Evaluation of Several Field Test Kits for Determining Concentrations of Arsenic in Drinking Water J. Mitchell Spear, You “Mark” Zhou Charles A. Cole and Yuefeng F. Xie Environmental Programs Penn State Harrisburg US EPA Small Public Water Systems Technology Assistance Center

Regulation Regulation –Published arsenic rule (January 22, 2001) –Lowers Maximum Contaminant Level from 50 ug/L to 10 ug/L Arsenic –Compliance date (January 23, 2006) Water Utilities affected Water Utilities affected –Approximately 4000 in US –97 % serving less than 10,000 people Removal Options Removal Options –Best Available Technologies (BAT) –Small System Compliance Technologies (SSCT) Background

Point-Of-Use (POU) Options Point-Of-Use (POU) Options –Activated Alumina –Ion Exchange –Iron Based Sorption Media –Reverse Osmosis Monitoring Monitoring –Graphite Furnace Atomic Absorption (GFAA) –Inductively Coupled Plasma Emissions Spectrophotometry (ICP-AES) –Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) –Hydride Generation Atomic Adsorption (HGAA) Background

Evaluate several commercially available field test kits and determine reliability and applicability to water utilities currently conducting noncompliance arsenic analyses. Evaluate several commercially available field test kits and determine reliability and applicability to water utilities currently conducting noncompliance arsenic analyses. Purpose

Test Kits Test Kits –selection –chemistry –reference method Laboratory performance Laboratory performance –accuracy –precision Matrix interference and field performance Matrix interference and field performance –Antimony and sulfide –Linearity on field sample Operator performance Operator performance –operator bias –“ease of use” Methods

Test Kits

General Characteristics Test KitConcentration IntervalsNumber of Reagents Test Time (min) BVC , 25, 50, 100, ECO- W100 25, 50, 100, 150, 200, 300, 500, Hach 10, 30, 50, 70, 300, LaMotte 4, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 100, 140, Merck 10, 25, 50, 100, Quick II 1, 2, 2.5, 3, 4, 5, 6, 7, 10, 12, 14, 20, 30, >30, >40, >60, >80, > Trace Detect Continuous310

General Characteristics Test Kit Sample size (ml) Unit Price ($ US dollars) Samples per kit$ Cost / test BVC ECO-W Hach LaMotte Merck Quick II Trace Detect 5012,

Methods Selection of Field Test Kits  Inexpensive  Commercially available  Portable  Multiple lot numbers  Seven field kits

Methods Chemistry of Field Test Kits  Arsine gas generation  (similar to SM 3114) Hydride generation  Semi-qualitative  Anodic Stripping Voltammetry (ASV)  (similar to SM 3130)  Qualitative

Methods Chemistry of Field Test Kits

Methods Reference Method  US EPA approved  EPA Method 7060A (Graphite Furnace Atomic Absorbance)

Laboratory Performance Accuracy and Precision  Traditionally (Method Detection Limit)  Accuracy (percent recovery) % Recovery = Conc TestKit / Conc GFAA * 100  Precision (standard deviation)  Arsenic III, V, III + V  Concentration  Replicates

Laboratory Performance Results

Matrix interference and Field Performance  Antimony levels  (0, 0.25, 1.0 and 5.0 mg/L)  Sulfide levels  (0, 0.5, 5.0 and 10.0 mg/L)  Linearity  (5, 10, 25, 50, 75 µg/L)

Operator Performance  Operator Bias  Schock and George (1993)  “Ease of Use”  Instructions  Chemical additions  Equipment  Result interpretation  Scale 1 - most difficult 1 - most difficult 10 - easiest 10 - easiest

Operator bias Test kitOperator 1 Slope (intercept) Correlation coefficient BVC-100 Operator (0.0) 0.897* ECO-W100 Operator (-1.6) 0.905* Hach Operator (2.44) 0.829* LaMotte Operator (0.77) 0.890* Merck Operator (4.9) 0.689* Quick II Operator (1.0) 0.873* * Significant to the 0.01 alpha level.

Operator “Ease of Use”

Conclusions  Three test kits performed well  Two field test kits met all criteria (easy to use, accurate, precise, inexpensive, no operator bias)  These two could be used by water operators for noncompliance testing

Acknowledgements  US EPA Small Public Water Systems Technology Assistance Center Grant  Peng Chen, Mukesh Pratap, Brian Montalbano, and Paul Deardorff for analytical analyses  Trace Detect for loan of there instrumentation

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