Oscar Amin

Biomarkers and heavy metal bioaccumulation in mussels transplanted to coastal waters of the Beagle Channel.

Mussels coming from a mussel farm at Brown Bay (Beagle Channel) were transplanted to four sites inside Ushuaia Bay for 2 and 4 weeks. The objective of this study was to assess the quality of coastal waters of Ushuaia Bay by measuring catalase activity, lipid peroxidation, total lipid content, bioaccumulation of heavy metals and condition index in transplanted mussel Mytilus edulis chilensis. Biomarkers except condition index showed significant differences among exposure times as well as among tissues. Digestive gland presented the highest catalase activity, malondialdehyde level and total lipid content. Digestive gland also was the main target tissue of accumulation of iron and copper, while gill accumulated the highest levels of zinc. A principal component analyzes with the whole set of data allowed to separate stations based on physicochemical conditions and biochemical responses of each studied area.

Heavy metal concentrations and biomarkers of oxidative stress in native mussels (Mytilus edulis chilensis) from Beagle Channel coast (Tierra del Fuego, Argentina).

The aim of this study was to evaluate the usefulness of oxidative stress biomarkers of pollution in native mussels Mytilus edulis chilensis from the Beagle Channel. Spatial and seasonal variations of catalase, glutathione-S-transferase and lipid peroxidation in gills and digestive gland were analyzed in relation to environmental parameters, heavy metals in sediment and in tissue. Four sites with anthropogenic impact and a control site were selected and monitored during the four seasons of 2007. We found significant differences among sites in concentrations of dissolved nutrients and heavy metals in sediments, with the highest values recorded at sites with anthropogenic pressure. Different patterns were observed between concentrations of metals in tissues and in sediments suggesting differences in bioavailability. There were also significant differences in biomarker responses among sites, despite the strong seasonal variability. Our results showed relatively moderate levels of pollution in the study area as a result of urban influences.

Heavy metal concentrations in litteral sediments from the Beagle Channel, Tierra del Fuego, Argentina

For the first time the concentration of trace metals (Fe, Pb, Cu, Zn, Cd and total Hg) of sediments from the coastal zone of the Beagle Channel (Tierra del Fuego, in Southern Argentina) were measured. Atomic absorption spectrophotometry was utilized in order to determine the metal contents. The level of metals as observed in the sediments was recognized as the natural background, even though the use of normalization of lead, copper, and zinc to iron allowed the identification of the main sources of metal pollution for this environment. In order to develop future environmental monitoring programmes for the area of Ushuaia city and the Beagle Channel, the present results need to be considered.

Heavy metals monitoring in the southernmost mussel farm of the world (Beagle Channel, Argentina).

Water quality surrounding the mussel farm of Mytilus edulis chilensis at Brown Bay (Beagle Channel) was evaluated. The levels of five heavy metals in sediment and in gill and digestive gland of mussels were examined to consider potential risks to human health. Cd showed the highest enrichment factor in relation to its level in Earth crust (3.85-21.58), which could be related to an upwelling phenomenon. A seasonal trend was found regarding metal bioaccumulation, being higher in winter than in summer. The bioaccumulation pattern in gill was Zn>Fe>Cu>Cd, meanwhile in digestive gland was Fe>Zn>Cu>Cd. Despite Pb was measured in sediment (15.59-23.91 microg/g dw), it was not available for being incorporated by mussels. In all cases it was below the detection limit (2.37 microg/g dw). With regard to human consumption of mussels from Brown Bay, none of the elements analyzed should cause concern for consumers. Values measured in tissue mussels were below the limit of 10 microg/g dw for Cd and Pb established by SENASA for molluscs. Considering that studied mussels are for human consumption and the relatively high levels of metals in sediment may vary their availability if physical parameters changes, periodical monitoring must be carried out to avoid human risks and to produce food in a responsible manner that complies with the food safety standards.

Assessment of recent sediment influence in an urban polluted subantarctic coastal ecosystem. Beagle Channel (Southern Argentina).

In this study, baseline information about the environmental status of Ushuaia (UB) and Golondrina (GB) bays is presented. Surface and bottom seawater and freshwater discharged from land were evaluated. Multivariate analysis identified different water quality zones within the bays, two of them located next to the north and northwest coastlines of UB, where the majority of human activities are developed. Porosity, total organic matter, biochemical components, ammonium, and phytopigments were determined in sediment samples from each quality zone. Benthic fluxes of nutrients and dissolved oxygen were assessed in situ using opaque chambers. In northwest zone of UB, carbon equivalents of proteins and carbohydrates in surficial sediments were the same order as in hypertrophic ecosystems, whereas ammonium and phosphate released from sediment greatly exceeded the allochthonous sources. Management of municipal wastewater is required to remediate this chronic pollution.

