# Technical Bulletin on Arsenic- A health risk assessment

Sanjay Kumar Singh, Ajeet Kumar, A.K. Singh

► To cite this version:

Sanjay Kumar Singh, Ajeet Kumar, A.K. Singh. Technical Bulletin on Arsenic- A health risk assessment. DR. RAJENDRA PRASAD CENTRAL AGRICULTURAL UNIVERSITY BIHAR, PUSA (SAMASTIPUR)-848125, INDIA. 2021, pp.1-33. [hal-04960965](https://hal.science/hal-04960965v1)

HAL Id: hal-04960965

https://hal.science/hal-04960965v1

Submitted on 21 Feb 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>
Technical Bulletin
On
# Arsenic- A health risk assessment
## आर्सेनिक- एक स्वास्थ्य जोखिम मूल्यांकन

<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

Department of Soil Science
Tirhut College of Agriculture,
Dholi, Muzaffarpur-843 121

<figure><img src="image_4.png" /></figure>

Dr. Rajendra Prasad Central Agricultural University
Pusa (Samastipur)-Bihar

November-2021
Technical Bulletin No. SS-1/2021: Arsenic- A health risk assessment

Technical Bulletin, November, 2021

Tirhut College of Agriculture, Dholi, Muzaffarpur-843 121,
RPCAU, Pusa (Samastipur), Bihar, India

Published by

**Dr. A.K. Singh**

Dean, Tirhut College of Agriculture, Dholi

RPCAU, Pusa (Samastipur), Bihar

Phone:9415920101

Email: dean.tca@rpcau.ac.in

Year of publication: November, 2021

Copy right reserved

All rights reserved. No part of this
publication shall be reproduced or
transmitted in any form by print,
microfilm or any other means
without written permission of the
Dean, TCA, Dholi, Muzaffarpur, ,
RPCAU, Pusa (Samastipur),
Bihar.

Authors: Conceptualized and written by

SANJAY KUMAR SINGH. Assistant Professor (Soil Science), TCA, Dholi, RPCAU, Pusa, Bihar.

AJEET KUMAR, Assistant Professor-cum-Scientist (Soil Science), SRI, RPCAU, Pusa, Bihar

Critically reviewed and edited: by

A. K. SINGH, Dean, Tirhut College of Agriculture, Dholi, RPCAU, Pusa, Bihar

Designed and Print: by

Maa Shakuntala Graphics, Imili Chatti, Muzaffarpur

Citation

Singh, S.K., Kumar, A. and Singh, A.K (2021). Arsenic- A health risk assessment; Technical Bulletin No.SS-1/2021. Tirhut College of Agriculture, Dholi, RPCAU, Pusa (Samastipur)-Bihar, India, pp. 1-33.
# Arsenic- A health risk assessment

## आर्सेनिक- एक स्वास्थ्य जोखिम मूल्यांकन

By

SANJAY KUMAR SINGH

AJEET KUMAR

A.K. SINGH

Department of Soil Science
Tirhut College of Agriculture
Dholi, Muzaffarpur-843 121

DR.RAJENDRA PRASAD CENTRAL AGRICULTURAL UNIVERSITY
PUSA, SAMASTIPUR-848125, BIHAR, INDIA

November-2021
CONTENTS

<table><thead><tr><td>Sl. No.</td><td>PARTICULARS</td><td>PAGES</td></tr></thead><tbody><tr><td>1.</td><td>Introduction</td><td>5-5</td></tr><tr><td>2.</td><td>Forms of Arsenic</td><td>6-11</td></tr><tr><td>3.</td><td>Distribution of arsenic in different components</td><td>12-15</td></tr><tr><td>4.</td><td>Arsenic distributions in Soils</td><td>15-20</td></tr><tr><td>5.</td><td>Effect of arsenic with various physicochemical properties</td><td>20-22</td></tr><tr><td>6.</td><td>Adverse Effect of Arsenic on Plants</td><td>23-23</td></tr><tr><td>7.</td><td>Methods of remediation</td><td>24-25</td></tr><tr><td>8.</td><td>Phytoremediation</td><td>25-26</td></tr><tr><td>9.</td><td>Health Implications of Arsenic Poisoning</td><td>26-26</td></tr><tr><td>10.</td><td>Arsenic toxicity in Human Being</td><td>27-27</td></tr><tr><td>11.</td><td>Arsenic Toxicity Remedial Options</td><td>28-28</td></tr><tr><td>12.</td><td>References</td><td>29-33</td></tr></tbody></table>
**1. Introduction**

Arsenic (As) present in the environment as simple metalloids belongs chemically in both inorganic and organic forms. It is most abundant in soils and occupies 20th rank in the earth's crust, and 14th rank in seawater, whereas for the human body, it ranks 12th (Singh *et al.*, 2015). The most common forms are arsenite viz., trivalent form (AsIII) being more water soluble and become more toxic than arsenate viz., pentavalent form (AsV) (Abdul *et al.*, 2015). Arsenic in water typically occurs in inorganic forms, as oxyanions of arsenite or arsenate, depending on the pH and also the redox potential of water (Ali *et al.*, 2018), however, its availability in food identified in both organic and inorganic forms depending on the specific food (EFSA 2009). Arsenic shows a complex chemical nature as it exhibits four different oxidative states in the environment and preserve in environment that arsenic species exhibit different toxicity (Khalid *et al.*, 2017; Naujokas *et al.*, 2013) and inorganic forms, as oxyanions of arsenite or arsenate, depending upon the pH and redox potential of water (EFSA, 2009; Ali *et al.*, 2019).

**2. Arsenic chemical properties**

○ Atomic Number : 33

○ Atomic Weight : 74.92

○ Elemental classification : Metalloid

○ Group : Pnictogen (VA)

○ Oxidation Number : +5, +3, 0, -3

○ Phase at STP : Solid

○ Electronic Configuration : 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p³

○ Estimated Crustal Abundance : 1.8 ppm

○ Estimated Oceanic abundance : 3.7 mg/L

○ Probable Arsenic Discoverer : Albert Magnus(1250)

<figure><img src="image_5.png" /></figure>
## 3. Forms of Arsenic

### INORGANIC FORMS

* Arsenate - As(V)

* Arsenite - As(III)

### ORGANIC FORMS

* Monomethyl Arsonic Acid (MMA)

* Dimethyl Arsonic Acid (DMA)

Arsenobetaine (AB)

In the worldwide scenario, 100 million populations, survives at risk of consuming contaminated water, however, more than 45 million people reside particularly in Asia. In India, the appearance of arsenic in groundwater found in several states mainly reported fluvial and deltaic deposits, however, in the regions of Karnataka and Chhattisgarh are

exceptional where arsenic identified in association with sulfide-rich arsenic minerals (arsenopyrite) (Bhattacharya, 2017). In Bihar states, initially, the contaminants were reported in the groundwater of Bhojpur district, in 2002, which contains the highest arsenic concentration of 1684 µg L-1 (Chakraborti et al., 2003) in which mainly the area of the Gangetic Plain found more prone to the arsenic pollutant. Several types of research were also studied in different locations along the Gangetic Plains identified (Chakraborti et al., 2018) contamination in groundwater with a concentration above the permissible limit. The occurrence of arsenic in groundwater and soil poses a serious health hazard occurs all over the world. Its frequent exposures to the environment raise various complications and symptoms in humans. Availability of arsenic pollutants depends on locations around the globe, arsenic can enter into different environmental components via four geological processes – alkaline

<figure><img src="image_6.png" /><figcaption>As(V)</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>As(III)</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>MMA</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>DMA</figcaption></figure>

