Nitrates and nitrites can be categorized into inorganic and organic forms based on their chemical structure. There are similarities and differences between these two chemical forms that affect their pharmacokinetic and pharmacodynamic properties and their subsequent biologic effects in humans. This artical will focus on inorganic nitrates.
Inorganic Nitrates and Nitrites
Inorganic nitrate (NO3–) and nitrite (NO2–) are water soluble (as a result of their interaction with the positively charged portions of polar water molecules)
and commonly exist as salts of nitric acid and nitrous acid, respectively. They are often bound to a metal cation such as Na+ or K+ and occur naturally through the fixation of atmospheric nitrogen and oxygen as part of the environmental nitrogen cycle (the cyclic movement of nitrogen in different chemical forms from the environment, to organisms, and then back to the environment as illustrated).
Inorganic nitrites are also produced endogenously through oxidation of nitrous oxide (NO) formed from the enzymatic degradation of L-arginine and through the reduction of nitrate with xanthine oxidoreductase.
Organic Nitrates and Nitrites
The organic forms of nitrates and nitrites are more complex and most are synthesized medicinal products (except ethyl nitrite). Organic nitrates are small non-polar hydrocarbon chains attached to a nitrooxy-radical (-ONO2; -ONO for amyl and ethyl nitrite). The addition of aliphatic or aromatic groups of variable length and volume affect the lipophilic properties of these molecules. It has been suggested that for some molecules, the greater the number of –ONO2 groups, the greater its potency; (the potency being dependent on the molecule’s lipophilicity).
Nitrates and Nitrites exist in organic and inorganic forms.
The chemical form affects the pharmacokinetic and pharmacodynamic properties of nitrates and nitrates.
Inorganic nitrates and nitrites are generally more water soluble than organic nitrates and nitrates.
Inorganic nitrates and nitrites are produced endogenously and exogenously.
Organic nitrates and nitrites are mostly synthesized medicinal products.
Organic nitrates and nitrites are generally more complex and lipophilic than inorganic nitrates and nitrites.
The SOEKS EcoVisor F4 is a 4-in-1 testing device that is designed to:
SOEKS EcoVisor F4 performs express analysis of nitrate content in fresh fruit and vegetables. Nitrate content analysis is based on conductivity of alternating high-frequency current in the measured product (ionometry).
SOEKS EcoVisor F4 defines radiation background level and identifies radioactive contaminated foods and construction supplies. The Ecotester can easily assess the level of radioactivity according to the power level of ion radiation (gamma radiation and beta particles flux).
SOEKS EcoVisor F4 records the electromagnetic field in facilities, living areas and from domestic appliances. When electromagnetic fields are detecting, electric and magnetic field intensities evaluate.
SOEKS EcoVisor F4 evaluates water quality. The analysis is based on measurement of high-frequency alternating current conductivity.
Measurement of nitrate content level is based on the patented technology of a biobased product ionometry (Patent of invention № 23 90 767 Ionometry Method for biobased products and the device for its performance) and has been developed by the SOEKS company.
The technology is based on a specialized procedure method that puts high-frequency electric current through pulp.
Every plant contains ions of potassium, magnesium, ferrum (iron), cuprum, chlorine, plenty of organic acids and other elements in certain amounts that are necessary for proper growth.
The amount of every single element (ionic or molecular) is determined by bio organics of certain plant (it has a basic level of ion concentration) and by contents of water and soil where the plant grows.
People often use fertilization for efficient growth of plants. For instance, saline fertilizers such as nitrates and phosphates. As they break down and the plant easily absorbs these fertilizers.
As it spreads around the plant, saline ions (nitrates, phosphates and etc.) accumulate in different plant parts including fruits. This leads to higher amount of electrolytes and to higher electrical conductivity of fruit as well.
SOEKS EcoVisor F4 has mastered the measurement of nitrate ions content in fruits and vegetables. A percentage of these in fruit and vegetables is identified by an independent analysis method (potentiometric identification of nitrate content according to Russian National Standard (GOST) “Fruit and vegetables recycling products. Nitrate content identification”).
The result of express analysis is shown by the device in the form of nitrate ion concentration and its comparison to maximum permissible concentration for certain product. The device measures the nitrate concentration per kilogram of product netto. 200-300 mg of nitrates eaten within 24 hours is considered to be safe for an adult. If 600-700 mg is eaten within 24 hours, nitrates are considered toxic.
For instance, when measuring a beetroot, the device shows 1000 mg of nitrates per kg. According to the standard measurement, it is safe to only eat 200-300 mg of this beetroot without damaging your health. When measuring a watermelon, the device shows 350 mg/kg. If a person eats 2 kg of watermelon, he or she will consume 700 mg (350 mg/kg x 2 kg) which is toxic.
One should also understand that the shown result is evaluative and cannot be compared to quantified chemical analysis at an advanced laboratory. That kind of analysis requires a lot of time and is not free. Nevertheless, the presence of such laboratory and qualified analytical chemist at home is impossible for the majority of people. The EcoVisor F4 is a like portable lab that allows you to avoid buying suspicious products. This will help protect yourself, your relatives and children from being exposed to these poisonous products.
The nitrate tester analysis takes only a few seconds. The only maintenance it requires is to change the battery or charge the accumulator just as you would your mobile phone.
Of course, you may ask yourself is there an increased electrical conductivity if a fruit or vegetable does not contain nitrate ions? This is possible. But will the consumer feel safer buying a product with increased amount of phosphates or any other ions instead of nitrates or when buying a product that is already going bad? One should not forget that basic electrical conductivity is determined for every single type of fresh fruit or vegetable. When a product goes bad, the content and concentration of organic acids change.
ATTENTION! We strongly do not recommend to measure nitrate content in liquids, chemically and heat-treated products, products that are not included in the device’s menu list. Received data will be misleading and uncertain.
One should also remember that the device is designed for measuring products at a room temperature. Change of the product temperature can increase measurement uncertainty. This regards to products that have just been taken out of fridge or have been exposed to sun rays. In SOEKS EcoVisor F4 there is a function of thermal compensation, which is achieved by means of embedded temperature gauge in probe of the device. Thanks to software patches, when measuring you can get the same measurement result even when temperatures of measured products are different.
There are fruit and vegetables in the list of Nitrate tester, which contain air cavities (for instance, sweet pepper). When measuring such products, it is important not to insert the probe into the air cavity. When the probe is inserted into the air cavity, the measurement result will be misleading.
Some chemical elements (so called radioactive isotopes) contain unstable nucleus that decay into small elementary particles or quanta. Detachment of elementary particles or quanta is called radiation.
Radiation is ionizing, because it leads to atomic ionization of substance that is struck by radiation. Ionization is called the process of striking one or a few electrons out of atom. After that, nucleus and left electrons create a system that is positively charged and is called an ion.
Ionized atoms strongly differ from average nucleus. Ions destroy other molecules by breaking a bond between nucleuses. That is the reason why ionized radiation influence on human’s health is harmful.
Radiation influence on the human body is called irradiation. Irradiation transpierces any body tissues and ionizes their particles and molecules. This leads to creation of ionized nucleuses (ions or so-called free radicals) that destroy molecules and lead to inclusive death of tissue cells.
As it was said before, nuclear disintegration into elementary particles is accompanied by radiation of these particles. This radiation is divided into following types:
Alpha decay (alpha particles) are inert helium nucleus, the most massive particles.
Beta decay (beta particles) are electrons that move with an enormous speed. They are able to penetrate our body for a few centimeters.
Gamma decay (gamma particles) consist of gamma ray quantum, which although are considered to be particles, represent at the same time electromagnetic radiation such as sunlight, radio waves and x-rays. Their differences consists only of a big energy that every gamma quantum carries. Gamma decay always spreads with the light velocity when other particles are not that speedy. In comparison with alpha and beta particles, you need more materials such as concrete or lead in order to protect yourself from gamma decay.
X-rays are electromagnetic radiation (just like gamma decay) but it has less energy. In everyday life, it is used only at medical institutions.
Neutron radiation is an uncharged particle streams (neutrons). It occurs only in nuclear reactors.
Modern domestic dosimeters measure radiation in micro Sieverts per hour (mSv/h) and micro roentgen per hour (mcR/h). The radiation dose absorbed by human’s body is measured in micro Sieverts and the radiation dose in the air at measurement spot is measured in micro roentgen.
To estimate the radiation influence on the human body, the concept of equivalent dose is used. Equivalent dose is an amount of energy absorbed by mass unit of biological tissue considering biological danger of this radiation type. The unit of measurement for equivalent dose is the Sievert (Sv).
To estimate the influence of gamma decay which are the most absorbed radiation type and give most impute to human exposure, the concept of air radiation dose is used. It has its own unit of measurement – roentgen (R).
There is no natural radiation background standard because radiation background depends on the region, district and amount of radioactive particles that are found in objects around. For instance, radiation background at highlands is always higher than at low land.
SOEKS EcoVisor F4 measures radiation in micro Sieverts per hour (mSv/h) and micro roentgen (mcR/h), where 0.01 mSv/h corresponds to 1 mcR/h according to biological radiation effect.
Natural radiation background usually ranges from 0.08 mSv/h till 0.18 mSv/h. Safe radiation background level for a human is considered to be up to 0.4 mSv/h (the 0.4 mSv/h exposure per hour).
When Level of Radiation is exceeded (more than 0.4 mSv/h), the recommended time of staying in an irradiation area is regressive. The Radiation Level amounts to 0.4 mSv/h, you can stay in the irradiation area for one hour. If the Radiation Level amounts to 0.8 mSv/h, you can stay in irradiation area for half an hour. Duration of stay in area with 1.6 mSv/h radiation amounts shouldn’t exceed 15 minutes and so on.
Electromagnetic Field Measurement – EMF meter EcoVisor F4
Electromagnetic field (EM field) is a special form of matter which measures the interaction of charged particles. It represents interrelated alternating electric and magnetic fields. EM field spreads from one space point to another in form of electromagnetic progressive waves running from source.
EM field is created of particle charges. For example, in physics, students do experiments with ebonite electrification to demonstrate the electric field.
Magnetic field is created when electrical charges move through a conductor.
In order to characterize electric field strength, we use “electric field intensity” definition (mark sign – E, measurement unit – V/m (Volt per meter)). Magnetic strength is characterized by N magnetic field strength, measurement unit – A/m (Ampere per meter). When measuring very low and extremely low frequency, “magnetic density” definition is often used (mark sign – V, measurement unit – Tl (Tesla)).
Electromagnetic Field Influence on Human’s Health
Experimental Data of Russian and foreign research show that electromagnetic fields are highly bioactive and can negatively affect our health.
Many researches of EM field’s biological effect allow us to detect the most susceptible body systems: nervous, immune, endocrine and reproductive systems. These body systems are critical in our daily function.
EM fields influence water rich body organs mostly which are the eyes, brain, stomach and kidneys.
The following are symptoms of high EM field exposure can cause fatigue, irritability, sleep disorders, memory impairment and lack of attention.
The biological effect of EM fields tends to accumulate and can consequentially cause the degenerative process of the central nervous system, blood cancer (leukemia), encephaloma and endocrine system.
EM fields are especially dangerous for children, pregnant women, people with disorders of central nervous, the endocrine or cardiovascular system, allergic individuals and people with a compromised immune system.
Research has shown that the nervous system of the human body is the most sensitive to EM fields. When affected, it can cause serious malfunctions at the neuronal level, neural synapse and isolated neural structures. People who are in contact with electromagnetic fields, eventually face memory and higher nervous activity disorders.
Nowadays it is experimentally proven that electromagnetic fields negatively affect immunologic reactivity of body. Research data points to the fact that immunogenesis processes are violated and suppressed when being affected by electromagnetic fields.
When being affected by electromagnetic fields, changes in the pituitary adrenal system may occur. When being affected by electromagnetic fields, pituitary adrenal system is stimulated and therefore the amount of adrenalin in the blood rises and can trigger blood clotting. It is acknowledged that hypothalamus – pituitary – adrenal cortex system reacts on environmental interaction immediately and consistently.
