W C Pfeiffer

Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil

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Publications (49)111.98 Total impact

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    ABSTRACT: Lignin phenols were measured in the sediments of Sepitiba Bay, Rio de Janeiro, Brazil and in bedload sediments and suspended sediments of the four major fluvial inputs to the bay; São Francisco and Guandu Channels and the Guarda and Cação Rivers. Fluvial suspended lignin yields (Σ8 3.5–14.6 mgC 10 g dw−1) vary little between the wet and dry seasons and are poorly correlated with fluvial chlorophyll concentrations (0.8–50.2 μgC L−1). Despite current land use practices that favor grassland agriculture or industrial uses, fluvial lignin compositions are dominated by a degraded leaf-sourced material. The exception is the Guarda River, which has a slight influence from grasses. The Lignin Phenol Vegetation Index, coupled with acid/aldehyde and 3.5 Db/V ratios, indicate that degraded leaf-derived phenols are also the primary preserved lignin component in the bay. The presence of fringe Typha sp. and Spartina sp. grass beds surrounding portions of the Bay are not reflected in the lignin signature. Instead, lignin entering the bay appears to reflect the erosion of soils containing a degraded signature from the former Atlantic rain forest that once dominated the watershed, instead of containing a significant signature derived from current agricultural uses. A three-component mixing model using the LPVI, atomic N:C ratios, and stable carbon isotopes (which range between –26.8 and –21.8‰) supports the hypothesis that fluvial inputs to the bay are dominated by planktonic matter (78% of the input), with lignin dominated by leaf (14% of the input) over grass (6%). Sediments are composed of a roughly 50–50 mixture of autochthonous material and terrigenous material, with lignin being primarily sourced from leaf.
    Estuarine Coastal and Shelf Science 01/2010; · 2.32 Impact Factor
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    ABSTRACT: The marine ecosystems of Todos os Santos Bay (TSB, The State of Bahia, Brazil) have been impacted by the presence on its coast of a large metropolitan area as well as of chemical and petrochemical activities. Despite its ecological importance, there is a lack of scientific information concerning metal contamination in TSB marine biota. Thus, we analyzed concentrations of metals in four species of marine benthic organisms (two seaweeds, Padina gymnospora and Sargassum sp. one seagrass, Halodule wrightii and one oyster, Crassostrea rhizophorae) in three sites from the TSB region that have been most affected by industrial activities. The concentrations of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined by Atomic Absorption Spectrophometry. The obtained data indicates that cadmium and copper in seaweeds, oysters and seagrass, as well as Ni concentrations in oysters, were in range of contaminated coastal areas. Cadmium and copper are available to organisms through suspended particles, dissolved fraction of water column and bottom sediment interstitial water. As oysters and other mollusks are used as food sources by the local population, the metal levels found in oysters in TSB may constitute a health risk for this population. Our results suggest implanting a heavy metals biomonitoring program in the TSB marine ecosystems.
    Brazilian Journal of Biology 01/2008; 68:95. · 0.64 Impact Factor
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    ABSTRACT: Spanish moss, the epiphyte bromeliad Tillandsia usneoides (in Brazil, “Barba-de-velho”), has been used as biomonitor to evaluate air pollutants. In this article, total Hg concentrations were determined in bromeliads exposed at different areas of a Brazilian chlor-alkali plant while a calibration curve was built under controlled conditions in order to estimate atmospheric Hg concentrations. Hg determinations were performed by atomic absorption spectrometry. In the laboratory, the bromeliad exhibited linear Hg retention (r = 0.99; p < 0.05) when exposed to different Hg concentrations for 15 days under controlled conditions. While Tillandsia usneoides allows simultaneous and continuous monitoring of several workplaces inside a factory, identifying critical areas where workers can be overexposed, we conclude that bromeliad biomonitoring does not appear to be a trustworthy procedure to estimate Hg concentration in the air. However, this just can be a useful method for identifying and monitoring critical sites in continuous occupational and environmental control risk programs.
    Journal of the Brazilian Society of Ecotoxicology. 01/2007; 2:129.