<figure><img src="image_10.png" /><figcaption>Arsenobetaine (AB)</figcaption></figure>
desorption, sulfide oxidation, reductive dissolution, and geothermal activities. Apart
from this, the elevated quantity of arsenic also builds up in the environment, through
various anthropogenic activities considering mining and smelting operations, fossil
fuel combustion, arsenic-based agrochemicals, and disposal of municipal and
industrial wastes leave adverse effects even at very low concentrations. As per the
provisional guidelines of the World Health Organization (WHO 2011) and BIS
(Bureau of India Standards), the permissible limit of arsenic in drinking water
considered 0.01 ppm (10 µgL⁻¹) and 0.05 ppm (50 µgL⁻¹) as the upper safe limit.
However, in the agricultural field, the maximum acceptable limit for arsenic is 20 mg
kg⁻¹ as recommended by European Community (Bhattacharya et al., 2009). some of
the blocks of West Bengal provinces also reported elevated total arsenic content in the
soil, and rice grains

<figure><img src="image_11.png" /><figcaption>Fig. 1. Arsenic affected countries of the world with intensity shown by the size of the plots irrigated with arsenic-contaminated groundwater in the affected area (Alam and Sattar, 2000; Golui *et al.*, 2017).</figcaption></figure>

The soil types also influence the distribution of arsenic content, the trend of
variability found may be due to the high arsenic sorption capacity of amorphous Al
and Fe oxides that occurred predominantly in the Andisols (Hua, 2010; Srivastava and
Sharma, 2013). Assessment of arsenic at the surface and sub-surface and plant part of paddy growing field obtained higher than the average of 10 mg kg-1 of arsenic naturally present in soil worldwide and 6.5 mg kg-1 of arsenic in the farmland in Taiwan (Lin et al., 2015). The accommodation of arsenic in the soil associated with physical-chemical parameters of soil and groundwater (Alam et al., 2016) and its uptake and accumulation through soils by plants are influenced by factors such as plant species (Matschullat et al., 2002), soil arsenic concentration (Jiang and Singh, 1994), and other physical and chemical soil properties, among which concentration of other ions particularly phosphate (Jiang and Singh, 1994; Matschullat et al., 2002). The description of statistical analysis and correlation coefficient have analyzed and arsenic contamination in soil and results were demonstrated through maps prepared by GIS interpolation (Kumar et al., 2017; Santhi et al., 2018; Khanda et al., 2018; Sethy et al., 2019). Few information's, are available about the special variability of arsenic and its correlation with soil quality attributes and their impacts on arsenic accumulation in agricultural produce. An earlier study done mainly in the Gangetic plains of Patna, Saran, and Vaishali districts of Bihar reported high levels of arsenic contamination (Kumar et al., 2010; Kumar et al., 2016). The results of previous studies indicate the need for monitoring approaches to arsenic contamination in water and soils. Despite the many studies, on the occurrence of arsenic in the soil along with drinking water in the country, it reveals, there is very little information has been generated on the arsenic concentration in soil and drinking water in this particular area. In current scenario water pollution due to arsenic contamination in ground water is a global issue, which not only pose a serious health risk (Shaji et al., 2021; Ravenscroft et al., 2011; Bhowmick et al., 2018), leading to adverse effect on human beings and ecosystem but also impedes the development of societies and their economy (Kamar et al., 2017). The appearance of arsenic in the environment mainly originated from natural and anthropogenic sources viz., mining process, burning of fossil fuels, use of arsenic containing fungicides, herbicides and insecticides in agriculture and use of wood preservatives also causing contamination of ground water (Islam et al., 2000; Bhattacharya, 2017; Chakarborti et al., 2018).
<figure><img src="image_12.png" /><figcaption>Fig. 2. Arsenic affected states and Union Territories in India.
(source: www.mapsofindia.com; Chakraborti et al., 2018; CGWB, 2018)</figcaption></figure>

<figure><img src="image_13.png" /><figcaption>Fig. 3 Status of total arsenic (mg L⁻¹) in groundwater</figcaption></figure>
<figure><img src="image_14.png" /></figure>

Fig. 4. Average arsenic concentrations in rocks, sediments and soils. The main sources of As could be slate/phyllite/mudstone/marine shale/peaty soils sources (www.igrac.net/publications/143)

The raised arsenic concentration is directly affecting the crops (Zhang et al., 2002; Reza and Singh, 2010) and it is the significant route of arsenic into the human body by means of food chain (Anawar et al., 2006). In India, the large-scale arsenic contaminated ground water is attributed to deltaic deposits. However, the region of
Karnataka and Chhattisgarh states of India are exceptional where it is associated with sulphide rich arsenic minerals (Bhattacharya, 2017). In Uttar Pradesh state of India, the earlier studies conducted by various researchers showed that more than 26 % water samples were contaminated with arsenic (>50 µgL⁻¹), and this might be released from associated sediments deposited from Himalayas (Sah, 2017; Srivastava and Sharma, 2013). The first arsenic contamination was reported in Bhojpur district of Bihar state of India in 2002, with the highest concentration of 1684 µgL⁻¹ (Chakraborti et al., 2003; CGWB, 2018).

## Arsenic Distribution

<figure><img src="image_15.png" /><figcaption>Fig. : Total Concentration of arsenic obtained by ICP/MS and the sum of As(III) and As(V) obtained by HPLC-HG-AFS in different parts of Brake fern (*Pteris vittata*)</figcaption></figure>

Source : Zhang et al., 2002

<figure><img src="image_16.png" /><figcaption>Fig. 5. Pie-chart showing continent-wise arsenic source characterisation.</figcaption></figure>
# Distribution of arsenic in different components

## Arsenic and other constituents' distribution in Groundwater

Chakrabarti et al. (2003) evaluated the arsenic exposure (first time in Bihar) in the Semaria Ojha Patti village of Bhojpur district of Bihar by analysing the arsenic content of water from the tube wells (95 % of the total in village), they observed that 56.8% samples got exceeded the arsenic concentration of 50 µg L⁻¹, however, 19.9% samples poses As concentration >300 µg L⁻¹. Shiber (2005) analysed nearly twenty seven tap water samples, from homes in 26 counties of Eastern Kentucky, Western West Virginia, South Eastern Ohio and North Eastern Tennessee, USA and reported that nearly half of samples i.e. 43% had 0.5–1.0 ppb, 34 % had 1.1–3.0 ppb, 6% had 3.1–5.0 ppb and 6% had arsenic for exceeding the maximum contamination level of 10 ppb recently set by United States Environmental Protection Agency (USEPA).

