Element Concentrations in Some Species of Seaweeds from La Paz Bay and La Paz Lagoon, South-Western Baja California, Mexico

Abstract

La Paz Bay and La Paz Lagoon are water bodies of the Gulf of California that are influenced by waste water discharges from the City of La Paz and from activities of the phosphorite mining company "Rofomex". Because seaweeds concentrate elements from the water and are used as effective indicators of contamination by metals, we investigated their usefulness in this region. Concentrations of certain major elements (Ca, Fe, K and Na) and trace elements (As, Ba, Co, Cr, Cs, Hf, Rb, Sb, Sc, Se, Sr, Ta, Th, U, Zn and Zr) were determined in 12 species of seaweeds from La Paz Bay and La Paz Lagoon using instrumental neutron activation analysis. The contents of trace elements of environmental importance (As, Co, Cr, Fe, Sb, Se and Zn) in all studied samples are within the range of typical levels for a pristine environment not subjected to anthropogenic impact. Somewhat higher concentrations of Cr (81 mg kg −1 ), Hf (4 mg kg −1 ), Rb (48 mg kg −1 ), Sc (6.3 mg kg −1 ), Ta (0.95 mg kg −1 ), Th (6.8 mg kg −1 ), U (33 mg kg −1 ) and Zn (90 mg kg −1 ) were found in the green seaweed species Ulva (formerly Enteromorpha) intestinalis, whereas such elements as As (77 mg kg −1 ), Sb (1.4 mg kg −1 ) and Se (1.8 mg kg −1 ) were mainly concentrated in the species Sargassum sinicola, Codium cuneatum and Padina mexicana respectively. Because of their higher abundance and heterogeneity in elemental composition the seaweeds species Ulva intestinalis and Caulerpa sertularioides seem to be more suitable for further biomonitoring of heavy metal pollution of the coastal waters in this zone.

Heavy metals dynamics in seaweeds and seagrasses in Bahía Magdalena, B.C.S., México

“…We found significant spatial and temporal variations in heavy metal concentrations in marine plants as previous spatial studies has shown in the region (Páez-Osuna et al 2000;Sánchez-Rodríguez et al 2001;Rodriguez-Castañeda et al 2006, Rodríguez-Meza et al 2008 (Zaytsev et al 2003). These levels of Cd in seaweeds has not been observed in the Gulf of California studied populations but strong species and spatial variations where observed (Páez-Osuna et al 2000;Sánchez-Rodríguez et al 2001;Rodriguez-Castañeda et al 2006).…”

“…These levels of Cd in seaweeds has not been observed in the Gulf of California studied populations but strong species and spatial variations where observed (Páez-Osuna et al 2000;Sánchez-Rodríguez et al 2001;Rodriguez-Castañeda et al 2006). The differences in heavy metal concentrations that we found in the seaweeds did not generally correspond with patterns of those elements previously observed in the sediment from the same region or seaweed species (Rodríguez-Meza et al 2008), contrary to the studied sites in the Gulf of California near a mine (Rodriguez-Castañeda et al 2006) or near industrial ports (Páez-Osuna et al 2000;Sánchez-Rodríguez et al 2001;Rodriguez-Castañeda et al 2006). This finding, together with the observed species differences, suggests that the metabolic condition and lifecycle stage of the individual species might influence metal uptake and accumulation (Lobban and Wynne 1981).…”

“…The process of metal bioaccumulation in marine food chains is poorly understood because very little data is available on metal concentration at different trophic levels (de la Lanza et al 1989;Talavera-Saenz et al 2007) or their temporal (Abdallah et al 2006;Rodriguez-Castañeda et al 2006) or spatial variation (Kalesh and Nair 2006) and their effects on the photosynthetic process (Catriona et al 2002). Previous studies in Magdalena Bay, Mexico (Méndez et al 2002;Gardner et al 2006) have found high concentrations of metals in marine vertebrates, despite the lack of obvious anthropogenic sources.…”

Chemical composition of cultivated seaweed Ulva clathrata (Roth) C. Agardh

“…Previous As values reported for other ulvales fluctuated on the same levels (1.1-16 mg kg À1 dw) and were reported to be non-toxic for human health (Pérez et al, 2010;Rodrí-guez-Castañeda et al, 2006). Lead concentration ranged between 1 and 3.5 mg kg À1 dw; these values were lower than those reported in other ulvales studies (Mohamed & Khaled, 2005;Orduña-Rojas & Longoria-Espinoza, 2006 (Paez-Osuna et al, 2000;Rodríguez-Castañeda et al, 2006). Ni concentrations among samples varied from 2.37 to 5.72 mg kg À1 dw, being higher in the LSS samples but consistent with values reported by and Paez-Osuna et al (2000).…”

“…A higher Ca content was observed in Ulva produced in shrimp ponds (LSS samples) than MSS samples (average 10 vs 19 g kg À1 dw). Nevertheless, Ca content in cultivated U. clathrata was lower than those reported for E. intestinalis (25 to 122 g Ca kg À1 ) collected in the La Paz bay and lagoon in Baja California México (Rodríguez-Castañeda, Sánchez-Rodríguez, Shumilin, & Sapozzhnikov, 2006) and also lower than values reported by for other ulvales (26 to 47 g Ca kg…”