Phytoremediation of landfill leachate with Colocasia esculenta, Gynerum sagittatum and Heliconia psittacorum in constructed wetlands

This study assessed the accumulation of Cd (II), Hg (II), Cr (VI) and Pb (II) in Gynerium sagittatum (Gs), Colocasia esculenta (Ce) and Heliconia psittacorum (He) planted in constructed wetlands treating synthetic landfill leachate. Sixteen bioreactors were operated in two experimental blocks. Metal concentrations in the influent and effluent; root, stem, branch and leaves of plants were analysed, as well as COD, N-NH4+, TKN, T, pH, ORP, DO, and EC. Average removal efficiencies of COD, TKN and NH4+-N were 66, 67 and 72%, respectively and heavy metal removal ranged from 92 to 98% in all units. Cr (VI) was not detected in any effluent sample. The bioconcentration factors (BCF) were 100 -102. The BCF of Cr (VI) was the lowest: 0.59 and 2.5 (L kg−1) for Gs and He respectively; whilst Cd (II) had the highest (130–135 L kg−1) for Gs. Roots showed a higher metal content than shoots. Translocation factors (TF) were lower, He was the plant exhibiting TFs >1 for Pb (II), Cr (T) and Hg (II) and 0.4–0.9 for Cd (II) and Cr (VI). The evaluated plants demonstrate their suitability for phytoremediation of landfill leachate and all of them can be categorized as metals accumulators

Mangrove timber use as an ecosystem service in the Colombian Pacific

Mangroves provide ecosystem services for local communities. However, in coastal systems it is yet unknown how human settlements are directly interacting with mangroves. We assessed the use of mangroves as an ecosystem service at Málaga and Buenaventura bays, on the Colombian Pacific coast, by interviewing local communities and examining the impact of mangrove harvest on the structure of the forest, an often overlooked effect. Results showed that mangroves are mainly harvested for their wood. Rhizophora spp. are the main source of wood for fuel purposes, whereas Mora oleifera (Triana ex Hemsl.) Ducke, a mangrove associate, provides 100% of the wood used for the construction of stilt houses. The selective extraction of these species has altered the composition and structure of the forest. Sample sites undergoing harvest have relatively low densities of mangroves; however, one site at Quebrada Valencia shows signs of copious regeneration (>9000 seedlings/ha). Due to the importance of mangroves for the subsistence of coastal communities, and the threat that mangroves are exposed to in Colombia, the management of mangroves should be a priority. Managers must address the sustainability of critical species as part of conservation strategies in order to maintain ecosystem services for local communitie