Guidelines on Collection of Water Samples for Phytoplankton Analysis

Transcription

1 Guidelines on Collection of Water Samples for Phytoplankton Analysis Principle of the Method The aim of this method is to collect samples of phytoplankton that are representative of the phytoplankton community in the water body being sampled. The water sample should be taken as close to the shellfish bed as possible and at the location from where shellfish samples for flesh testing are taken. The sampling method used will be dependent on the depth of water at the site. Water samples should ideally be taken at high tide (+/- 1 hour) particularly at inshore sites. Sampling at low tide should be avoided. Surface sampling may result in predominantly freshwater (rainwater/river run-off) being collected. Variation in the depth of water sampled means that different methods may be employed in order to collect this sample. Water Depth Method < 2m Bucket > 2m Tube sampler The water collected should be mixed before a 500 ml sub-sample is taken using a brown Nalgene bottle. This sub-sample is then preserved in acidic Lugol s iodine fixative. The bottle should be externally labelled and returned to SAMS (Oban) for analysis as soon as possible. Samplers are requested to collect samples early in the week to allow for delivery, settling and analysis of the sample, and reporting of results within same week. This is to enhance the capability of phytoplankton analysis to act as an early warning mechanism for potential biotoxin accumulation in shellfish. Samples should be collected according to the sampling schedule agreed with SAMS. If it is not possible to obtain a sample as planned, SAMS should be informed as soon as possible. Phytoplankton sample collection: 01-Feb-2012 Page 1 of 4

2 Safety The tube sampler may provide a trip hazard please take care during its deployment. Personal Protective Equipment required: Safety goggles, gloves. The water sampling kit contains 5ml of cell fixative called Lugol s Iodine Solution in a glass vial. This is a dilute mixture of glacial acetic acid, iodine and potassium iodide. Although dilute, it is still classified as harmful and care should be taken. Ensure that the lid of the fixative vial is tightly closed and that it is stored in a safe place out of the reach of children and animals. The fixative will stain clothing and more importantly skin, so gloves must be worn during the handling process. Goggles must also be worn to protect the eyes. If the fixative splashes into the eyes then wash out with copious amounts of water and seek medical advice immediately. If the chemical is swallowed seek medical advice immediately. If spilled, dilute/wash away with large quantities of water. Refer to NERC COSHH record number 1361 (supplied by SAMS) for hazard identification and management. Note: The fixation of water samples should be done as soon as possible after taking the sample, BUT should always be done on dry land with a water supply on hand in case of splash/spillage. Phytoplankton sample collection: 01-Feb-2012 Page 2 of 4

3 Sampling and Sample Preparation The sampling method varies with the depth of water sampled. A different method is used if the depth of water is greater or less than 2m. Before use, all equipment should be checked to ensure that it is clean. After use, all equipment should be washed in freshwater, dried and stored in a clean, dry place. 1. Water Depth < 2m 1.1 At those sites where the water depth is less than 2m and the water column is well mixed, a bucket should be used to collect the water sample. 1.2 Take a near-surface sample of sea water using a bucket from as far from the shore as practicable, but from the same location as the shellfish sample is obtained, or in the vicinity of the shellfish harvesting area. Avoid stirring up the sediment before sample collection. 1.3 Mix the contents of the bucket and immediately fill a 500 ml Nalgene sample bottle to the neck by immersing the bottle in the bucket. Do not allow the contents of the bucket to settle before filling the bottle. 1.4 Check the Lugol s solution provided is within the use-by date specified on the label before adding the contents of the fixative bottle to the Nalgene sample bottle (back on land). 1.5 Close the Nalgene sample bottle lid tightly and gently invert the sample bottle three times to ensure complete mixing of the fixative and seawater. 1.6 Seal the lid with insulating tape. 1.7 Label the bottle with the following details: Site location SIN (Site Identification Number for classified shellfish growing areas) Name of person collecting sample Date collected Time collected Sample depth (in metres) Mode of collection (specify bucket or sampling tube) Tidal state (ideally within +/- 1h of high water) GPS/OS grid reference (8 digits = 10m accuracy) 1.8 Wrap the labelled Nalgene sample and the empty glass vial in bubble-wrap, place in a plastic bag and then in the pre-labelled cardboard box (if posting), or return to SAMS (Oban) for analysis. Phytoplankton sample collection: 01-Feb-2012 Page 3 of 4

