Environ. Sci. Technol. 2002, 36, 1893-1898
Distribution of Haloacetic Acids in the Water Columns of the Laurentian Great Lakes and Lake Malawi B R I A N F . S C O T T , * ,† CHRISTINE SPENCER,† CHRISTOPHER H. MARVIN,† DAVID C. MACTAVISH,‡ AND DEREK C. G. MUIR† National Water Research Institute, Environment Canada, P.O. Box 5050, Burlington, Ontario, L7R 4Q6, Canada, and Canadian Air and Precipitation Monitoring Network, Meteorological Services Canada, 4905 Dufferin Street Downsview, Ontario, M3H 5T4 Canada
Haloacetic acids (HAAs) are persistent and mildly phytotoxic compounds that have been detected in many aquatic environments, including the waters of the Great Lakes. Sources of HAAs, especially of trifluoroacetic acid (TFA), are not well understood. In this study we assessed the influence of urbanization on the concentrations and profiles of HAAs in the Laurentian Great Lakes and in Lake Malawi, an African Great Lake. Vertical depth profiles for these compounds were taken for each of the Great Lakes with additional profiles taken 2 years later for Lakes Erie and Ontario. The results showed that while TFA was relatively constant throughout the water column, the chloroacetic acids (CAAs) varied with depth. There was a trend of increasing TFA proceeding from Lake Superior to Lake Ontario (18-150 ng/L). Total CAA concentrations were relatively constant throughout the lakes (∼500 ng/L) with dichloroacetic acid being the most abundant. No bromoacetic acids were detected. In the Detroit River, a connecting channel between Lakes Huron and Erie, the TFA values were similar to those in Lake Huron, but the CAAs levels were higher than in the upstream lakes and dependent on location, indicating inputs from urban areas along the river. These results were compared to those from Lake Malawi, which has a high population density within the watershed but no heavy industry. CAAs were nondetectable, and TFA concentrations were just at the detection limit (1 ng/L). Total HAA in the water column of Lakes Superior and Huron was compared to annual precipitation inputs at a site situated near both lakes. For Lake Huron, precipitation was a minor contributor to the total HAA inventory of the lake, but for Lake Superior precipitation could be the major contributor to the mass of HAA in this lake. Generally, high HAA levels paralleled the degree of industrial activity in the adjacent waters.
Introduction The presence of haloacetic acids (HAAs) in precipitation (1, 2), surface waters (1, 3, 4), snow (5), treated water (6), marine * Corresponding author phone: (905)336-4934; fax: (905)336-4989; e-mail:
[email protected]. † National Water Research Institute. ‡ Canadian Air and Precipitation Monitoring Network. 10.1021/es011156h CCC: $22.00 Published on Web 03/30/2002
Published 2002 by the Am. Chem. Soc.
waters (7), and remote sites (8, 9) is well documented. These compounds are phytotoxic (10, 11). Most studies have focused on the chloroacetic acids (CAAs). Concentrations of these compounds are very low (
