Geology professor to present paper on arsenic

Lois K. Ongley, assistant professor of geology at Bates, will discuss the results of a study of the sorption of dissolved arsenic by sand at the 1996 Northeastern Section Meeting of the Geological Society of America on Friday at 8:40 a.m. in Regency A of the Hyatt Regency Hotel in Buffalo, N.Y.

Ongley conducted a study to determine the nature of arsenic sorption to sand. In an effort to make class laboratories relevant to water contamination issues in Maine, Ongley and five Bates students designed and conducted this experiment during the fall 1996 semester. Jon Eden, Jerimiah Hubeny, Erica Montgomery, Ray Pavlik, and Sara Tichenor are co-authors of the paper.

Arsenic contaminated water was placed in vials with sand and allowed to sit for three and then 18 days. The experiments, run in triplicate, yielded the following conclusions: arsenic is absorbed readily by uncontaminated sandy aquifer materials; the sorption appears to be time-dependent; the arsenic probably undergoes cation exchange with the naturally occurring calcium, magnesium, sodium and potassium in the mineral grains; the absorptive capacity of the sand probably exceeds 60 micrograms of arsenic per gram of sand.

Ongley intends to continue her study of the absorption of arsenic with a focus on time dependence and absorption by size fractions and minerals. She also plans to investigate the desorption process and the transport of arsenic through aquifer material.

In 1995, the National Science Foundation awarded a grant to Ongley to promote undergraduate research in hydrology in Maine and Mexico. Under the terms of this grant, twelve students study the arsenic contamination of aquifers in Zimapan, Mexico, under the direction of Ongley and her colleagues: Aurora Armienta (National Autonomous University of Mexico, Mexico), Alison Lathrop (Millersville University, Pa.) and Helen Mango (Castleton State College, Vt.).

A member of the Bates faculty since 1992, Ongley graduated from Middlebury College, earned a master’s degree in geology from Texas A & M University, and received master’s and doctor’s degrees in environmental science and engineering from Rice University.

From 1977 to 1982, she worked as an oil and gas exploration geologist in south Texas, the Gulf of Mexico coast and the mid-continent area of the United States. From 1973 to 1975, Ongley was one of the first women to work as a shipboard technician for Lamont-Doherty Earth Observatory of Columbia University.