs) and National Environment Protection Council of Australia Guideline on Investigation Levels in Soil and Groundwater.

People's Republic of China

The immense and sustained growth of the

contaminated water being used to irrigate a further 32.5 million mu (21,670 square kilometres) and another 2 million mu (1,300 square kilometres) covered or destroyed by solid waste. In total, the area accounts for one-tenth of China's cultivatable land, and is mostly in economically developed areas. An estimated 12 million tonnes of grain are contaminated by heavy metals every year, causing direct losses of 20 billion yuan ($2.57 billion USD).[28] Recent survey shows that 19% of the agricultural soils are contaminated which contains heavy metals and metalloids. And the rate of these heavy metals in the soil has been increased dramatically.[29]

European Union

According to the received data from Member states, in the European Union the number of estimated potential contaminated sites is more than 2.5 million[30] and the identified contaminated sites around 342 thousand. Municipal and industrial wastes contribute most to soil contamination (38%), followed by the industrial/commercial sector (34%). Mineral oil and heavy metals are the main contaminants contributing around 60% to soil contamination. In terms of budget, the management of contaminated sites is estimated to cost around 6 billion Euros (€) annually.[30]

United Kingdom

Generic guidance commonly used in the United Kingdom are the Soil Guideline Values published by the Department for Environment, Food and Rural Affairs (DEFRA) and the Environment Agency. These are screening values that demonstrate the minimal acceptable level of a substance. Above this there can be no assurances in terms of significant risk of harm to human health. These have been derived using the Contaminated Land Exposure Assessment Model (CLEA UK). Certain input parameters such as Health Criteria Values, age and land use are fed into CLEA UK to obtain a probabilistic output.[31]

Guidance by the Inter Departmental Committee for the Redevelopment of Contaminated Land (ICRCL)[32] has been formally withdrawn by DEFRA, for use as a prescriptive document to determine the potential need for remediation or further assessment.

The CLEA model published by DEFRA and the

Soil Guideline Values (SGVs) have currently been derived for ten contaminants to be used as "intervention values".[33] These values should not be considered as remedial targets but values above which further detailed assessment should be considered; see Dutch standards
.

Three sets of CLEA SGVs have been produced for three different land uses, namely

  • residential (with and without plant uptake)
  • allotments
  • commercial/industrial

It is intended that the SGVs replace the former ICRCL values. The CLEA SGVs relate to assessing chronic (long term) risks to human health and do not apply to the protection of ground workers during construction, or other potential receptors such as groundwater, buildings, plants or other ecosystems. The CLEA SGVs are not directly applicable to a site completely covered in hardstanding, as there is no direct exposure route to contaminated soils.[34]

To date, the first ten of fifty-five contaminant SGVs have been published, for the following: arsenic, cadmium, chromium, lead, inorganic mercury, nickel, selenium ethyl benzene, phenol and toluene. Draft SGVs for benzene, naphthalene and xylene have been produced but their publication is on hold. Toxicological data (Tox) has been published for each of these contaminants as well as for benzo[a]pyrene, benzene, dioxins, furans and dioxin-like PCBs, naphthalene, vinyl chloride, 1,1,2,2 tetrachloroethane and 1,1,1,2 tetrachloroethane, 1,1,1 trichloroethane, tetrachloroethene, carbon tetrachloride, 1,2-dichloroethane, trichloroethene and xylene. The SGVs for ethyl benzene, phenol and toluene are dependent on the soil organic matter (SOM) content (which can be calculated from the total organic carbon (TOC) content). As an initial screen the SGVs for 1% SOM are considered to be appropriate.[35]

Canada

As of February 2021, there are a total of 2,500 plus contaminated sites in Canada.[36] One infamous contaminated sited is located near a nickel-copper smelting site in Sudbury, Ontario. A study investigating the heavy metal pollution in the vicinity of the smelter reveals that elevated levels of nickel and copper were found in the soil; values going as high as 5,104ppm Ni, and 2,892 ppm Cu within a 1.1 km range of the smelter location. Other metals were also found in the soil; such metals include iron, cobalt, and silver. Furthermore, upon examining the different vegetation surrounding the smelter it was evident that they too had been affected; the results show that the plants contained nickel, copper and aluminium as a result of soil contamination.[37]

Further information: Pollution in Canada § Soil pollution

India

In March 2009, the issue of

Bhatinda districts of Punjab. The news reports claimed the uranium levels were more than 60 times the maximum safe limit.[38][39] In 2012, the Government of India confirmed[40] that the ground water in Malwa belt of Punjab has uranium metal that is 50% above the trace limits set by the United Nations' World Health Organization (WHO). Scientific studies, based on over 1000 samples from various sampling points, could not trace the source to fly ash and any sources from thermal power plants or industry as originally alleged. The study also revealed that the uranium concentration in ground water of Malwa district is not 60 times the WHO limits, but only 50% above the WHO limit in 3 locations. This highest concentration found in samples was less than those found naturally in ground waters currently used for human purposes elsewhere, such as Finland.[41]
Research is underway to identify natural or other sources for the uranium.