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    ABSTRACT: This work presents quality control results on the mercury concentrations in different environmental (river sediments, forest soils, river suspended matter and fish) and human samples from the lower Madeira River, Amazon sampled between 2001 and 2003, about 15-20 years after the nearly cessation of gold mining activities in the region, which reached its peak in the late 1980s. The study aimed to compare mercury concentrations in these environmental samples with those reported by other authors during the gold rush of the Madeira River Basin. Today, in the Madeira River the releases of mercury register a sudden reduction due the gold price fall in the international trade. However, about 100 t of Hg were released to the atmosphere and to aquatic systems in the region during the gold rush. The present survey shows that notwithstanding the reduction of Hg emissions to the Madeira River Basin from gold mining proper, concentrations in fish and humans are similar to those measured during the gold rush. Reduction in Hg concentrations is restricted to areas close to old point sources and only for abiotic compartments (air and sediments). Remobilization of Hg from bottom sediments plus re-emission from soils due to land use changes are probably responsible for keeping high Hg concentrations in biological samples.
    Science of The Total Environment 10/2006; 368(1):344-51. · 3.26 Impact Factor
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    ABSTRACT: In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.
    Marine Environmental Research 06/2005; 59(4):277-85. · 2.34 Impact Factor
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    M F Rebelo, M C R Amaral, W C Pfeiffer
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    ABSTRACT: The condition index (CI) of oysters represents an ecophysiological approach to estimate meat quality and yield in cultured bivalve mollusks. In the present study, the CI of oysters from a heavy-metal polluted bay was analyzed with respect to Zn and Cd contamination in soft tissues, spawning, and polychaete infestation. The CI was calculated through a new technique based on molds made to measure the volume of oyster-shell internal cavities. The higher CI values (over 9 in the dry season) were probably related availability of suspended particles rich in organic matter in the bay, while the rapid reduction in the CI from one season to the next at some stations suggests the effect of spawning. Polychaete infestation was considered low (18.7%) and produced no clear CI effects. The Cd in the oyster tissue collected during the rainy season was weak, although still significantly correlated with the CI (r = -0.36; p < 0.05). All other comparisons of CI and metal concentrations demonstrated a non-significant correlation. The CI variations observed on the temporal and spatial scale were likely to have been caused by availability of organic matter and spawning, rather than spionid infestation or metal body burdens.
    Brazilian Journal of Biology 05/2005; 65(2):345-51. · 0.64 Impact Factor
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    ABSTRACT: We evaluated the indoor atmospheric Hg contamination in gold trade shops in two Brazilian cities of the Legal Amazon area using the Spanish moss (Tillandsia usneoides, Bromeliaceae) as a sentinel species. Plants inside plastic cages were exposed to a controlled atmosphere to evaluate the rate of Hg retention over time and then distributed in several stores with different characteristics to enable a relative comparison. Hg concentrations were determined by cold vapor atomic absorption spectrophotometry. Plants exposed in active stores with good air circulation exhibited lower levels. Ex-gold trade shops that were kept closed for long periods exhibited higher values. Stores that have been restored before being transformed into new businesses exhibited lower values than nonrestored ones. Direct measurements suggest that indoor Hg air concentrations were below the threshold limit recommended by the World Health Organization to occupational exposure; nevertheless, restoring ex-gold trade shops could ensure a healthier working environment.
    Environmental Research 11/2004; 96(2):235-8. · 3.24 Impact Factor
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    ABSTRACT: A semi-quantitative RT-PCR protocol was developed to directly evaluate metallothionein (MT) mRNA expression in different tissues of mangrove oysters (Crassostrea rhizophorae), using beta-Actin (ACT) as a normalizing gene. Clones with high degree of identity from partial coding sequences were obtained for both MT and ACT. Although not statistically significant, high relative accumulation of MT mRNA was observed in the digestive gland (DGG), but not in the gills, from samples collected from both control and contaminated sites. Nevertheless, MT expression was not comparable to the high levels of metal in the contaminated oysters. Results indicate that the variation in relative MT mRNA levels from different samples of the same site could be due to multiple gene copies or different MT isoform induction.
