Marine and coastal Water Quality Standard
Marine and coastal Water Quality Standard of Thailand
Marine water means all waters within Thai territorial waters, excluding water in the surface water under the Notifications of National Environment Board on the Water Quality Standards for Surface Waters.
Thai waters mean all territorial waters under the sovereignty of Thailand according to the Maritime Law Vessel Act of Thailand.
Minimum transparency level means the lowest level of transparency of water that measured and collected from the same station in the past a year during the same tides and seasons.
Minimum salinity level means the minimum salinity of water that measured and collected from the same station in the past a year during the same tides and seasons.
Buffer zone means the joint areas between different types of marine water utilization. The zone is defined based on the parallel distance of 500 meters from the water that has lower water quality.
Classification of marine water quality standard in Thai waters, the water quality can be classified into 6 types as follows:
Class 1 The marine water quality standard for natural resource preservation areas cover to the water that is not reserved for a particular use and is naturally suitable for breeding or nurturing newborn marine organisms as well as being able to serve as food sources and natural habitats for marine animals, plants and seagrasses.
Class 2 The marine water quality standard for coral reef conservation areas cover to the water densely inhabited by coral reefs, covering the area with 1,000 meter extension from the most exterior ridge of the coral reef.
Class 3 The marine water quality standard for aquaculture areas cover to the water designated as to be utilized for aquaculture by the fisheries laws.
Class 4 The marine water quality standard for recreation areas cover to the water declared by the local administrative organizations for swimming or other recreational activities.
Class 5 The marine water quality standard for industrial or ports zone cover to the water that is adjacent to an industrial estate, which conformed to the law governing the Industrial Estate Authority of Thailand; adjacent to port zones governed by any ports and maritime laws; governed by the standard shall extend from the lowest tide line up to 1,000 meters.
Class 6 The marine water quality standard for residential areas cover to the water that is close to residential areas under the municipal laws, Pattaya Municipality or Bangkok Municipality; the standard shall be applicable specifically to the parts of Pattaya, Bangkok and other municipalities whose borders are attached to the coastal area and extend from the lowest tide line up to 1,000 meters.
The marine water quality standard for natural resource preservation areas
No unpleasant objects floating on the water surface.
No oil or visible fat floating on the water surface.
The color of marine water is in the range from 1-22 in the scale of Forel-Ule solution.
The odor must not be obnoxious; No odors of oil, hydrogen sulfide, chemicals, garbage, etc.
The temperature can be increased for not more than 1 Degree Celsius compared with natural background condition.
The pH must be in the range of 7.0-8.5.
The reduction of water transparency from natural background conditions shall not exceed 10 percent, compared with the minimum transparency level.
Increase of suspended solids shall not exceed the summation of average daily, monthly, or annual value and their standard deviation; the average daily value calculated from the measurements of every hour or at least five times a day and the interval time sampling should be equal; the average monthly value calculated from the measurements of every day or at least four times a month in the same station and the interval time sampling should be equal; the average annual value calculated from the measurements of every month in the same station and sampling time.
Salinity change shall not exceed 10 percent of minimum salinity.
Petroleum Hydrocarbon shall not exceeded 0.5 microgram per liter.
Dissolved oxygen is not less than 4 milligram per liter.
Total Coliform Bacteria shall not exceed 1,000 MPN per 100 millimeters.
Fecal Coliform Bacteria shall not exceed 70 CFU per 100 millimeters.
Nitrate-Nitrogen shall not exceed 20 microgram – nitrogen per liter.
Phosphate-Phosphorus shall not exceed 15 micrograms-phosphorus per liter.
Ammonia-Nitrogen (Unionized ammonia) shall not exceed 70 micrograms-nitrogen per liter.
Total mercury shall not exceed 0.1 microgram per liter.
Cadmium shall not exceed 5 micrograms per liter.
Total chromium shall not exceed 100 micrograms per liter.
Chromium Hexavalent shall not exceed 50 micrograms per liter.
Lead shall not exceed 8.5 micrograms per liter.
Copper shall not exceed 8 micrograms per liter.
Manganese shall not exceed 100 micrograms per liter.
Zinc shall not exceed 50 micrograms per liter.
Iron shall not exceed 300 micrograms per liter.
Fluoride shall not exceed 1 microgram per liter.
Phenol shall not exceed 0.03 micrograms per liter.
Sulfide shall not exceed 10 micrograms per liter.
Cyanide shall not exceed 7 micrograms per liter.
Polychlorinated Biphenyl (PCB) must not be detected.
