Spatial Analysis, Seasonal Partitioning, and Chemical Speciation of Arsenic Compounds in Urban Coastal Aquifers

International Journal of Chemistry | Vol. 5, No. 12, December 2014 | pp. 89–96

DOI: 10.46882/2014/IJC/000075

Article Type: Original Research Paper

Title: Spatial Analysis, Seasonal Partitioning, and Chemical Speciation of Arsenic Compounds in Urban Coastal Aquifers

Names of Authors: T. H. Awotunde¹, E. C. Silva²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Agriculture, Abeokuta, Nigeria.
²Department of Earth Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

Abstract: Arsenic leaching into shallow drinking water wells from nearby electronic wastes and industrial dumpsites poses severe public health threats due to its systemic toxicity and carcinogenicity. This study monitors the spatial variations, chemical speciation, and seasonal partitioning profiles of arsenic compounds across twenty communal wells located in a crowded coastal industrial zone. Water monitoring was executed concurrently across dry and wet seasons. Total arsenic and inorganic arsenic species [As(III) and As(V)] were resolved quantitatively using Hydride Generation Atomic Absorption Spectrophotometry (HG-AAS). Total arsenic concentrations ranged from 2.15 to 45.8 μg/L, with 40% of the sampled groundwater sites exceeding the strict WHO maximum drinkable contaminant limit of 10.0 μg/L. Speciation mapping showed that toxic As(III) was the dominant form in highly reducing, low-oxygen shallow aquifers. Seasonal evaluations confirmed elevated arsenic migration during the rainy period, driven by fluctuating water tables and aquifer leaching pathways. Chronic Hazard Index (HI) calculations for infant exposure pathways surpassed 3.2 at peripheral coordinates, emphasizing an immediate public health risk and highlighting the necessity for widespread local bone-char filtration setups.

Keywords: Groundwater quality; Arsenic speciation; Hydride generation; Seasonal variations; Bioavailability; Hazard index

Manuscript Timeline: Received: March 15, 2014; Revised: May 02, 2014; Accepted: June 12, 2014; Published: December 04, 2014.

Citation: Awotunde, T. H., & Silva, E. C. (2014). Spatial Analysis, Seasonal Partitioning, and Chemical Speciation of Arsenic Compounds in Urban Coastal Aquifers. International Journal of Chemistry, 5(12), 89–96.

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