Abstract
Mercury (Hg total) fluxes were calculated for rainwater, throughfall and stream water in a small catchment located in the northeastern region of the Brazilian Amazon (Serra do Navio, Amapá State), whose upper part is covered by a natural rainforest and lower part was altered due to deforestation and activities related to manganese mining. The catchment area is 200 km from the nearest gold mining (garimpo). Minimum and maximum Hg concentrations were measured monthly from October 1996 to September 1997 and were 3.5–23.4 ng l −1 for rainwater, 16.5–82.7 ng l −1 for throughfall (March–August 1997) and 1.2–6.1 and 4.2–18.8 ng l −1 for stream water, in natural and disturbed areas, respectively. In the natural area, the inputs were 18.2 μg m −2 year −1 in rainwater and 72 μg m −2 year −1 in throughfall. This enrichment was attributed to dry deposition. The stream output of 2.9 μg m −2 year −1 indicates that Hg is being recycled within the forest as other chemical species or is being retained by the soil system, as confirmed by the cumulative Hg burden in the 0–10 cm surface layer, which was 36 480 μg m −2. When the disturbed area of the catchment was included, the stream output was 9.3 μg m −2, clearly indicating the impact of the deforestation of the lower part of the basin on the release of mercury. The Hg burden in the disturbed area was 7560 μg m −2 for the 0–10 cm surface layer.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.