Reproductive system disorders are usually connected with changes in its regulation within the nervous and neuroendocrine systems. This has been shown in research concerning the pituitary gonadotropic activity condition as it is affected by electromagnetic fields. Continuous EM field irradiation leads to lower pituitary activity.
Many scientists refer EM fields to teratogens that influence women’s health during pregnancy and fetus development. It is thought that electromagnetic fields can, for example, lead to physical defects of fetus. The fetus is very vulnerable at infancy during period of implantation and early organogenesis.
It is proven that fetus sensitivity to EM field is notably higher in mothers and may cause damage during it’s development. Results of epidemiological studies allow us to estimate that pregnant women who are in contact with electromagnetic field might suffer from premature birth. It might negatively affect fetus development and even cause congenital malfunctions of fetus.
Electromagnetic Field in Facilities
Electric field strength of 50 Hz commercial frequency in facilities (at 0.2 m distance from windows and walls, 0.5-1.8 m high from floor) should not exceed 500 V/m (kilovolt per meter).
Magnetic field strength of 50 Hz commercial frequency in facilities (at 0.2 m distance from windows and walls, 0.5-1.5 m high from floor) should not exceed 10 mcTl (microtesla).
Electric and magnetic fields of 50 Hz commercial frequency can be evaluated when domestic appliances are turned off and local lighting is turned on. The electric field is evaluated when ambient lighting is off and magnetic field is evaluated when ambient lighting is on.
Electromagnetic Field in Living Area
The electrical field of 50 Hz commercial frequency from overhead transmission lines and other objects on the territory of residential constructions should not exceed 1 kV/m (kilovolt per meter) 1.8 m high from ground.
The magnetic field strength of 50 Hz commercial frequency from overhead transmission lines and other objects on the territory of residential constructions should not exceed 25 mcTl (microtesla) 1.8 m high from ground.
Electromagnetic Field from Domestic Appliances
In home, domestic appliances are sources of electromagnetic exposure. A person should evaluate their effect at a distance 10 ± 0.1 cm while standing in front, behind and next to the object (except TV).
Electromagnetic field from TV with a diagonal less than 51 cm (20”) is measured at a distance of 50 ± 1 cm in front, behind and next to the TV. When screen diagonal is more than 51 cm, the EM field is measured the same way at a distance of 100 ± 1 cm. The device must be preliminarily turned on and work at least 20 minutes before measuring.
Electromagnetic Field from PC
The electrical field strength from PC ranging from 5 Hz to 2000 Hz should not exceed 25 V/m (volt per meter). The magnetic flux density from a PC ranging from 5 Hz to 2 KHz should not exceed 0.25 mcTl (microtesla).
Electromagnetic field is measured at 50 cm distance from the screen.
Water Measurement (Quality Evaluation) – TDS Meter EcoVisor F4
Water quality measurement is intended for quality evaluation of drinking water, as well as of water from treatment systems such as hydroponics, fish tanks, swimming pools, domestic appliances and from water wells.
The device measures the amount of solid particles that have been dissolved in water (TDS- total dissolved solids) per 1 million water particles – ppm (parts per million).
Among water particles, there is an enormous amount of dissolved water impurities in it. The main impurities are both inorganic salts (such as chlorides, sulfate bicarbonate of calcium, sodium, magnesium, potassium) and a small amount of organic substances.
The amount of dissolved in water solid particles depends on natural environment and varies from region to region. In the city, water content is influenced by it’s industrial drainage, rainfall drainage, chlorination etc.
Solids dissolved in water determine our water quality and can affect our bodily functions.
Potassium and magnesium salts affect water hardness. High levels of these elements can worsen the water’s taste, smell, muddiness etc. Hard water negatively affects digestive system, hair and skin when we shower. It can also cause kidney diseases. With the help of EcoVisor F4 now, it is possible to determine whether the water is suitable for drinking, domestic needs or if it requires purification.
