Heavy metals in benthic organisms from Todos os Santos Bay, Brazil.

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.

Oyster condition index in Crassostrea rhizophorae (Guilding 1828) from a heavy-metal polluted coastal lagoon.

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.

Study of zinc and growth hormone in sickle cell disease.

About 25% of children with sickle cell disease (SCD) have statural deficit and retarded skeletal maturation and pubertal development. These disorders have been attributed to low serum concentrations of zinc. We report the study of serum zinc in 34 patients with SCD, of whom 17 had statural deficit (SCS group) and 17 without growth deficiency (SCN group). They were compared with 20 normal children (N group). GH secretion and thyroid function were investigated in the group with short stature (SCS) in order to rule out GH deficiency and hypothyroidism. The mean serum zinc concentration was 108.45+/-22.888 microg/100 ml in the N group, 87.529+/-30.069 microg/100 ml in the SCN group and 82.765+/-34.766 microg/100 ml in the SCS group. There was a statistically significant difference between the mean of the N group and the mean of the SCN group (p<0.05) but no difference was found between the two groups of patients (N>SCN=SCS). Although there is a well-established zinc deficiency in patients with SCD, the statural retardation found in the SCS group could not be attributed only to zinc deficiency. Many other severe metabolic disturbances are also involved.

Trace metal accumulation by algae in Sepetiba Bay, Brazil.

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.

Mercury concentrations in inland waters of gold-mining areas in Rondônia, Brazil.

Total mercury concentrations in water, sediments and fish from the gold-mining areas of Brazil, especially the Amazon region, are presented. Mercury concentrations were variable among rivers, with the highest values found in samples from tributary forest rivers. Concentrations in water samples varied between 0.1 and 8.6 micrograms l-1, while in bottom sediments they reached 19,800 micrograms kg-1. Concentrations in edible parts of locally consumed fish reached up to 2700 micrograms kg-1 wet wt, surpassing by almost five times the Brazilian advisory level for human consumption.

Mercury and methylmercury in fish and human hair from the Tapajós river basin, Brazil.

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.

Effects of milk yield on biological efficiency and profit of beef production from birth to slaughter.

Effect of milk yield (MY) on biological efficiency and gross margin as an indicator of profit potential of beef production from birth to slaughter was determined. Data included 9 yr of spring-born single male calves. Biological efficiency was calculated as carcass weight/total feed energy intake, including nonlactating and lactating intakes of cow and creep and feedlot intakes of calf. Slaughter end point was finish constant at 9 mm of fat thickness. Gross margin was determined as returns minus feed costs. Three breeding systems were analyzed: purebred Hereford (HE), large rotational (LR), and small rotational (SR). Analyses were performed separately by breeding system when differences in the effect of MY among breeding systems were significant. Increased MY was associated with increased preweaning gain (P < .001), increased weight at start of feedlot trial (P < .001), and increased hot carcass weight (P < .05). No significant (P > .10) effect of MY on age at slaughter or on carcass weight per day of age at slaughter was found. Increased MY was associated with increased cow lactating energy intake (P < .10) and negatively associated with calf creep intake (P < .01). No effects of MY on intake of the cow during the nonlactating period, calf feedlot intake, or total feed intake were found. Increased MY was associated with a reduction in backfat thickness of the cow during the lactating period (P < .01) with no change in body weight. In the subsequent nonlactating period, increasing MY was associated with increased backfat thickness (P < .10) and body weight (P < .05). No effect of MY on change in backfat or weight of cow from calving to the end of the next nonlactating period was found. No effect of MY on biological efficiency to slaughter was detected. Milk yield was positively associated with gross margin from birth to slaughter (P < .05); results were similar when cow feed prices were reduced by 30%. Increased MY was associated with increased biological efficiency to weaning in HE (P < .01) and SR (P < .10), with no effect found in LR. When feeding cows to requirements, milk yield has a positive effect on the profit potential of beef production from birth to slaughter.

Feed intake, weaning weight and net returns comparisons for four breeding systems.

