What physicochemical analyses of water are performed to meet the 201 Standard for purified water for human consumption?
Standard 201 NOM-201-SSA1-2015 establishes a series of permissible limits for testing the quality of water for products, services, water and purified ice and human consumption.
Cyanides
Cyanides are toxic and dangerous substances for human health and the environment. For this reason, it is important to control their presence in water, air and food. NOM-201-SSA1-2015 establishes the maximum permissible limits for cyanides to ensure that people are not exposed to dangerous levels of these substances. The standard applies to water for human use and consumption, treated wastewater, discharges to receiving bodies and ambient air. Mexican Official Standard NOM-201-SSA1-2015 establishes the following limits for cyanides:
- In water for human use and consumption, the maximum permissible limit for total cyanides is 0.07 mg/L.
- In treated wastewater, the maximum permissible limit for total cyanides is 0.2 mg/L.
- In wastewater treated for discharge to receiving bodies, the maximum permissible limit for total cyanides is 0.05 mg/L.
- In ambient air, the maximum permissible limit for hydrogen cyanide (HCN) is 1.5 mg/m3 as an 8-hour weighted average limit value and 3 mg/m3 as an instantaneous maximum limit value.
It is important to keep in mind that these limits are intended to protect human health and the environment, so they must be complied with by industries and entities that generate or handle cyanides.
Chlorine residual
It is important to note that chlorine is a disinfectant used to eliminate or reduce microorganisms present in water for human consumption. However, its excessive use can have negative effects on the health and taste of water. For this reason, NOM-201-SSA1-2015 establishes these maximum permissible limits of residual chlorine to ensure the quality of drinking water. NOM-201-SSA1-2015 establishes the following limits for residual chlorine in water for human use and consumption:
- The maximum permissible limit for free residual chlorine in drinking water is 5 mg/L.
- The maximum allowable limit for combined residual chlorine in drinking water is 5 mg/L.
Color scale Pt-Co
Apparent color is a measure of the color intensity of water and is expressed in units of the Pt-Co (platinocobalt) scale. The presence of color in water can be indicative of the presence of organic or inorganic substances, and its excess can affect the quality and appearance of water for human consumption. NOM-201-SSA1-2015 establishes the following limits for Pt-Co scale color in water for human use and consumption:
- The maximum permissible limit for apparent color (Pt-Co scale) in drinking water is 15 units.
It should be noted that the maximum permissible limits for apparent color in drinking water established by NOM-201-SSA1-2015 are intended to ensure the quality of water for human use and consumption. In addition, the standard establishes the methods of analysis and quality specifications for reagents and analysis equipment used for the measurement of apparent color in drinking water.
Fluorides
Dental fluorosis is an alteration of tooth enamel caused by prolonged and excessive exposure to fluorides during tooth development, which can result in staining or discoloration of the teeth. Bone fluorosis is a disease that occurs when excessive amounts of fluorides are ingested over long periods of time, which can lead to abnormal bone density and increase the risk of fractures. Therefore, regulating the concentration of fluorides in drinking water is an important public health measure to prevent dental and bone fluorosis. In addition to the limits established in NOM-201-SSA1-2015, it is important to remember that children are more vulnerable to excessive exposure to fluorides, so additional precautions should be taken to protect their dental and bone health. For example, parents should monitor the amount of fluoride toothpaste their children use and ensure that they do not ingest it in large amounts. The Official Mexican Standard NOM-201-SSA1-2015 establishes limits for the concentration of fluorides in drinking water. The limits are as follows:
- In drinking water supplied to the general population, the maximum allowable concentration of fluorides is 1.5 milligrams per liter (mg/L).
- In drinking water supplied to children in day care centers, kindergartens, elementary schools and communities with a high prevalence of dental caries, the maximum allowable concentration of fluorides is 0.7 mg/L.
Foreign matter
The presence of foreign matter in drinking water can be caused by different sources, such as, for example:
- Chemical contaminants: these can come from industry, agriculture, mining, among other human activities. Examples include heavy metals, pesticides, herbicides, chemicals used in the manufacture of cleaning products and volatile organic compounds.
- Microorganisms: may be present in water due to fecal or environmental contamination. Examples are bacteria, viruses, parasites and fungi.
- Solid particles: can come from soil erosion, sedimentation and human activity. Examples include sand, mud, dust and fibers.
