Elemental composition of marine sponges from the Berlengas natural park, western Portuguese coast

Abstract

Analytical studies of sponges have recently become a matter of interest, since these organisms have been reported to accumulate high levels of some elements, including heavy metals, which may have an anthropogenic origin, allowing their application as environmental pollution indicators. In the present work, 35 sponges collected in August 1998 at the Berlengas Natural Park were classified and analysed by secondary target energy-dispersive x-ray fluorescence spectrometry (EDXRF). Some major, minor and trace elements could be determined: Al, Si, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Zr, I and Pb. To assess some local influences on the sponge composition, two sediment samples were also taken from the area and analysed. Besides these elements, sponges are constituted by fairly high percentages of elements that do not emit characteristic x-ray lines. Therefore, absorption corrections for quantitative calculations were carried out taking into account the ratio between the inelastic and elastic scattered incident radiation from a silver secondary target to calculate the mean atomic number of the light matrix. Calibration was performed using chemical compounds and standard reference materials. Precision, accuracy and detection limits for the range of elements determined by the method are particularly suitable for the chemical analysis of these organisms. Results for the sediment chemical composition indicated the existence of high Ca and low Si levels and confirmed the absence of any trace metal contamination in the region. The sponge composition showed low Si contents, even in siliceous specimens. Certain high elemental contents determined in some species indicated a clear selective bioaccumulation of particular trace elements, such as Ni, Zn and As, which is not dependent on local influences.

Trace metal concentrations in the tropical sponge Spheciospongia vagabunda at a sewage outfall: synchrotron X-ray imaging reveals the micron-scale distribution of accumulated metals

“…and Halichondria phakellioides, Padovan unpublished data). Arsenic, copper, lead, manganese, silicon and sulphur levels in S. vagabunda were in the range reported for other sponge species (Patel et al, 1985;Verdenal et al, 1985;Araújo et al, 1999Araújo et al, , 2003Denton et al, 1999;Rao et al, 2009). Phosphorus was present at 703-1,760 ppm in sponge tissue (no published values could be found for comparisons).…”

“…Cobalt concentrations have received relatively little attention, with published values ranging from below detection limits to 50 ppm (Bowen & Sutton, 1951;Patel et al, 1985;Rao et al, 2006Rao et al, , 2009. High iron content has been reported in Spongia agaricina, Ircinia fasciculata, Cacospongia scalaris and Spongia officinalis (Verdenal et al, 1985;Vacelet et al, 1988;Araújo et al, 1999Araújo et al, , 2003 and has been attributed to incorporation of iron into spongin fibres. Suberites carnosus also had high iron content but in this species, the iron was due to incorporation of sediment particles (Araújo et al, 1999).…”

Copper, zinc and lead impact in SW Iberian shelf sediments: An assessment of recent historical changes in Guadiana river basin

“…The precision is better than 10% for most of the elements. A detailed description of the sample preparation, quantitative analysis as well as the accuracy and precision of the overall procedure has been previously published (Araújo et al, 2003).…”

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“…(2003) reported that ability of marine sponge in accummulating heavy metals depends on the metal types (Mn, Fe, Ni, Cu, Zn, As, Sr, Zr and Pb, etc.) (Araujo et al 2003). Olesen at al.…”