4 2. Water Depth >2m 2.1 At those sites where the water depth is greater than 2m, a tube sampler should be used to collect the water sample. 2.2 The tube sampler takes an integrated sample from the surface to a depth defined by the depth of water at the site. The tube sampler has been marked at 1m intervals with insulating tape, so that the depth over which the sample has been taken can be estimated. 2.3 Attach a line/rope to the bottom of the tube sampler to allow it to be raised from its base. 2.4 Open the valve at the top of the tube. 2.5 Slowly lower the weighted end of the tube into the water until most of it is immersed or until the weight is approximately 1m from the seabed. The tube sampler must remain taut and vertical in order to take an even sample of the whole water column. If the weight touches the bottom, redeploy the tube sampler as disturbed sediment will affect the quality of the water sample collected. 2.6 Take note of the depth using the guide of 1m intervals on the tube. 2.7 Close the valve at the top of the tube sampler and retrieve the bottom of the tube sampler using the attached line/rope. 2.8 Empty all the contents of the tube sampler into a bucket by opening the top valve. If necessary, lift the valve end of the tube sampler up to allow the water to drain into the bucket. 2.9 Mix the contents of the bucket and immediately fill a 500 ml Nalgene sample bottle to the neck by immersing the bottle in the bucket. Do not allow the contents of the bucket to settle before filling the bottle Check the Lugol s solution provided is within the use-by date specified on the label before adding the contents of the fixative bottle to the Nalgene sample bottle (back on land) Close the Nalgene sample bottle lid tightly and gently invert the sample bottle three times to ensure complete mixing of the fixative and seawater. Seal the lid with insulating tape Label the bottle as detailed in section Wrap the labelled Nalgene sample and the empty glass vial in bubble-wrap, place in a plastic bag and then in the pre-labelled cardboard box (if posting), or return to SAMS (Oban) for analysis. Phytoplankton sample collection: 01-Feb-2012 Page 4 of 4

5 Phytoplankton sample collection using a sampling tube DUNSTAFFNAGE MARINE LABORATORY OBAN ARGYLL PA37 1QA SCOTLAND T: (+44) (0) F: (+44) (0) E: info@sams.ac.uk W:

6 Phytoplankton sample collection Phytoplankton sample should be representative of community in the water body being sampled The water sample should be taken as close to the shellfish bed as possible and at the location from where shellfish samples for flesh testing are taken The sampling method used will be dependent on the depth of water at the site Water samples should ideally be taken at high tide (+/- 1 hour) particularly at inshore sites - sampling at low tide should be avoided Surface sampling may result in predominantly freshwater (rainwater/river run-off) being collected

7 Phytoplankton sampling kit Sampling kit: 500 ml nalgene bottle 5 ml Lugol s fixative bottle labels tape for sealing lid bubble wrap plastic bag box for posting parcel tape pre-paid postage labels

8 Use of Lugol s Use of Lugol s fixative fixative Iodine will stain clothing and (more importantly) skin - wear gloves and safety glasses If spilled, dilute/wash away with large quantities of water If Lugol s splashes into the eyes then wash out with copious amounts of water and seek medical advice immediately

9 IMPORTANT: Wash equipment with freshwater after sample collection and between sample collection at different sites BUCKET sample: - at sites where water depth < 2m and water column well-mixed - collect sample from as far as shore line as practicable, but in vicinity of shellfish harvesting area TUBE sample (preferred method): - at sites where water depth > 2m - collect sample from a boat or nearby pier if no boat available

10 Phytoplankton sampling tube for collecting an integrated water sample sampler is marked at 1m intervals with insulating tape so the depth over which the tube sample is taken can be estimated

11 Attach a rope to the weighted end of the sampling tube around the groove

12 Open the tap before lowering the sampling tube into the water

13 Lower the tube into the water as far as possible Take care not to touch the sea bed - avoid disturbing the sediment X

14 Close the tap while the weighted end of the tube is still in the water (at maximum depth)

15 Raise the sampling tube by the weighted end first, using the rope

16 Hold the weighted end of the tube over the bucket and open the tap Raise the tap end of the tube, allowing the water to run out into the bucket

17 Mix the contents of the bucket and fill the 500 ml nalgene bottle NOTE: If you are collecting samples from more than one site, the tube and bucket should be rinsed between sampling

18 Using personal protective equipment, pour the complete contents of the Lugol s fixative (5 ml) into the nalgene bottle Note: The fixation of water samples should be done as soon as possible after taking the sample, BUT ensure a water supply is on hand in case of splash/spillage

19 Complete bottle label details fully or unverified Co-ordinates to a minimum 10 m accuracy from GPS AB or write unverified if not known Post/deliver same day if possible, or by following day INFORM SAMS IF YOU ARE UNABLE TO COLLECT A SAMPLE toxic.algae@sams.ac.uk

20 X Screw the lid on firmly and seal with electrical tape

21 Place in a plastic bag (in case of leakage) and wrap with bubble wrap Return empty Lugol s bottles for re-use

22 Place in a pre-labelled box and seal around both ends with tape Post box to: Scottish Association for Marine Science