Accumulation, distribution and cellular partitioning of mercury in several halophytes of a contaminated salt marsh

• Published in: Chemosphere (Oxford) 2009-09, Vol.76 (10), p.1348-1355
• Main Authors: Castro, Rita, Pereira, Sofia, Lima, Ana, Corticeiro, Sofia, Válega, Mónica, Pereira, Eduarda, Duarte, Armando, Figueira, Etelvina
• Format: Article
• Language: English
• Subjects: Amaranthaceae - metabolism; Animal, plant and microbial ecology; Applied ecology; bioaccumulation; Biological and medical sciences; cell membranes; cell walls; Cellular; Communities; Contamination; cytochemistry; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Environmental Monitoring; Environmental Restoration and Remediation; Fundamental and applied biological sciences. Psychology; Halimione portulacoides; halophytes; Juncus; Juncus maritimus; Marine and brackish environment; Mercury; Mercury - analysis; Organs; Partitioning; Plant community; Plant Roots - metabolism; Plant Stems - metabolism; roots; Salt marsh plants; Salt marshes; Salt-Tolerant Plants - metabolism; Sarcocornia perennis; Sediments; shoots; Soil Pollutants - analysis; species differences; Strategy; Translocation; translocation (plant physiology); Triglochin maritima; water pollution; Wetlands
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2009.06.033

This work evaluates the role of a plant community in mercury (Hg) stabilization and mobility in a contaminated Portuguese salt marsh. With this aim, the distribution of Hg in below and aboveground tissues, as well as the metal partitioning between cellular fractions (soluble and insoluble) in four different species ( Triglochin maritima L., Juncus maritimus Lam, Sarcocornia perennis (Miller) A.J. Scott, and Halimione portulacoides (L.) Aellen) was assessed. Mercury accumulation, translocation and compartmentation between organs and cellular fractions were related to the plant species. Results showed that the degree of Hg absorption and retention was influenced both by environmental parameters and metal translocation/partitioning strategies. Different plant species presented different allocation patterns, with marked differences between monocots ( T. maritima and J. maritimus) and dicots ( S. perennis, H. portulacoides). Overall, the two monocots, in particular T. maritima showed higher Hg retention in the belowground organs whereas the dicots, particularly S. perennis presented a more pronounced translocation to the aboveground tissues. Considering cellular Hg partitioning, all species showed a higher Hg binding to cell walls and membranes rather than in the soluble fractions. This strategy can be related to the high degree of tolerance observed in the studied species. These results indicate that the composition of salt marsh plant communities can be very important in dictating the Hg mobility within the marsh ecosystem and in the rest of the aquatic system as well as providing important insights to future phytoremediation approaches in Hg contaminated salt marshes.