Ghosh et al. (2007) conducted a survey at Patna, Vaishali, Bhojpur and Bhagalpur districts of Bihar. Their findings concluded that Maner and Danapur blocks of Patna district and Hajipur block of Vaishali district were found the worst affected blocks on the basis of percentage of the samples collected containing more than 10 ppb arsenic. In their study the highest arsenic concentration of 1861 ppb among all the tested samples, was obtained in village Pandey Tola of Bhojpur district. Bang et al. (2009) investigated that the characteristics of arsenic-contaminated groundwater and the potential risks from the groundwater in four villages (Vinh Tru, Bo De, Hoa Hau, Nhan Dao) in Ha Nam province of northern Vietnam. The concentrations of arsenic in the three villages (Vinh Tru, Bo De, Hoa Hau) significantly exceeded the Vietnamese drinking water standard for arsenic (10 µg L⁻¹) with average concentrations of 348, 211, and 325 µg L⁻¹, respectively. According to their results of the arsenic speciation testing, the predominant arsenic species in the groundwater existed was arsenite. Chetia et al. (2010) collected two hundred twenty-two (222) groundwater samples for the study from shallow and deep tubewells of six blocks of Golghat district in Assam. In the investigation, all the samples of block had As and Fe concentration above the WHO permissible limit (0.01 and 0.3 ppm), with the highest As and Fe concentration recorded was 0.128 and 5.9 ppm respectively. They concluded that it may be due to a strong co-relation between As and Fe (0.697 at p<0.01) reductive dissolution might be
the possible reason for the mobilization of the As in the groundwater of the surveyed
region. Ranjan *et al.* (2012) studied the chemical quality of the groundwater of thirty
(30) water samples received from the Phalgu river plains of Gaya district, and
analyzed the cationic and anionic concentration as Ca²⁺>Mg²⁺>Na⁺>K⁺ and
HCO₃⁻>Cl⁻>SO₄²⁻>NO₃⁻>PO₄³⁻ respectively. The arsenic concentration occurred in
all the samples ranged from negligible to 5.79 ppb and none of the analysed samples
exceeded the WHO permissible limit of As content in drinking water. Khan *et al.*
(2012) have explained, in order to understand the water quality of Triveni Lake,
physico-chemical parameters were studied and analysed for the period of one year.
They have studied on various physicochemical parameters, such as water temperature,
air temperature, pH, humidity, conductivity, free CO₂, total solid, dissolved oxygen,
Total alkalinity, total hardness, CaCO₃, Ca⁺⁺, Mg⁺⁺. The results revealed that there
was significant seasonal variation in some physico-chemical parameters and most of
the parameters were in normal range and indicated better quality of lake water.

Nath *et al.* (2013) investigated that the quality of drinking water samples
collected from all 23 blocks of Patna, and estimated their arsenic concentration via
atomic absorption spectrophotometry with vapor generation assembly (AAS-VGA).
Analysis revealed that the arsenic concentration in samples showed 50 and 100 ppb,
respectively. Surveyed population also showed high incidence of cancers of various
organs such as skin, breast, liver, and gall bladder. Rodríguez-Lado *et al.* (2013)
carried out a study considered16 environmental proxies, in the form of 30 arcsec (~1
km²) digital raster maps, as potential factors for identifying areas affected by geogenic
arsenic hazard. Only eight proxies were significantly linked to the regional
distribution of high arsenic occurrence and were used, together with geo-referenced
arsenic measurements, to develop an ensemble model with binomial logistic
regression as the base classifier. The model forecasts that the area at risk of
groundwater arsenic contamination (>10 mg L⁻¹) may encompass more than 580,000
km², and it pinpoints elevated arsenic concentrations in regions where endemic arsenic
poisoning has already been detected earlier. Large areas such as Tarim basin
(Xinjiang), Ejina basin (Inner Mongolia), Heihe basin (Gansu), Qaidam basin
(Qinghai), the Northeastern plain (Inner Mongolia, Jilin, and Liaoning), and the North China plain (Henan and Shandong) were identified as being potentially affected.

Gaikwad and Sasane (2014)haveassessed the water quality of the groundwater in and around Lonar Lake. Water quality has considered pH, total hardness, calcium, magnesium, bicarbonate, chloride, nitrate, sulphate, total dissolved solids, iron, manganese and fluorides. In the study, the higher values found mainly with Iron, Total hardness, chloride, fluoride, calcium and magnesium, many literature shown that groundwater quality in Lonar Taluka has been badly affected by nitrate contamination. Shrestha et al. (2014) determined the variability of arsenic contamination in groundwater and total 55 groundwater samples in post-monsoon season and 45 groundwater samples in pre-monsoon season were collected. The level of arsenic contamination in groundwater was noticed above the Nepal interim standard of 50 ppb. About 28 water samples showed higher quantity of arsenic out of total 42 water samples in each pre monsoon season. Singh et al. (2014) conducted a survey in some villages of Vaishali and Bhagalpur district of Bihar, and found that only in Bhagalpur district concentration of arsenic exceeded the FAO standard of 100µg L⁻¹ for irrigation water. The arsenic concentration in the ground water of both the districts exceeded the maximum permissible limit as prescribed by WHO (10 ppb), with a maximum value of 20µg L⁻¹ in Vaishali and 143µg L⁻¹ in Bhagalpur. Chakraborti et al. (2016) investigated the arsenic contamination in five blocks of Patna district, and found that about 61% and 44% of the tube wells had arsenic contaminated above 10 µg L⁻¹ and 50 µg L⁻¹, respectively and the maximum arsenic concentration was recorded as high as 1466 µg L⁻¹. They also found that 100% of the biological samples had arsenic above the normal levels (concentrations of arsenic in hair, nail and urine of unexposed individuals usually ranges from 20 to 200 µg kg⁻¹, 20–500 µg kg⁻¹ and <100 µgL⁻¹,respectively), indicating many people are sub-clinically affected. Jangle et al. (2016) developed a geo-statistical model based on measured arsenic concentration in the aquifers and hydro-geomorphological factor for Vaishali district. They found the groundwater arsenic concentration in the range of 50 – 88 µg L⁻¹; and got high spatial variability of arsenic concentration can be modelled well based on hydro-geomorphological parameters, most importantly proximity to river and depth of hand
tube well. Patel *et al.* (2016) conducted a survey to study the groundwater arsenic in Rajnandgaon district, Chattisgarh in 20 groundwater samples in each season from Ambagarh Chowki region in post monsoon and premonsoon period. Arsenic concentrations in water of the tube wells were above the WHO drinking water guideline value (10 µg L⁻¹) ranging from 148 to 985 µg L⁻¹ with a mean value of 506 ± 118 µg L⁻¹.

Litter *et al.* (2019) presented an overview about the presence of arsenic in groundwater’s of Argentina, made by a trans disciplinary group of experts. The most affected region in Argentina, where approximately 88% of 86 groundwater samples collected in 2007 exceeded the World Health Organization (WHO) guideline value. In the Salí river basin, arsenic concentrations ranged from 11.4-1660 µg L⁻¹, with 100% of the samples above the WHO guideline value. In the Argentine Altiplano (Puna) and Subandean valleys, 61% of 62 samples collected from surface and groundwater’s exceeded the WHO limit. Maity *et al.* (2020) assessed the levels of various parameters, including Arsenic and other heavy metals, of hand dug wells groundwater collected from six villages of Bhojpur district. Analysis revealed that the water samples were highly contaminated with arsenic and iron with the concentration ranging from 24.3 to 168.07 mg L⁻¹ and 0.17 to 1.16 mg L⁻¹ respectively, that indicated the excessive withdrawal of groundwater for domestic and irrigation purposes with a significant correlation between both the metals. They suggested that all hand pumps which should be capped immediately and if and wherever possible, supply for alternate sources of drinking water like piped water, should be implemented.