According to Standard 201 NOM-201-SSA1-2015 the limits for the amount of foreign matter in drinking water are as follows:
- In drinking water supplied to the general population, the maximum allowable amount of foreign matter is 0.5 milligrams per liter (mg/L).
- In drinking water supplied to children in day care centers, kindergartens, primary schools and communities with a high prevalence of gastrointestinal diseases, the maximum allowable amount of foreign matter is 0.3 mg/L.
Nitrate nitrogen
Consumption of nitrates in high amounts can be harmful to human health. Nitrates are chemical compounds found naturally in water and in some foods, but can also be present in water as a result of human activity, such as intensive agriculture or contamination of water sources by organic waste. The Official Mexican Standard NOM-201-SSA1-2015 establishes the concentration limits for nitrates in drinking water, which are as follows:
- In drinking water supplied to the general population, the maximum allowable concentration of nitrates is 45 milligrams per liter (mg/L).
- In drinking water supplied to children in day care centers, kindergartens, elementary schools and communities with a high prevalence of gastrointestinal diseases, the maximum allowable concentration of nitrates is 10 mg/L.
Nitrite nitrogen
Drinking water with elevated levels of nitrites can cause health problems, especially in infants and young children. Nitrites are converted to nitrosamines in the human body, which has been linked to an increased risk of cancer, especially of the stomach and colon. In addition, nitrites can interfere with the blood’s ability to carry oxygen and lead to a condition known as methemoglobinemia or “blue baby syndrome.” Therefore, it is essential that the limits established in the standard be met to ensure the safety of drinking water for the general population and especially for the child population. The nitrite concentration limits established in NOM-201-SSA1-2015 are as follows:
- In drinking water supplied to the general population, the maximum allowable concentration of nitrites is 1 milligram per liter (mg/L).
- In drinking water supplied to children in day care centers, kindergartens, elementary schools and communities with a high prevalence of gastrointestinal diseases, the maximum allowable concentration of nitrite is 0.1 mg/L.
Methylene blue active substances
Methylene blue is a chemical compound used in some industries and wastewater treatment processes, which can be toxic if ingested in large quantities as its effects can include gastrointestinal irritation, nausea, vomiting, diarrhea and abdominal pain. Mexican Official Standard NOM-201-SSA1-2015 establishes limits for the concentration of methylene blue in drinking water, in order to protect the health of the population According to the standard, the maximum allowable concentration of methylene blue in drinking water is 0.1 micrograms per liter (µg/L). This limit applies to all sources of drinking water, including water supplied to the general population and water supplied to children in daycare centers, kindergartens, elementary schools and communities with a high prevalence of gastrointestinal diseases.
Water turbidity
Turbidity is a measure of water clarity and refers to the amount of suspended particles in the water. The Mexican Official Standard NOM-201-SSA1-2015 establishes limits for drinking water turbidity, under which the presence of microorganisms or particles that may be harmful to health is avoided. According to the standard, the turbidity of drinking water must not exceed 5 nephelometric turbidity units (UNT). The NTU is a unit of measurement used to measure water turbidity using a method known as nephelometry, which measures the amount of light scattered by particles in the water.
Analysis of metals in water to comply with Standard 201
NOM-201-SSA1-2015 establishes a series of permissible limits through metal tests to check the quality of water for products, services, water and purified ice and human consumption.
Arsenic
Arsenic is a metalloid that can be found in groundwater and some foods, and can be toxic to human health if consumed in high concentrations over time. According to Standard 201 NOM-201-SSA1-2015, the maximum allowable concentration of arsenic in drinking water is 0.01 milligrams per liter (mg/L), or 10 micrograms per liter (µg/L). This limit applies to all drinking water sources, including water supplied to the general population and water supplied to infant populations in daycare centers, kindergartens, elementary schools and communities with a high prevalence of gastrointestinal diseases.
Barium
Barium is a chemical element that can be found in groundwater and can be harmful to human health if consumed in high concentrations over the long term. Barium is used in a variety of industrial applications, such as steel manufacturing, chemical production, and oil and gas exploration. As a result, barium can be released into the environment and contaminate groundwater sources. Chronic exposure to barium in drinking water can increase the risk of long-term health problems. For this reason, NOM-201-SSA1-2015 establishes a maximum concentration limit for barium in drinking water to protect the health of the population.
