Official Mexican Standard for processes of purifying drinking water for human consumption.

 

Amendment to the Official Mexican Standard NOM- 127- SSA1 - 1994, Environmental Health. Water for human use and consumption.

 

Permissible limits of quality and must undergo treatment to the water to make it drinkable .

The margin a seal with the national emblem , which reads: United States of Mexico. - Ministry of Health.

AMENDMENT TO THE OFFICIAL STANDARD NOM -127- SSA1 - 1994, ENVIRONMENTAL HEALTH. WATER USE AND HUMAN CONSUMPTION. PERMISSIBLE LIMITS OF QUALITY AND TREATMENTS TO BE BOUND WATER FOR DRINKING WATER .

JAVIER CASTELLANOS Coutinho, President of the National Advisory Committee on Health Regulation and Development, based on Article 39 of the Organic Law of Federal Public Administration; 4o. and 69 -H of the Federal Administrative Procedure Act, 13, section A) fraction I, 118, and 119 fraction II , Section II of the General Health Law, 41, 43, 45, 46, section II, and 47 of Federal Law on Metrology and Standardization, 28 and 34 of the Regulations of the Federal Law on Metrology and Standardization; 214, section IV and 225 of the Rules of the General Health Law Sanitary Control of Activities, establishments, Products and Services and 7, fractions V and XIX and 25, section IV of the Internal Regulations of the Ministry of Health, and

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WHEREAS
That on December 16, 1999, pursuant to the agreement of the Committee and to the provisions of Article 47 of the Federal Law on Metrology and Standardization, was published in the Official Journal of the Federation on the draft of this Mexican Official Standard for effect within sixty calendar days after such publication, interested parties submit their comments to National Advisory Committee on Regulation and Health Promotion.

That on June 20, 2000, were published in the Official Journal of the Federation responses to comments received by the said Committee, in terms of Article 47, paragraph III of the Federal Law on Metrology and Standardization.

That in view of the foregoing , with the approval of the National Advisory Committee on Health Regulation and Development, is issuing the following:

AMENDMENT TO THE OFFICIAL STANDARD NOM -127- SSA1 - 1994, ENVIRONMENTAL HEALTH. WATER USE AND HUMAN CONSUMPTION. PERMISSIBLE LIMITS OF QUALITY AND TREATMENTS TO BE BOUND WATER FOR DRINKING WATER
INDEX

0 . introduction
1. Objective and scope
Two. References
Three. Definitions
April. Permissible limits of water quality
May. Treatments for water purification
June. Test Methods
July. Compliance with international standards and Mexican
August. bibliography
9. Observance of Standard
10. validity
0. introduction

The supply of water for human use and consumption of adequate quality is essential to prevent and avoid transmission of gastrointestinal diseases and others, for which is required to establish permissible limits in terms of its microbiological, physical, organoleptic, chemical and radioactive, with ensure and preserve water quality in systems, to delivery to the consumer.

For these reasons the Ministry of Health, proposes to amend the Official Mexican Standard, in order to establish an effective health monitoring of water purification treatments subjected to in order to make it suitable for human use and consumption, according to the current needs.

1. Objective and scope
1.1 This Mexican Official Standard establishes the permissible limits of quality water purification and treatment of water for human use and consumption .

1.2 This Standard is applicable to all public water supply systems and private and any person or entity that distributes throughout the country.

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Two. References
NOM- 008- 2.1 - 1993 SCF1 General System of Units.

2.2 NOM-012-SSA1-1993 Sanitary requirements to be met by water systems for human use and consumption public and private.

2.3 NOM- 013- SSA1 - 1993 Sanitary requirements to be met by the tank of a vehicle for the transport and distribution of water for use and consumption.

2.4 NOM-014-SSA1-1993 Sanitary procedures for sampling of water for human use and consumption in water supply systems public and private.

