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Growth and nitrite and nitrous oxide accumulation of Paracoccus denitrificans ATCC 19367 in the presence of selected pesticides

2003; Wiley; Volume: 22; Issue: 9 Linguagem: Inglês

10.1897/02-351

1552-8618

Florentina Sáez, Clementina Pozo, M.A. Gómez, B. Rodelas, Jesús González,

Environmental Toxicology and Ecotoxicology

Abstract The effects of the application of eight pesticides (aldrin, lndane, dimetoate, methylparathion, methidation, atrazine, simazine, and captan) on growth, respiratory activity (as CO 2 production), denitrifying activity (as N 2 O released), and nitrite accumulation in the culture medium by Paracoccus denitrificans strain ATCC 19367 were studied. The fungicide captan totally inhibited growth and biological activity of P. denitrificans , while the rest of the tested pesticides delayed the growth and CO 2 release of P. denitrificans but did not drastically affect the bacterial growth or respiratory capacity after 96 h of culture. The denitrifying activity of P. denitrificans ATCC 19367 (as N 2 O released) was negatively affected by all tested pesticides. The release of N 2 O was strongly inhibited by several organochlorinated and organophosphorated insecticides (aldrin, lindane, dimetoate, and methidation), which led to high accumulation of nitrite in the surrounding medium. Atrazine decreased N 2 O release after 48 h of culture because of negative effects on growth, and methylparathion and simazine delayed the onset of N 2 O release by P. denitrificans. These three pesticides reduced the accumulation of NO 2 compared to unamended control cultures.