Attenuation of insecticide impact by a small wetland in a stream draining a horticultural basin, Argentina

SOLIS M; CAPPELLETTI N; BONETTO C; FRANCO M; FANELLI S.L.; AMALVY J; MUGNI H

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2021 vol. 785

0048-9697

Horticulture has greatly increased in Argentina in recent decades mainly due to increasing greenhouse utilizationand agrochemical consumption, thus representing a threat to adjacent water bodies. Riparian wetlands, however,could attenuate agrochemical contamination. The present work therefore compared insecticide concentrations inbottom sediments in addition to sediment toxicity to the amphipod Hyalella curvispina and investigated the macroinvertebrate composition upstream and downstream from a natural wetland in a small stream draining a basinundergoing intense horticultural production. The wetland surface was covered by macrophytes, mainly Thyphasp., and the insecticide concentrations measured downstream from the wetland were significantly lower, atroughly 19% of the upstream values. The growth rates of H. curvispina were significantly higher when exposedto the sediments downstream from the wetland, while the macroinvertebrate-assemblage composition was significantly different upstream and downstream: the snail Pomacea canaliculata was the dominant species upstream while the amphipod H. curvispina was dominant downstream. Pomacea canaliculata is often thedominant species in the regional streams draining agriculture and horticultural basins. Hyalella curvispina is sensitive to pesticide toxicity and is often dominant in streams draining extensive livestock basins and within a biosphere reserve. We conclude that riparian wetlands effectively attenuate horticulture contamination in pampeanstreams and should therefore be preserved and restored.