JoVE Logo
Faculty Resource Center

Sign In





Representative Results






Clean Sampling and Analysis of River and Estuarine Waters for Trace Metal Studies

Published: July 1st, 2016



1Department of Oceanography, National Sun Yat-sen University, 2Institute of Oceanography, National Taiwan University, 3Taiwan Ocean Research Institute, National Research Laboratories, 4Department of Oceanography and Marine Sciences, Texas A&M University at Galveston
* These authors contributed equally

Special care using "clean techniques" is required to properly collect and process water samples for trace metal studies in aquatic environments. A protocol for sampling, processing, and analytical procedures with the aim of obtaining reliable environmental monitoring data and results with high sensitivity for detailed trace metal studies is presented.

Most of the trace metal concentrations in ambient waters obtained a few decades ago have been considered unreliable owing to the lack of contamination control. Developments of some techniques aiming to reduce trace metal contamination in the last couple of decades have resulted in concentrations reported now being orders of magnitude lower than those in the past. These low concentrations often necessitate preconcentration of water samples prior to instrumental analysis of samples. Since contamination can appear in all phases of trace metal analyses, including sample collection (and during preparation of sampling containers), storage and handling, pretreatments, and instrumental analysis, specific care needs to be taken in order to reduce contamination levels at all steps. The effort to develop and utilize "clean techniques" in trace metal studies allows scientists to investigate trace metal distributions and chemical and biological behavior in greater details. This advancement also provides the required accuracy and precision of trace metal data allowing for environmental conditions to be related to trace metal concentrations in aquatic environments.

This protocol that is presented here details needed materials for sample preparation, sample collection, sample pretreatment including preconcentration, and instrumental analysis. By reducing contamination throughout all phases mentioned above for trace metal analysis, much lower detection limits and thus accuracy can be achieved. The effectiveness of "clean techniques" is further demonstrated using low field blanks and good recoveries for standard reference material. The data quality that can be obtained thus enables the assessment of trace metal distributions and their relationships to environmental parameters.

It has been commonly recognized that some trace metal results obtained for natural waters may be inaccurate owing to artifacts arising from inadequate techniques applied during sample collection, treatments and determination1,2. The true concentrations (in sub-nM to nM range in surface waters 3) of dissolved trace metals are now up to two orders of magnitude lower than previously published values. The same situation has been found in marine chemistry where the accepted dissolved trace metal concentrations in oceanic waters have decreased by orders of magnitude over the last 40 years or so as improved sampling and analytical methods have been intr....

Log in or to access full content. Learn more about your institution’s access to JoVE content here

1. Sampler Preparation

  1. Sampler
    1. Assemblage of sampler
      1. Connect a 4 m long fluorinated ethylene propylene (FEP) tubing (I.D. 0.635 cm, O.D. 0.95 cm or similar) to a 1.5-m chemically resistant silicone pumping tube (O.D. 0.635 cm).
      2. Insert a polypropylene Y-connector into the pumping tube, and connect a 50-cm pumping tube to one outlet, and a 0.45 μm capsule filter (by a 20-cm pumping tube) to the other.
      3. Assemble the tubings in a clean room (bench) after they .......

Log in or to access full content. Learn more about your institution’s access to JoVE content here

With the development and use of "clean techniques", it is now well recognized that in order to obtain accurate trace metal concentrations in ambient waters, preconcentration of trace metals in waters samples is a common practice. While most water quality criteria for trace metals in natural waters are in the low μg/L range, lower detection limits are needed to investigate geochemical and biological effects on trace metals at ambient concentrations in aquatic environments.


Log in or to access full content. Learn more about your institution’s access to JoVE content here

Obtaining reliable trace metal data in natural waters requires great care as emphasized during sample collection, processing, pretreatments, and analysis that aim to reduce contamination. Trace metal concentrations in natural waters obtained using "clean techniques" in the last two decades found that the concentrations can be orders of magnitude lower than previously reported. Water quality criteria for trace metals in waters are now more readily assessed when trace metal levels are accurately measured resulting .......

Log in or to access full content. Learn more about your institution’s access to JoVE content here

The authors thank Drs. Bobby J. Presley, Robert Tayloy, Paul Boothe, Mr. Bryan Brattin, and Mr. Mike Metcalf for their assistance during the laborious field sampling and lab work for the practical development and application of "clean techniques".


Log in or to access full content. Learn more about your institution’s access to JoVE content here

Name Company Catalog Number Comments
Nitric Acid Seastar Chemicals Baseline grade
Ammonium hydroxide Seastar Chemicals Baseline grade
Acetic Acid Seastar Chemicals Baseline grade
Nitric Acid J. T. Baker 9601-05 Reagent grade
Hydrochloric acid J. T. Baker 9530-33 Reagent grade
Chromatographic columns Bio-Rad 7311550  Poly-Prep
Column stack caps Bio-Rad 7311555
Cap connectors (female luers) Bio-Rad 7318223
2-way stopcocks Bio-Rad 7328102
Cation exchange resin Bio-Rad 1422832  Chelex-100
Portable sampler (sampling pump) Cole Palmer EW-07571-00
FEP tube Cole Palmer EW-06450-07 6.4 mm I.D., 9.5 mm O.D.
Pumping tube Cole Palmer EW-06424-24 6.4 mm I.D. C-Flex
Capsule filter (0.4 mm) Fisher Scientific WP4HY410F0 polypropylene casing
1 L low density polyethylene bottle NALGE NUNC INTERNATIONAL 312088-0032
1 L (or 500 ml) FEP bottle NALGE NUNC INTERNATIONAL 381600-0032

