Low-cost electrochemical detection of arsenic in the groundwater of Guanajuato state, central Mexico using an open-source potentiostat

Arsenic is a carcinogenic groundwater contaminant that is toxic even at the parts-per-billion (ppb) level and its on-site determination remains challenging. Colorimetric test strips, though cheap and widely used, often fail to give reliable quantitative data. On the other hand, electrochemical detection is sensitive and accurate but considerably more expensive at the onset. Here, we present a study on arsenic detection in groundwater using a low-cost, open-source potentiostat based on Arduino technology. We tested different types of gold electrodes (screen-printed and microwire) with anodic stripping voltammetry (ASV), achieving low detection limits (0.7 μg L-1). In a study of arsenic contaminated groundwaters in Mexico, the microwire technique provides greater accuracy than test strips (reducing the median error from -50% to +2.9%) and greater precision (reducing uncertainties from ±25% to ±4.9%). Most importantly, the rate of false negatives versus the World Health Organisation’s 10 μg L-1 limit was reduced from 50% to 0% (N = 13 samples). Arsenic determination using open-source potentiostats may offer a low-cost option for research groups and NGOs wishing to perform arsenic analysis in-house, yielding superior quantitative data than the more widely used colorimetric test strips

Engineering: Cornell Quarterly, Vol.10, No.3 (Autumn 1975): Managing Our Water Resources

IN THIS ISSUE: Planning Water Resource Systems /2 (Better methods of planning our water resource systems depend on better knowledge of the physical, biological, chemical, economic, political, and social processes that are involved, according to Daniel P. Loucks, chairman of the Department of Environmental Engineering and a specialist in systems analysis.) ... Water Quality Control: High on the List of National Priorities /9 (The importance and means of quality control of the nation's water resources are discussed by Charles D. Gates, professor of civil and environmental engineering.) ... Resources Management of the Great Lakes: The Interaction of Engineering and Public Policy /16 (How individuals and universities can instigate action in public affairs is illustrated by Professor Leonard B. Dworsky in his case study of the Cornell project on Great Lakes management.) ... NEWRIT: Water Resources Information Retrieval Center at Cornell /24 (How a computer can do the literature search for water resources and other scientific and technological studies is described in an article on a valuable service available at Cornell.) ... Register /28 ... Faculty Publications /3

A Comparison of Payments to a For-profit Dialysis Firm From Government and Commercial Insurers.

This study assesses differences in payments from government and commercial insurers to dialysis clinics using data from a single for-profit organization