NOM-201-SSA1-2015 states that the maximum allowable concentration of barium in drinking water is 0.7 milligrams per liter (mg/L), or 700 micrograms per liter (µg/L).
Boron
Boron is a chemical element present in groundwater that can be toxic to health if consumed in high concentrations over the long term. NOM-201-SSA1-2015 establishes limits for boron concentration in drinking water to protect the health of the population. According to the standard, the maximum allowable concentration of boron in drinking water is 5 milligrams per liter (mg/L), or 5 parts per million (ppm). This limit applies to all sources of drinking water, including water supplied to the general population and water supplied to infant populations in daycare centers, kindergartens, elementary schools and communities with a high prevalence of gastrointestinal illnesses.
Cadmium
NOM-201-SSA1-2015 establishes that the maximum allowable limit for cadmium in drinking water is 0.003 milligrams per liter (mg/L). This limit applies to all drinking water sources to protect the health of the population. If water with a cadmium concentration above this limit is consumed over an extended period of time, it can cause kidney damage, cardiovascular disease, bone disorders and cancer. To ensure compliance with the established limit, the standard also establishes procedures and methods of sampling and analysis to measure the concentration of cadmium in drinking water. In the event that a cadmium concentration above the established limit is detected, immediate action must be taken to remedy the situation and protect the health of the population. Therefore, it is important that the procedures and methods of analysis established by the standard are rigorously followed to ensure the accuracy of the results and the quality of the drinking water.
Copper
Copper is a metal found in nature in various minerals and rocks. It is an important metal for industry and construction, but it is also used in many consumer products, such as plumbing pipes and cookware. Copper is essential to the human body, as it aids in the formation of red blood cells, the maintenance of connective tissue and the absorption of iron. Excess consumption can have negative effects. Prolonged ingestion of water with high copper concentrations can cause long-term toxic effects, including liver, kidney and nervous system problems. For this reason, the NOM-201-SSA1-2015 standard establishes that the maximum allowable limit of copper in drinking water is 0.05 milligrams per liter (mg/L). This limit is established to prevent the population from consuming water with excessive levels of copper that may be harmful to health.
Chrome
NOM-201-SSA1-2015 establishes limits for the concentration of total chromium in drinking water. Total chromium is a measure that includes both hexavalent chromium (Cr(VI)), which is considered more toxic to health, and trivalent chromium (Cr(III)). The limits established in the standard are as follows:
- For drinking water intended for direct human consumption: the maximum permissible concentration of total chromium is 0.05 milligrams per liter (mg/L).
- For drinking water intended for the preparation of food and beverages: the maximum permissible concentration of total chromium is 0.1 mg/L.
It is important to note that long-term exposure to high concentrations of chromium in drinking water can have negative health effects. Hexavalent chromium can cause damage to the kidneys, liver and lungs, as well as increase the risk of lung cancer. Trivalent chromium, on the other hand, is an essential nutrient for the human body and is found in many foods.
Manganese
Manganese is an element that can be naturally present in water or introduced by human activity, such as industry or agriculture. If manganese levels are too high, it can cause odor and taste problems, as well as discoloration. NOM-201-SSA1-2015 establishes limits for manganese concentration in drinking water. These limits are as follows:
- For drinking water intended for direct human consumption: the maximum permissible concentration of total chromium is 0.05 milligrams per liter (mg/L).
- For drinking water intended for the preparation of food and beverages: the maximum permissible concentration of total chromium is 0.1 mg/L.
Mercury
Mercury is a metal that can be toxic to human health. Long-term exposure to high concentrations of mercury in drinking water can have negative health effects, especially on the nervous system, kidneys and cardiovascular system. The NOM-201-SSA1-2015 standard establishes two limits for mercury concentration in drinking water. Which are:
- For drinking water intended for direct human consumption: the maximum allowable concentration of mercury is 0.001 milligrams per liter (mg/L).
- For drinking water intended for the preparation of food and beverages: the maximum allowable concentration of mercury is 0.005 mg/L.
Nickel
Nickel is a metal that can be present in water from a variety of sources, such as soil leaching and industrial pollution. Prolonged exposure to elevated concentrations of nickel in drinking water can have adverse effects, such as skin and eye irritation, respiratory problems, and liver damage. The limits established in the standard for nickel concentration in drinking water are as follows:
- For drinking water intended for direct human consumption: the maximum allowable concentration of nickel is 0.02 milligrams per liter (mg/L).