## 2.2 Arsenic distributions in Soils

Islam *et al.* (2000) analysed the arsenic content in surface soil and observed that the values exceeded the typical world soil concentration of 5 mg kg⁻¹ reported by Wedepohl (1969-1979) and opined that this was because of strong affinity of arsenic to organic matter, hydrous oxide of Fe and Mn, and clay mineral. Chen *et al.* (2002) studied the arsenic concentrations in 441 taxonomically geographically representative surface soils of Florida, USA using the EPA method 3052 (HCl-HNO₃-HF digestion) and they found that arsenic concentrations (mg kg⁻¹) followed the soil
taxonomic order viz., Histosols (2.35) > Inceptisols (0.98) > Mollisols (0.72) > Ultisols (0.51) Alfisols (0.39) > Entisols (0.36) > and Spodosols (0.18). The highest arsenic concentrations were found in soils that occur exclusively or prevalently in wetlands, such as Hemists (3.16-9.44), Saprists (0.15-11.7), Aquents (0.10-50.6), Aquolls (0.03-3.34), and Aquepts (0.03-38.2). Arsenic release from bedrock (limestone) and arsenic bioaccumulation by aquatic organism are possible explanations for relatively high arsenic in those wetland soils. While the use of a single regulatory value criterion for arsenic contamination in soil cannot provide an adequate assessment given in the natural variation in soil arsenic, baseline soil-As concentration (defined as 95 percent of the expected range of background arsenic concentrations in different soil categories), is necessary for proper assessment of potential arsenic contamination. De Gregori *et al.* (2003) determined the arsenic concentration of agricultural soils in three different geographical zones of Chile, namely Tarapaca, Antofagasta and Valparaiso. They observed that the total arsenic concentration varied from 2.7 to 202 mg kg⁻¹, where, maximum arsenic concentration of about 106 and 202 mg kg⁻¹ was found in soils of Calama and Quillagua belonging to Antofagasta site. This high arsenic concentration is attributed to Calama and Quillagua sites are irrigated with water from the Loa River, that receives the Salado River as an effluent, which has a genetic relation with the geothermal field “El Tatio”, contaminated naturally with this element. Bhattacharya *et al.* (2009) studied the status of soil arsenic level in Nadia district of West Bengal, which is irrigated by groundwater having high arsenic level (0.11±0.012 and 0.76±0.014 mg L⁻¹). They also found that the total arsenic concentration in the soil ranged from 1.38±0.108 to 12.27± 0.094 mg kg⁻¹ (on dry weight basis), which was below the maximum acceptable limit for agricultural soil of 20 mg kg⁻¹ as recommended by European Community. Bhattacharya *et al.* (2010) investigated the arsenic concentration in irrigation water and soil of Nadia District, West Bengal and observed that the arsenic contaminated in irrigation water (0.318-0.643 mg L⁻¹) and soil (5.70-9.71 mg kg⁻¹) which considerably influenced the accumulation of arsenic in rice, pulse and vegetables in the study area. Arsenic concentrations of irrigation water samples were many folds higher than the WHO recommended permissible limit for drinking water (0.01 mg kg⁻¹) and FAO
recommended permissible limit for irrigation water (0.1mg L⁻¹). However, the levels of arsenic in soil were, noticed lower than the global reported average 10 mg kg⁻¹ which was below the EU recommended maximum acceptable limit for agricultural soil (20.00 mg kg⁻¹). In order of accumulation of arsenic (mean concentration) was found as follows: potato > rice grain (Boro) > arum > amarnath > radish > rice grain (Aman) > lady's finger > cauliflower > brinjal > papaya > spinach > cabbage > mustard seed > pumpkin > onion bulb > pea > wheat > garlic > lentil > beans > green chili > tomato > bitter gourd > lemon > turmeric. A field study was carried out by Hue (2010) to study about the total arsenic content in some soil orders, sediments and stream waters of Hawaii. According to him, arsenic levels in Hawaii soils were quite variable, ranging from 15 to 950 mg kg⁻¹. Andisols contained more arsenic (mean 163 mg kg⁻¹) than the other soil orders followed by Oxisols (mean 72 mg kg⁻¹) and Ultisols (mean 60 mg kg⁻¹). This trend was found perhaps due to high arsenic sorption capacity of amorphous Al and Fe oxides that are predominant in the Andisols. He also reported that arsenic level in some stream waters are likely related to arsenic impacted soil.

Srivastava and Sharma (2013) conducted a surveywork to estimate the arsenic content in the soils of four villages belonging to two eastern districts, namely Ballia (Sohaon and Haldi village) and Ghazipur (Karkatpur and Dharmarpur village), of Uttar Pradesh. They found that the arsenic content in soil samples ranged from 5.40 to 15.43 ppm, where, maximum concentration (15.43 ppm) detected in soil of Sohaon village. The average value of arsenic levels in soils followed the order: Karkatpur (9.24 ppm) < Haldi (9.82 ppm) < Dharmarpur (11.32 ppm) < Sohaon (14.08 ppm). The arsenic present in the soil was gradually accumulated by application of highly contaminated arsenic water for 10 – 20 years. Lin *et al*. (2015) conducted a field experiment over an extensive area of Beitou in Taipei, Taiwan, to measure the arsenic content in paddy soil and in different parts of paddy plant. The arsenic levels in paddy topsoil and subsoil ranged from 62 to 531 mg kg⁻¹ and 52–530 mg kg⁻¹ dry weight, respectively. The mean ± SD concentrations were 192 ± 99 and 212 ± 107 mg kg⁻¹, which were far higher than both of the reported average of 10 mg kg⁻¹ of arsenic naturally present in soil worldwide and 5.65 mg kg⁻¹ of arsenic in the farmland in Taiwan. The mean ± SD total arsenic concentrations in rice grain was 0.201 ± 0.198
mg kg⁻¹ dry weight, with a range of 0.076–1.183 mg kg⁻¹ in the extremely contaminated soil (62–531 mg arsenic kg⁻¹ dry weight in topsoil). Golui *et al.* (2017) conducted a survey in twenty eight farmers field located within Kaliachak II, Kaliachak III and English Bazar block of Malda district, West Bengal and determined the arsenic content in soil, irrigation water and rice grains. The total and Olsen extractable arsenic concentration ranged from 0.55 – 11.5 mg kg⁻¹ and 10.9 – 606 µg kg⁻¹ respectively. Irrigation water used in the rice field was within range from 0.18 to 0.57 mg L⁻¹, and the concentration of arsenic in the rice grain was in range of 2 – 1260 µg kg⁻¹ with mean concentration of 146 µg kg⁻¹. Further, they analysed the arsenic content in drinking water and found in the range of 4.2 – 884 µg L⁻¹ with mean concentration of 271 µg L⁻¹. In 12.1% and 77.3% of the collected drinking water samples the levels of arsenic concentration were 10 – 50 µg L⁻¹ and >50 µg L⁻¹ respectively. Out of the total surveyed drinking water only 10.6% sources were safe compared to the WHO provisional drinking water guideline of 10 µg L⁻¹. Khalid *et al.* (2017) stated that arsenate (As⁺⁵) and arsenite (As⁺³) prevail in the natural environment are highly toxic and mobile As⁺³ prevails in reduced conditions, and As⁺⁵ is dominant under oxidized environments. Various reactions occurring in soil could affect solution and solid-phase arsenic speciation in soil and as such could control plant uptake of As and its biogeochemical behaviour in the soil-plant system. These dynamic soil reactions affecting arsenic biogeochemical behaviour, such as oxidation-reduction, sorption-desorption, precipitation/dissolution, volatilization, biological transformations, formation of As-ligand complex and plant species diversity, could be physical, biological, and chemical in nature. Mandal *et al.* (2019) conducted a field experiment at Mamalkha (22°22'38"N, 87°11'38"E), Sabour, Bihar, India, using wheat and maize as test crops, to determine the efficacy of organic amendment in reducing the availability of arsenic in arsenic contaminated soil. The effect of organic amendment in reducing the availability of arsenic was brought forward through the determination of Olsen's extractable arsenic in post-harvest soil of both the crops. It showed that the plot treated with sugarcane bagasse had least extractable arsenic content for both crops. The different organic amendment reduced the accumulation of arsenic in wheat grain to the extent of 84% (sugarcane bagasse), 50% (decomposed
rice straw) and 40% (paddy husk) compared with the control. Similarly, the reduction of arsenic concentration in maize grain was found highest in the plot treated with sugarcane bagasse (18%), and followed by decomposed rice straw (14%) and paddy husk (7%). Sugarcane bagasse was most effective in reducing the extractable arsenic because it had high binding capacity than other traditional organic amendment, and this effectiveness was mainly due to presence of cellulose, hemicellulose and lignin with a large number of functional groups (–OH, –COOH, –NH2, –CONH2, –SH2 and –OCH3) providing strong binding sites for oxyanions.

