Occurrence of current-use pesticides in sediment cores from lakes and peatlands in pristine mountain areas of Brazilian national parks.

This study assessed the occurrence of current-use pesticides in sediment cores from six lakes and peatlands in high-altitude (1952-2374 m) pristine areas within two southeastern Brazilian National Parks: Itatiaia National Park (IT-NP) and Serra dos Órgãos National Park (SO-NP). We sampled three sediment cores from lakes at IT-NP and three from peatlands at SO-NP, totaling 60 subsamples. Among the 38 current-use pesticides assessed, 17 were found in at least one sample, with 14 - including herbicides, insecticides, fungicides, and acaricides - identified in both parks. The most frequently detected pesticides were carbendazim and carbaryl (75-95%), followed by acetochlor, chlorpyrifos, diuron, metolachlor and tebuconazole (40-70%) and, to a lesser extent, terbuthylazine and malathion (10-30%). The organophosphates disulfoton (6.83 ± 20.18 ng g-1 dry weight) and chlorpyrifos (4.34 ± 6.81 ng g-1 dw) registered the highest concentrations across all compounds in the sediment layers, with chlorpyrifos showing the greatest relative abundance (65.9-92.8%) in four out of six sites. Risk characterization results revealed highest risk quotient (RQ) values (416-14,589) for chlorpyrifos, indicating potential ecological risks. High RQs were also obtained for acetochlor (5.76-94.6), carbaryl (0.4-4.08), carbendazim (0.09-3.46), diazinon (2048), disulfoton (34-569), diuron (1.45-35.0) and malathion (10.94). These results highlight the threat posed by long-range pesticide transport to pristine areas at National Parks. Urgent regulatory measures are needed to mitigate their impact and safeguard these ecosystems from degradation.