The Chemical Analysis of Fresh Water

The document provides detailed standard operating procedures for the chemical analysis of freshwater, focusing on micronutrients and aquatic productivity. It covers the measurement of anions, cations, carbon speciation, nitrogen and phosphorus speciation, chlorophyll-a, dissolved oxygen, pH, conductivity, and soluble reactive silicon. The guide details labware cleaning, calibration of balances and pipettes, sample preparation using 1.2 µm GF/C filters, and the use of the Sample Master® Laboratory Information Management System (LIMS) for data tracking and validation. It also specifies protocols for outsourced analyses conducted at the University of Alberta's Biogeochemical Analytical Service Laboratory.

• The laboratory uses Whatman GF/C filters (1.2 µm) to operationally define dissolved and particulate fractions, a practice maintained since the early 1970s because they are faster and can be ignited for carbon and nitrogen determination.
• Sample data in the Sample Master® LIMS is assigned one of three quality statuses: "Entered" for data passing analytical QC, "Validated" for data assessed for outliers via trend analysis, and "Approved" for data that has undergone peer review.
• The laboratory employs a specific cleaning regimen for different labware: general use items are rinsed with hot tap water and DRO water, while vials for particulate phosphorus and iron are soaked in a 10% HCl bath for at least four hours.
• Reference samples are prepared using Lake 239 surface water, which is aged for at least one year at 4 °C to ensure analytes reach equilibrium.
• Dissolved oxygen is determined using the Winkler titration method, with a method detection limit of 0.2 mg/L O2 and an operating range of 0–20 mg/L O2.
• Specific conductance is measured at 25 °C using platinum electrodes, with a method detection limit of 0.05 µS/cm and a limit of quantitation of 0.16 µS/cm.
• pH measurements are conducted using an Orion Ross type “Sur Flow” electrode, with samples equilibrated to 25 ± 1 °C and spiked with 200 µl of 3N KCl to stabilize electrode performance in low ionic strength waters.
• Dissolved Inorganic Carbon (DIC) is measured using a Li-Cor 850 CO2/H2O gas analyzer, with an operating range of 0–3,000 µM.
• Dissolved Organic Carbon (DOC) is determined by acidifying samples to pH 2–3, sparging with ultra-high-purity compressed air to remove inorganic carbon, and oxidizing the remainder at 720 ºC.
• Nitrite, nitrate, and ammonia are analyzed using a SEAL AutoAnalyzer 3 HR, with nitrate reduced to nitrite via a copper-cadmium reduction column.
• Total Dissolved Nitrogen (TDN) is measured by exposing samples to high-intensity short-wave UV radiation for four hours to oxidize organic nitrogen into inorganic constituents.
• Total Dissolved Phosphorus (TDP) is determined by photo-oxidizing organic phosphorus to orthophosphate using short-wave UV radiation, followed by the soluble reactive phosphorus method.
• Particulate phosphorus is measured by combusting filter-retained matter at 500 °C in a muffle furnace, extracting phosphorus oxides with dilute hydrochloric acid, and measuring the resulting orthophosphate.
• Soluble reactive silicon is measured spectrophotometrically at 820 nm, with an operating range of 0.003–2.50 mg/L Si.
• Particulate iron is determined by digesting filter-retained matter with nitric acid and analyzing the extract using an atomic absorption spectrometer with an acetylene flame.
• Chlorophyll-a is measured using a gross fluorescence method with excitation at 440 nm and detection emission at 660 nm, though this may over-estimate Chl-a if degradation products are present.
• Certain analyses, including alkalinity, anions (Cl and SO4), cations (Na, Mg, K, Ca, Mn, Fe), and particulate carbon and nitrogen, are outsourced to the Biogeochemical Analytical Service Laboratory (BASL) at the University of Alberta.

APA

Havens, S., Cooney, B., & Stainton, M. (2024). The Chemical Analysis of Fresh Water. International Institute for Sustainable Development. https://www.iisd.org/system/files/2024-10/chemical-analysis-fresh-water-third-edition.pdf

Chicago

Havens, Sonya, Blake Cooney, and Michael Stainton. The Chemical Analysis of Fresh Water. International Institute for Sustainable Development, 2024. https://www.iisd.org/system/files/2024-10/chemical-analysis-fresh-water-third-edition.pdf.

Wikipedia

{{cite report |last1=Havens |first1=Sonya |last2=Cooney |first2=Blake |last3=Stainton |first3=Michael |title=The Chemical Analysis of Fresh Water |publisher=International Institute for Sustainable Development |date=October 2024 |url=https://www.iisd.org/system/files/2024-10/chemical-analysis-fresh-water-third-edition.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{havens2024chemical, author = {Havens, Sonya and Cooney, Blake and Stainton, Michael}, title = {{The Chemical Analysis of Fresh Water}}, institution = {International Institute for Sustainable Development}, year = {2024}, month = oct, url = {https://www.iisd.org/system/files/2024-10/chemical-analysis-fresh-water-third-edition.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }