Nitrite levels above 0.75 ppm in water can cause stress in fish and greater than 5 ppm can be toxic. Nitrate levels from 0 – 40 ppm are generally safe for fish. Anything greater than 80 can be toxic.

10 mg/L

In the United States the EPA, under the authority of the Safe Drinking Water Act (SDWA), has set the Maximum Contaminant Level Goal (MCLG) for total nitrate/nitrite at 10.0 mg/L and for nitrite at 1.0 mg/L (measured as nitrogen, N).

Nitrates and nitrites are compounds that occur naturally in the human body and some foods. They’re also added to certain processed foods to extend shelf life. They can change into nitric oxide, dilate your blood vessels, and lower blood pressure. Moreover, they may enhance physical performance.

Health risks of consuming added nitrates, include: Methemoglobinemia in infants (blue baby syndrome) Increased risk of cancer. Complications during pregnancy.

Systemic nitrate and nitrite was circulating among blood, saliva and tissues, after a rich nitrate diet, the nitrate was absorbed and the plasma level peak up in 15-30 minutes with a half-life of about 5-8 hours [3, 21, 22].

Common side effects:

• Dizziness.
• Headaches.
• Flushing of your face and neck.
• Upset stomach or throwing up.
• Low blood pressure (hypotension)
• Irregular heart rhythms (arrhythmia)

Vegetables particularly rich in nitrates include green leafy vegetables such as spinach and lettuce as well as fennel, rocket, radishes, Chinese cabbage, and parsley [3, 5, 6].

Root vegetables such as carrots, beets and broccoli all contain nitrates though at a much lower level than do the leafys. Leafy vegetables include spinach, cabbage or other greens like kale.

Cooking, boiling, steaming, broiling, baking and blanching all destroy the nitrates necessary for N-O production.

Researchers found that artichokes, tomatoes, asparagus, sweet potatoes, broad beans, summer squash, eggplant, potatoes, garlic, onion, peppers, green beans, mushrooms and peas are classified as very low in nitrates, according to a study published in “The American Journal of Clinical Nutrition” in July 2009.

So, here’s a consumer tip: When you see a “no nitrates added” label, look for an asterisk pointing to fine print that may say something like “no nitrates except those naturally occurring in celery powder.” That asterisk basically contradicts the nitrate-free claim.

For ‘Hass’ avocado leaves and young actively growing roots, nitrate concentrations were 0.21 ± 0.02% and 0.18 ± 0.02%, respectively (table 4).