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.