Plants, nitrosamines

In recent years greater attention has been given to nitrogen containing pesticides and the possibility of their nitrosation in soil. The N-nitrosamines that form may arise from the parent pesticide or from a pesticide metabolite. The reaction calls for favourable pH conditions (pH 3-4) and excess nitrite. Under field conditions, the nitrosable residues are usually present in traces and only small quantities of these will actually be nitrosated in soils. However, the possibility exists that the small amounts of N-nitrosamines could be assimilated by plants. 

We initiated an investigation to examine the possibility of N-nitrosamine formation from the herbicide glyphosate in different soils. It was also of interest to determine whether uptake of N-nitroso compound by plants would occur from soil. 

W-nitrosodiethylamine from soil by wheat, barley and several vegetable crops has been demonstrated (17,18). Rapid disappearance of the N-nitrosoamine absorbed by plants was observed. Sander et al. (19) observed that several W-nitrosoamines could be removed from water by cress, but the residues rapidly decreased when W-nitrosamine containing water was replaced with non-contaminated water. Dean-Raymond and Alexander (20) reported... 

Possible exposure to pesticide-derived N,-nitroso compounds depends on environmental processes that influence formation, movement, and degradation of the compounds. Although laboratory studies have shown the feasibility of environmental nitrosamine formation, there has been little evidence that it is an important process. Nitrosamines vary greatly in their environmental stabilities, but all seem to be susceptible to one or more modes of decomposition including photolysis, microbiological degradation, and plant metabolism. 

This relationship, studies less than that of nitrosamines and microorganisms, offers similar possibilities. Plants could presumably affect nitrosation of secondary amines under certain... 

NDMA (and other nitrosamines) can dramatically increase in concentration in distribution systems (relative to finished water at the drinking water-treatment plant). For example, an initial level of 67 ng/L in drinking water-treatment plant effluent was shown to increase to 180 ng/L in the distribution system [53]. As a result, measurements taken at water-treatment plants may substantially underestimate the public s exposure to this carcinogen. 

Planas C, Palacios O, Ventura F, Rivera J, Caixach J (2008) Analysis of nitrosamines in water by automated SPE and isotope dilution GC/HRMS - Occurrence in the different steps of a drinking water treatment plant, and in chlorinated samples from a reservoir and a sewage treatment plant effluent. Talanta 76 906-913... 

A Health Hazard Evaluation of Nitrosamines in a Tire Manufacturing Plant... 

Figure 1. Volatilized N-nitrosamines found in this tire plant and typical vulcaniza-...

Air Samples NMOR, NDMA, and NPYR were found during the first NIOSH visit in air samples collected at a tire manufacturing plant in Maryland. One process sample, collected at a feedmill, contained 250 yg/M3 of NMOR, a level several times higher than has been reported for any airborne nitrosamine at any industrial site (1). Maximum concentrations of NDMA and NPYR found in the hot process areas were 4.4 yg/M3 and 3.4 yg/M3, respectively. Over the following 7 months, ventilation improvements and changes in chemical formulation of the rubber resulted in a 200-fold reduction in NMOR levels and elimination or reduction of other nitrosamines at most sites. Results are shown in Figure 2, and Table I. 

In summary, nitrosamines were detected in every area of the tire plant where NIOSH sampled. Only outside the plant, next to the guard house, nearly 400 yards away, were nitrosamines not detected. Generally, highest nitrosamine levels were in the hot process areas, in particular, the feedmill and calendering area. With the exception of the guard house, the lowest... 

Any secondary amine will react with nitrous acid to form a nitrosamine (Eq. 27-25). Tertiary amines can also react with loss of one alkyl group. This can occur in the stomach, and the nitrosamines may be absorbed into the system. All plants contain some nitrate and some, such as spinach and beets, have large amounts. Bacon and other cured R R meats contain both nitrites and nitrates, and many drugs and natural food... 

L 1 and 0.6 jag L, respectively. Due to photolysis, nitrate present in the water at a concentration of 55 mg L 1 was reduced to nitrite generating an additional problem (see section II.D.l). This is because nitrite is thought to be involved in the formation of nitrosamines. Experimental conditions in this plant have been investigated to provide the optimum operating conditions for the removal of herbicides and to minimize the impact of nitrate photolysis. The results obtained in this plant led to concentrations of atrazine and nitrite in the effluent lower than 0.1 and 100 pg L 1, respectively. It must be said, for safe operation of the plant, that an equivalent ozone dose higher than 3 kW energy and a radiant power for the UV lamp between 20 and 35 kW were needed. 

Large amounts of nitrosamines leak into the environment from the pharmaceutical and food industries, plastics industry, textile industry, waste transport (motor vehicles), industrial effluents (dyes, lubricants, mbber), and the production of solvents. Fuel manufacturing plants and oil refineries are also important emitters of nitrosamines, as well as landfills and fossil fuel combustion processes (to produce heat and power). These compounds naturally penetrate the environment through animal droppings. 

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