Hossain *et al.* (2001) reported arsenic distribution depth wise in soils of three districts, namely Moulavibazar, Habiganj and Sylhet, of Bangladesh. The average arsenic content in whole soil profile of each district ranged from 1.32–31.89, 0–16.87 and 0.66–17.57 ppm for Moulavibazar, Habiganj and Sylhet districts respectively. Whereas, in depth wise distribution (for three districts), the value ranged from 1.98–25.76, 3.96–30.68 and 3.96–38.23 ppm for 0–15, 15–30 and 30–45 cm depth. Thus, there was a gradual increase in arsenic concentration along with depth, with the highest value of 38.23 ppm (30–45 ppm) found at Sylhet district. Huq *et al.* (2006) studied the mechanism transfer of arsenic into soil through groundwater irrigation in Bangladesh. They reported that, irrigating rice field with groundwater containing 0.55 mg L⁻¹ of arsenic with a water requirement of 1,000 mm results in an estimated addition of 5.5 kg arsenic ha⁻¹ per annum. In most of the soil, concentration of arsenic in surface (0-15 cm) soils typically exceeded sub-surface layer. Concentration of aquaregia extractable arsenic in surface soil of an area was as high as 80 mg kg⁻¹, whereas its concentration in the subsurface soil of that area was 3 mg kg⁻¹. The highest concentration of arsenic was recorded for the arum vegetable, and this ranged from <10 mg kg⁻¹ to >100 mg kg⁻¹ in the peeled root samples. Samal *et al.* (2010) studied on transfer of arsenic from contaminated groundwater and soils to crop and vegetable and concluded that the concentration of arsenic varied with depth; and in the upper surface (0–15 cm) concentration of arsenic is higher than in sub-surface (15–30 cm) and seasonal variation was also found in the concentration of arsenic which was higher in pre-monsoon season than post monsoon season. Srivastava and Sharma (2013) conducted a survey at four villages, of Ballia and Ghazipur districts of Uttar
Pradesh, they collected 30 soil samples from two different depths i.e. 0–15 cm and 15–30 cm and found that the mean arsenic concentration of all the samples was higher in the lower depth (15–30 cm) than the upper layer (0–15 cm) of the corresponding site. The arsenic concentration(ppm) in (top soil and sub soil of) three villages were as 13.12 & 15.04, 9.48 & 10.15, and 10.09 & 12.55 for Sohaon (Ballia), Haldi (Ballia) and Dharmapur (Ghazipur) respectively. A micro level investigation was conducted by Patley et al. (2017) in the arsenic affected 10 villages of Ambagarh Chowki block, Rajnandgaon district, Chhattisgarh. Depth wise 120 samples were analysed from different villages during pre-monsoon season. The arsenic content varied from 3.36 to 6.15 mg kg⁻¹ with an average of 5.30 ± 0.867 mg kg⁻¹ in 0-20cm depth. In 20-40 cm soil depth it varied from 3.12 to 5.89 mg kg⁻¹ with an average of 4.84 ± 0.965 mg kg⁻¹ and at 40 – 60 cm soil depth arsenic content varied from 1.65 to 5.12 mg kg⁻¹ with an average of 3.36 ± 1.227 mg kg⁻¹. While, in post monsoon season in 0 – 20 cm depth, arsenic content varied from 3.01 to 5.95 mg kg⁻¹ with an average of 4.40 ± 0.933 mg kg⁻¹. In 20-40 cm soil depth it varied from 2.91 to 5.49 mg kg⁻¹ with an average of 4.40 ± 0.933 mg kg⁻¹. At 40–60 cm soil depth, arsenic content varied from 1.01 to 5.12 mg kg⁻¹ with an average of 3.36 ± 1.227 mg kg⁻¹.

## Effect of arsenic with various physicochemical properties

Hossain et al. (2001) studied the correlation between arsenic concentration in soil with some soil properties viz. texture, soil pH, electrical conductivity (EC) and organic matter content of soils collected from three districts of Bangladesh. They found a positive correlation with pH in soils of all the districts, whereas a negative correlation was found with EC in soils of Moulavibazar and Habiganj districts. The clay concentration in the soils of Habiganj and Sylhet was found negatively correlated with arsenic. Only in Habibganj district the soil organic matter content was noticed positively correlated with arsenic content of soil. Chen et al. (2002) studied on multiple regressions with soil properties (clay, pH, cation exchange capacity [CEC], organic C, and total Al), especially total Fe and P, are important factors affecting natural background concentration of arsenic in Florida soils. Clay, organic carbon, pH, CEC, total Al, total Fe and total P of soil varied significantly with arsenic concentration in soil, based on soil order. However, a positive correlation was found
between the total Fe, total Al, and organic carbon content of the soil. The pH-H₂O was non-significant with arsenic content.

Majumdar and Sanyal (2003) studied the specific arsenic adsorption by Alfisols and Entisols in West Bengal at varying initial arsenic concentrations and pH of equilibrium solution. They found that for Alfisols, arsenic sorptions decreased with increasing pH of the equilibrating solutions at a lower concentration of arsenic in the bathing solution. Interestingly, this trend got reversed at higher equilibrium arsenic concentration. The Entisols also showed the above trend but such reversal occurred at a much lower concentration of arsenic. Kouras et al. (2007) studied on the occurrence and distribution of arsenic in groundwater in the area of Chalkidiki, Northern Greece, analyzed groundwater samples from public water supply wells and private wells for arsenic and other quality parameters (T, pH, EC, Ca, Mg, Na, K, Cl, HCO₃⁻, NO₃⁻, SO₄²⁻, B, Fe, Mn). Their study revealed high spatial variation of arsenic, ranging from 0.001 to 1.840 mg L⁻¹. Almost 65% of the examined groundwater exhibited arsenic concentrations higher than the maximum concentration limit of 0.010 mg L⁻¹, proposed for water intended for human consumption. Correlation analysis revealed that arsenic was highly correlated with potassium, boron, bicarbonate, sodium, manganese and iron and suggested common geogenic origin of these elements. Shahnawazet al. (2009) presented an analysis of physico-chemical characteristics of some groundwater samples collected from shallow hand pumps, deep hand pumps and public water supply at different locations of Piro and Jagdishpur blocks of Bhojpur District of Bihar. The pH, EC, total dissolved solid, iron, sulphate and arsenic value ranged followed 6.5 – 8.5, 0.55–1.0 mmho cm⁻¹, 270–1011 mg L⁻¹, 0.11–0.65 mg L⁻¹, 12.3–80 mg L⁻¹, and 0.004–0.051 µg L⁻¹ respectively. Malana and Khosa (2011) analysed the physical and chemical quality parameters including arsenic of randomly collected 32 representative samples of groundwater from Dera Ghazi Khan (City) of Pakistan and observed that the arsenic concentration in groundwater of the study area varying from 1 to 29 µg L⁻¹. These values were within the satisfactory range recommended by WHO (i.e. <10 µg L⁻¹), for most of the samples examined except for few ones. Electrical conductance (EC) and total dissolved solids (TDS) values of groundwater were extremely high from WHO guideline values with no appreciable
change in pH values for virtually all samples. Likewise, the chemical quality of
groundwater samples also exceeded the WHO guideline values for parameters such as
chlorides, sulphates, sodium, calcium, magnesium and total hardness (TH). Oinam et
al. (2011) carried out studied to assess the groundwater quality of Bhishnupur district,
Manipur, revealed that phosphate and iron levels were highest during the pre-monsoon
season, whereas the arsenic concentration were higher during the post monsoon (1-
200 µgL⁻¹) compared to pre-monsoon (1-108 µg L⁻¹). The study also showed a strong
positive correlation between arsenic and phosphate, and negative correlation between
arsenic and sulphate, suggesting a partial influence of anthropogenic sources.