    Aquatic Toxicology 09/2003; 64(3):359-62. · 3.73 Impact Factor
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    ABSTRACT: Seaweed species from a coastal area contaminated by heavy metals (Sepetiba Bay) in Rio de Janeiro State (Brazil) presented different levels of Zn concentrations. In some species the levels were 20 times higher than that from a noncontaminated area. The present study was undertaken to investigate the capability of different species to tolerate and accumulate zinc. For this purpose six species, Ulva lactuca, Enteromorpha flexuosa, Padina gymnospora, Sargassum filipendula, Hypnea musciformis, and Spyridia filamentosa, were cultivated under laboratory semistatic conditions in five Zn concentrations in seawater, 10, 20, 100, 1000, and 5000 micrograms.liter-1 for a period of 21 days. All species died at 5000 micrograms.liter-1 of Zn, two species (U. lactuca and E. flexuosa) died at 1000 micrograms.liter-1, and one, H. musciformis, died with 100 micrograms.liter-1. The lowest concentration of Zn that presented growth inhibition in the six species was 20 micrograms.liter-1. The brown alga P. gymnospora presented the highest accumulation level of Zn, and H. musciformis the lowest level. The results of tolerance and accumulation under laboratory conditions, associated with field results, indicate the species of Padina and Sargassum as the best species for monitoring heavy metals in tropical coastal areas, and the potential use of their biomass to remove heavy metals from wastewaters.
    Ecotoxicology and Environmental Safety 09/1997; 37(3):223-8. · 2.20 Impact Factor
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    ABSTRACT: Informal economy of gold mining has contaminated some important river basins in Amazon. Follow-up studies on critical compartments showed some areas with high Hg levels in fish as well as in human hair samples. Average Hg in piscivorous fish in the Madeira river itself was 846 ppb (N=284) with a maximum of 3921 ppb. Mercury in fish from non polluted areas in this basin shows high variability, even for single species. A seasonal variation in Hg content was observed, with higher values at the end of the dry season. In the upper Tapajs basin comparable values were found for fish but with a definite decreasing trend downstream. Average value for piscivorous fish in the whole Tapajs basin is 482 ppb (N=122) with a maximum value of 3770 ppb. Hair Hg was higher in fishing villages in the Tapajs (average: 17 ppm; with N=432 and maximum value of 176 ppm) than in the Madeira (average: 9 ppm; N=169; maximum 71 ppm), and data from some areas of the Tapajs suggest a decrease with time. Mercury was much higher in urine of goldshop workers in Santarm (low Tapajs) than in Alta Floresta (high Tapajs) and show a decreasing trend in both cases, probably related to the significant decline in gold mining activities during the study period (1986-1994).
    Water Air and Soil Pollution 05/1997; 97(1):45-51. · 1.75 Impact Factor
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    ABSTRACT: Occupational exposure to Hg vapour was investigated in 78 workers during three periods with different temperatures: August 1991, December 1991, and February 1992. Each individual was sampled twice in each period; before and after a six working days period (with a two free days interval). As an attempt to normalise Hg excretion urine was sampled always after a normal 8 hours night sleeping and immediately frozen. Mineralisation was done with acid and oxidant mixture and determination by cold vapour Atomic Absorption Spectrophotometry (Varian VGA-76 and AA-1475). Analytical accuracy was controlled by routine analysis of certified reference material (Seronorm TM trace elements, Nycome As diagnostics Olso — Norway) and all samples were analysed in triplicates. Of a total of 355 samples analysed 13% were over the maximum limit for occupational exposure (50 μg.l−1 or ppb). From the 78 individuals investigated 13% presented average value smaller than 10 ppb; just 8% had the average over 50 ppb; 64% showed averages smaller than 30 ppb; and 28% were between 30 and 50 ppb. Seasonal variation was observed with the highest values in the hottest periods. High variability was observed in the same individual even within an interval of just few days (seven days). No increase of Hg in urine after the six days of exposure was observed when compared with the values after the two free days interval.
    Water Air and Soil Pollution 05/1997; 97(1):185-191. · 1.75 Impact Factor
  • J R Guimarães, W C Pfeiffer
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    ABSTRACT: Different aspects of mercury accumulation, retention, and elimination in temperate fish species have been reported, but few data are available for tropical species. In this work Hg accumulation in Trichomycterus zonatus, where experimental losses were estimated, was studied. Forty individuals (males and females) of T. zonatus were acclimatized for 30 days. In each experiment 10 aquaria were used, with 1 fish each (5 exposed to HgCl2 and the others as controls). The concentration tested was 15 microg Hg x liter-1 including 18 kBq x liter-1 203HgCl2 as tracer. Fish were dissected and measured for Hg by gamma scintillation spectrometry at regular intervals, and after 96 hr were transferred to mercury-free tap water. Approximately 40% of added mercury was lost by volatilization (20%) and adsorption (20%) in 48 hr. A faster absorption of inorganic mercury was observed initially in gills, a higher and lower retention in kidney and muscle, respectively. For T. zonatus the kidney, gills, and liver were considered the critical organs, but this order changed after 98 hr in mercury-free tap water. The distribution of inorganic mercury in T. zonatus seems quite similar to that found in temperate species, but the sensitivity of this species to Hg seems higher.