2.5 NOM-112-SSA1-1994 Determination of coliform bacteria. Most probable number technique.

2.6 NOM-117-SSA1-1994, Goods and Services. Test method for the determination of cadmium, arsenic, lead, tin , copper, iron, zinc and mercury in food, drinking water and purified water by atomic absorption spectrometry.

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Three . Definitions
For purposes of this Mexican Official Standard is defined as:

3.1 Softening the process of removing calcium and magnesium ions, major contributors to water hardness.

3.2 Adsorption, removal of ions and molecules in a solution have an affinity to a suitable solid medium, such that they are separated from the solution.

3.3 Water for human use and consumption, water that does not contain objectionable pollutants, whether chemical or infectious agents that cause no adverse health effects. Also referred to as drinking water.

3.4 Microbiological characteristics, due to microorganisms harmful to human health. For control purposes is determined by the contents of general indicators of microbiological contamination, specifically total coliforms and Escherichia coli or fecal coliforms.

3.5 Physical and organoleptic sensory which are detected. For evaluation, taste and smell are weighted by means of the senses and the color and turbidity are determined through laboratory analytical methods.

3.6 Chemical characteristics, due to chemical elements or compounds, as a result of scientific research has proven that they can cause harmful effects to human health.

3.7 Features radioactive, those resulting from the presence of radioactive elements.

3.8 Coagulation chemistry, chemical addition to water, to alter the physical state of the dissolved solids, colloidal or suspended, in order to facilitate its removal by precipitation or filtration.

3.9 Contingency, unforeseen change situation water features external pollution, threatening human health.

3.10 disinfection, the destruction of pathogenic organisms through the application of chemical or physical processes.

3.11 evaporation, separation of water from dissolved solids using heat as a stripping agent, finally condensing water for utilization.

3.12 Filtration, removal of suspended particles in water, by flowing through a suitable porosity filter medium.

3.13 Flocculation destabilized particle agglomeration in the process of chemical coagulation, through mechanical or hydraulic means.

3.14 ion exchange process of removing specific anions or cations dissolved in the water, through its replacement with anions or cations from a medium of exchange, natural or synthetic, with which it contacts.

3.15 Permissible Limit, or maximum concentration or range of values of a component, it will not cause harmful effects to the health of consumers.

Neutralization 3.16, adding basic or acidic substance to the water to obtain a neutral pH.

3.16.1 Stabilization obtaining certain concentration of salts and pH of the water to avoid fouling or corrosion of materials used to manufacture the elements that contain lead or.

3.17 reverse osmosis process for removing physical essentially ions and molecules dissolved in water, in which by means of high pressure will force the passage of it through a specific porosity semipermeable membrane, said membrane being retained on the ions and molecules of larger.

3.18 Oxidation loss of electrons of an element or compound ion by the action of oxygen or other oxidizing agent.

3.19 Purification, assembly operations and processes, physical and / or chemical processes that apply to water supply systems in public or private, to make it suitable for human use and consumption.

3.20 Sedimentation physical process is the separation of particles suspended in water, by gravitational effect .

3.21 Water Supply System, composed itemset waterworks intake, transmission, purification, disinfection, storage or regulation and distribution.

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April . Permissible limits of water quality

4.1 Permissible limits of microbiological characteristics.

4.1.1 The content of organisms resulting from examination of a single sample of water, must comply with the provisions in Table 1.

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TABLE 1
FEATURE PERMISSIBLE LIMIT
Total coliforms Absence or undetectable
E. coli or fecal coliforms or thermotolerant organisms Absence or undetectable
 
4.1.2 Under emergency situations, the competent authorities may establish biological agents harmful to health should be investigated.

4.1.3 Units of measurement should be reported according to the methodology used.

4.1.4 The water supplied by the distribution system must not contain E. coli or thermotolerant coliform or agencies in any 100 ml sample. Total Coliform organisms should not be detectable in any 100 ml sample; supply systems towns with a population over 50 000 inhabitants, these organisms should be absent in 95 % of samples taken from the same web site distribution, over a twelve month period of the same year.

