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The manner in which samples are collected has a direct impact on the quality of analytical findings. To minimize the risks of sample contamination by the sample collector and to ensure sample integrity, basic precautions must be taken to obtain a representative sample. Samples can become contaminated through careless sampling techniques. It is therefore the responsibility of the sample collector or of an artificial reservoir manager to ensure the quality of sample collection, preservation and suitable transportation of samples that are sent to a laboratory accredited by the Ministère de l’Environnement et de la Lutte contre les changements climatiques. The sample collector or of an artificial reservoir manager is also responsible for ensuring a representative sampling where on-site analyses are conducted.
Specific Precautions
The following precautions are necessary to prevent sample contamination:
closely follow the instructions provided by the manufacturer of the chemical test kits used at the sampling site;
always use contaminant-free containers and where possible, prepare containers and testing equipment at sampling sites;
keep an accurate record of each sample collected using the correct form;
always use devices or instruments that have been calibrated at the required frequency (thermometer and pH-meter);
reagents that are used for analysis must be kept in a clean, dry, well-ventilated and dark location until use;
always take measurements with reagents in a suitable location. Avoid leaving reagents in prolonged sun exposure;
seal reagent bottles correctly after use;
never place wet fingers on reagent bottles; this may lead to inaccurate results;
verify product expiry dates. Once the date indicated is past, you cannot be certain that results are reliable;
discard expired products, in accordance with regulations in effect
The methods of preserving the analytical parameters prescribed in the Regulation respecting the water quality of pools and other artificial reservoirs are closely tied to analysis methods and are described in Table 1.
Table
1 - Preservation methods for chemical parameters (on-site analysis)
| Parameter | Preservative* | Container* | Recommended volume (ml) | Time between sample collection and analysis |
| Alkalinity | N | P or G | 10 | 30 minutes |
| Hardness | N | P or G | 10 | 30 minutes |
| Total residual bromine | N | P or G | 10 | 30 minutes |
| Chloramines | N | P or G | 10 | 30 minutes |
| Free residual chlorine | N | P or G | 10 | 30 minutes |
| Total residual chlorine | N | P or G | 10 | 30 minutes |
| pH | N | P or G | 10 | 2 hours |
| Water temperature | N | P or G | 125 | 3 minutes |
Sampling Method
Samples intended for chemical analysis must be collected during normal operating hours, 15 to 30 cm below the surface of the water or, where a reservoir is less than 30 cm deep, halfway between the surface of the water and bottom of the reservoir.
Samples must be collected in an area that is not very frequented by bathers at the time of sampling. It is also important to collect the sample in an area between the filtration system intake and water return. In the case of whirlpool baths, samples can be collected anywhere below the surface of the water.
It is important to carefully follow the instructions provided by the manufacturer of the chemical test kits used. It is also essential that the hands of the person who is collecting the samples be extremely clean to prevent subsequent contamination (by sweat, chemical residues, etc.) when handling samples.
The measuring cells of the kit must remain clean and transparent. Cells must be rinsed with the sample before their filling up and the level of liquid adjusted. They must then be wiped with a soft clean cloth before making colour comparisons, so that outer surfaces remain clean and dry. Always fill cells to the required level to prevent discrepancies in measurements.
Analysis MethodsFor a water temperature reading, the following is required:
A water temperature reading can also be taken directly in the artificial reservoir.
Other Parameters
It is possible to obtain different types of test kits for on-site analysis of chemical parameters (pH; free, total and combined residual chlorine; alkalinity; etc.). These kits are very useful for verifying the principal parameters that can be used to analyze water quality and therefore ensure that treatment systems are operating correctly.
These kits generally include test containers, measuring cells and reactive products that help to determine concentrations of the products tested by using colorimetric comparators. Analyses must be conducted using reliable equipment and appropriate and not expired reagents.
The reservoir manager must at least have a test kit capable of measuring free residual chlorine to between 0.2 mg/1 and 5.0 mg/1 with a precision of 0.2 mg/l. If using brome as a disinfectant, it is also necessary to have a test kit capable of measuring total brome to between 1.0 mg/l and 5.0 mg/ with a precision of 0.5 mg/l.
Test kits must also be capable of measuring pH with a precision of 0.2 units, hardness and total alkalinity of the water with a precision of 10 mg/l.
Specific Precautions
Preservation Methods
The preserving methods for the analytical parameters prescribed in the Regulation respecting the water quality of pools and other artificial reservoirs are closely tied to laboratory analysis methods. In fact, the desired sensitivity and quantification limits can be used to determine the volume and type of sample to be collected. The type of container and sample preservation technique are also determined on the basis of the analysis method. It is therefore vital to work in close cooperation with laboratory staff to obtain the proper additional information. In addition to the specific provisions detailed in Table 2, the following general considerations apply:
Table 2 - Preservation methods for microbiological and chemical parameters (laboratory analysis)
| Parameter | Preservative* | Container* | Recommended volume (ml) | Time between sample collection and analysis |
| MICROBIOLOGY | ||||
| Fecal coliforms | ST3 | PPS or GS | 100 | 48 hours |
| Escherichia coli | ST3 | PPS or GS | 100 | 48 hours |
| Pseudomonas aeruginosa | ST3 | PPS or GS | 100 | 48 hours |
| Staphylococcus aureus | ST3 | PPS or GS | 100 | 48 hours |
| CHEMISTRY | ||||
| Turbidity | N/A | P or G | 125 | 48 hours |
Sampling Method
Samples sent for microbiological and turbidity analysis must be collected during normal operating hours, 15 to 30 cm below the surface of the water or where the reservoir is less than 30 cm deep, halfway between the surface of the water and the bottom of the reservoir. Samples must be collected in an area that is not very frequented by bathers at the time of collection and in an area between the filtration system intake and water return. In the case of whirlpool baths, samples can be collected anywhere below the surface of the water. Bottles must be filled to the rim, leaving an air space of at least 2.5 cm and the lid must be sealed immediately after collection.
For water samples from an artificial reservoir destined for microbiological analysis, sampling containers contain a reagent. This reagent neutralizes the residual disinfectant present in the water when a sample is collected. To preserve the reagent, ensure that you tip the container towards the bottom of the reservoir at a 45° angle in one motion. This preventive measure is necessary, otherwise results may be negatively distorted. It’s also possible to collect sample by adding immediately and aseptically a sterile solid tablet of sodium thiosulfate in the sample. Samples for microbiological analysis must be collected with very particular attention paid to avoiding hand contamination, even when a collector has washed his or her hands before. If more than one sample is required, always begin with microbiological samples, and after with the chemical samples, to avoid dipping a microbiological analysis container in water that has been contaminated by the collector.
| CONTAINERS | |
| P | Bottles and lid linings are made of the following plastics: high- or low-density polyethylene, polypropylene, polystyrene, polyvinyl chloride or teflon |
| PPS | Sterile polypropylene bottle |
| G | Glass bottle |
| GS | Sterile glass bottle |
| PRESERVATIVES | |
| N | No preservative required |
| ST3 | Sodium thiosulfate at a final concentration of 0.01 % (p/v) |
| OTHER | |
| N/A | Not applicable |