Alam et al. (2016) studied the level of arsenic and associated physicochemical parameters of groundwater, of Sahibganj district along the river Ganga in Jharkhand for three seasons. The arsenic concentration in the groundwater was found highest in Post-monsoon ranging between 1 and 133 µg L⁻¹, compared to monsoon (2 to 98 µg L⁻¹) and pre-monsoon (7 to 115 µg L⁻¹) seasons. Groundwater rich in bicarbonate and total dissolved solids. The arsenic in groundwater was found to be positively correlated with depth, phosphate, and iron suggesting both natural and anthropogenic role in the mechanism. Health risk analysis revealed high to very high carcinogenic and non-carcinogenic risk for adults and children in the communities dependent on groundwater of the study area. Rasool et al. (2016) highlighted the arsenic, heavy metals concentrations as well as their source of contamination in tube-well water and associated potential health risk to local residents of Tehsil Mailsi (Punjab), Pakistan. They observed that average concentrations of anion and heavy metals such as iron, cadmium, lead, sodium, bicarbonate, sulfate and arsenic exceeded the WHO limits. Among which EC and bicarbonate had significant positive correlation with arsenic concentration in drinking water.
Adverse Effect of Arsenic on Plants

O Arsenate (AsV): Being Analogous to Phosphate, interferes with the phosphate dependent metabolism

O Arsenite (AsIII): Disrupts functioning of thiol (-SH) rich amino acid & protein

O Reduction of Arsenate to Arsenite: Generation of Reactive Oxygen Species (ROS)

<figure><img src="image_17.png" /></figure>

<figure><img src="image_18.png" /><figcaption>Figure 6. Arsenic toxicity in plants: morphological, physiological, and biochemical</figcaption></figure>
# Methods of remediation

## Phytoremediation

* Phyto (Ancient Greek) = plant remedium (Latin) = restoring balance

* The use of green plants and the associated microorganisms, along with proper soil amendments and agronomic techniques to either contain, remove or render toxic environmental contaminants harmless.

* Process of phytoremediation

* Phytovolatization

* Phytostabilization

* Phytodegradation

* Phytoextraction

* Rhizofiltration

* Phytostimulation

<figure><img src="image_19.png" /><figcaption>Fig.1: Phytoremediation Process</figcaption></figure>

<figure><img src="image_20.png" /><figcaption>Fig.2: Phyto-extraction of metal from soils</figcaption></figure>

Phytoextraction (or phytoaccumulation or phytosequestration) uses plants or algae to remove contaminants from soil or water into harvestable plant biomass. The roots take up substances from the soil or water and concentrate it above ground in the plant biomass. The plants that can accumulate metals to exceptionally high concentration (>1000 ppm) in their shoots, are called hyperaccumulators.
<figure><img src="image_21.png" /><figcaption>Fig. 3 Arsenic (As) uptake, transport, translocation, and detoxification in plants</figcaption></figure>
Health Implications of Arsenic Poisoning

Arsenic is a widely occurring toxic metalloid in natural ecosystems. As small as 0.1 g of arsenic trioxide can prove lethal to humans. Early symptoms of arsenic poisoning include skin disorders, weakness, languor, anorexia, nausea and vomiting with diarrhoea or constipation. With the progress of poisoning, the symptoms attain more characteristic features, which include acute diarrhoea, edema (especially of the eyelids and ankles), skin pigmentation, arsenical melanosis and hyperkeratosis, enlargement of the liver, respiratory diseases and skin cancer. Some of these symptoms are shown in below given figure.

<figure><img src="image_22.png" /></figure>

<figure><img src="image_23.png" /></figure>

<figure><img src="image_24.png" /></figure>

<figure><img src="image_25.png" /></figure>
Arsenic toxicity in Human Being

In severe cases, gangrene in the limbs and malignant neoplasm are also observed. The 'Bell Ville Disease' (typical arsenic-induced cutaneous manifestations among the people of Bell Ville) in Argentina, 'Black Foot Disease' in Taiwan and 'Kai Dam' disease in Thailand are well-established as health disorders due to arsenic poisoning. As a matter of fact, the hair, nail, ski n-scale and urine samples of a large number of people, residing in the affected belt of West Bengal (India) and Bangladesh, have been analyzed by several workers. Many of these samples had more arsenic loading than permissible. Few reports are available that characterize the daily arsenic exposure through water and diet among the people living in groundwater contaminated regions and correlate the former with arsenic biomarkers. Demographic characteristics and the total daily arsenic intake through water and diet were determined in 167 participants (Group-1 participants, selected from the arsenic-endemic region) and 69 participants (Group-2 participants, selected from the arsenicnon-endemic region) in a study conducted in West Bengal by physicians working alongside agricultural scientists in a consortium mode. The findings showed significantly high dietary arsenic intake in people living in Nadia district of West Bengal, where contaminated groundwater was used for irrigation purpose, but significantly low in the region of Hooghly district, where groundwater was uncontaminated. Even after lowering the arsenic level in drinking water to 50 µg As. L (the permissible limit in India), significant arsenic exposure occurred through water and diet, reflected by the elevated level of arsenic in the arsenic biomarker, namely urine, in people living in the arsenic-endemic region studied. Those with skin lesions were found to have a higher level of arsenic in urine and hair, compared to those without skin lesion. In yet another study, the dose of daily arsenic intake from both water and diet was found to be significantly and positively associated with urinary arsenic levels in an arsenic-endemic region of West Bengal, even when people were using arsenic-safe water (50 µg As. L) for drinking and cooking purposes. When arsenic levels in drinking water were further reduced to 10 µg As. L (WHO safe limit), the dose from the diet was still found to be significantly associated with< -1 (Guha Mazumder et al., 2013 Guha Mazumder et al., 2014)
## Arsenic Toxicity Remedial Options

A number of remedial measures have been noted to be quite effective in reducing the arsenic loading in the economic produce of several crops including rice. Some of these have been mentioned earlier. The more effective ones are summarized below: Optimum conjunctive use of ground and surface water (e.g. harvested rainwater), to reduce contaminated groundwater for irrigation during the lean period, and recharge of groundwater resource with harvested rainwater, free of arsenic. Develop/ identify low arsenic-accumulating, less water-intensive high yielding crop varieties and cropping sequences suitable for arsenic-contaminated areas, especially for the lean period of January to May (e.g. cropping sequences, Elephant foot yam-mustard-sesame, Green gram-rice-mustard, etc., instead of, for instance, Olitorius jute-rice-rice and Green manure-rice-rice). Irrigate with pond-stored groundwater in which partial decontamination is facilitated by sedimentation-cum-dilution with rainwater. Enhancing the water use efficiency (through optimum water management) for groundwater irrigation, especially for summer (boro) paddy (e.g. by having recourse to judicious intermittent ponding of summer paddy during the vegetative growth period, followed by continuous ponding during the subsequent reproductive phase, which does not affect the yield significantly while cutting down the contaminated groundwater use considerably). Increased use of FYM and other organic manures + green manure crops, as well as the application of appropriate inorganic amendments (zinc/ iron salts as and wherever applicable). Identification/ development of varieties/ crops which accumulate less arsenic in the consumable parts, and where the ratio of inorganic to organic forms of arsenic is low. Developing cost-effective phyto- and bio-remediation options. Creation of general awareness through mass campaigning, holding of farmers' day, field demonstrations, taking due cognizance of the socioeconomic factors. People's participatory approach in the creation of mass-awareness about the menace as well as adopting and popularizing the remedial measures to address the problem at the local level
References

Akai, J.; Izumi, K.; Fukuhara, H.; Masuda, H.; Nakano, S.; Yoshimura, T.; Ohfuji, H.; Anawar, H.M.; Akai, K., 2004. Mineralogical and geomicrobiological investigations on groundwater arsenic enrichment in Bangladesh. Appl. Geochem. 19, 215-230.