4.2 Permissible limits of physical and organoleptic characteristics.

4.2.1 The physical and organoleptic characteristics shall conform to the provisions in Table 2.

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TABLE 2
  
FEATURE PERMISSIBLE LIMIT
Color 20 true color units on the platinum-cobalt scale.
Pleasant smell and taste ( they accept those that are tolerable for most consumers, provided they are not objectionable conditions result from the standpoint of biological or chemical ).

Turbidity 5 nephelometric turbidity units (NTU ) or its equivalent in
another method.

4.3 Permissible limits of chemical characteristics.

4.3.1 The content of chemical constituents shall be as established in Table 3. The limits are expressed in mg / l, except where otherwise unit.

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TABLE 3
  
FEATURE PERMISSIBLE LIMIT
Aluminum 0.20
Arsenic ( Note 2) 0.05
Barium 0.70
Cadmium 0.005
Cyanides ( as CN- ) 0.07
Free residual chlorine from 0.2 to 1.50
Chlorides ( as Cl-) 250.00
Copper 2.00
 
Total chromium 0.05
Total hardness ( as CaCO3 ) 500.00
Phenols or phenolic compounds 0.3
Fierro 0.30
Fluoride ( as F- ) 1.50
Aromatic hydrocarbons in micrograms / l :
benzene 10.00
ethylbenzene 300.00
toluene 700.00
Xylene ( three isomers ) 500.00
Manganese 0.15
mercury 0.001
Nitrate ( as N ) 10.00
Nitrite ( as N ) 1.00
Ammonia nitrogen ( as N ) 0.50
pH (potential of hydrogen) at pH 6.5-8.5 units
Pesticides in micrograms / l:
Aldrin and Dieldrin ( separate or combined ) 0.03
Chlordane (total isomers ) 0.20
DDT ( all isomers ) 1.00
Gamma -HCH (lindane ) 2.00
Hexachlorobenzene 1.00
Heptachlor and heptachlor epoxide 0.03
methoxychlor 20.00
2,4 - D 30.00
Lead 0.01
Sodium 200.00
1000.00 Total Dissolved Solids
Sulphates ( as SO4 = ) 400.00
Active substances methylene blue ( SAAM ) 0.50
Total trihalomethanes 0.20
Free residual iodine 0.2-0.5
Zinc 5.00

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Note 1. The permissible limits for metals refer to the total concentration in the water, which includes the suspended and dissolved.

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Note 2. The permissible limit for arsenic is adjusted annually in accordance with the following table gradual compliance:
GRADUAL IMPLEMENTATION CHART
permissible limit
mg / l Year
0.045 2001
0.040 2002
0.035 2003
0.030 2004
0.025 2005
 
4.3.2 Where the supply system used for water disinfection, methods that do not include chlorine or its derivatives, the health authority shall determine the cases in which additionally should water distributed chlorine dosed to maintain concentrations of free chlorine residual within the allowable limit set in Table 3 of this Standard.

4.4 Permissible limits of radioactive properties .

The content of radioactive constituents shall be as established in Table 4. The limits are expressed in Bq / l (Becquerel per liter).

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TABLE 4
FEATURE PERMISSIBLE LIMIT
Bq / l
Gross alpha
0.56 beta activity
1.85
 
May. Treatments for Water potabilisation
The potable water from a particular source, must be supported by quality research and treatability tests in the laboratory to ensure their effectiveness.

It should apply the following specific treatments or those resulting from treatability tests when microbiological contaminants, the physical and chemical water constituents listed below exceed the permissible limits laid down in paragraph 4 of this Standard.

5.1 Microbiological contamination.

5.1.1 bacteria, helminths, protozoa and viruses. Should be disinfected with chlorine, chlorine compounds, yodo1, ozone, ultraviolet light, ionic silver or colloidal coagulation - sedimentation - filtration, multi-stage filtration.

