W C Pfeiffer

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

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Publications (43)103.06 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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    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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    Marine Pollution Bulletin 11/2003; 46(10):1354-8. · 2.53 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. · 3.51 Impact Factor
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    ABSTRACT: Dichlorodiphenyltrichloroethane (DDT), its main metabolites, and other organochlorines were analyzed in soils (n=6), fluvial sediments (n=14), and fish (n=10) that were collected in several areas of the Amazon region in Brazil. The samples were analyzed by capillary column gas chromatography coupled to electron capture detection. DDT residues were present in most of the collected sediments in concentrations of approximately 10 to 100 micro/kg (ppb, dry weight). Some urban top soils were found to have more than 1 mg/kg (ppm). In fish, as much as 0.5 mg/kg of total DDT (wet weight) was found in the edible parts. The presence of p,p'-DDT in most of the samples reflects the use of this insecticide against vectors of malaria between 1946 and 1993, which has led to its ubiquitous presence in the environment of the Brazilian Amazon.
    Environmental Research 03/2002; 88(2):134-9. · 3.24 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: 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
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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
  • 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: 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. · 3.16 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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    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: Trace metal concentrations (Zn, Cd, Pb, Cr and Cu) were determined in some benthic algae from Sepetiba Bay, Brazil. This region has been modified by the increase of industrial activities during the last 30 years. Among species sampled the brown algae Padina gymnospora contained the greatest amount of Zn. The Bioconcentration Factor for Zn in P. gymnospora was found to be 10(4) under laboratory conditions. The absorption of (65)Zn depended on exposure time and increased with Zn concentrations in the medium. An insignificant amount of Zn desorbed from algae suggested a very high affinity with cellular binding sites. Zinc uptake by P. gymnospora is discussed by considering field and laboratory conditions.
    Environmental Pollution 02/1994; 83(3):351-6. · 3.73 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
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    W. C. Pfeiffer, L. D. Lacerda, W. Salomons, O. Malm
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    ABSTRACT: Large quantities of mercury are being released into the waters of the Amazon and its tributaries by gold-mining activities. Large releases are also taking place into the air. In this paper, the fate of mercury released to the environment by gold mining in the Brazilian Amazon is reviewed. Mercury contamination is presently widespread in the Amazon region. A major source of mercury in the local environment is the burning of the gold–mercury amalgam, which releases from 30 to 150 t of mercury yearly into the Amazon atmosphere. Air samples collected close to mining sites showed extremely high mercury concentrations (up to 7.5 μg∙m−3). Inside gold-dealers' shops or in amalgam-burning stations, ambient air concentrations may reach 100 μg∙m−3. A secondary source is the discharge of metallic mercury into rivers during the amalgamation process. Sediment concentrations frequently range from 0.3 to 3.0 μg∙g−1 in contaminated sites. However, values as high as 19.8 μg∙g−1 have been reported in some sites. Waters of many rivers are also contaminated, although reliable data on dissolved mercury concentrations are still lacking. Local carnivorous fishes typically show mercury concentrations higher than 1.0 μg∙g wet wt.−1 in contaminated sites and methyl mercury represents over 90% of the total content. Human groups with fish-based diets frequently show evidence of mercury contamination, with high mercury concentrations in hair (up to 70 μg∙g−1). However, a reliable epidemiological study on the affected population still has to be carried out.Key words: mercury, gold mining, Amazon, sediments, aquatic biota, humans.
    Environmental Reviews 02/1993; 1(1):26-37. · 1.65 Impact Factor
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    ABSTRACT: Discharge of heavy metals from the Acari‐São João de Merití River System into Guanabara Bay and the physico‐chemical mechanisms involved in the transport of these pollutants to the sea are evaluated. Determination of Hg, Cd, Pb, Zn, Mn, Fe, Cr, Cu and Ni concentrations by atomic absorption spectrophotometry were carried out for water, suspended particulate matter and bottom sediment samples. Transport of heavy metals occurs primarily via the particulate phase where mobile forms of metals prevail. Contamination of bottom sediments are indicated for Hg, Cd, Pb, Zn, Cu and Cr.
    Environmental Technology. 02/1993; 14(2):167-174.
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    Marine Pollution Bulletin 01/1993; 26(4):220-222. · 2.53 Impact Factor
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    Nature 05/1992; 356(6368):389. · 38.60 Impact Factor

Publication Stats

879 Citations
103.06 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
  • 1997–2008
    • Instituto de Pesquisas Jardim Botânico do Rio de Janeiro
      Rio de Janeiro, Rio de Janeiro, Brazil
    • University of Florida
      Gainesville, Florida, United States
  • 1996
    • Universidade Federal do Paraná
      Pontal do Paraná, Paraná, Brazil
  • 1991–1994
    • Universidade Federal Fluminense
      • Departamento de Geoquímica (GEO)
      Niterói, Rio de Janeiro, Brazil