Arsenic (As) is a heavy metal. After accessing its certain (WHO recommended) concentration level in soil, water and crops it will be harmful to human health. But how is it increase in soil and water?
Arsenic (As) increases in soil and water mostly due to anthropogenic activities such as mining, and industrial activities such as metallurgy among others. Mining operations in particular is one of the major source of As in environment, it liberates As from oxidation of metal ores such as Arsenopyrite in the presence of water and atmospheric oxygen.
Attached are some of the research papers;
Article Assessment of water quality of man-made lakes in Klang Valle...
Article Consumption of water from ex-mining ponds in Klang Valley an...
Article Application of Multivariate Analysis in the Evaluation of Me...
Article Spatial variability in surface water quality of lakes and ex...
In soil and water, arsenic mainly increase by anthropogenic acitivities
Arsenic is a metalloid or semi-metal and can be added to soil and water through natural and anthropogenic activities. In Indian and its subcontinents, the geological formations due to volcanic activities in the lower Himalayan-Gangetic and Brahmaputra basin is a major reason for increased As concentration in groundwater. Bangladesh, and Bihar and West Bengal state of India are worst affected due to As from natural sources. The depletion of the groundwater table can also add to its concentration increment. Mining and several industrial discharges can also contaminate soil and water with As.
Arsenic contamination and pollution of soils arises from the activities listed by Isa but also from agricultural activity - specifically the use of arsenical pesticides and herbicides. For example, it was common for cotton farmers in the USA to defoliate the cotton plants by spaying with arsenical herbicide (to make the leaves drop off) before machines could pick the cotton bolls. The As accumulated in soils and could poison other crops when grown in place of cotton: rice has straighthead disease if grown straight after cotton. Arsenic also has been known to accumulate in fruit orchards from the use of arsenical spray used as insecticides. Livestock dipping once used arsenical tickicides but in such cases pollution was highly localised around the dipping pens.
More diffuse loading of arsenic onto soils arises from the widespread use of arsenic-polluted groundwater for irrigation, a growing problem in deltaic regions, especially the Bengal basin.
As sort-of-in-between case was the spill of arsenic from a pesticide factory in Kolkata, India, in the 1980s that polluted groundwater under a large part of southern Kolkata - it had almost disappeared by 2018.
In Northern India, arsenic pollution of groundwater has a natural, not an anthropogenic, source and is driven by reduction of sedimentary iron oxides onto which arsenic was sorbed. Neither the source of arsenic, nor its mobilization, is connected in any way with volcanism.
Relevant articles to illustrate these points are on ReseachGate under my name.
Arsenic may increase in soil and water via both natural and anthropogenic sources...!
Arsenic-enriched minerals, volcanic action, erosion of rocks, and forest fires are the primary natural sources of As in the environment (hydrosphere, pedosphere, biosphere, and atmosphere) and insecticides, herbicides and phosphate fertilizers, semi-conductor industries, mining and smelting, industrial processes, coal combustion, timber preservatives, etc. are the anthropogenic sources ...
Arsenic is a naturally-occurring metalloid in many flood-basin sediments around the world, such as the Ganges-Brahmaputra-Meghna Delta. It commonly occurs as chemically-bound in Fe(II) oxyhydroxides, pyrite, and as such is inert. Trouble starts if the shallow aquifer domain in the basin is anoxic and rich in organic carbon. This cocktail triggers the reductive dissolution of As by microbial metabolism. The dissolved arsenic then enters the aquifer and is prone to human consumption by direct ingestion and irrigated crops.
For more on this I refer to our recent publication: Ghosh et al. (2021) https://doi.org/10.1016/j.scitotenv.2020.144400
It also depends if you mean what's is the reason of As increase in the surface soil. A number of articles have found that frequent As rich groundwater irrigation during rice cultivation also increases As content in the surface soil. This is one of the classic reason for high As content in the topsoil (especially in the agricultural fields) in Bangladesh. This plays a significant role for As uptake in the rice and other crops frequently grown here.
Dear Md. Abul Kalam Azad many thanks for raising this important and serious technical question. Arsenic is indeed highly toxic for both animals and humans, and bioaccumulation of arsenic is a severe problem. For more detailed information about various aspects of arsenic bioaccumulation please see the following relevant articles:
1. Arsenic bioaccumulation in arsenic-contaminated soil: a review
Article Arsenic bioaccumulation in arsenic-contaminated soil: a review
This is a highly useful review article which will provide you with a comprehensive overview of the topic. It covers the arsenic bioaccumulation in soil, water, and air. As a review article it has the additional advantage that it contains numerous references to original research work in the field. The article can be freely downloaded from the general internet. For your information please find attached a pdf file of this paper.
2. Bioaccumulation of Arsenic in Marine Fish and Invertebrates from Alaska and California
Article Bioaccumulation of Arsenic in Marine Fish and Invertebrates ...
This article is freely available as public full text on RG.
- Badges
- Science topic
- Similar topics
- Agricultural Science
- Agronomy
- Crop Science
- Crop