5.2 Physical and organoleptic.

5.2.1 Color, smell, taste and turbidity. -Oxidation-coagulation-flocculation-sedimentation-filtration, adsorption on activated carbon.

5.3 Chemical constituents.

5.3.1 Arsenic. Coagulation-flocculation-sedimentation, filtration, ion exchange or reverse osmosis.

5.3.2 aluminum, barium, cadmium, cyanide, copper, total chromium and lead. Coagulation-flocculation-sedimentation, filtration, ion exchange or reverse osmosis.Chlorides

 

5.3.3. Ion exchange, reverse osmosis or evaporation.

5.3.4 Hardness. Softening or ion exchange chemical.Phenols or phenolic

 

5.3.5. Oxidation - coagulation-flocculation - sedimentation, filtration, activated carbon adsorption or oxidation with ozone.

5.3.6 Iron and / or manganese. Oxidation- filtration, ion exchange or reverse osmosis.

5.3.7 Fluoride. Activated alumina, bone char or reverse osmosis.

5.3.8 Aromatic hydrocarbons. Oxidation - filtration or adsorption on activated carbon.

5.3.9 Mercury. Coagulation-flocculation - sedimentation, filtration, granular activated carbon adsorption or reverse osmosis as the source of supply containing up to 10 micrograms/l. Adsorption on PAC when the supply source containing more than 10 micrograms/l.

Nitrates and nitrites

 

5.3.10 . Ion exchange or coagulation -flocculation - sedimentation - filtration.

5.3.11 ammonia nitrogen. Coagulation -flocculation - sedimentation - filtration, degassing or desorption column.

5.3.12 pH (potential hydrogen). Neutralization.

5.3.13 Pesticides. Granular activated carbon adsorption.

5.3.14 Sodium. Ion exchange.

5.3.15 Total Dissolved Solids. Coagulation-flocculation - sedimentation, filtration and / or ion exchange. Sulfates

 

5.3.16 . Ion exchange or reverse osmosis.

5.3.17 Substances methylene blue active. Adsorption on activated carbon.

5.3.18 trihalomethanes. Aeration or oxidation with ozone and granular activated carbon adsorption.

5.3.19 Zinc. Evaporation or ion exchange.

5.4 In the event of a contingency , the result of the presence of substances specified or not specified in paragraph 4, the local authorities, the National Water Commission, responsible for the supply and individuals, public or private companies involved in the contingency, must be coordinated with the public health authority, to determine the actions to be performed in relation to water supply to the population.

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June.

Test Methods
The selection of test methods for determining the parameters defined in this standard, it is the responsibility of the utilities of water supply systems for human use and consumption, and approved by the Ministry of Health through the corresponding area . Should be established in a Programme of Analytical Quality Control of Water, and be available to the competent authority, upon request, for evaluation accordingly.

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July.

Compliance with international standards and national
This Mexican Official Standard is not equivalent to any international standard.

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August.

bibliography
8.1 Guidelines for Canadian Drinking Water Quality. 6ta. edition. Ministry of Health. 1996.

8.2 Water Disinfection. Oscar Cáceres López. Lima, Peru. Ministry of Health. Pan American Health Organization. World Health Organization . 1990.

8.3 Guidelines for Drinking Water Quality. Volume 1. Recommendations. Pan American Health Organization. World Health Organization. 1985.

8.4 Guidelines for Drinking Water Quality. Volume 1. Recommendations. Pan American Health Organization. World Health Organization . 1995.

8.5 Guidelines for Drinking Water Quality.

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Volume 2.

Criteria for health and other background information.

Pan American Health Organization. World Health Organization. 1987.

8.6 Guide to Writing, Structuring and Presentation of the Official Mexican Standards. Review Project. SECOFI. 1992.

8.7 Guidelines for selecting and applying disinfection technologies for drinking water in small towns and rural communities in Latin America and the Caribbean. Pan American Health Organization. World Health Organization. 1995.
8.8 Guide to Selection of Water Treatment Processes. Carl L. Hamann Jr., P.E. J. Brock Mc . Ewen, P.E. Anthony G. Meyers, P.E.

