A few hints on health effects of nitrate -
page quickly provides a bit of information on health effects of nitrate
for those readers which are not yet informed. Please read special
literature for more details!
is not considered as to be toxic. In the digestive tract, it can
however be reduced to nitrite leading to the formation of
methaemoglobine especially dangerous for (less than 1 year old)
babies. 5 "blue-baby syndromes" have been observed in an Ukrainian
village of 3500 inhabitants in the year 2002. The figure shows that the
problem is of high importance.
with secondary amines, nitrate forms nitrosamine, which is one of the
most effective carcinogens. This is why the nitrate concentration of
drinking water in Ukraine is limited to 45 mg/L (ca. 10 mg/L N).
Some more hints including pesticides, published by various US offices, are put together here:
Nutrient (lifetime health advisory) mg/L
Nitrate (as N) 10.0
Nitrite (as N) 1.0
Lifetime health advisory is US EPA's specific level of chemical
concentration in water that is acceptable for drinking over a person's
residues and nutrients in drinking water may cause health problems.
Pesticides, if ingested in large quantities over a relatively short
period of time may cause damage to the nervous system and internal
organs of both animals and humans. Long term effects on humans are
unclear and studies are ongoing.
impairment of ground water by nitrate can endanger the lives of
children under the age of one year. Infants can develop a potentially
fatal condition known as methaemoglobinemia, or "blue baby syndrome."
Within the infant's digestive tract, nitrate is readily converted to
toxic nitrite in the oral cavity and the stomach. The nitrite is then
absorbed through the infant's gastro-intestinal tract into the blood
and there it bonds to ferric (Fe+3) iron found in blood methaemoglobin.
The nitrite prevents the reduction of ferric iron back to the ferrous
(Fe+2) form required in haemoglobin for the transport of oxygen by
blood. With greatly decreased blood-oxygen carrying capacity, the
infant's tissues become oxygen-starved, the blood turns dark-brown and
the skin exhibits a bluish tint. Nitrate in ground water may also be
toxic to adults.
"Concrete figures are
given in the book of the geographer A. CAPCELEA. He writes that
in Moldawia about 1 million people in rural areas are subject to
the harmful influence of nitrates (over 300 mg per 24 hours).
investigation have shown that the continuous loading of the human body,
especially of children, with increased doses of nitrates contribute to
the onset of the tissue hypoxic state, to metabolism misbalance,
immunity loss, etc. In affected localities, a big number of children
show retarded biologic development (s. tab., source 3 from literature
list below), with certain consequences in physical development and with
excess body mass..
|adequate to age||
Competition between nitrate and iodide with its admission into the thyroid.
in the blood competes with the transport of iodide into the thyroid.
Iodide is needed for the synthesis of the vital hormone thyroxin. With
normal supply of iodide outweighing of this transportation mechanism
adjusts the competition of nitrate. However if the offer of
iodide is scarce and the nitrate pollution high, the thyroid seeks to
adjust the lack of iodide (which is intensified artificially by
nitrate) by enlargement and new formation of thyroxin forming cells. If
this is not successful, iodine lack can cause damages.
Pesticide Residues and Nutrients
Montana General Agricultural Chemical Ground Water Management Plan
addresses pesticide and nutrient use and best management practices to
implement to prevent impairment of ground water and surface water. The
following contaminant levels are established concentrations of
pesticides and residues that are allowed in water.
contaminant levels: A maximum contaminant level or MCL are the highest
concentration of a contaminant allowable in a public water supply.
These MCLs are specified in the National Primary Drinking Water
Standards for the United States. There are no known adverse health
effects that exist at the recommended MCLs. MCLs are based on a
lifetime exposure with a consumption of 0.52 gallons of water per day.
This provides good protection to all people using a public water supply.
maximum contaminant levels: A secondary maximum contaminant level has
been established for contaminants that may affect taste, odor, colour
and appearance of drinking water. These MCLs have also been established
to prevent adverse health affects. Although secondary MCLs represent
reasonable goals for drinking water, they are not federally
enforceable. Yet, each state is encouraged to implement the secondary
advisories: Health advisories are guidance documents issued by the
Environmental Protection Agency. These health advisories contain
information on health risks, water treatment technologies and specific
levels of chemical concentrations in water that are acceptable for
drinking. The EPA reviews available human data and experimental animal
studies in evaluating potential human health effects. The health
advisories are updated as new information becomes available.
Any questions or concerns about health effects of specific pesticides can be directed to DHES or MDA.
require a good water supply, both in quality and quantity. Generally
speaking, the maximum level of contaminants allowable in livestock
water is higher than those levels acceptable for human consumption.
Safe levels of agricultural chemicals in livestock water, especially
pesticides, has not been thoroughly examined. Nitrate poses the
greatest health hazard to livestock (especially young animals).
itself is not very poisonous, but it will become poisonous when it
changes to nitrite in an animal's digestive system. Once converted it
enters the bloodstream and reacts with haemoglobin to render it
incapable of carrying oxygen in much the same manner as was previously
described for infants. The animal will begin to show signs of a lack of
oxygen such as laboured breathing and a lack of coordination.
poisoning is more likely to occur in ruminant animals such as cattle
and sheep. Research also shows, horses are more susceptible than swine
and poultry. When livestock consume both well water and feed which is
high in nitrate, the health hazard becomes even higher.
Table 1: Effects of nitrate in water used by livestock (Jackson, 1983, Olson, N.D., United States Department of Agriculture, Soil Conservation Service, 1982).
|reported as NO3-N (nitrate-nitrogen) ||reported as N03 (nitrate)|| Interpretation|
| 0-10 ppm|| 0-44 ppm|| Safe for all animals|
| 10-20 ppm || 44-88 ppm||Safe for all livestock unless feed is also high in nitrates|
| 20-40 ppm || 88-176 ppm ||Risky, especially over long periods of time|
| 40-100 ppm || 176-440 ppm ||Interference syndrome likely (trembling, weakness)|
| 100-200 ppm || 440-880 ppm|| Should not be used (acute losses possible)|
programs of the Montana Extension Service are available to all people
regardless of race, creed, colour, sex or national origin.
in furtherance of cooperative extension work in agriculture and home
economics; acts of May 8 and June 30, 1914. In cooperation with the
U.S. Department of Agriculture, Andrea Pagenkopf, Associate Vice
Provost for Outreach and Director Extension Service, Montana State
University, Bozeman, Montana 59717.
provided by the Montana Agricultural Chemical Ground Water Protection
Act and Fertilizer Checkoff. Additional information may be found in the
General Agricultural Chemical Ground Water Management Plan (GMP).
of Drinking Water, Office of Water, U.S. Environmental Protection
Agency (19990): Risk Assessment, Management and Communication of
Drinking Water Contamination. - Seminar Publication EPA/625-4-89/024
- CAPCELEA, A. (1996): The Republic of Moldova on the way to the sustainable development (edit. by SOROS Foundation, Moldova
- National Strategic Program for Environmental Protection till 2010. - Chisinau, 1995
links for the evaluation of pesticides see there!