Seasonal disparity in the co-occurrence of arsenic and fluoride in the aquifers of the Brahmaputra flood plains, Northeast India

Nilotpal Das, Kali P. Sarma, Arbind K. Patel, Jyoti P. Deka, Aparna Das, Abhay Kumar, Patrick J. Shea, Manish Kumar

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Arsenic (As) and fluoride (F) in groundwater are increasing global water quality and public health concerns. The present study provides a deeper understanding of the impact of seasonal change on the co-occurrence of As and F, as both contaminants vary with climatic patterns. Groundwater samples were collected in pre- and post-monsoon seasons (n = 40 in each season) from the Brahmaputra flood plains (BFP) in northeast India to study the effect of season on As and F levels. Weathering is a key hydrogeochemical process in the BFP and both silicate and carbonate weathering are enhanced in the post-monsoon season. The increase in carbonate weathering is linked to an elevation in pH during the post-monsoon season. A Piper diagram revealed that bicarbonate-type water, with Na+, K+, Ca2+, and Mg2+ cations, is common in both seasons. Correlation between Cl and NO3 (r = 0.74, p = 0.01) in the post-monsoon indicates mobilization of anthropogenic deposits during the rainy season. As was within the 10 µg L−1 WHO limit for drinking water and F was under the 1.5 mg L−1 limit. A negative correlation between oxidation reduction potential and groundwater As in both seasons (r = −0.26 and −0.49, respectively, for pre-monsoon and post-monsoon, p = 0.05) indicates enhanced As levels due to prevailing reducing conditions. Reductive hydrolysis of Fe (hydr)oxides appears to be the predominant process of As release, consistent with a positive correlation between As and Fe in both seasons (r = 0.75 and 0.73 for pre- and post-monsoon seasons, respectively, at p = 0.01). Principal component analysis and hierarchical cluster analysis revealed grouping of Fe and As in both seasons. F and sulfate were also clustered during the pre-monsoon season, which could be due to their similar interactions with Fe (hydr)oxides. Higher As levels in the post-monsoon appears driven by the influx of water into the aquifer, which drives out oxygen and creates a more reducing condition suitable for reductive dissolution of Fe (hydr)oxides. An increase in pH promotes desorption of As oxyanions AsO4 3− (arsenate) and AsO3 3− (arsenite) from Fe (hydr)oxide surfaces. Fluoride appears mainly released from F-bearing minerals, but Fe (hydr)oxides can be a secondary source of F, as suggested by the positive correlation between As and F in the pre-monsoon season.

Original languageEnglish (US)
Article number183
JournalEnvironmental Earth Sciences
Volume76
Issue number4
DOIs
StatePublished - Feb 1 2017

Fingerprint

Arsenic
fluorides
arsenic
Fluorides
Aquifers
fluoride
floodplains
aquifers
monsoon
aquifer
India
monsoon season
Oxides
oxides
oxide
Weathering
weathering
Groundwater
groundwater
Carbonates

Keywords

  • Arsenic
  • Brahmaputra River
  • Fluoride
  • Groundwater Quality
  • Hydrogeochemical process
  • India
  • Weathering

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Water Science and Technology
  • Soil Science
  • Pollution
  • Geology
  • Earth-Surface Processes

Cite this

Seasonal disparity in the co-occurrence of arsenic and fluoride in the aquifers of the Brahmaputra flood plains, Northeast India. / Das, Nilotpal; Sarma, Kali P.; Patel, Arbind K.; Deka, Jyoti P.; Das, Aparna; Kumar, Abhay; Shea, Patrick J.; Kumar, Manish.

In: Environmental Earth Sciences, Vol. 76, No. 4, 183, 01.02.2017.