    Ecotoxicology and Environmental Safety 08/1996; 34(2):190-5. · 2.20 Impact Factor
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    ABSTRACT: The ability of young plants of the brown alga Padina gymnospora to tolerate and accumulate zinc was determined for different zinc concentrations in seawater over a period of 21 days. This species, among 10 macroalgae species studied in a contaminated coastal area near Rio de Janeiro city, presented the highest zinc contents. The accumulation of zinc by this species determined from in vitro experiments increased approximately linearly with the zinc concentration in the water. A steady state was not reached even for high concentrations (1000 g 1–1). Analytical electron microscopy techniques used for subcellular localization of this metal showed that the zinc was present as dense granules along the cell walls, starting in a region 15 to 25 cells away from the thallus apex, but being absent in the cytoplasm of viable cells. It is suggested that the cell walls play the main role in the zinc accumulation in Padina gymnospora.
    Hydrobiologia 06/1996; 326-327(1):451-456. · 1.99 Impact Factor
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    ABSTRACT: Mercury is being released in the Amazon in an abusive way due to goldmining activities. The Tapajós river basin was the first to be intensively exploited in the modern Amazon gold rush. Fish and hair samples as the best indicators of human methylmercury contamination were investigated in the main cities and villages along the Tapajós river basin. The upper basin has typical fish fauna with much larger carnivorous fish with higher mercury levels reaching an average value of 0.69 microgram.g-1 wet wt. in 43 fish. This was accompanied by high levels in hair of the human population living in the same area. The maximum hair value reach 151 micrograms.g-1 dry wt. with two villages presenting an average value close to 25 micrograms.g-1 dry wt. An analytical laboratory intercalibration exercise was performed between Japanese and Brazilian laboratories for total mercury analysis. Critical fish, areas, and more exposed human groups are identified.
    Science of The Total Environment 01/1996; 175(2):141-50. · 3.26 Impact Factor
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    ABSTRACT: To obtain the basic information on human exposure to mercury (Hg) due to gold mining activities in Amazon, total mercury (T-Hg) and methylmercury (MeI Ig) were determined for human hair, blood and/or urine samples collected from populations living in gold mining area and fishing villages upstream of the Tapajos River basin. Abnormally high levels of T-Hg were observed in hair and blood from all fishing villages investigated and more than 90% of T-Hg was in the form of MeHg in both samples, whereas in goldrnining area the value were much lower and the %MeHg values varied widely (20–100%) with individuals even in blood samples. Urine from gold shop workers contained Hg mostly in inorganic form at 165g/g creatinine on the average, with the range of 20 to 450g/g creatinine. A good correlation between Hg in hair and blood was found in fishing villages and the ratios of hair Hg to blood Hg were very close to 250, generally established for MeHg. T-Hg and inorganic Hg levels in urine from gold shop workers were also significantly correlated with inorganic Hg in blood.
    Water Air and Soil Pollution 01/1995; 80(1):85-94. · 1.75 Impact Factor
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    Jean R.D. Guimarães, Olaf Malm, Wolfgang C. Pfeiffer
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    ABSTRACT: Current Hg0 emissions from goldmining activities in the Amazon basin reach 100 tons·year−1, but very little is known about Hg methylation rates in local aquatic systems. Simplified versions of the Furutani and Ruddi (1980) radiochemical method were tested and applied in the determination, by in-situ incubations, of specific net Hg methylation rates in water and surface sediments of the Madeira river goldmining area. Efficiency for Me203 Hg extraction from water and sediment was in the 75.3–96.77% range, depending on sample type and extraction procedure. Methylation was not detectable in water but rates in surface sediments ranged from 10−5 to 10−1% · g−1. h−1, the higher rates being found in sites in a reservoir area. Methylation was absent or strongly depressed in sterilized sediments. The effect of delays between sampling, incubation and extraction on methylation rates and Me203Hg recovery was documented. Despite their limited spatial and temporal range, these data are further evidence that concerns about the potential toxicological impacts of Hg emissions in the Amazon basin are justified.