8.9 Environmental Engineering. Magazine No. 23. Year 7. 1994.

8.10 Sanitary Engineering Applied to Public Health . Unda Francisco Opazo. UTEHA 1969.

8.11 Sanitary Engineering and Waste Water. Purification and Treatment of Water and Wastewater Removal. Gordon M. Fair, John C. Geyer, Daniel A. Okun. Limusa Wiley. 1971.

8.12 Instructions for Monitoring and Certification of Sanitary Quality of Drinking Water . International Commission of Occupational and Environmental Health . Ministry of Health 1987.

8.13 Public Health Significance of Bacterial Indicators that Found in Drinking Water. Martin J. Allen. Pan American Health Organization. WHO. Lima Peru, 1996.

8.14 Integrated Design of Water Treatment Facilities. Susumu Kawamura. John Willey and Sons, Inc. 1991.

8.15 Standards Manual for Drinking Water Quality. Ministry of Human Settlements and Public Works. 1982.

8.16 Technical Standards Manual for Water Treatment Plants Project. Ministry of Human Settlements and Public Works. 1979.

8.17 Handbook of Analytical Techniques of the National Public Health Laboratory. Ministry of Health.

8.18 Method Defined Substrate Technology for Rapid and Specific Simultaneous Counting of Total Coliforms and Escherichia coli from water. Stephen C. Edberg, Martin J. Darrell Allen & B. Smith. Official Analytical Chemists Association Journal (Vol. 74 No. 3, 1991).

8.19 Project-NOM-SSA1-1996 Monitoring and evaluation of the control of water quality for human use and consumption, distributed by public water supply systems.

8.20 Regulation of the General Law of Health Sanitary Control of Activities, Establishments, Products and Services. Official Journal of the Federation. January 18, 1988.

8.21 Regulations National Primary Drinking Water, Analytical Techniques: coliform bacteria. Environmental Protection Agency ( USA). 1992.

8.22 Revision of the WHO Guidelines for Drinking -Water Quality. IPS. International Programme on Chemical Safety. United Nations Environment Programme. International Labour Organization. World Health Organization. 1991.

8.23 WHO Guidelines for Drinking -Water Quality. Volume 1. Recommendations. World Health Organization. 1992.

8.24 Standard Methods for the Examination of Water and Wastewater. 19th. Edition. American Public Health Association, American Water Works Association , Water Environment Federation. 1995.

8.25 WHO Guidelines for Drinking -Water Quality . Volume 2. Health Criteria and Other Supporting Information. Chapter 1: Microbiological Aspects. United Nations Environment Programme. International Labour Organization. World Health Organization. 1992.

9.Observance

of Standard The enforcement of this Mexican Official Standard is for the Ministry of Health in coordination with state and municipal governments, the Federal District, the State Commissions Water and Sanitation and the National Water Commission, within their respective spheres of competence.

10. validity
This Mexican Official Standard shall enter into force ninety days after its publication in the Official Journal of the Federation.

Effective Suffrage. No Reelection.

Mexico City, October 20, 2000. - The Chairman of the National Advisory Committee on Health Regulation and Development, Javier Castellanos Coutiño. - Category.
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MEXICAN OFFICIAL STANDARD NOM-127-SSA1-1994.

"ENVIRONMENTAL HEALTH, WATER FOR HUMAN CONSUMPTION USE AND QUALITY-ALLOWABLE LIMITS AND TREATMENTS TO BE BOUND WATER FOR DRINKING WATER".

The margin a seal with the national emblem, which reads: United States of Mexico. - Ministry of Health.