See also

References

  1. ^ Risk Assessment Guidance for Superfund, Human Health Evaluation Manual, Office of Emergency and Remedial Response, U.S. Environmental Protection Agency, Washington D.C. 20450
  2. ^ George, Rebecca; Joy, Varsha; S, Aiswarya; Jacob, Priya A. "Treatment Methods for Contaminated Soils – Translating Science into Practice" (PDF). International Journal of Education and Applied Research. Retrieved February 19, 2016.
  3. S2CID 45282896.Free full-text Archived 2011-07-13 at the Wayback Machine
    (registration required)
  4. PMID 22921257
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  5. ^ "Pesticides: MedlinePlus Medical Encyclopedia". medlineplus.gov. Retrieved 2022-04-01.
  6. ^ "Pesticides".
  7. ^ "Paraquat poisoning: MedlinePlus Medical Encyclopedia". medlineplus.gov. Retrieved 2022-04-01.
  8. PMID 15822177
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  9. ^ "DDT and Birds". web.stanford.edu. Retrieved 2022-04-04.
  10. ^ US EPA, OCSPP (2014-01-07). "DDT - A Brief History and Status". www.epa.gov. Retrieved 2022-06-17.
  11. ^ "Parathion Methyl - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-06-17.
  12. ^ – Six Mustard gas sites uncovered – The Independent
  13. ^ Britain's Anthrax Island – BBC
  14. ISBN 978-94-009-1586-2
    , retrieved 2022-04-03
  15. ^
    S2CID 242232889
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  16. ^ European Society of Cardiology (7 July 2022). "Now cardiovascular researchers are worried about soil pollution". Yakhte.com.[permanent dead link]
  17. ^ yosemite.epa.gov
  18. ^ Article on soil contamination in China[permanent dead link]
  19. Computer modelng of pesticide transport in soil for five instrumented watersheds, prepared for the U.S. Environmental Protection Agency
    Southeast Water laboratory, Athens, Ga. by ESL Inc., Sunnyvale, California (1973)
  20. PMID 28652852
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  21. S2CID 242232889. Retrieved 2022-07-10. {{cite book}}: |website= ignored (help
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  22. S2CID 212689936
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  23. OCLC 801654870.{{cite book}}: CS1 maint: others (link
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  24. ^ S.K. Gupta, C.T. Kincaid, P.R. Mayer, C.A. Newbill and C.R. Cole, "A multidimensional finite element code for the analysis of coupled fluid, energy and solute transport", Battelle Pacific Northwest Laboratory PNL-2939, EPA contract 68-03-3116 (1982)
  25. PMID 26414316
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  26. ^ A. Agarwal, Y. Zhou, Y. Liu (2016) Remediation of oil contaminated sand with self-collapsing air microbubbles. Environmental Science and Pollution Research DOI: 10.1007/s11356-016-7601-5
  27. S2CID 239680091
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  28. ^ Facing up to "invisible pollution"
  29. PMID 25514502
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  30. ^
    PMID 23843802
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  31. ^ Jannik, T.; Stagich, B. (2017-05-25). Land and Water Use Characteristics and Human Health Input Parameters for use in Environmental Dosimetry and Risk Assessments at the Savannah River Site 2017 Update (Report). Office of Scientific and Technical Information (OSTI).
  32. ^ "www.ContaminatedLAND.co.uk - ICRCL 59/83 Trigger Concentrations". Archived from the original on 2016-10-09. Retrieved 2016-05-04.
  33. ^ "What are "Soil Guideline Values" and which should I use?". Manaaki Whenua. 10 August 2019. Retrieved 2022-07-10.
  34. ^ "LCRM: Stage 1 risk assessment". GOV.UK. Retrieved 2022-07-10.
  35. ISSN 0269-7491
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  36. ^ contenu, English name of the content author / Nom en anglais de l'auteur du (1994-01-01). "English title / Titre en anglais". www.tbs-sct.gc.ca. Retrieved 2021-02-19. {{cite web}}: |first= has generic name (help)
  37. S2CID 86686979
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  38. ^ Yadav, Priya (2 April 2009). "Uranium deforms kids in Faridkot". The Times of India.
  39. ^ Jolly, Asit (2 April 2009). "Punjab disability 'uranium link'". BBC News.
  40. ^ Uranium in Ground Water Ministry of Drinking Water and Sanitation, Government of India (2012)
  41. ^ Atomic Energy Report – Malwa Punjab Uranium Q&A Archived 2014-02-28 at the Wayback Machine Lok Sabha, Government of India (2012)

External links

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