Vertical distribution of al, cu, fe and zn in the soil salt marshes of the Sado estuary, Portugal

Abstract

The vertical distribution of Al, Cu, Fe and Zn in the soil salt marsh of the river Sado estuary was studied. The results obtained by an acid digestion procedure, indicate that the mean values at the first sampling point (near the Atlantic Ocean and very close to a populous city) are lower when compared with those found at the other Stations (approximately 8.0 and 20.0 km upstream), where they are very similar. These findings are related to the different nature of the soil matrix (essentially sand at Station 1 and silt-clay at Station 2 and 3), and the reduced availability of the sandy fraction to bind trace metals. A correlation analysis for all the metals in different soil cores indicate that the correlation values at Station 1 are, generally, not significant at a 0.05 significance level.

Trace metal content of live tissues inhalimione portulacoidesfrom coastal areas of the Sado estuary, Portugal

“…These findings can be due to thesimilar nature of the soil marsh, 11 and the similar growth state of the studied species. In Station 1 the species lives about 15.0 m from the low tide line and the root system is present in an essentially sandy matrix, while in the other sampling points a very high silt-clay fraction is observed and the species lives near the drainage channels.…”

“…Soil water retention in the first sampling point is much lower as indicated by the water content (percent of dry weight) of different cores, 11 and pore waters of soil marsh cannot probably develop high concentrations of metals, as stated by Elderfield and Hepworth, 1;> nor important amounts of essential nutrients. On the other hand, the concentration of trace metals in different soil cores from Station 1 is much lower when compared with those found in the other Stations.…”

“…In Station 1 the species lives about 15.0 m from the low tide line and the root system is present in an essentially sandy matrix, while in the other sampling points a very high silt-clay fraction is observed and the species lives near the drainage channels. 11 Beeftink etal. 14 have reported differences in the Cu content of Halimione portulacoides collected at different salt marsh levels (based upon tidal submergence).…”

Nutritional profile of the Portuguese cabbage (Brassica oleracea L var. costata) and its relationship with the elemental soil analysis

“…These findings are probably related with the chemical speciation of soil nutrients and the variable degree of solubility/insolubility of some elements, mainly a function of soil pH. Iron, for example, although abundant in soils is predominantly in the highly insoluble form Fe(OH)3 (Reboredo and Ribeiro, 1984), while the solubility of silicic acid is of the order of 100 ppm at near-neutral pH, rising considerably above pH 9.0 due to silicate ion formation (Birchall, 1978). Thus, with the current soil pH values (between 7.7 and 8.2) the Si uptake is favored compared with the Fe uptake.…”

Impact of human activities on coastal vegetation ? A review

“…In that sense, several studies have been undertaken in different coastal world areas, in order to evaluate the PCBs, PAHs and heavy metal contamination degree of fauna, flora and substrata. For example, in Portugal mainland, estuarine sediments of Tejo River (Reboredo, 1981;Reboreda and Caçador, 2007), Sado River (Reboredo and Ribeiro, 1984;Reboredo, 1988) Ria Formosa Lagoon (Padinha et al, 2000) Ria de Aveiro Lagoon (Ramalhosa et al, 2005) and Lima River (Almeida et al, 2011), were monitored in terms of their metal content.…”