OLAIZ GUSTAVO FERNANDEZ, CEO of Environmental Health, by resolution of the National Advisory Committee on Health Regulation and Development, based on Article 39 of the Organic Law of Federal Public Administration, the 3rd. Section XIV, Section I, paragraph A 13, 118 and 119 Section II Section II of the General Health Law, 38 fraction II, 40 fraction I and 47 of the Federal Law on Metrology and Standardization, 209, 210, 211, 212, 213, 214, 215, 218, 224, 227 and other applicable provisions of the Regulations of the General Law of Health Sanitary Control of Activities, establishments, Products and Services, the 8th. fraction fraction IV and V of Regulation 25 governing the Ministry of Health, and INDEX

 

0. INTRODUCTION
1. PURPOSE AND SCOPE
Two. REFERENCES
Three. DEFINITIONS
April. PERMISSIBLE LIMITS OF WATER QUALITY
May. TREATMENTS FOR WATER PURIFICATION
June. REFERENCES
July. ACCORDING TO INTERNATIONAL STANDARDS
August. ENFORCEMENT OF THE STANDARD
9. EFFECTIVE
0 . introduction

The supply of water for human use and consumption of adequate quality is essential to prevent and avoid transmission of gastrointestinal diseases and others, for which is required to establish permissible limits as to its bacteriological, physical, organoleptic , chemical and radioactive.

In order to secure and preserve water quality in systems, to delivery to the consumer, shall be subjected to purification treatments.

1. Objective and scope
This Mexican Official Standard establishes the permissible limits of quality and water purification treatments for human use and consumption, to be met by public water supply systems and private or any person or entity that distributes throughout the country.

 

Two . References
NOM-008-SCFI-1993 "General System of Units". Three. Definitions

3.1 Softening: The process of removing calcium and magnesium ions, major contributors to water hardness.

3.2 Adsorption: Removal of ions and molecules in a solution have an affinity to a suitable solid medium, such that they are separated from the solution.

3.3 Water for human use and consumption: That which does not contain objectionable pollutants, whether chemical or infectious agents and does not cause harmful effects to humans.

3.4 Bacteriological characteristics: Those due to microorganisms harmful to human health. For control purposes is determined by the contents of general indicators of microbiological contamination, specifically total coliforms and fecal coliforms.

3.5 Physical and organoleptic: Those that are detected sensorially. For evaluation, taste and smell are weighted by means of the senses and the color and turbidity are determined through laboratory analytical methods.

3.6 Chemical properties: They are those due to chemical elements or compounds, as a result of scientific research has proven that they can cause harmful effects to human health.

3.7 Features radioactive: Those resulting from the presence of radioactive elements.

3.8 Coagulation chemistry: Addition of chemicals to water, to alter the physical state of the dissolved solids, colloidal or suspended, in order to facilitate its removal by precipitation or filtration.

3.9 Contingency: State of unforeseen changes in water characteristics from external pollution, threatening human health.

3.10 Disinfection destruction of pathogenic organisms through the application of chemical or physical processes.

3.11 Filtration: Removal of suspended particles in water, by flowing through a suitable porosity filter medium.

3.12 Flocculation: Agglomeration of particles in the disrupted chemical coagulation process, through mechanical or hydraulic means.

3.13 Ion Exchange: The process of removing specific anions or cations dissolved in the water, through its replacement with anions or cations from a medium of exchange, natural or synthetic, with which it contacts. Permissible limit

 

3.14: Concentration or maximum or range of values of a component, which ensures that water will be pleasing to the senses and will not cause harmful effects to the health of consumers .

3.15 Neutralization: Adjust pH by addition of acidic or basic chemicals to water in the case, in order to prevent fouling or corrosion of materials that can affect their quality.

3.16 Reverse Osmosis: A process for removing physical essentially ions and molecules dissolved in water, in which by means of high pressure will force the passage of it through a specific porosity semipermeable membrane, said membrane being retained on the ions and molecules larger.

3.17 Oxidation: Introduction of oxygen in the molecule of certain compounds to form oxides.

3.18 Purification: Set of operations and processes, physical and / or chemical processes that apply to water to improve its quality and make it suitable for human use and consumption.

3.19 Precipitation: physical process that involves the separation of particles suspended settleable water by gravitational effect.

