In-Situ Measurements of Cu in an Estuarine Environment Using a Portable Spectrophotometric Analysis System

• Published in: Environmental science & technology Vol. 38; no. 2; pp. 587 - 593
• Main Authors: Callahan, Michael R, Kaltenbacher, Eric A, Byrne, Robert H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.01.2004
• Subjects: Analysis methods; Applied sciences; Chemical contaminants; Copper; Copper - analysis; Earth sciences; Earth, ocean, space; Ecosystem; Engineering and environment geology. Geothermics; Environmental Monitoring - instrumentation; Exact sciences and technology; Geological Phenomena; Geology; Natural water pollution; Pollution; Pollution, environment geology; Rivers; Spectrophotometry - methods; Spectrum analysis; Water Pollutants - analysis; Water treatment and pollution; Florida; United States; North America; America; ASW, USA, Florida, Tampa Bay; USA, Florida, Tampa Bay; Concentration measurement; Measurement in situ; Detection limit; Portable equipment; Water pollution; Bay; Copper; Spectrophotometry; Real time system; Coastal zone; Heavy metal; Seawater
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es034538r

Application of a portable in-situ spectrophotometric analysis system for the measurement of Cu in estuarine environments is described in this work. Our spectrophotometric elemental analysis system (SEAS) used for in-situ observations of Cu concentrations is capable of fully autonomous or user-controlled operations. The optical cells used in SEAS systems are flexible liquid core waveguides (LCWs) with optical path lengths as long as 5 m. The 1-m waveguide used in the present study provided a 3.0 nM detection limit and a 5.0% relative standard deviation for a 25 nM copper sample. Analysis times range between 1 and 5 min, allowing for acquisition of data on scales appropriate to the highly dynamic biogeochemical nature of copper in the coastal environment. Field deployments of SEAS-Cu in Tampa Bay, FL, showed low Cu concentrations near the mouth of the estuary (3−4 nM), with elevated concentrations (∼25 nM) in anthropogenically impacted regions of the bay (e.g., marinas and areas adjacent wastewater treatment plants). Transect data between Tampa Bay and a deep water harborage exhibited copper concentrations ranging between 5 and 50 nM.