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Water and aqueous solutions
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METALS IN WATER: GENERAL INFORMATION
SELECTING THE
RIGHT METAL PACKAGE
Natural waters include groundwater, lake water, river water and seawater. Wastewate include sample types such as high-salinity leachates from deposits, industrial sewage etc.
The following multi-element packages are recommended for natural water:
V-1 Natural freshwater not requiring determination of very low concentrations
V-2 Natural freshwater requiring determination of very low concentrations
V-5 Seawater (salt content 1.2-3.5%)
V-6 Brackish water (salt content approx. 0.3-1.2%)
The following multi-element packages are suitable for polluted water:
V-3a Determination of low metal concentrations without digestion of the sample
V-3b Determination of low metal concentrations with digestion of the sample
V-4a Determination of high metal concentrations without digestion of the sample
V-4b Determination of high metal concentrations with digestion of the sample
If there is uncertainty regarding the classification of the water, please contact the laboratory.
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SAMPLING - METALS
It is essential to avoid the risk of contamination, especially when determining very low metal concentrations. For analyses in the µg/L range or lower, specially washed (acid cleaned) sample containers should be ordered from the laboratory. The sample volume should be 100 ml.
If the analysis is to comprise dissolved elements only, the water shall be free from particles. The sample should then be filtered through a 0.45 µm filter promptly after sampling (preferably in the field) but before preservation with acid. Please contact the laboratory for recommendations regarding filter quality. If particle-bound elements shall be included in the analysis, the sample shall not be filtered. PLEASE NOTE: If filtration in the laboratory is requested, this must be stated on the order (additional charge: SEK 75/sample (NOK 75/DKK 65)).
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USE PLASTIC GLOVES!
When taking water samples, the use of skin care products should be avoided since such products may contain metals, especially Zn, in high concentrations. It is recommended to use plastic gloves in order to avoid contamination.
SAMPLE STORAGE
Generally, water samples should be kept in a cool and dark container and be delivered to the laboratory promptly after sampling. Instructions for sample handling, applying to ALS Scandinavia's analyses, are found under the packages on this website as well as on separate sheets which can be ordered or downloaded. |
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PRESERVATION - METALS
All samples are acidified upon receipt at the laboratory, provided that they are not already acidified when they arrive. If samples are preserved outside the laboratory, high-purity nitric acid (SUPRAPUR or equivalent, 1 ml per 100 ml of sample) should be used. PLEASE NOTE: Use no other acids for preservation!
OTHER INFORMATION
Water samples should be well oxidised when sulphur is to be determined.
ORGANIC COMPOUNDS
When organic compounds are to be determined, it is especially important to consider that different analytical methodologies, including sample preparation, may give different results. The exchange may also change between extraction methods. When different analytical results are to be compared, it is thus important to ascertain that the same methods have been used.
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OIL ANALYSES
Hydrocarbons: Oils are mixtures of aliphatic and aromatic hydrocarbon chains. Analyses by GC show the composition of these mixtures, based on size and character of the various compounds.
Aliphatics: Aliphatics are present in petroleum products such as petrol, diesel, fuel oil and in some solvents. Analysis of fractions indicate which type of contamination is detected in the water.
Aromatics: Aromatics are present mainly in diesel, fuel oil and heavier petroleum products. Ususally, aromatics occur in lower concentrations than aliphatics. Analysis for aromatics give supplementary information on the type of contaminant.
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SAMPLE HANDLING FOR ORGANIC COMPOUNDS
When organic compounds are to be determined it is more important (compared to metals) that samples are kept in cool and dark containers and that they are delivered to the laboratory as soon as possible after sampling. In addition, bottles should be top-filled in order to avoid losses of volatile compounds. There is usually no need for adding preservatives to these samples, except when chlorophenols are to be determined. In this case preservation is however normally done in the laboratory. |
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