Environmental arsenic contamination and its health effects in a historic gold mining area of the Mangalur greenstone belt of Northeastern Karnataka, India

Abstract

This report summarizes recent findings of environmental arsenic (As) contamination and the consequent health effects in a community located near historic gold mining activities in the Mangalur greenstone belt of Karnataka, India. Arsenic contents in water, hair, nail, soil and food were measured by FI-HG-AAS. Elemental analyses of soils were determined by ICP-MS (inductively coupled plasma-mass spectrometry). Of 59 tube-well water samples, 79% had As above 10 μg L(-1) (maximum 303 μg L(-1)). Of 12 topsoil samples, six were found to contain As greater than 2000 mg kg(-1) possibly indicating the impact of mine tailings on the area. All hair and nail samples collected from 171 residents contained elevated As. Arsenical skin lesions were observed among 58.6% of a total 181 screened individuals. Histopathological analysis of puncture biopsies of suspected arsenical dermatological symptoms confirmed the diagnosis in three out of four patients. Based on the time-course of As-like symptoms reported by the community as well as the presence of overt arsenicosis, it is hypothesized that the primary route of exposure in the study area was via contaminated groundwater; however, the identified high As content in residential soil could also be a significant source of As exposure via ingestion. Additional studies are required to determine the extent as well as the relative contribution of geologic and anthropogenic factors in environmental As contamination in the region. This study report is to our knowledge one of the first to describe overt arsenicosis in this region of Karnataka, India as well as more broadly an area with underlying greenstone geology and historic mining activity.

Keywords: Arsenic; Arsenical skin lesions; Gold mine; Greenstone; Groundwater; Karnataka.

Fig. 1

Location of the surveyed villages and local historic gold mining activities [27] in Yadgir District, Karnataka, India. (A) Karnataka State (gold), India; (B) Gulbarga District, after the creation of Yadgir District in 2009 (dark red), Yadgir District (medium red), and Raichur District (pink), Karnataka; (C) Mangalur and Hutti-Maski greenstone belts [33,41] located within Yadgir and Raichur Districts, respectively; the border between these two districts is the Krishna River; (D) surveyed villages and historic gold mine workings within the Mangalur greenstone belt.

Fig. 2

Locations and levels of As in water and soil samples collected from Kiradalli Tanda and the surrounding communities during the second more detailed survey of the study area in September 2009. Two groundwater samples, which are not plotted, were collected without spatial information: Kiradalli Tanda (144 μg/L) and Gowdigeri (13 μg/L).

Fig. 3

Comparative prevalence of dermatologic symptoms of identified individuals of Kiradalli Tanda with arsenicosis (age quartiles). Abbreviations: DM, diffuse melanosis; SM, spotted melanosis; WM, whole body melanosis; LM, leucomelanosis (white-spotted pigmentation alongside black-spotted); SKP, spotted keratosis palm; DKP, diffuse keratosis palm; SKS, spotted keratosis sole; DKS, diffuse keratosis sole; DK, dorsal keratosis; SB, suspected Bowen’s Disease; SC, suspected skin cancer; MM, mucous melanosis.

Fig. 4

Histopathological section showing, A) thickened epidermis (10x) and B) Bowen’s disease (carcinoma in situ) (45x).

Fig. 5

Characteristics of three individuals from Kiradalli Tanda suffering from chronic As toxicity.