Luis Felipe Hax Niencheski

Trace Metal Content Trend of Mussel Perna Perna (Linnaeus, 1758) from the Atlantic Coast of Southern Brazil

The concentration assessment of Hg, Pb, Cd, Cu, Zn, Cr, Mnand Fe in marine mussels Perna perna, sampled at 15stations along the 800 km Southern Brazilian Coast, has beencarried out. Samplings were taken twice, in summer andwinter of 2000. The concentrations found were lower thansimilar studies carried out along the Central Coast of Brazil andlower than the maximum limits permitted in bivalve molluscsdesignated for human consumption (Brazilian, Spanish andLuxembourg legislation sets). The data also showed lowervalues compared with other regions of the world. Thecomparison of present data with the data obtained 10 years agoat the same stations did not show significant differences,consequently the concentrations found could be used asbaseline values.

Litter contamination processes and management perspectives on the southern Brazilian coast

Beach litter contamination has been reported internationally as a major coastal issue needing evaluation for management strategies. The extent of contamination by litter has been assessed throughout a 12-month field investigation at Cassino beach, a long and wide sandy beach of great ecological importance and a major resort area of the southern Brazilian coast. This has been the first systematic study on the subject, and followed the IOC/FAO/ UNEP (1989) methodological guidelines. Further to the results identifying the most contaminated areas and times of the year and characterising the major components and likely sources of the litter collected, this study provides for estimations on the litter accumulated over Cassino beach on a global perspective, and refers to existing and future management perspectives. Although the main problem appeared to be waste left by beach-goers during summer, results also suggest that year-round inputs from other sources should not be neglected, and point to the need for prevention and control measures under an integrated approach to management.

Lithium as a normalizer for the assessment of anthropogenic metal contamination of sediments of the southern area of Patos Lagoon

In order to compare their usefulness, various approaches were used for the assessment of the natural background of metals in sediments of the Southern end of Patos Lagoon, Brazil. Lithium and aluminum were chosen as the most appropriate normalizers for the sampling sites because iron demonstrated elevated values, particularly in the harbor. A strong correlation of Li with Al was observed, which confirmed the presence of pegmatite in the studied area which is rich in Li minerals. Using Li as a normalizer and applying an enrichment factor, cadmium presented elevated results, mainly in the harbor, probably due to 25 years of activity of a fertilizer complex, which uses raw material enriched with Cd up to 100 times the regions natural background.

The effect of accidental sulphuric acid leaking on metal distributions in estuarine sediment of Patos Lagoon

In August of 1998 the tanker BAHAMAS belonging to the Chem Oil Company containing 12,000 t of concentrated sulphuric acid, had an accident on board, after which estuarine water entered one of the compartments of the tanker, resulting in a vigorous exothermic reaction. The reaction of acid with the metallic interior hull of the ship and the accompanying heat and H2 production resulted in an imminent risk of explosion. To avoid an explosion, given the fact that neutralization was not possible, some of the cargo was discharged into the surrounding water. Neutralization was done in January 1999, after the acid concentration in the tanker had decreased and the concentrations of Fe, Cr and Ni remained elevated. Metal concentrations in bottom sediments showed significant modifications. Leached mercury migrated and redeposited downstream, reaching approximately 76 times the background values. Such an anomaly has a well expressed barrier character. The mechanism for redeposition of Hg and other metals probably followed the pattern: Downstream as a result of dilution and mixing with seawater the pH of acid-water increases, favouring adsorption and/or precipitation of metals. The leading edge of a geochemical barrier, at positions 7-9 of sampling sites (Fig. 1), is confirmed by pH variations in the water. The reestablishment of normal pH occurred after a short time due to the high buffering capacity of seawater and large natural dilution process. The concentration of metals in estuarine water during and after the accident showed insignificant anomalies.

Nutrients and Suspended Matter Behaviour in the Patos Lagoon Estuary (Brazil)

Estuaries are distinctive environments where continental runoff interacts with sea water. They are characterized by complex and usually strong circulation and this, along with the typically shallow depths of estuarine systems, leads to intense sediment-water interactions. Estuaries are generally also biologically productive.