    Science of The Total Environment 01/1995; 175(2):151-162. · 3.26 Impact Factor
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    ABSTRACT: In order to evaluate the extent of environmental mercury pollution due to goldmining activities in the Amazon, concentrations of total mercury and methylmercury were determined for human hair and fish samples from five fishing villages located mainly in the Tapajos river basin. Abnormally high levels of mercury were found in human hair from Jacareacanga and Brasilia Legal located near the main goldmining area as well as from Tres Bocas facing the lake in Amapa state, whereas the levels were much lower in Ponta de Pedras, a long way downstream. The values of male samples were about twice as high as females even in the same family. The predominant form of mercury in hair samples was methylmercury (average 90%), while high hair mercury observed in goldminers and workers in goldshops was mostly in the inorganic form. Longitudinal analyses of long hairs from people in fishing villages showed fairly constant and continuous exposure to methylmercury at least over the last few years with seasonal variations. Fish contained relatively high levels of mercury (up to 3.82 ppm) mostly in the form of methylmercury and most of the fish from upstream and some from downstream exceeded the allowable level of 0.5 ppm in Brazil.
    Science of The Total Environment. 01/1995;
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    ABSTRACT: Metallic mercury used in gold prospecting is being dispersed over Amazon ecosystems through atmospheric emissions as well as directly to aquatic systems. Total mercury concentrations in the more representative environmental (air, soil, bottom sediments, fishes and plants) and human (hair and urine) indicators, collected in the last 7 years in different goldmining areas (garimpos) are presented and discussed. Critical exposure situations, pathways, areas and human groups are indicated. The goldminers (garimpeiros) that manipulate a major part of the Hg are not the critical group either from exposure to metallic mercury (Hg0) by inhalation or exposure to methylmercury by ingestion of contaminated fish. Results obtained from air and urine sampling show that people working in gold dealers shops are the critical group concerning Hg0 risk, while riverine communities are the risk group with respect to methylmercury.
    Science of The Total Environment - SCI TOTAL ENVIR. 01/1995; 175(2):127-140.
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    ABSTRACT: The concentrations of zinc, cadmium and copper were determined in different benthic algal species from some sites located in Guanabara Bay, Sepetiba Bay and Ribeira Bay (State of Rio de Janeiro). The aim is to verify the possibility of using algae as indicators of metallic contamination in these areas. According to our results, the highest concentrations of Zn and Cd in algae were observed in Sepetiba Bay. In this region, the differences among the concentrations of the metals were analysed in three sampling sites. Padina gymnospora was the species recommended to monitor the contamination of Zn and Cd in Sepetiba Bay, for the following reasons: 1) its great abundance and distribution in the areas, and 2) its high ability to accumulate metals. More studies are suggested to evaluate the levels of metals in Guanabara Bay.
    Anais da Academia Brasileira de Ciências 07/1994; 66(2):205-11. · 0.85 Impact Factor
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    ABSTRACT: This paper reports on total Hg concentrations in muscle tissue from 12 fish species collected in the Itacaiúnas and Parauapebas Rivers in the Carajás region, South Pará. It is found that carnivorous species present Hg concentrations higher than herbivorous and omnivorous species. Also, large carnivorous species presented higher Hg concentrations than smaller carnivorous species. Significant positive relationships are found between fish weight and total Hg concentrations for at least two species studied in detailed, the carnivorous Paulicea lutkeni (jaú) and Serrasalmus nattererii (piranha).
    Anais da Academia Brasileira de Ciências 02/1994; 66(3):373-9. · 0.85 Impact Factor

Publication Stats

955 Citations
111.98 Total Impact Points

Institutions

  • 1980–2010
    • Federal University of Rio de Janeiro
      • • Instituto de Biofísica Carlos Chagas Filho (IBCCF)
      • • Instituto de Física (IF)
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 2004–2006
    • Universidade Federal de Rondônia
      Velho, Rondônia, Brazil
  • 1997
    • University of Florida
      Gainesville, Florida, United States
    • Instituto de Pesquisas Jardim Botânico do Rio de Janeiro
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 1996
    • Universidade Federal do Paraná
      Curityba, Paraná, Brazil
  • 1991–1994
    • Universidade Federal Fluminense
      • Departamento de Geoquímica (GEO)
      Niterói, Rio de Janeiro, Brazil