EcoVisor F4 can be used for evaluation of water filter efficiency. In addition, EcoVisor F4 is used for reverse osmosis filter. Such filters have a few filtration levels. One of them is represented by reverse-osmosis membrane which stops water impurities that cannot be stopped by other filters. This membrane’s service life period depends on amount of impurities in stream water. If the membrane clogs, it can lead to its mechanical damage and the whole filtration system can break down.
EcoVisor F4 can measure the amount of solid particles entering and exiting the filtration system and record its indication. If the amount of salts when exiting has increased, it is time to wash and change the membrane.
In addition, EcoVisor F4 is used in aquaristics. The device can pick water with necessary amount of solids.
Moreover, EcoVisor F4 can be used when watering plants and flowers. Harsh water can negatively affect plants because it increases concentration of lime in the ground. As the result, the ground becomes alkaline and blocks the nutrition for the plants.
Water with high amount of solids is harmful for domestic appliances (washing machines, coffee machines, and irons with steam generator, kettles, dishwashers and boilers). In all of these devices, there is a heating spiral. The scale on the heating spiral can overheat and breakdown. The EcoVisor F4 can help to evaluate quality of water in domestic appliances and take precautions when using it in the future.
The primary routes of exposure to nitrates and nitrites may differ depending on occupational and non occupational factors. Non-occupational factors may include:
Hobbies (such as gardening, arc welding, etc.),
History of inhalational drug use,
Source of drinking/cooking water and how it is supplied,
The chemical form of the nitrates and nitrites.
Occupational and Paraoccupational Exposures
Occupational exposure occurs primarily through the inhalation and dermal routes. Explosive and fertilizer industry workers may be exposed to nitrate through inhalation of dusts containing nitrate salts. Dusts can also dissolve in sweat exposing skin to concentrated solutions of the salts. Farmers may experience periodic exposures depending on their activities, especially with regard to the handling of fertilizers. Exposure of family members to nitrates from dusts brought home on work clothes has been reported.
The primary route of non-occupational exposure is ingestion of water or foodstuffs that contain high levels of nitrates or nitrites. Inhalation exposures may occur from inhalant drug use and dermal exposures may occur from some topical medications. These would be special instances and not the primary routes of exposure for the general population.
Primary occupational routes of exposure to nitrates and nitrites include inhalation and dermal routes.
The primary route of exposure to nitrates and nitrites for the general population is ingestion.
Inhalation and dermal exposures have been reported in non-occupational settings under certain circumstances, but are not the primary routes of exposure for the general population.
Understanding the environmental fate of nitrates and nitrites may help pinpoint potential sources of exposure. This would be important in assessment of patient exposure risk, prevention and mitigation of nitrate / nitrite overexposure and in the prevention of adverse health effects from exposure.
Environmental Nitrogen Cycle
In general, the following describes the activity of nitrates and nitrites in the environment. Microbial action in soil or water decomposes wastes containing organic nitrogen into ammonia, which is then oxidized to nitrite and nitrate.
Because nitrite is easily oxidized to nitrate, nitrate is the compound predominantly found in groundwater and surface waters.
Contamination with nitrogen-containing fertilizers (e.g. potassium nitrate and ammonium nitrate), or animal or human organic wastes, can raise the concentration of nitrate in water.
Nitrate-containing compounds in the soil are generally water soluble and readily migrate with groundwater.
Shallow, rural domestic wells are those most likely to be contaminated with nitrates, especially in areas where nitrogen-based fertilizers are widely used.
Approximately 15 percent of Americans rely on their own private drinking water supplies which are not subject to U.S. Environmental Protection Agency (EPA) standards, although some state and local governments do set guidelines to protect users of these wells.
In agricultural areas, nitrogen-based fertilizers are a major source of contamination for shallow groundwater aquifers that provide drinking water.
A recent United States Geological Survey study showed that 7 percent of 2,388 domestic wells and about 3 percent of 384 public-supply wells nationwide were contaminated with nitrate levels above the EPA drinking water standard of 10 parts per million (ppm) or 10 mg/L.
Elevated concentrations were most common in domestic wells that were shallow (less than 100 feet deep) and located in agricultural areas because of relatively large nitrogen sources, including septic systems, fertilizer use, and livestock.