Feed intake, weaning weight and direct and maternal contributions to weaning weight were estimated for four breeding systems using data collected between 1979 and 1986 from 773 cow-calf pairs at the Elora Beef Research Centre. Breeding systems included purebred Hereford (HE), small rotational dual purpose (SR) (a four-way rotational crossing system utilizing Tarentaise, Angus, Gelbvieh and Pinzgauer breeds), large rotational beef (LR) (composed of Maine-Anjou, Simmental and Charolais) and Angus-sired large rotational beef (AL) utilizing Angus as the sire breed and LR as the maternal breed. Large rotational dams had the highest feed intakes for both dry (8.9 kg DM/d) and lactation (11.5 kg DM/d) periods. Conversely, HE calves consumed the greatest amounts of creep feed (309 kg DM), followed by AL, SR and LR. The large rotational system had the highest weaning weights (265 kg) and direct (12.3 kg greater than average of observations) and maternal (9.6 kg greater than average of observations) contributions to weaning weight, followed by AL, SR and HE for all three traits. An equation was derived for net returns that included parameters for feed intake and direct and maternal weaning weight. A linear programming model was designed to incorporate this equation as the objective function and determine the breeding system(s) that maximized net returns under various production conditions. In general, LR produced the greatest net returns, followed by SR and either AL or HE, depending on specific resource constraints (limited feed supply or herd size) included in the model.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of variations in biological and economical parameters on beef production net returns.

Net returns were defined as a function of the monetary returns (revenue) generated by the outputs less the monetary costs generated by the variable inputs. Outputs included total weaning weights of steers and heifers, weight of cull cows and weight of open heifers. Inputs included both feed and nonfeed costs. The net returns equation was incorporated as the objective function in a linear programming model. By maximizing the objective function, the breeding system that generated the highest net returns could be identified considering certain resource constraints. Breeding systems included purebred Herefords; small rotational dual purpose (SR), utilizing the breeds Angus, Pinzgauer, Gelbvieh and Tarentaise; large rotational (LR), a three-way rotational cross with the breeds Charolais, Simmental and Maine-Anjou; and Angus-sired terminal (AL) utilizing Angus as the sire breed and LR heifers as the maternal breed. Large rotational generally produced the greatest net returns, followed by SR and either AL or HE, depending on specific resource constraints (limited feed supply or herd size), calving rates, management systems, environment, beef to feed price ratios and purchased or farm-produced (inexpensive) feed utilized. Only under the conditions of a herd size constraint and farm-produced feed did AL exceed SR in net returns. Hereford had larger net returns than LR only when the two breeding systems were evaluated in an environment assumed to be reproductively stressful to LR. Ranking of breeding systems were dependent on specific conditions and indicated that one must consider each resource constraint and environment in which cattle are expected to produce before making breeding system recommendations.

Accumulation and distribution of inorganic mercury in a tropical fish (Trichomycterus zonatus).

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.

[Metal concentrations in benthic marine algae in 3 regions of the state of Rio de Janeiro]. / Concentrações de metais em algas marinhas bentônicas de três regiões do estado do Rio de Janeiro.

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.

Comparative uptake, bioaccumulation, and gill damages of inorganic mercury in tropical and nordic freshwater fish.

This paper reports comparative results on the bioaccumulation of inorganic mercury and resulting gill damages in the tropical fish, Trichomycterus zonatus, and a nordic species, Salvelinus alpinus, using radioisotope 203Hg techniques and scanning electron microscopy. Uptake of inorganic Hg from water was much more important in T. zonatus than in S. alpinus and the Hg concentration in S. alpinus increased at a slower rate in all tissues during the first 24 h of exposure. After 96 h, Hg concentration was 70 times higher in the kidney, 10 times higher in liver, intestine, skin, and brain, and 3 times higher in gills, muscle, and the rest of body of T. zonatus compared to S. alpinus. Gill damages in T. zonatus were more evident and occurred much earlier than for S. alpinus. According to our data, the high differences observed in the inorganic mercury uptake, bioaccumulation, and gills damages strongly suggest that T. zonatus is more sensitive to inorganic mercury pollution than S. alpinus. Further studies are urgently needed to determine whether the high sensitivity observed for T. zonatus to inorganic Hg is also present in the majority of tropical species or whether this species presents an isolated case.

Mercury concentrations in fish from the Itacaiúnas-Parauapebas River system, Carajás region, Amazon.

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).

Effects on growth and accumulation of zinc in six seaweed species.

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.

Measurements of environmental radiation exposure dose rates at selected sites in Brazil.

