2 research outputs found
Ecotoxicological effects of rice field waters on selected planktonic species: comparison between conventional and organic farming
The aim of this study was to assess the ecotoxicological
effects of water coming from untreated organic
and conventional rice field production areas in the Ebro
Delta (Catalonia, Spain) treated with the herbicides oxadiazon,
benzofenap, clomazone and bensulfuron-methyl and
the fungicides carbendazim, tricyclazole and flusilazole.
Irrigation and drainage channels of the study locations were
also included to account for potential toxic effects of water
coming in and out of the studied rice fields. Toxicity tests
included four species (Pseudokirchneriella subcapitata,
Desmodesmus subcapitatus, Chlorella vulgaris and Daphnia
magna), three endpoints (microalgae growth, D. magna
mortality and feeding rates), and two trophic levels: primary
producers (microalgae) and grazers (D. magna). Pesticides
in water were analyzed by solid phase extraction-liquid
chromatography-electrospray-tandem mass spectrometry
(LC-ESI-MS/MS). Negative effects on algae growth and
D. magna feeding rates were detected mainly after application
of herbicides and fungicides, respectively, in the
conventional rice field. Results indicated that most of the
observed negative effects in microalgae and D. magna were
explained by the presence of herbicides and fungicides. The
above mentioned analyses also denoted an inverse relationship
between phytoplankton biomass measured as chlorophyll a and herbicides. In summary, this study indicates
that in real field situations low to moderate levels of
herbicides and fungicides have negative impacts to planktonic
organisms and these effects seem to be short-lived.This study was carried out with the financial
support of the Spanish Ministry of Environment and the Catalan
Water Agency (ACA), Department of Environment, Government of
Catalonia (MOBITROF project). We thank for field and laboratory
assistance to Mireia San Lorenzo, David Mateu and Lluı´s Llornet. We
are grateful to Rafael Verdiell and Riet Vell S.A. (owners of the rice
fields) for their collaboration. We also thank Katherine Sharpe for
helping to improve the English and providing useful comments on a
previous version of the manuscript.Peer reviewe