Ali, W., Rasool, A., Junaid, M., Zhang, H., 2019. A comprehensive review on current status, mechanism, and possible sources of arsenic contamination in groundwater: a global perspective with prominence of Pakistan scenario. Environmental geochemistry and health. 41, 737-760.

Anawar, H.M., Garcia-Sanchez, A., Murciego, A., Buyolo, T., 2006. Exposure and bioavailability of arsenic in contaminated soils from the La Parrilla mine, Spain. Environ Geol. 50, 170-179.

Atteia, O., Dubois, J. P., Webster, R., 1994. Geostatistical analysis of soil contamination in the Swiss Jura. *Environmental Pollution*, 86,, 315-327.

Barbier, E., 2019. The Water Paradox: Overcoming the Global Crisis in Water Management. Yale University Press, London.

Berg, M., Tran, H. C., Nguyen, T. C., Pham, H. V., Schertenleib, R., Gigar, W. 2001. Arsenic contamination of ground water and drinking water in Vietnam: A Human Health Threat. Environ, Sci. Technol. 35, 2621-2626.

Bhattacharya, A. K., 2017. Arsenic Contamination in Indian Groundwater. Journal of the Institution of Public Health Engineers, India. 45, 18-36.

Bhattacharya, P., Jacks, G., Ahmed, K. M., Khan, A. A., Routh, J., 2002. Arsenic in groundwater of the Bengal Delta Plain aquifers in Bangladesh. Bull. Environ. Contam. Toxicol. 69, 538-545.

Bhattacharya, P., Samal, A. C., Majumdar, J., Santra, S. C., 2009. Transfer of arsenic from groundwater and paddy soil to rice plant (Oryza sativa L.): a micro level study in West Bengal, India. *World Journal of Agricultural Sciences*. 5, 425-431.

Bhowmick, S., Pramanik, S., Singh, P., Mondal, P., Chatterjee, D., Nriagu, J., 2018. Arsenic in groundwater of West Bengal, India: a review of human health risks and assessment of possible intervention options. *Sci. Total Environ.* 612, 148-169.

BIS (Bureau of Indian Standard). 2012. Specification for drinking water IS-10500: 2021, New Delhi, India.

Carvalho, J.R.P.D., Silveira, P.M.D., Vieira, S.R., 2002. Geostatistics in determining the spatial variability of chemical characteristics of the soil under different tillage. Pesquisa Agropecuária Brasileira. 37, 1151-1159.

CGWB, 2018. Groundwater Quality in Shallow Aquifers of India. CGWB, Faridabad, pp. 18-21.
Chakraborti, D., Mukherjee, S. C., Pati, S., Sengupta, M. K., Rahman, M. M., Chowdhury, U.U.K., Lodh, D., Chanda, C.R., Chakraborti, A.K., Basu, G.K., 2003. Arsenic groundwater contamination in Middle Ganga Plain, Bihar, India: a future danger? *Environmental health perspectives*, 11, 1194-1201.

Chakraborti, D., Rahman, M. M., Ahamed, S., Dutta, R. N., Pati, S., Mukherjee, S. C., 2016. Arsenic groundwater contamination and its health effects in Patna district in the middle Ganga plain, India. *Chemosphere*, 152, 520-529.

Chakraborti, D., Singh, S. K., Rahman, M. M., Dutta, R. N., Mukherjee, S. C., Pati, S., Kar, P. B. 2018. Groundwater arsenic contamination in the Ganga River Basin: a future health danger. *International journal of environmental research and public health*, 15, 180.

Chetia, M., Chatterjee, S., Banerjee, S., Nath, M. J., Singh, L., Srivastava, R. B., Sarma, H. P. 2011. Groundwater arsenic contamination in Brahmaputra River basin: a water quality assessment in Golaghat (Assam), India. *Environmental Monitoring and Assessment*, 173(1-4), 371-385.

Dey, T. K., Banerjee, P., Bakshi, M., Kar, A., Ghosh, S., 2014. Groundwater arsenic contamination in West Bengal: Current scenario, Effects and probable ways of mitigation. *International Letters of Natural Sciences*. 8, 45-58.

EFSA (European Food Safety Authority) (2009). Scientific opinion on arsenic in food chain (CONTAM). EFSAJ, 12:1352.

Ghosh, A. K., Bose, N., Kumar, R., Bruining, H., Lourma, S., Donselaar, M.E., Bhatt, A.G., Ng, J.C., Noller, B.N., Naidu, R., Bundschuh, J., 2012. Geological origin of arsenic groundwater contamination in Bihar, India. Understanding the geological and medical interface of arsenic, As. 85-87.

Ghosh, A., Singh, S. K., Bose, N., Chowdhary, S., 2007. Arsenic contaminated aquifers: a study of the Ganga levee zone in Bihar, India. In *Symposium on Arsenic: the geography of a global problem*, Royal Geographical Society, London, 29th August.

Guidelines for Drinking-Water Quality. Recommendations World Health Organization; WHO Press; Incorporating the First and Second Addenda. Vol. 1, 3rd ed. Geneva, Switzerland: World Health Organization; 2008

Hue, N., 2010. Arsenic levels, chemistry and bioavailability in Hawaii soils. In 19th World Congress of Soil Science, Soil Solutions for a Changing World (1-6).

Islam, M. R., Salminen, R., Lahermo, P. W., 2000. Arsenic and other toxic elemental contamination of groundwater, surface water and soil in Bangladesh and its possible effects on human health. *Environmental Geochemistry and Health*. 22, 33-53.

Issa, N., Rajaković-Ognjanović, V., Marinković, A., Rajaković, L., 2011. Separation and determination of arsenic species in water by selective exchange and hybrid resins. *Analytica Chimica Acta*. 706, 191-198.
Jangle, N., Sharma, V., Dror, D. M., 2016. Statistical geospatial modelling of arsenic concentration in Vaishali district of Bihar, India. *Sustainable Water Resource Management*. 2, 285-295.

Kashiwar, S.R., Kundu, M.C. & Dongarwar, U.R., 2021. Soil erosion estimation of Bhandara region of Maharashtra, India, by integrated use of RUSLE, remote sensing, and GIS. Nat Hazards.

Khalid, S., Shahid, M., Niazi, N.K., Rafiq, M., Bakhat, H.F., Imran, M., Abbas, T., Bibi, I. Dumat, C., 2017. Arsenic behaviour in Soil-Plant system: Biogeochemical Reactions and Chemical Speciation Influences. Enhancing Cleanup of Environmental Pollutants; Springer: Berlin, Germany. 97-140.

Kumar, A., Srivastava, L. K., Mishra, V. N., Banwasi, R., 2017. Major and micro nutrient status of rice-chickpea grown in soils of Chhattisgarh Plain region of India. Indian Journal of Agricultural Research. 51, 1-8.

Kumar, M., Das, A., Das, N., Goswami, R., Singh, U.K., 2016b. Co-occurrence perspective of arsenic and fluoride in the groundwater of Diphu, Assam, Northeastern India. Chemosphere. 150, 227-238.