Starvation effects on physiological parameters and biochemical composition of the hepatopancreas of the southern king crab Lithodes santolla (Molina, 1782)

Este estudio evalua los efectos del ayuno en la centolla Lithodes santolla. Machos adultos de la centolla fueron mantenidos en condiciones de ayuno durante 12 dias. Cada 3 dias (i.e., 0, 3, 6, 9 y 12 dias) se evaluo en subgrupos el consumo de oxigeno, la excrecion de amonio, la relacion atomica O:N y la composicion bioquimica del hepatopancreas. El indice hepatosomatico (calculado individualmente como el porcentaje del peso humedo del hepatopancreas en relacion al peso humedo total del individuo) fue menor a 12 dias de ayuno, coincidiendo con el menor contenido de proteinas en el hepatopancreas. No se detectaron diferencias significativas en la composicion bioquimica porcentual (contenido de agua, materia organica y cenizas). El contenido lipidico no fue significativamente diferente durante el experimento aunque el mayor valor fue registrado a los 3 dias de ayuno. Entre los 3 y 9 dias de ayuno, la excrecion de amonio y el contenido de proteinas en el hepatopancreas fue mayor y la actividad enzimatica de tripsina, menor. Esto podria indicar que el catabolismo de proteinas fue el mas importante durante ese periodo. Este hecho tambien se confirma por los bajos valores de O:N detectados en el periodo mencionado. A los 9 dias de ayuno se incremento el consumo de oxigeno, acompanado con un alto valor de excrecion de amonio, originados probablemente por una demanda extra de energia producida por el ayuno. Se concluye que L. santolla para estos rangos de tiempo experimental utiliza proteinas como fuente primaria de energia.

Organotin compounds in sediments of three coastal environments from the Patagonian shore, Argentina

One of the most toxic compounds that have been introduced into the marine environment is Tributyltin (TBT) used as a biocide in antifouling paints. The aim of this study was to obtain the first information of TBT pollution in sediments of three environments of the Argentinean coastline. Sediments from the Bahia Blanca estuary, San Antonio Bay and Ushuaia Bay were sampled to determine TBT and dibutyltin (DBT) concentration. The butyltin compounds were identified and quantified by gas chromatography and mass spectrometry (GC?MS). The different amount of organotin compounds detected shows dissimilar pollution levels and degradation processes along the Argentinean coasts.

Use of biomarkers in resident organisms as a tool for environmental monitoring in a cold coastal system, Tierra del Fuego Island.

Antioxidant status of Nacella (P) magellanica and Mytilus edulis related with heavy metal in sediment and tissues were analysed in five stations close to Ushuaia city in winter and spring. The principal component analysis produced a two-dimensional pattern of the degree of similarity between sites. The Industrial-Urban Contamination Index (IUCI) showed that the Industrial Zone (IZ) and Oil Marine Station (OMS) represent areas with anthropic inputs. Heavy metals have differential association with biomarkers depending on the species. In limpets, digestive gland presented major activities of enzyme defence in winter and gonads have shown higher values of Catalase (CAT) during spring while lipid peroxidation (LPO) presented higher values in IZ. For mussels CAT and LPO increased in spring time. For superoxide dismutase (SOD) peaks have been detected in IZ and NW stations for winter. Differences in biomarker responses due to seasons did not influence the grouping of the sites into references and contaminated groups.

Biochemical response of amphipods (Gammarid: Paramorea) in a sediment laboratory exposure from Ushuaia Bay, Beagle Channel.

A coastal system (Ushuaia Bay, Argentina) impacted by anthropogenic activities was studied by the response of local amphipods (Parmorea sp., Gammaridae) to the exposure of coastal sediments in a laboratory assay. Four coastal areas with different loadings of contaminants and one considered as reference were studied. Organic matter, carbohydrates, proteins and heavy metals were measured in sediment samples. Organisms were exposed to sediments for seven days and catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE) and lipid peroxidation (LPO) were measured afterward. Amphipods exhibited an activation of GST and inhibition of AChE in most impacted areas. Principal Component Analysis (PCA) was conducted in order to associate the biological responses with sediment metal concentration and its eutrophicated status. Levels of Cd and Cr were associated with the inhibition of AChE and with the enhancement of GST. CAT and LPO were enhanced in most areas, but no link was found with the contaminants studied by PCA, suggesting that other parameters present in sediments not included in the PCA affect the amphipods. The most impacted area corresponds to Nautical Club station, with a highly eutrophicated status and high content of metals, where amphipods after the exposure were affected in a biochemical level.