Research output: Contribution to journalArticle

Das, Nilotpal ; Sarma, Kali P. ; Patel, Arbind K. ; Deka, Jyoti P. ; Das, Aparna ; Kumar, Abhay ; Shea, Patrick J. ; Kumar, Manish. / Seasonal disparity in the co-occurrence of arsenic and fluoride in the aquifers of the Brahmaputra flood plains, Northeast India. In: Environmental Earth Sciences. 2017 ; Vol. 76, No. 4.
@article{3527d6b7c068478fb8de0448207969f0,
title = "Seasonal disparity in the co-occurrence of arsenic and fluoride in the aquifers of the Brahmaputra flood plains, Northeast India",
abstract = "Arsenic (As) and fluoride (F−) in groundwater are increasing global water quality and public health concerns. The present study provides a deeper understanding of the impact of seasonal change on the co-occurrence of As and F−, as both contaminants vary with climatic patterns. Groundwater samples were collected in pre- and post-monsoon seasons (n = 40 in each season) from the Brahmaputra flood plains (BFP) in northeast India to study the effect of season on As and F− levels. Weathering is a key hydrogeochemical process in the BFP and both silicate and carbonate weathering are enhanced in the post-monsoon season. The increase in carbonate weathering is linked to an elevation in pH during the post-monsoon season. A Piper diagram revealed that bicarbonate-type water, with Na+, K+, Ca2+, and Mg2+ cations, is common in both seasons. Correlation between Cl− and NO3 − (r = 0.74, p = 0.01) in the post-monsoon indicates mobilization of anthropogenic deposits during the rainy season. As was within the 10 µg L−1 WHO limit for drinking water and F− was under the 1.5 mg L−1 limit. A negative correlation between oxidation reduction potential and groundwater As in both seasons (r = −0.26 and −0.49, respectively, for pre-monsoon and post-monsoon, p = 0.05) indicates enhanced As levels due to prevailing reducing conditions. Reductive hydrolysis of Fe (hydr)oxides appears to be the predominant process of As release, consistent with a positive correlation between As and Fe in both seasons (r = 0.75 and 0.73 for pre- and post-monsoon seasons, respectively, at p = 0.01). Principal component analysis and hierarchical cluster analysis revealed grouping of Fe and As in both seasons. F− and sulfate were also clustered during the pre-monsoon season, which could be due to their similar interactions with Fe (hydr)oxides. Higher As levels in the post-monsoon appears driven by the influx of water into the aquifer, which drives out oxygen and creates a more reducing condition suitable for reductive dissolution of Fe (hydr)oxides. An increase in pH promotes desorption of As oxyanions AsO4 3− (arsenate) and AsO3 3− (arsenite) from Fe (hydr)oxide surfaces. Fluoride appears mainly released from F−-bearing minerals, but Fe (hydr)oxides can be a secondary source of F−, as suggested by the positive correlation between As and F− in the pre-monsoon season.",
keywords = "Arsenic, Brahmaputra River, Fluoride, Groundwater Quality, Hydrogeochemical process, India, Weathering",
author = "Nilotpal Das and Sarma, {Kali P.} and Patel, {Arbind K.} and Deka, {Jyoti P.} and Aparna Das and Abhay Kumar and Shea, {Patrick J.} and Manish Kumar",
year = "2017",
month = "2",
day = "1",
doi = "10.1007/s12665-017-6488-x",
language = "English (US)",
volume = "76",
journal = "Environmental Earth Sciences",
issn = "1866-6280",
publisher = "Springer Verlag",
number = "4",

}

TY - JOUR

T1 - Seasonal disparity in the co-occurrence of arsenic and fluoride in the aquifers of the Brahmaputra flood plains, Northeast India

AU - Das, Nilotpal

AU - Sarma, Kali P.

AU - Patel, Arbind K.

AU - Deka, Jyoti P.

AU - Das, Aparna

AU - Kumar, Abhay

AU - Shea, Patrick J.

