Evaluación preliminar del área agrícola y su influencia sobre la calidad del agua en el Golfo Dulce, Costa Rica
Archivos
Fecha
2019
Autores
Fournier, María Luisa
Castillo, Luisa E.
Ramírez-Muñoz, Fernando
Moraga López, Geannina
Ruepert, Clemens
Título de la revista
ISSN de la revista
Título del volumen
Editor
Universidad Nacional, Costa Rica.
Resumen
Se realizó una evaluación preliminar de la agricultura en las subcuencas Esquinas, Coto Colorado, Rincón, Conte, Agujas, Tigre y Palma, como criterio base para el diseño de un plan de seguimiento de la calidad del agua que ingresa al estuario. Se determinó el área de los cultivos, mediante interpretación de imágenes satelitales, para un total aproximado de 10 000 ha de arroz Oryza sativa y 31 000 ha de palma aceitera Elaeis guineensis. El uso de agroquímicos se estimó con base en información secundaria publicada y con encuestas administradas a grupos productores. El uso anual estimado de plaguicidas fue de 20.4 kg ha-1 en arroz y 6.6 kg ha-1 en palma, y 840 kg ha-1 año-1 de fertilizantes granulados en ambos cultivos. Asimismo, se hizo un muestreo puntual de residuos de plaguicidas en agua, sedimento y peces, analizados con cromatografía de gases acoplada a espectrometría de masas y cromatografía de líquidos con detector de arreglo de diodos. En todas las muestras de agua se detectó el herbicida clomazone. Además, en la subcuenca Coto Colorado, la cual abarca el 95 % del total del área agrícola que drena al golfo, se detectó el insecticida triazofos y los fungicidas isoprotiolano y propiconazol. La extensión y el manejo de las plantaciones agrícolas en la cuenca del Golfo Dulce, aunada a factores ambientales, podría representar una amenaza sobre los recursos del estuario. Por ello, se recomienda monitorear la calidad del agua en los ríos, así como iniciar programas de restauración de los bosques de ribera como medida de mitigación.
A preliminary assessment of agriculture in the Esquinas, Coto Colorado, Rincón, Conte, Agujas, Tigre and Palma sub-basins was carried out as a basis for the design of a monitoring plan for water quality entering the estuary. The area under cultivation was determined by interpreting satellite images for a total of approximately 10,000 ha of Oryza sativa rice and 31,000 ha of Elaeis guineensis oil palm. Agrochemical use was estimated based on published secondary information and surveys administered to producer groups. The estimated annual use of pesticides was 20.4 kg ha-1 in rice and 6.6 kg ha-1 in oil palm, and 840 kg ha-1 year-1 of granular fertilizers in both crops. In addition, pesticide residues in water, sediment and fish were sampled by gas chromatography coupled to mass spectrometry and liquid chromatography with diode array detector. The herbicide clomazone was detected in all water samples. In addition, the insecticide triazophos and the fungicides isoprothiolane and propiconazole were detected in the Coto Colorado sub-basin, which covers 95% of the total agricultural area draining into the gulf. The extension and management of agricultural plantations in the Golfo Dulce watershed, together with environmental factors, could represent a threat to the estuarine resources. Therefore, it is recommended that water quality in the rivers be monitored and that riparian forest restoration programs be initiated as a mitigation measure.
A preliminary assessment of agriculture in the Esquinas, Coto Colorado, Rincón, Conte, Agujas, Tigre and Palma sub-basins was carried out as a basis for the design of a monitoring plan for water quality entering the estuary. The area under cultivation was determined by interpreting satellite images for a total of approximately 10,000 ha of Oryza sativa rice and 31,000 ha of Elaeis guineensis oil palm. Agrochemical use was estimated based on published secondary information and surveys administered to producer groups. The estimated annual use of pesticides was 20.4 kg ha-1 in rice and 6.6 kg ha-1 in oil palm, and 840 kg ha-1 year-1 of granular fertilizers in both crops. In addition, pesticide residues in water, sediment and fish were sampled by gas chromatography coupled to mass spectrometry and liquid chromatography with diode array detector. The herbicide clomazone was detected in all water samples. In addition, the insecticide triazophos and the fungicides isoprothiolane and propiconazole were detected in the Coto Colorado sub-basin, which covers 95% of the total agricultural area draining into the gulf. The extension and management of agricultural plantations in the Golfo Dulce watershed, together with environmental factors, could represent a threat to the estuarine resources. Therefore, it is recommended that water quality in the rivers be monitored and that riparian forest restoration programs be initiated as a mitigation measure.
Descripción
Palabras clave
ARROZ, CALIDAD DEL AGUA, CULTIVOS (AGRICULTURA), GOLFO DULCE (COSTA RICA), PALMA ACEITERA