3.20 Supply System: Wired or interconnected set of sources, headworks, cloradoras plants, water treatment plants, storage tanks and regulation, pumping stations, pipelines and distribution network.

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April.

Permissible limits of water quality
Permissible limits 4.1 bacteriological characteristics
The content of organisms resulting from examination of a single sample of water, must comply with the provisions in Table 1.

Under emergency situations , the competent authorities should establish biological agents harmful to health research.

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TABLE 1
FEATURE PERMISSIBLE LIMIT
Total coliform MPN/100 ml 2
2 CFU/100 ml
No detectable fecal coliform MPN/100 ml
Zero CFU/100 ml
The bacteriological test results should be reported in units of MPN/100 ml (most probable number per 100 ml), using the most probable number technique or CFU/100 ml (colony forming units per 100 ml), if using the membrane filtration technique.

4.2 Permissible limits of physical and organoleptic characteristics
Physical and organoleptic characteristics shall conform to the provisions in Table 2.

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TABLE 2
FEATURE PERMISSIBLE LIMIT
Color 20 true color units on the platinum-cobalt scale.
Pleasant smell and taste (be accepted those tolerable for most consumers, if they are not objectionable conditions results from the standpoint of biological or chemical).

Turbidity 5 nephelometric turbidity units (NTU ) or its equivalent in another method.

4.3 Permissible limits of chemical characteristics
The content of chemical constituents shall be as established in Table 3. The limits are expressed in mg / l, except where otherwise unit.

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TABLE 3
FEATURE PERMISSIBLE LIMIT
Aluminum 0.20
Arsenic 0.05
Barium 0.70
Cadmium 0.005
Cyanides (as CN-) 0.07
Free residual chlorine 0.2-1.50
Chlorides (as Cl-) 250.00
Copper 2.00
Total chromium 0.05
Total hardness (as CaCO3) 500.00
Phenols or phenolic compounds 0.001
Fierro 0.30
Fluoride (as F-) 1.50
Manganese 0.15
mercury 0.001
Nitrate (as N) 10.00
Nitrite (as N) 0.05
Ammonia nitrogen (as N) 0.50
pH (potential hydrogen) in 6.5-8.5 pH units
Pesticides in micrograms / l: Aldrin and Dieldrin (separate or combined) 0.03
Chlordane (total isomers) 0.30
DDT (all isomers) 1.00
Gamma -HCH (lindane) 2.00
Hexachlorobenzene 0.01
Heptachlor and heptachlor epoxide 0.03
methoxychlor 20.00
2,4 - D 50.00
Lead 0.025
Sodium 200.00
1000.00 Total Dissolved Solids
Sulphates (as SO4 =) 400.00
Active substances methylene blue (SAAM) 0.50
Total trihalomethanes 0.20
Zinc 5.00
The permissible limits for metals refer to the total concentration in the water, which includes the suspended and dissolved.

4.4 Permissible limits of radioactive properties
The content of radioactive constituents shall be as established in Table 4. The limits are expressed in Bq / l (Becquerel per liter).

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TABLE 4
FEATURE PERMISSIBLE LIMIT
Gross alpha 0.1
Gross beta 1.0
May. Treatments for water purification
The potable water from a particular source, should be based on quality studies and treatability tests in the laboratory to ensure their effectiveness.

It should apply the following specific treatments or those resulting from treatability testing when biological contaminants , the physical and chemical water constituents listed below exceed the permissible limits laid down in paragraph 4.

5.1 Biological contamination

5.1.1 bacteria, helminths, protozoans and viruses. - Chlorination, chlorine compounds, ozone or ultraviolet light.

5.2 Physical and organoleptic.

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June.
Ministry of Health. 1990.
1985.
1987.
1992.
J.
1994.
Francisco
1987.
1982.
1979.
Official Journal of the Federation.
1991.
Volume 1. 1992.
1992.

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July.

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Augus.

9. validity
Effective Suffrage.

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