Although suppliers of public water sources are required to monitor nitrate concentrations regularly, few private rural wells are routinely tested for nitrates.
During spring melt or drought conditions, both domestic wells and public water systems using surface water can show increased nitrate levels.
Drinking water contaminated by boiler fluid additives may also contain increased levels of nitrites.
Mixtures of nitrates / nitrites with other well contaminants such as pesticides and VOCs have been reported.
Nitrate and nitrite overexposure has been reported via ingestion of foods containing high levels of nitrates and nitrites. Inorganic nitrates and nitrites present in contaminated soil and water can be taken up by plants, especially green leafy vegetables and beet root.
Contaminated foodstuffs, prepared baby foods, and sausage / meats preserved with nitrates and nitrites have caused overexposure in children.
Although vegetables are seldom a source of acute toxicity in adults, they account for about 80% of the nitrates in a typical human diet.
Celery, spinach lettuce, red beetroot and other vegetables have naturally greater nitrate content than other plant foods do.
The remainder of the nitrate in a typical diet comes from drinking water (about 21%) and from meat and meat products (about 6%) in which sodium nitrate is used as a preservative and color- enhancing agent.
For infants who are bottle-fed, however, the major source of nitrate exposure is from contaminated drinking water used to dilute formula.
Bottled water is regulated by the U.S. Food and Drug Administration (FDA) as a food. It is monitored for nitrates, nitrites and total nitrates / nitrites.
Nitrate or nitrite exposure can occur from certain medications and volatile nitrite inhalants.
Accidental and inadvertent exposures to nitrites as well as ingestion in suicide attempts have been reported.
Deliberate abuse of volatile nitrites (amyl, butyl, and isobutyl nitrites) frequently occurs. Amyl nitrite (nicknamed by some as “poppers”) is used commercially as a vasodilator and butyl / isobutyl nitrites can be found in products such as room air fresheners.
Fatalities have been reported in adults exposed to nitrates in burn therapy; however infants and children are especially susceptible to adverse health effects from exposure to topical silver nitrate used in burn therapy.
Other medications implicated in methemoglobinemia include:
Quinone derivatives (antimalarials),
Bismuth subnitrite (antidiarrheal),
Ammonium nitrate (diuretic),
Amyl and sodium nitrites (antidotes for cyanide and hydrogen sulfide poisoning),
Isosorbide dinitrate/tetranitrates (vasodilators used in coronary artery disease therapy),
Benzocaine (local anesthetic), and
Other possible sources of exposure include ammonium nitrate found in cold packs and nitrous gases used in arc welding.
An ethyl nitrite folk remedy called “sweet spirits of nitre” has caused fatalities.
Shallow, rural domestic wells are those most likely to be contaminated with nitrates, especially in areas where nitrogen based fertilizers are in widespread use.
Other nitrate sources in well water include seepage from septic sewer systems and animal wastes.
Foodstuffs high in nitrates, home prepared baby foods, and sausage/meats preserved with nitrates and nitrites have caused overexposure in children.
Nitrate or nitrite exposure can occur from certain medications and volatile nitrite inhalants.
Who is at most Risk of Adverse Health Effects from Overexposure to Nitrates and Nitrites?
Infants less than 4 months of age are most at risk of adverse health effects from over exposure to nitrates and nitrites through ingestion of formula diluted with nitrate contaminated water.
Although there is no nutritional indication to add complementary foods to the diet of a healthy term infant before 4 to 6 months of age, the American Academy of Pediatrics suggests that home-prepared infant foods from vegetables (i.e. spinach, beets, green beans, squash, carrots) should be avoided until infants are 3 months or older.
Gastroenteritis with vomiting and diarrhea can exacerbate nitrite formation in infants and has been reported to be a major contributor to methemoglobinemia risk in infants independent of nitrate / nitrite ingestion.
In addition, the pregnant woman and her fetus might be more sensitive to toxicity from nitrites or nitrates at or near the 30th week of pregnancy.
Individuals with glucose-6-phsphate dehydrogenase (G6PD) deficiency may have greater susceptibility to the oxidizing effects of methemoglobinemia inducers.
