In situ toxicity and ecological risk assessment of agro-pesticide runoff in the Madre de Dios River in Costa Rica

Abstract

The River Madre de Dios (RMD) and its lagoon is a biodiversity rich watershed formed by a system of streams, rivers, channels, and a coastal lagoon communicating with the Caribbean Sea. This basin sustains a large area of agricultural activity (mostly banana, rice, and pineapple) with intensive use of pesticides, continually detected in water samples. We investigated in situ the toxicological effects caused by pesticide runoff from agriculture and the relation of pesticide concentrations with different biological organization levels: early responses in fish biomarkers (sub-organismal), acute toxicity to Daphnia magna (organismal), and aquatic macroinvertebrate community structure. The evaluation was carried out between October 2011 and November 2012 at five sites along the RMD influenced by agricultural discharges and a reference site in a stream outside the RMD that receives less pesticides. Acute toxicity to D. magna was observed only once in a sample from the RMD (Caño Azul); the index of biomarker responses in fish exposed in situ was higher than controls at the same site and at the RMD-Freeman. However, only macroinvertebrates were statistically related to the presence of pesticides, combined with both physical-chemical parameters and habitat degradation. All three groups of variables determined the distribution of macroinvertebrate taxa through the study sites.

Evaluación preliminar del área agrícola y su influencia sobre la calidad del agua en el Golfo Dulce, Costa Rica

“…En otras áreas tropicales del Pacífico occidental, se ha estudiado la pérdida del bosque de ribera causada por el cultivo de palma aceitera y los efectos sobre los cuerpos de agua (Sheaves et al, 2018). En esta evaluación preliminar de la agricultura en la cuenca del Golfo Dulce, se determinó la extensión de dos monocultivos: arroz y palma aceitera, de uso medio y bajo de plaguicidas respectivamente, en contraposición a otros de alto insumo como banano y piña, sembrados en otras regiones del país (Echeverría-Sáenz et al, 2018). No obstante, se logró detectar, en un único muestreo, residuos en el agua de las desembocaduras de los ríos.…”

Early Toxic Effects in a Central American Native Fish (Parachromis dovii) Exposed to Chlorpyrifos and Difenoconazole

“…Certain unsuitable agricultural practices, combined with the rainy weather in some areas of the country, with up to 4500 mm/yr (Instituto Meteorológico Nacional 2020) in regions of intensive agriculture, favor the transport of these substances toward aquatic environments by drift, runoff, or leaching. In these ecosystems, pesticide residues may become bioavailable to nontarget species such as fish or macroinvertebrates, which may be exposed and suffer toxic effects (Echeverría-Sáenz et al 2018).…”

What are the Main Sensor Methods for Quantifying Pesticides in Agricultural Activities? A Review

“…Not surprisingly, the highest percentage by volume of imported pesticides in Costa Rica is used in the banana agroindustry, particularly fungicides and insecticides, which are intensively used to prevent Black Sigatoka and other diseases. Approximately 76 kg of active pesticide ingredients (i.e., fungicides, nematicides-insecticides and herbicides) are applied annually per hectare in the banana agroindustry [10]. Some quantities of the main pesticides used in Costa Rica are shown in Table 1.…”

“…According to the Maximum Tolerable Risk (MTR), the surface water for ethoprophos and chlorpyrifos is on the order of 0.063 and 0.003 µg/L. High pesticide residues were detected in surface water samples, in the surroundings of the banana plantations of Costa Rica, in higher levels than those allowed for ethoprophos and chlorpyrifos, i.e., between 1.5 and 0.7 µg/L, respectively [10].…”