Influência de um cultivo de camarão sobre o metabolismo bêntico e a qualidade da água

Shrimp farming activities tend to increase the organic matter sedimentation rate, by extreme inputs of excreta products and shrimp food (commercial shrimp diet) into the environment. In certain environmental conditions, the auto-depuration system can be surpassed, generating a high production of nutrients at the sedimentary layer as a result of benthic metabolism intensification. Consequently the system can be induced to a eutrophication processes and anoxia. In the present study, in situ incubations with transparent and opaque chambers have been used to evaluate the benthic metabolism in semi-intensive shrimp farming areas in the Patos Lagoon Estuary (pen enclosures). Existence of clear interference of the cultivation in the processes of benthic regeneration of nutrients was evident, resulting in increases of phosphorus (phosphate) and nitrogen (in the ammonium form) fluxes. Even considering that this activity has a local and temporary distribution (only 4 to 5 months of the year), it is important to call attention to the sediment oxygen consumption and the input of nutrients deriving from the regeneration of organic matter, which is enhanced in shallow waters and restricted circulation areas (such as small bays), locations where shrimp cultivation is developed in the Patos Lagoon Estuary.

History of human activity in coastal southern Brazil from sediment

This study reports results of analysis of sediment cores collected from the Patos Lagoon estuary. This estuary receives materials from land runoff into Patos and Mirim lagoons and from exchange with the adjacent South Atlantic Ocean through a narrow inlet. Sediment from these sources is mostly natural, but additional contributions associated with source/activities related to the port of Rio Grande. The aim of this study was to estimate rates of accumulation of the sediments and to assess the significance of metal inputs from these activities relative to natural inputs. Our results indicate an average sedimentation rate of 0.3 cm/yr and that the transport of suspended solids from offshore sources into the estuary was enhanced after the deepening of the channel and construction of the breakwaters (in the early 1900). Results for metal accumulation in these sediments suggest that there have been only minor enrichments which can be attributed to anthropogenic sources.

Development and application of methods using SPE, HPLC-DAD, LC-ESI-MS/MS and GFAAS for the determination of herbicides and metals in surface and drinking water

A preliminary study of the pollution in surface and drinking waters caused by herbicides and metals in the Municipal Water Supply System (CORSAN) in Rio Grande city, RS, Brazil, is reported. The occurrence of 5 herbicides and 9 metals was studied in surface and drinking water through the analysis of 2 sampling spots at CORSAN. The analytical determination was performed by solid-phase extraction (SPE), high performance liquid chromatography-photodiode array detection (HPLC-DAD) and liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) for herbicides, and graphite furnace atomic absorption spectrometry (GFAAS) for metals. The concentrations of herbicides in the surface water were very low; however, the herbicide clomazone was detected in more than 50% of the samples analysed in concentration exceeding 1.0 µg L−1. The concentration of metals was below the Maximum Contaminant Level (MCL) set by the Brazilian regulation.

In situ measurement of trace metals in estuarine waters of Patos Lagoon using diffusive gradients in thin films (DGT)

The diffusive gradients in thin-films (DGT) technique was used to determine labile metals in situ during different hydrological conditions in the Patos Lagoon estuary. Water samples were also analyzed for Chelex-labile fractions of Cd, Co, Cu, Mn, Ni and Zn using Chelex-100 resin. DGT-labile concentrations of Cd, Cu, Ni and Zn were lower than Chelex-labile concentrations, possibly because colloids were trapped in the Chelex resin column. There was a decrease with increasing deployment time in the concentrations of all elements measured by DGT, reflecting changes in metal speciation in solution caused by the decrease in the salinity and associated with change in pH in the estuary. The results demonstrated the sensitivity of DGT to metal speciation and the feasibility of using the DGT technique in highly dynamic estuarine waters to obtain a time-integrated record of labile trace metals.

DNA strand breaks in grass shrimp embryos exposed to highway runoff sediments and sediments with coal fly ash

Embryo production was reduced in female grass shrimp exposed to sediments with added coal fly ash and to sediments collected from an estuarine station containing high PAH concentrations due to its proximity to a highway storm drain. Grass shrimp embryos exposed to pore water from the high PAH and high metal sediments showed both reduced hatching and increases in DNA strand breaks (comet assay). Sediments with added coal fly ash had high concentrations of vanadium and selenium which may have contributed to effects similar to those observed with sediments with high PAH. The embryo pore water bioassay (hatching/DNA strand breaks) gave results comparable to those observed for reproduction effects (reduced embryo production/embryo hatching) with female grass shrimp exposed to whole sediment.