Universität zu Köln

Matern, Katrin (2017). Chromium contamination associated with Chromite Ore Processing Residue (COPR) in the area of Kanpur, Uttar Pradesh, India. PhD thesis, Universität zu Köln.

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Abstract

Chromite ore processing residue (COPR) is a hazardous waste derived from the chromate extraction roasting process. Despite its (eco)toxicological potential, COPR has been dumped in uncontrolled surface landfills in several countries. The leaching of Cr(VI), resulting in the contamination of groundwater, is a key environmental risk arising from these CORR dumps. Since the contamination pathways of Cr(VI) are not fully understood, the objective of this dissertation was to evaluate the Cr contamination associated with COPR in the area of Kanpur (Uttar Pradesh, India). Hence, COPR samples were taken from two landfill sites and characterized in terms of their chemical and mineralogical nature. The total Cr content in the studied COPR samples amounted to 81 and 74 g/kg, 20 and 13% of which was Cr(VI) respectively. Column experiments under water-saturated conditions showed that during leaching, Cr(VI) concentrations decreased from 1800 to 300 and 1200 to 163 mg/L during 12 pore volumes, which conforms to two years of monsoon precipitation. Batch studies showed that chromate adsorption from COPR eluates was inhibited due to the high pH of the eluates and the investigated soils. Results of column experiments with a COPR-contaminated soil at varying water content and redox conditions indicated that Cr(VI) was highly mobile under oxidizing conditions and Cr was gradually immobilized and irreversibly sequestered via reductive precipitation under moderately reducing conditions. To evaluate the role of monsoon precipitation on Cr(VI) contamination of groundwater in the vicinity of COPR dumps, samples were taken both in the pre-monsoon season (n = 57) and during the monsoon season (n = 70). The Cr(VI) concentrations of groundwater ranged from <0.005 to 115 mg/L, with the maximum values found close to the COPR dumpsites. Additionally, the results showed that most samples exhibited multiple non-COPR contaminates including fluoride, nitrate, arsenic, molybdenum, and uranium. Overall, the water from 95% of the wells was not drinkable. This study has shown that the area of Kanpur is highly affected by COPR dumps that continuously leach Cr(VI) into the groundwater. This is particularly alarming since the local population uses the groundwater not only to water livestock and for irrigation but also as drinking water.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Matern, Katrin k.matern@hotmail.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-73765
Date:	25 January 2017
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Geographisches Institut
Subjects:	Natural sciences and mathematics Chemistry and allied sciences Geography and travel
Uncontrolled Keywords:	Keywords Language Chromium, COPR, Leaching, India, Speciation, Mineralogy, Soil, Groundwater, Column experiment, Monsoon UNSPECIFIED
Date of oral exam:	13 April 2016
Referee:	Name Academic Title Mansfeldt, Tim Prof. Dr. Bareth, Georg Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/7376