AU - Kumar, Manish

PY - 2017/2/1

Y1 - 2017/2/1

N2 - Arsenic (As) and fluoride (F−) in groundwater are increasing global water quality and public health concerns. The present study provides a deeper understanding of the impact of seasonal change on the co-occurrence of As and F−, as both contaminants vary with climatic patterns. Groundwater samples were collected in pre- and post-monsoon seasons (n = 40 in each season) from the Brahmaputra flood plains (BFP) in northeast India to study the effect of season on As and F− levels. Weathering is a key hydrogeochemical process in the BFP and both silicate and carbonate weathering are enhanced in the post-monsoon season. The increase in carbonate weathering is linked to an elevation in pH during the post-monsoon season. A Piper diagram revealed that bicarbonate-type water, with Na+, K+, Ca2+, and Mg2+ cations, is common in both seasons. Correlation between Cl− and NO3 − (r = 0.74, p = 0.01) in the post-monsoon indicates mobilization of anthropogenic deposits during the rainy season. As was within the 10 µg L−1 WHO limit for drinking water and F− was under the 1.5 mg L−1 limit. A negative correlation between oxidation reduction potential and groundwater As in both seasons (r = −0.26 and −0.49, respectively, for pre-monsoon and post-monsoon, p = 0.05) indicates enhanced As levels due to prevailing reducing conditions. Reductive hydrolysis of Fe (hydr)oxides appears to be the predominant process of As release, consistent with a positive correlation between As and Fe in both seasons (r = 0.75 and 0.73 for pre- and post-monsoon seasons, respectively, at p = 0.01). Principal component analysis and hierarchical cluster analysis revealed grouping of Fe and As in both seasons. F− and sulfate were also clustered during the pre-monsoon season, which could be due to their similar interactions with Fe (hydr)oxides. Higher As levels in the post-monsoon appears driven by the influx of water into the aquifer, which drives out oxygen and creates a more reducing condition suitable for reductive dissolution of Fe (hydr)oxides. An increase in pH promotes desorption of As oxyanions AsO4 3− (arsenate) and AsO3 3− (arsenite) from Fe (hydr)oxide surfaces. Fluoride appears mainly released from F−-bearing minerals, but Fe (hydr)oxides can be a secondary source of F−, as suggested by the positive correlation between As and F− in the pre-monsoon season.

AB - Arsenic (As) and fluoride (F−) in groundwater are increasing global water quality and public health concerns. The present study provides a deeper understanding of the impact of seasonal change on the co-occurrence of As and F−, as both contaminants vary with climatic patterns. Groundwater samples were collected in pre- and post-monsoon seasons (n = 40 in each season) from the Brahmaputra flood plains (BFP) in northeast India to study the effect of season on As and F− levels. Weathering is a key hydrogeochemical process in the BFP and both silicate and carbonate weathering are enhanced in the post-monsoon season. The increase in carbonate weathering is linked to an elevation in pH during the post-monsoon season. A Piper diagram revealed that bicarbonate-type water, with Na+, K+, Ca2+, and Mg2+ cations, is common in both seasons. Correlation between Cl− and NO3 − (r = 0.74, p = 0.01) in the post-monsoon indicates mobilization of anthropogenic deposits during the rainy season. As was within the 10 µg L−1 WHO limit for drinking water and F− was under the 1.5 mg L−1 limit. A negative correlation between oxidation reduction potential and groundwater As in both seasons (r = −0.26 and −0.49, respectively, for pre-monsoon and post-monsoon, p = 0.05) indicates enhanced As levels due to prevailing reducing conditions. Reductive hydrolysis of Fe (hydr)oxides appears to be the predominant process of As release, consistent with a positive correlation between As and Fe in both seasons (r = 0.75 and 0.73 for pre- and post-monsoon seasons, respectively, at p = 0.01). Principal component analysis and hierarchical cluster analysis revealed grouping of Fe and As in both seasons. F− and sulfate were also clustered during the pre-monsoon season, which could be due to their similar interactions with Fe (hydr)oxides. Higher As levels in the post-monsoon appears driven by the influx of water into the aquifer, which drives out oxygen and creates a more reducing condition suitable for reductive dissolution of Fe (hydr)oxides. An increase in pH promotes desorption of As oxyanions AsO4 3− (arsenate) and AsO3 3− (arsenite) from Fe (hydr)oxide surfaces. Fluoride appears mainly released from F−-bearing minerals, but Fe (hydr)oxides can be a secondary source of F−, as suggested by the positive correlation between As and F− in the pre-monsoon season.

KW - Arsenic

KW - Brahmaputra River

KW - Fluoride

KW - Groundwater Quality

KW - Hydrogeochemical process

KW - India

KW - Weathering

UR - http://www.scopus.com/inward/record.url?scp=85013466944&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85013466944&partnerID=8YFLogxK

U2 - 10.1007/s12665-017-6488-x

DO - 10.1007/s12665-017-6488-x

M3 - Article

AN - SCOPUS:85013466944

VL - 76

JO - Environmental Earth Sciences

JF - Environmental Earth Sciences

SN - 1866-6280

IS - 4

M1 - 183

ER -