Characterization and treatment of water used for human consumption from six sources located in the Cameron/Tuba City abandoned uranium mining area

Abstract

The purpose of this research was the characterization and improvement of the quality of water used for human consumption of unregulated/regulated water sources located in the Cameron/Tuba City abandoned uranium mining area (NE Arizona, western edge of the Navajo Nation). Samples were collected at six water sources which included regulated sources: Wind Mill (Tank 3T-538), Badger Springs and Paddock Well as well as unregulated sources: Willy Spring, Water Wall and Water Hole. Samples taken from Wind Mill, Water Wall and Water Hole were characterized with high turbidity and color as well as high level of manganese, iron and nickel and elevated value of molybdenum. High level of iron was also found in Badger Spring, Willy Spring, and Paddock Well. These three water sources were also characterized with elevated values of fluoride and vanadium. Significant amounts of zinc were found in Water Wall and Water Hole samples. Water Wall sample was also characterized with high level of Cr(VI). Compared to primary or secondary Navajo Nation Environmental Protection Agency (NNEPA) water quality standard the highest enrichment was found for turbidity (50.000 times), color (up to 1.796 times) and manganese (71 times), Cr(VI) (17.5 times), iron (7.4 times) and arsenic (5.2 times). Activities of (226)Ra and (238)U in water samples were still in agreement with the maximum contaminant levels. In order to comply with NNEPA water quality standard water samples were subjected to electrochemical treatment. This method was selected due to its high removal efficiency for heavy metals and uranium, lower settlement time, production of smaller volume of waste mud and higher stability of waste mud compared to physico-chemical treatment. Following the treatment, concentrations of heavy metals and activities of radionuclides in all samples were significantly lower compared to NNEPA or WHO regulated values. The maximum removal efficiencies for color, turbidity, arsenic, manganese, molybdenum and nickel were 100.0%. Maximum removal percentage of Cu, F(-), V, Zn, (137)Cs, (226)Ra, (232)Th, (238)U were as follows: 98.0%; 82.7%; 99.9%; 95.6%; 75.0%; 76.9%; 80.0% and 99.2%. From the results presented it could be concluded that electrochemical treatment is a suitable approach for the purification of drinking water with complex mixture of contaminants, especially those with high turbidity and color.

Arsenic Concentrations in Ground and Surface Waters across Arizona Including Native Lands

“…The most sampling has occurred on the Navajo and Hopi lands, where water quality issues, especially related to widespread arsenic and uranium contamination occur (Brugge and Gobble 2002; Hoover et al 2017, 2018). Unfortunately, while water quality information exists for some of these Nations (TerraSpectra Geomatics et al 2000; Orescanin et al 2011; Hoover et al 2017, 2018), for many, if the data exist, it requires strict approval by the various tribal governments to publish them in a public location (Kickingbird and Rhoades 2000). An added barrier to such publication is the hesitation of some tribal governments to associate a location identification with any specific problem, which may lead to social or local stigmatization for continued monitoring (Sharp and Foster 2002; Manson et al 2004).…”

The Electrocoagulation/Advanced Oxidation Treatment of the Well Water From Županja

“…Either Fe or Al electrode set was placed at the bottom of the reaction vessel perpendicular to the vessel bottom. In the end of electrochemical treatment the suspension was re-circulated in strong electromagnetic field for 10 minutes and subjected to slow mixing for another 15 minutes while the settlement time was 30 minutes (11,12). After the settlement clear water was decanted and post-treated with ozone in the presence of hydrogen peroxide (30% H 2 O 2 ; volume of H 2 O 2 = 5 mL) for 10 minutes in order to remove ammonia.…”

“…For the analysis of heavy metals and arsenic 100 mL of the original or purified water was adjusted to pH 0.1, 3 and 11 by addition of hydrochloric acid and ammonium hydroxide, preconcentrated by ammonium pyrrolidine-dithiocarbamate (APDC), filtered through a Millipore HAWP filter (pore size 0.45 mm; diameter 25 mm) using a Millipore micro filtration system) and analyzed by energy dispersive X-ray spectrometry (EDXRF) (11,12).…”

“…Relative standard deviation based on five consecutive measurements of the target containing 100 mg/L of Fe, Mn and As prepared from the Merck standard solution was < 3% for all three elements. pH value, electrical conductivity (EC) and total dissolved solids (TDS) were determined by PHT-027 -water quality multiparameter monitor (Kelilong Electron) (11,12). Minimum detection limit for the parameters pH, EC and TDS were 0.01, 0.01 mS/cm, and 10 mg/L, respectively.…”

“…Color, turbidity, calcium, phosphates, fluorides, COD and ammonia were determined using HACH DR890 colorimeter (Hach Company, Loveland, Colorado, USA) (11,12). Minimum detection limit for the above mentioned parameters were 1 PtCo, 1 NTU, 10 mg/L, 0.02 mg/L, 0.05 mg/L, 1 mg/L and 0.02 mg/L, respectively.…”