Diuron

see also: Etymology of Diuron

Diuron (of formula: 3 (3,4-dichlorophenyl) - 1,1-dimethyl-urea) is a Weeding very much used, in vine growing in particular, or like anti-alga and anti-foamer. Of the family of the halogéno Phénylurée S (N (3,4-dichlorophenyl) - NR' - (dimethyl) - urea) i.e. group known as of the substituted ureas , it belongs to the vast chemical family of the Pesticide S. It carries the n° CASE: 330-54-1.

Its solubility in water (42 ppm) is average but sufficient so that one finds it in surface waters or of tablecloths, or after evaporation in the rains, fogs, fogs and dew.
Selon the manufacturer, his time of half-life in the grounds would be of approximately a year (372 days), but of the important variations seem possible according to the nature of ground (pH, oxygenation, high content in organic matter and living organism, moisture, altitude, exposure to the sun or not, etc). In the air environment, oxidation by the air or ozone and degradation by photochemistry seem to degrade it slowly. In the ground and the sediments, it could persist longer before complete mineralization.

Several studies found presences significant of Diuron in fresh water and navy (Recall: it is also one of the components of the Antifouling S, but it can be brought at sea by the rivers, the air or the Pluie).

Toxicology

Absorbed by inhalation or contact, it can induce irritating Dermite S, light burns and ocular irritations, as well as a cutaneous sensitizing in the event of repeated contacts. The ingestion induced of the digestive burns, the vomiting and diarrhea beyond 50 G introduced by an adult. A risk of “chloric Acné” of the face could be explained by the chlorobenzenic impurities ( Tétrachloroazobenzène ) which accompany it, which can also let suppose a cancerogenicity.

Reproductive health

Noxious effects were detected on the human spermatozoon, and more still following exposure to the one of its by-products of degradation, the 3,4-dichloroaniline (3,4-DCA) which kills it after 30 minutes or 24 hours respectively for amounts of 5 mm and 1 mm of 3,4-DCA for 250 μl. Other breakdown products could have toxic and ecotoxic impacts:

- N (3,4 dichlorophenyl) - N (methyl) - urea (DCPMU),

- N (3,4 dichlorophenyl) - N (methyl) - urea (DCPU).

Ecotoxicology

This product which seems rather widespread in the Environnement can evaporate in the air, be transported and fall down remotely in the rains. Decomposition of Diuron by the fire led to gases, smoke and ashes highly toxic.

High rates of Diuron (approximately eight times more than of Irgarol (another biocide present in the antifoulings) were found in Rade of Brest in 2003-2004, with according to the IFREMER, of the contents climbing with 6,7 µg/L in Marina S or others port areas. These figures are probably not the maximum ones, because measurements are rare. They are however already enough high to induce an effect on the phytoplankton, and perhaps in these zones on all the food chain. These contents exceed, and by far the European standards of potability, whereas moulds and oysters or scallops can grow in the vicinity or downstream from these zones and be marketed.

References

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