Arsenic shall not exceed 10 micrograms per liter.
Radioactivity in the form of alpha shall not exceed 0.1 Becquerel per liter, in the form of beta shall not exceed 1.0 Becquerel per liter.
Tributyltin compounds shall not exceed 10 micrograms per liter.
Chlorinated Chemicals used as pesticides include:
Aldrin shall not exceed 1.3 micrograms per liter
Chlordane shall not exceed 0.04 micrograms per liter
DDT shall not exceed 0.01 micrograms per liter
Dieldrin shall not exceed 0.0019 micrograms per liter
Endrin shall not exceed 0.0023 micrograms per liter
Endosulfan shall not exceed 0.0087 micrograms per liter
Heptachlor shall not exceed 0.0036 micrograms per liter
Lindane shall not exceed 0.16 micrograms per liter
The chemicals used as pesticides and herbicides include Alachlor, Ametryn, Atrazine, Carbaryl, Carbendazim, Chlorpyrifos, Cypermethrin, 2,4-D, Diuron, Glyphosate, Malathion, Mancozeb, Methyl Parathion, Parathion, and Propanil, shall be undetectable.
The marine water quality standard for coral reef conservation areas must be in line with the water quality standard for natural resource preservation areas, except:
Temperature shall not be changed from nature background conditions.
Dissolved oxygen shall not be less than 6 milligrams per liter.
Enterococci bacteria shall not exceed 35 CFU per 100 milliliters.
The marine water quality standard for aquaculture areas must be in line with the water quality standard for natural resource preservation areas, except:
Nitrate-Nitrogen shall not exceed 60 micrograms-Nitrogen per liter.
Phosphate-phosphorus shall not exceed 45 micrograms – phosphorus per liter.
Ammonia – Nitrogen (unionized ammonia) shall not exceed 100 micrograms – Nitrogen per liter.
The marine water quality standard for recreation areas must be in line with the water quality standard for natural resource preservation areas, except:
Temperature changes shall not exceed 2 degree Celsius from nature
Petroleum hydrocarbon shall not exceed 1 microgram per liter
Fecal Coliform Bacteria shall not exceed 100 CFU per 100 millimeters
Enterococci Bacteria shall not exceed 35 CFU per 100 millimeters
Nitrate-Nitrogen shall not exceed 60 micrograms-Nitrogen per liter
In case, industrial or ports zone or residential areas is overlapped with the coral reef conservation areas, aquaculture areas or recreation areas, as the case may be, the strictest standard of marine water quality shall be applied for the overlapped zone.
Method of sample collection and analysis
If the sampling site is less than 5 meters in depth, the samples at one meter below sea surface and above the seabed shall be collected.
If the sampling site is between 5 - 20 meters in depth, the samples at one meter below sea surface, and above the seabed, and at mid-depth of water column shall be collected.
If the sampling site is between 20 - 40 meters in depth, the samples at 1, 10, and 30 meters below sea surface, and 1 meter above the seabed, column shall be collected.
If the sampling site is more than 100 meters in depth, the samples at every 50 meters below sea surface, and 1 meter above the seabed, column shall be collected.
If the sampling sites is less than or equal to one meter in depth, the samples at the middle of the depth of water shall be collected; sampling for evaluation of Fecal Coliform Bacteria and Enteroccocci Bacteria, the sample shall be collected at 30 centimeters below the surface. The evaluation of floating objects, colors, transparency, fat and oil can be visually assessed without sampling.
Sampling shall be conducted during the neap tide, especially, the area that influenced by tides.
The collection of marine water samples and requirements of equipment used shall be under the Standard Method for the Examination of Water and Wastewater (APHA, AWWA and WEF, the latest edition), Method of Seawater Analysis (Grasshoff, 1999) Practical Handbook of Seawater Analysis (Strickland and Parson, 1972), A Manual of Chemical and Biological Methods for Seawater Analysis (Parsons et al., 1984), Recommended guidelines for measuring organic compounds in Puget Sound water, sediment and tissue samples (Puget Sound Estuary Program, 1997), Prescribed Procedures for Measurement of Radioactivity in Drinking Water (Krieger and Whittaker, 1980), Proceedings of the Organotin Symposium, Comprehensive Method for Determination of Aquatic Butyltin and Butylmethyltin Speciesat Ultra Trace Levels Using Simultaneous Hybridization/Extraction with GC/FPD Detection (Matthias et. al. 1986 a,b), or any other methods declared by the Pollution Control Committee regarding the reduction of chloride ion interference or pre-concentration techniques.