Vietnam: Contents of salinity monitoring at the identified measurement points

Vietnam: Contents of salinity monitoring at the identified measurement points - Illustrative Image

Under Article 8 of Circular 39/2016/TT-BTNMT, at the identified measurement points, salinity monitoring in Vietnam shall be conducted according to the following contents:

1. Measurement of depth

- Determine the vertical water depth (refer to the National Technical Regulation on Hydrological Monitoring).

- Determine the depth at various salinity measurement layers.

- Record depth values into salinity depth recording forms M-1a or M-1b (Appendix 1 issued with this Circular).

2. Measurement of salinity: To be conducted by the following two methods:

- Directly measure the salinity in the field (using instruments):

+ Clean and rinse the sensor probe with distilled water before measurement;

+ Proceed with the measurement by lowering the sensor probe to the identified layers (wait for about 1 minute) or as per the usage instructions of the measuring instrument;

+ Record salinity results, measurement time (hour, day, month, year), and weather phenomena into salinity recording forms M-1a or M-1c (Appendix 1 issued with this Circular);

+ For continuous automatic salinity meters, depending on the measurement conditions, measure at the middle layer or all three layers.

- Measure salinity after sample collection

+ Before sample collection and measurement, sample collection equipment and water sample containers must be cleaned and rinsed with distilled water;

+ Proceed with sampling by lowering the sample collection equipment to the identified layers, fill with water, lifting it, and transferring the sample into the sample container;

+ Determine salinity using direct measurement instruments or the Silver Nitrate AgNO3 method (immediately after sampling).

Use instruments:

+ Immerse the sensor probe into the water sample (wait for about 1 minute) or as per the usage instructions of the measuring instrument;

+ Record salinity results, sample collection time, sample measurement time (hour, day, month, year), and weather phenomena into salinity recording forms M-1a or M-1c (Appendix 1 issued with this Circular);

+ When switching the sensor probe to another sample, rinse the probe with distilled water, wipe dry with absorbent paper or a soft cloth.

Determe salinity by using the Silver Nitrate AgNO3 method:

+ Detailed procedure for determining salinity using the AgNO3 method is provided in Appendix 4 issued with this Circular;

+ Record salinity results, sample collection time, sample analysis time (hour, day, month, year), and weather phenomena into salinity recording forms M-1b (Appendix 1 issued with this Circular).

- After each measurement session, the sensor probe and analysis tools must be cleaned and rinsed with distilled water, dried with absorbent paper or a soft cloth, and stored properly.

Detailed regulations may be found in Circular 39/2016/TT-BTNMT issued on December 19, 2016.

Le Vy

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