Article pubs.acs.org/est
Increased Concentrations of Polycyclic Aromatic Hydrocarbons in Alpine Streams during Annual Snowmelt: Investigating Effects of Sampling Method, Site Characteristics, and Meteorology Pourya Shahpoury,†,⊥ Kimberly J. Hageman,*,† Christoph D. Matthaei,‡ Robert E. Alumbaugh,§ and Michelle E. Cook† †
Department of Chemistry, University of Otago, Dunedin, New Zealand Department of Zoology, University of Otago, Dunedin, New Zealand § Department of Pharmacology & Toxicology, University of Otago, Dunedin, New Zealand ‡
S Supporting Information *
ABSTRACT: Silicone passive samplers and macroinvertebrates were used to measure time-integrated concentrations of polycyclic aromatic hydrocarbons (PAHs) in alpine streams during annual snowmelt. The three sampling sites were located near a main highway in Arthur’s Pass National Park in the Southern Alps of New Zealand. A similar set of PAH congeners, composed of 2−4 rings, were found in silicone passive samplers and macroinvertebrates. The background PAH concentrations were similar at all sites, implying that proximity to the highway did not affect concentrations. In passive samplers, an increase of PAH concentrations by up to seven times was observed during snowmelt. In macroinvertebrates, the concentration changes were moderate; however, macroinvertebrate sampling did not occur during the main pulse observed in the passive samplers. The extent of vegetation in the catchment appeared to affect the concentration patterns seen at the different stream sites. A strong correlation was found between PAH concentrations in passive samplers and the amount of rainfall in the study area, indicating that the washout of contaminants from snowpack by rainfall was an important process.
■
activity.10 For example, the larvae of many aquatic macroinvertebrates emerge during late spring and early summer.16 Distinct concentration pulses of organic contaminants in aquatic systems during the snowmelt period have been reported previously, specifically in the St. Lawrence River and four of its tributaries in Canada,17 a river catchment on Cornwallis Island in Arctic Canada,18 in snowmelt-fed streams in Bow Lake, Alberta,3 in streamwater and stream macroinvertebrates in the Italian Alps,13,19 and in an urban catchment in the city of Toronto, Canada.20 However, very little is known about the role that site characteristics and meteorological conditions play in controlling the timing, intensity, or location of snowmeltinduced contaminant pulses. Gaining more information about the environmental processes that control contaminant pulses is essential for understanding their potential impacts. While it is apparent that further study regarding the processes that control snowmelt-induced contaminant pulses is needed, it is also clear that alternative methods for making such measurements need investigation. The previously reported
INTRODUCTION
Semivolatile organic contaminants can travel through the atmosphere to regions distant from where they originated.1−7 In cold regions, snow can efficiently scavenge these chemicals from the atmosphere,8 especially when temperatures are