What are U.S. Standards and Regulations for Nitrates and Nitrites Exposure?
EPA has set an enforceable standard called a maximum contaminant level (MCL) in water for nitrates at 10 parts per million (ppm) (10 mg/L) and for nitrites at 1 ppm (1 mg/L).
EPA believes that exposure below this level is not expected to cause significant health problems.
All public water supplies must abide by these regulations.
Given present technology and resources, this MCL is also a level to which water systems can reasonably be required to remove this contaminant should it occur in drinking water.
Once a water source is contaminated, the costs of protecting consumers from nitrate exposure can be significant. This is because:
Nitrate is not removed by conventional drinking water treatment processes.
Its removal requires additional, relatively expensive treatment units.
Intake Nitrate Limits
The Joint Expert Committee on Food Additives (JECFA) of the Food and Agriculture Organization of the United Nations / World Health Organization and the European Commission’s Scientific Committee on Food have set an acceptable daily intake (ADI) for nitrate of 0–3.7 milligrams (mg) nitrate ion / kilogram (kg) body weight. This intake appears to be safe for healthy neonates, children, and adults. The same is also true of the EPA reference dose (RfD) for nitrate of 1.6 mg nitrate nitrogen / kg body weight per day (equivalent to about 7.0 mg nitrate ion / kg body weight per day).
JECFA has proposed an ADI for nitrite of 0–0.07 mg nitrite ion/kg body weight. EPA has set an RfD of 0.l mg nitrite nitrogen/kg body weight per day (equivalent to 0.33 mg nitrite ion/kg body weight per day).
Bottled Water and Food Additives Nitrate Limits
The FDA regulates allowable levels of inorganic nitrate and nitrite in bottled water [FDA 2005] as well as levels allowable in foodstuffs.
The FDA’s bottled water standard is based on the EPA standards for tap water. The bottled water industry must also follow FDA’s Current Good Manufacturing Practices (CGMPs) for processing and bottling drinking water. If these standards are met, water is considered safe for most healthy individuals. However, although not often reported, bottled water outbreaks do occur.
Allowable nitrite levels in bottled water:
Nitrate 10 mg/L (as nitrogen)
Nitrite 1 mg/L (as nitrogen)
Total nitrates, nitrites 10 mg/L (as nitrogen)
Allowable nitrite levels as an additive to foods:
As a preservative and color fixative, with or without sodium nitrite, in Smoked, cured sablefish; Smoked, cured salmon; Smoked, cured shad, so that the level of sodium nitrate does not exceed 500 parts per million (ppm) and the level of sodium nitrite does not exceed 200 ppm in the finished product.
As a preservative and color fixative, with or without sodium nitrite, in meat-curing preparations for the home curing of meat and meat products (including poultry and wild game), with directions for use which limit the amount of sodium nitrate to not more than 500 ppm in the finished meat product and the amount of sodium nitrite to not more than 200 ppm in the finished meat product.
The food additive potassium nitrate may be safely used as a curing agent in the processing of cod roe, in an amount not to exceed 200 ppm of the finished roe.
The U.S. Department of Agriculture’s (USDA’s) Food Safety and Inspection Service (FSIS) regulates food ingredients approved for use in the production of meat and poultry products. This includes inspection for required labeling of meat products when substances such as sodium nitrate are used in meat packaging.
Environmental Nitrate and Nitrite Standards
The current water standard for nitrate is based on levels considered low enough to protect infants from methemoglobinemia.
Some published results suggest a possible association between nitrate exposure during pregnancy and human malformations.
However, a review of the toxicology in relation to possible adverse effects on reproduction and development offers no evidence for teratogenic effects attributable to nitrate or nitrite ingestion.
The present maximum contaminant level appears to adequately protect even sensitive populations from nitrate-induced toxicity.
EPA concludes that the evidence in the literature showing an association between exposures to nitrate or nitrites and cancer in adults and children is conflicting.
Key Points of Nitrate and Nitrite Standards
The current water standard for nitrate is based on protection of infants from methemoglobinemia.
In vivo conversion of nitrates to nitrites significantly enhances nitrates’ toxic potency.