Two types of portable instruments were developed by the former Health and Safety Laboratory of the U.S. Atomic Energy Commission to characterize external gamma radiation fields and to estimate individual exposure dose rates from major natural or fission radionuclides distributed in the soil: a pressurized ionization chamber and a NaI(T1) gamma-ray spectrometer. The two instruments were used to measure environmental radiation exposure rates at three distinct geological areas of Brazil: - in the towns of Guarapari and Meaípe located on the monazite sand belt, ES. - on the vicinities of the uranium mine of Poços de Caldas, MG. - around the site of the Brazilian first nuclear power plant, in Angra dos Reis, RJ. The radiometric survey demonstrated once more the usefulness and versatility of the two instruments used. The measurements around the nuclear installations of Poços de Caldas and Angra dos Reis, allowed a rapid assessment of the local radiation background and its variability, as well as the selection of stations for the routine monitoring program. Radioactive anomalies were detected and characterized previously to the start of plant operations. The survey in Guarapari and Meaípe confirmed the results obtained by Roser and Cullen in 1958 and 1962, except on sites where considerable changes took place since then. The spectrometric measurements gave estimations of the relative proportion of 40K, 238U and 232Th series in the ground and also indications on the homogeneity of their distribution in the soil.

Heavy metals in benthic organisms from Todos os Santos Bay, Brazil

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.

A Baía de Todos os Santos (TSB, Estado da Bahia, Brasil), vem sendo impactada pela presença, em seu entorno, de uma extensa área metropolitana e por atividades químicas e petroquímicas. Apesar de sua importância ecológica, existe pouca informação sobre a contaminação da biota marinha da TSB por metais pesados. Neste contexto, foram analisadas as concentrações de metais em quatro espécies de organismos bentônicos: duas algas, Padina gymnospora e Sargassum sp.; uma grama marinha, Halodule wrightii; e uma ostra, Crassostrea rhizophorae, em três locais das regiões da TSB mais afetadas pelas atividades industriais. As concentrações de Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn foram determinadas por espectrofotometria de absorção atômica. Os resultados obtidos indicaram que o cádmio e o cobre em algas, gramas marinhas e ostras, assim como o níquel em ostras estão, em concentrações de áreas contaminadas. Pelos resultados obtidos o cádmio e o cobre estão biodisponíveis a partir das partículas de sedimento em suspensão, fração dissolvida da coluna da água e da água intersticial do sedimento de fundo. Como ostras e outros moluscos são utilizados como fonte de alimento pelas populações locais, as concentrações de metais encontradas nas ostras da TSB podem constituir risco para as populações humanas locais. Os resultados obtidos sugerem a necessidade de implementação de um programa de monitoramento das concentrações de metais pesados em organismos dos ecossistemas marinhos da TSB.

Oyster condition index in Crassostrea rhizophorae (Guilding, 1828) from a heavy-metal polluted coastal lagoon

O índice de condição (IC) de ostras é um índice ecofisiológico utilizado para avaliar a qualidade e a produtividade em cultivos de bivalves. No presente estudo, o IC de ostras de uma baía contaminada por metais pesados foi analisado em relação ao conteúdo de Zn e Cd nos tecidos moles, à liberação de gametas após o período reprodutivo e à infestação por poliquetas. O IC foi calculado com uma nova técnica que utiliza moldes da cavidade interna da concha para medir seu volume. Os maiores valores de IC (acima de 9 na estação seca) podem estar relacionados à disponibilidade de material particulado em suspensão rico em matéria orgânica na baía, enquanto a rápida redução do IC observada de uma temporada a outra em algumas estações é um provável efeito da liberação de gametas. A infestação por poliquetas foi considerada baixa (18,7%) e não apresenta efeitos claros no IC. Apenas Cd nos tecidos de ostras coletadas durante a estação das chuvas apresentou correlação baixa, porém significativa (r = ù0,36; p < 0,05), com o IC. Todas as outras correlações entre metais e IC foram estatisticamente não significativas. As variações do IC observadas em escala espacial e temporal parecem ser causadas mais pela disponibilidade de material particulado rico em material orgânico e pela liberação de gametas do que pela infestação por poliquetas e acúmulo de metais nos tecidos.

Mercury concentrations in fish from the Itacaiúnas-Parauapebas river system, Carajás region, Amazon

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 carnivorus species presented higher Hg concentrations than smaller carnivorus species. Significant positive relationship are found between fish weight and total Hg concentrations for at least two studied in detailed, the carnivorous Paulicea likeni (jaú) and Serrasalmus nattererii (piranha)