  1. Taylor, H. E., Shiller, A. M. Mississippi River Methods Comparison Study: Implications for water quality monitoring of dissolved trace elements. Environmental Science and Technology. 29, 1313-1317 (1995).
  2. Windom, H. L., Byrd, J. T., Smith, R. G., Huan, F. Inadequacy of NASQAN data for assessing metal trends in the nation's rivers. Environmental Science and Technology. 25 (6), 1137-1142 (1991).
  3. Mason, R. P. . Trace Metals in Aquatic Systems. , (2013).
  4. Wen, L. -. S., Santschi, P., Gill, G., Paternostro, C. Estuarine trace metal distributions in Galveston Bay: importance of colloidal forms in the speciation of the dissolved phase. Marine Chemistry. 63, 185-212 (1999).
  5. Wen, L. -. S., Stordal, M. C., Tang, D., Gill, G. A., Santschi, P. H. An ultraclean cross-flow ultrafiltration technique for the study of trace metal phase speciation in seawater. Marine Chemistry. 55, 129-152 (1996).
  6. Benoit, G. Clean technique measurement of Pb, Ag, and Cd in freshwater: A redefinition of metal pollution. Environmental Science and Technology. 28, 1987-1991 (1994).
  7. Benoit, G., Hunter, K. S., Rozan, T. F. Sources of trace metal contamination artifacts during collection, handling, and analysis of freshwater. Analytical Chemistry. 69 (6), 1006-1011 (1997).
  8. Jiann, K. -. T., Presley, B. J. Preservation and determination of trace metal partitioning in river water by a two-column ion exchange method. Analytical Chemistry. 74 (18), 4716-4724 (2002).
  9. Fardy, J. J., Alfassi, Z. B., Wai, C. M. . Preconcentration Techniques for Trace Elements. , 181-210 (1992).
  10. Pai, S. -. C. Pre-concentration efficiency of Chelex-100 resin for heavy metals in seawater. Part 2. Distribution of heavy metals on a Chelex-100 column and optimization of the column efficiency by a plate simulation method. Analytica Chimica Acta. 211, 271-280 (1988).
  11. Pai, S. -. C., Fang, T. -. H., Chen, C. -. T. A., Jeng, K. -. L. A low contamination Chelex-100 technique for shipboard pre-concentration of heavy metals in seawater. Marine Chemistry. 29, 295-306 (1990).
  12. Pai, S. -. C., Whung, P. -. Y., Lai, R. -. L. Pre-concentration efficiency of Chelex-100 resin for heavy metals in seawater. Part 1. Effects of pH and salts on the distribution ratios of heavy metals. Analytica Chimica Acta. 211, 257-270 (1988).
  13. Salbu, B., Oughton, D. H., Salbu, B., Steinnes, E. . Trace Elements in Natural Waters. , 41-69 (1995).
  14. . U.S. Environmental Protection Agency. Method 1669. Sampling ambient water for trace metals at EPA Water Quality criteria levels Available from: (1996)
  15. Horowitz, A. J., et al. Problems associated with using filtration to define dissolved trace metal concentrations in natural water samples. Environmental Science and Technology. 30, 954-963 (1996).
  16. Cortecci, G., et al. Geochemistry of trace elements in surface waters of the Arno River Basin, northern Tuscany, Italy. Applied Geochemistry. 24 (5), 1005-1022 (2009).
  17. Markich, S. J., Brown, P. L. Relative importance of natural and anthropogenic influences on the fresh surface water chemistry of the Hawkesbury-Nepean River, south-eastern Australia. The Science of the Total Environment. 217, 201-230 (1998).
  18. Shafer, M. M., Overdier, J. T., Hurley, J. P., Armstrong, D., Webb, D. The influence of dissolved organic carbon, suspended particles, and hydrology on the concentration, partitioning and variability of trace metals in two contrasting Wisconsin watersheds (U.S.A.). Chemical Geology. 136, 71-97 (1997).
  19. Warren, L. A., Haack, E. A. Biogeochemical controls on metal behaviour in freshwater environments. Earth-Science Reviews. 54, 261-320 (2001).
  20. Jiann, K. -. T., Santschi, P. H., Presley, B. J. Relationships between geochemical parameters (pH, DOC, SPM, EDTA Concentrations) and trace metal (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) concentrations in river waters of Texas (USA). Aquatic Geochemistry. 19 (2), 173-193 (2013).
  21. Peltzer, E. T., et al. A comparison of methods for the measurement of dissolved organic carbon in natural waters. Marine Chemistry. 54, 85-96 (1996).
  22. Nowack, B., Kari, F., Hilger, S. U., Sigg, L. Determination of dissolved and adsorbed EDTA species in water and sediments by HPLC. Analytical Chemistry. 68 (3), 561-566 (1996).
  23. Bergers, P. J. M., de Groot, A. C. The analysis of EDTA in water by HPLC. Water Research. 28 (3), 639-642 (1994).

This article has been published

Video Coming Soon

JoVE Logo


Terms of Use





Copyright © 2024 MyJoVE Corporation. All rights reserved