- For drinking water intended for the preparation of food and beverages: the maximum permissible concentration of nickel is 0.1 mg/L.
Lead
Standard 201 NOM-201-SSA1-2015 establishes that the concentration of lead in drinking water must not exceed the limits established to protect human health. Lead is a heavy metal that can be toxic and harmful to health if ingested in large quantities. For this reason, strict limits have been established for the amount of lead that may be present in drinking water intended for direct human consumption and for the preparation of food and beverages. Prolonged exposure to lead can have detrimental health effects, especially on children, who are more vulnerable to its effects. Lead can accumulate in the body and affect cognitive and physical development. Even small amounts of lead can have a negative impact on long-term health. The standard limits for lead concentration in drinking water are as follows:
- For drinking water intended for direct human consumption: the maximum allowable concentration of lead is 0.01 milligrams per liter (mg/L).
- For drinking water intended for the preparation of food and beverages: the maximum allowable concentration of lead is 0.05 mg/L.
Selenium
The NOM-201-SSA1-2015 standard establishes that the concentration of selenium in drinking water should not exceed 0.01 milligrams per liter (mg/L) to protect human health. Selenium is an essential chemical element found in small amounts in the human body and is necessary for the proper functioning of the organism. However, prolonged exposure to high levels of selenium can be toxic and cause negative health effects. Selenium occurs naturally in the earth’s crust and can enter drinking water through natural processes, such as soil erosion and leaching. It can also be released into water through human activities, such as mining and agriculture.
Microbiological analysis of water for drinking water standard 201
The NOM-201-SSA1-2015 Standard establishes a series of permissible limits for testing the quality of water for products, services, water and purified ice and human consumption in terms of microbiological tests.
Total coliforms
NOM-201-SSA1-2015 establishes that the maximum permissible limit for total coliforms in water intended for human consumption is 5 CFU (colony forming units) per 100 ml of water. It is important to note that the presence of total coliforms indicates the possible presence of fecal contaminants in the water, which can be a source of illness for consumers. For this reason, it is essential that adequate drinking water treatment and monitoring measures be carried out to ensure that it meets the quality standards established in the regulations.
Analysis of pesticides in water for Standard 201 for human consumption
The NOM-201-SSA1-2015 standard establishes a series of permissible limits for testing the quality of water for products, services, water and purified ice and human consumption in terms of pesticides.
Pesticides
Standard 201 NOM-201-SSA1-2015 establishes maximum permissible limits for various pesticides in water intended for human consumption, including insecticides, herbicides and fungicides. Below are some of the limits established for certain specific pesticides:
- Aldicarb: 0.010 µg/L
- Endosulfan: 0.05 µg/L
- Heptachlor: 0.03 µg/L
- Lindane: 0.002 µg/L
- Methoxychlor: 0.30 µg/L
- Paraquat: 0.01 µg/L
- Carbofuran: 0.700 µg/L
It is important to note that these maximum permissible limits are established to protect the health of the population, and appropriate drinking water treatment and monitoring measures must be applied to ensure that it meets the quality standards established in the regulations. In addition, it is essential to follow proper pesticide management practices to avoid water contamination and protect human health.
Analysis of trihalomethanes for drinking water Standard 201
NOM-201-SSA1-2015 establishes a series of permissible limits for testing the quality of water for products, services, water and purified ice and human consumption in terms of trihalomethanes.
Total trihalomethanes
NOM-201-SSA1-2015 establishes a maximum permissible limit of 0.1 mg/L for total trihalomethanes in drinking water. Trihalomethanes are organic compounds that are formed when chlorine is used to disinfect water and reacts with organic matter present in the water. Trihalomethanes can be carcinogenic and have been linked to health problems in the central nervous system, reproductive system, and other systems of the human body. Therefore, it is important to stay within regulatory limits. We do not have the service to perform these analyses, we suggest you go to a laboratory certified by CONAGUA: Comisión Nacional del Agua (conagua.gob.mx) in its laboratory search engine by state.
If you need to comply with Standard 201 for water purification, come to us with an analysis of the parameters you need to comply with to help you.