Kumar, M., Ramanathan, A. L., Rahman, M. M., Naidu, R., 2016a. Concentrations of inorganic arsenic in groundwater, agricultural soils and subsurface sediments from the middle Gangetic plain of Bihar, India. Science of the Total Environment. 573, 1103-1114.

Kumar, P., Kumar, M., Ramanathan, A. L., Tsujimura, M., 2010. Tracing the factors responsible for arsenic enrichment in groundwater of the middle Gangetic Plain, India: a source identification perspective. Environmental geochemistry and health. 32, 129-146.

Kumari, N., Rana, A., Jagadevan, S., 2019. Arsenite biotransformation by Rhodococcus sp.: Characterization, optimization using response surface methodology and mechanistic studies. Sci. Total Environ. 687, 577-589.

Lindsay, W.L., Nrvell, W. A. (1978). Development of a DTPA soil test for zinc, iron, manganese and copper. Soil Science Society of America Journal. 42, 421-428.

Maity, S., Biswas, R., Sarkar, A., 2020. Comparative valuation of groundwater quality parameters in Bhojpur, Bihar for arsenic risk assessment. Chemosphere. 259, 1273-1298.

Mandal, B. K., & Suzuki, K. T., 2002. Arsenic round the world: a review. Talanta. 58, 201-235.

McArthur, J.M., 2019. Arsenic in groundwater. In: Sikdar, P.K. (Ed.), Groundwater Development and Management. Springer, Cham, pp. 279-308.

Mendoza-Chávez, C.E., Carabin, A., Dirany, A., Drogui, P., Buelna, G., Meza-Montenegro, M.M., Ulloa-Mercado, R.G., Diaz-Tenorio, L.M., Leyva-Soto, L.A., Gortáres-Moroyoqui, P., 2020. Statistical optimization of arsenic removal
from synthetic water by electrocoagulation system and its application with real
arsenic-polluted groundwater. Environ. Technol. 1–12.

Mukherjee, A., von Bromssen, M., Scanlon, B. R., Bhattacharya, P., Fryar, A. E., Hasan, M. A., 2008. Hydrogeochemical comparison and effects of overlapping redox zone on groundwater near the Western (Bhagirathi subbasin, India) and Eastern (Meghna sub-basin, Bangladesh) mergins of the Bengal Basin. Journal of Contaminant Hydrology. 99, 31-48.

Nath, A., Vendan, P. S., Kumar, S., Kumar, A., Singh, J. K., 2013. Toxicity due to arsenic in Gangetic Zone of Patna, India and its linkage with cancer. J Environ Anal Toxicol. 3, 2161-0525.

Naujokas, M. F., Anderson, B., Ahsan, H., Aposhian, H. V., Graziano, J. H., Thompson, C., Suk, W. A., 2013. The broad scope of health effects from chronic arsenic exposure: update on a worldwide public health problem. Environmental health perspectives. 121, 295-302.

Rajaković, L., Todorović, Ž., Rajaković-Ognjanović, V., Onjia, A., 2013. Review: Analytical methods for arsenic speciation analysis. Journal of the Serbian Chemical Society. 78, 1-32. UDC JSCS-5666.

Rajmohan, N., Prathapar, S. A., 2016. Arsenic distribution in ground water and soil in the Eastern Ganges basin. A Review, Proceedings, Sixth International Ground Water Conference, 11-13 February, 2016, Chennai, Paper ID TS4-05, Pages TSIV-78-93.

Ranjan, R. K., Ramanathan, A. L., Parthasarathy, P., Kumar, A., 2012. Hydrochemical characteristics of groundwater in the plains of Phalgu River in Gaya, Bihar, India. Arabian Journal of Geosciences. 6, 3257-3267.

Ravenscroft, P., Brammer, H., & Richards, K., 2011. Arsenic pollution: a global synthesis (Vol. 94). John Wiley & Sons.

Reza, R., Singh, G., 2010. Heavy metal contamination and its indexing approach for river water. Int. J Environ Sci. Technol. 7,785–792.

Saxena, M. M., 1994. Environmental analysis-water, soil and air. Agrobotanical Publishers (India), 2nd Edition, 86, 121-125.

Seulki, J., Hosub, L., Youn-Tae, K., Hye-On, Y., 2017. Development of a simultaneous analytical method to determine arsenic speciation using HPLC-ICP-MS: Arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, dimethyldithioarsinic acid, and dimethylmonothioarsinic acid. Microchemical Journal. 134, 295-300. DOI: 10.1016/j.microc.2017.06.011.

Shah, B. A., 2017. Groundwater arsenic contamination from parts of the Ghaghara Basin, India: influence of fluvial geomorphology and Quaternary morpho stratigraphy, Appl Water Sci. 7, 2587–2595.
Shaji, E., Santosh, M., Sarath, K. V., Prakash, P., Deepchand, V., Divya, B. V. 2021. Arsenic contamination of groundwater. A Global Synopsis with focus on the Indian Peninsula, Geoscience Frontier. 12, 101079.

Singh, A. K., 2006. Arsenic and fluoride in groundwater: An emerging problem in North-eastern India. In A. L. Ramanathan (Ed.), International Conference on Groundwater for Sustainable Development: Problems, Perspectives and Challenges (IGC-2006). Abstr. New Delhi: IGC.

Singh, S. K., Ghosh, A. K., Kumar, A., Kislay, K., Kumar, C., Tiwari, R. R., Parwez, R., Kumar, N., Imam, M. D., 2014. Groundwater arsenic contamination and associated health risks in Bihar, India. *International Journal of Environmental Research*. 8, 49-60.

Singh, S. K., Tiwari, S., Prasad, S. S., Singh, P., Singh, S. K., Singh, S. K., 2018. Quality assessment of drinking water in some selected villages of Muzaffarpur district, Bihar. *Current Advances in Agricultural Sciences*, 10, 26-32.

Sinha, S. K., Shankar, R., 2018. Assessment of drinking water in a rural area of Patna (Bihar) with special reference to human health. Indian Journal of Preventive & Social Medicine. 49, 3-3.

Smedely, P. L., Kinniburg, D. G., 2002. A review of sources, behaviour and distribution of arsenic in natural waters. Appl. Geochem. 17, 517-568.

Srivastava, S., Sharma, Y. K., 2013. Arsenic occurrence and accumulation in soil and water of eastern districts of Uttar Pradesh, India. Environmental monitoring and assessment. 185, 4995-5002.

Sukumaran, D., Saha, R., & Saxena, R. C., 2015. Ground water quality index of Patna, the capital city of Bihar, India. American Journal of Water Resources. 3, 17-21.

Thakur, B.K., Gupta, V., 2019. Valuing health damages due to groundwater arsenic contamination in Bihar, India. Econ. Hum. Biol. 35, 123-132.

Tiankao, W., Chotpantarat, S., 2018. Risk assessment of arsenic from contaminated soil to shallow ground water in Ong Phrasub-District, Suphanburi Province, Thailand. J. Hydrol. Reg. Stud. 19, 80-96.

Verma, D. K., Bhunia, G. S., Shit, P. K., Kumar, S., Mandal, J., Padbhushan, R. 2017. Spatial variability of groundwater quality of Sabour block, Bhagalpur district (Bihar, India). Applied Water Science. 7, 1997-2008.

WHO, 2011. Guidelines for drinking water quality, 4th Edition, Geneva.

Wong M.H., 2003. Ecological restoration of mine degraded soils with emphasis on metal contaminated soils. Chemosphere. 50,775-780.

Zhang, W., Cai, Y., Tu, C., Ma, L.Q., 2002. Arsenic speciation and distribution in an arsenic hyper accumulating plant. *Science Total Environ*. 300,167-177.