Comparison between the macroinfauna of urbanized and protected beaches in Rio de Janeiro State, Brazil

The intertidal macroinfauna of five sandy beaches with similar morphodynamics conditions was studied to compare composition and structure between beaches near urbanized centers and protected beaches located in Rio de Janeiro State. The beaches were sampled in winter 1996 and summer 1997 according to a systematic design with stratification. A total of nine species were identified with the crustaceans being the most abundant and frequent animals. Species richness showed little variation between beaches while density of some species such as Emerita brasiliensis (Crustacea) and Phaleria testacea (Insecta) were lower at urbanized beaches when compared to protected ones. At the most urbanized beaches, Pseudorchestoidea brasiliensis was absent during both sampling periods. The negative relationships between human recreational activities (e.g., trampling) and density of macroinfaunal species was recently gained support and in Barra da Tijuca beach these relation is very clear. In the developed and most-visited sector, Barra (Alvorada), the amphipod Pseudorchestoidea brasiliensis was never collected whereas in the protected portion, Barra (Reserva), the same species occurred in high densities. Thus, our results suggested that the amphipod Pseudorchestoidea brasiliensis is more vulnerable to trampling than are other species.     

Exposure to metallic mercury in workers in a tropical chloralkali plant evaluated through urine analysis,Rio de Janeiro,Brazil.

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.     

Hydrogeochemistry of Sand Pit Lakes at Sepetiba Basin, Rio de Janeiro, Southeastern Brazil

Four sand pit lakes, at the Rio de Janeiro Sand Mining District, were monitored from November 2003 to November 2005, in order to characterize their hydrogeochemistry aiming to provide information to their possible use as fishponds at the end of mining activities. The results show diluted waters (low electrical conductivity) with low pH (<4) and relatively high sulfate and aluminum concentrations. The major water components (in particular Fe, Mn, SiO₂, Al and SO₄) are related to water acidity, since it controls solubility of aluminum silicate minerals and Mn and Fe oxides. Fe, Mn and Al availability in these waters are probably associated to organic colloids formation. On the other hand, the SiO₂ content, as well as the decrease of sand mining in rainy season, may partially control Al availability by the formation of hydroxi-aluminum silicates. These geochemical processes together with the interruption of sand mining in the rainy season and the dilution of sand pit lakes water by rainwater can support the use of these pit lakes as fishpond for aquaculture.     

Atmospheric Total Suspended Particulate Trace Element Identification by XRF at Ilha Grande, State of Rio De Janeiro, Brazil

Phosphorus, manganese, sulfur (S), lead, and strontium of atmospheric total suspended particulate matter, sampled during the rainy season and the dry season 2002 at the Ilha Grande Island (Rio de Janeiro State, Brazil) have been analyzed by XRF techniques. The results showed total mean concentrations of 27?±?16 ng P m^-3, 11?±?7 ng Mn m^-3, 159?±?126 ng S m^-3, 4.3?±?2.6 ng Pb m^-3, and 208?±?148 ng Sr m^-3. Generally, there is no clear influence of the two different climatic periods on the concentrations of most analyzed trace elements, with exception of sulfur the mean concentration of which, during the dry season, is about 60% higher than during the rainy season. This is probably due to biomass burning, a common practice in the Brazilian Southeast and Amazon region and/or to the presence of marine aerosols. The linear correlation coefficients strongly suggest the same source for P, Pb, and Mn. Some Pb, Mn, and P concentrations are in the range of typical values of urban areas. Potential sources of such elements are the urban and industrial emissions from the States of Rio de Janeiro and/or São Paulo.     

Polycyclic Aromatic Hydrocarbons and their Molecular Diagnostic Ratios in Airborne Particles (PM10) Collected in Rio de Janeiro, Brazil

Atmospheric polycyclic aromatic hydrocarbons (PAHs) were determined in particulate matter (PM10) collected in a suburban area with industrial and vehicular emissions in the Metropolitan Area of Rio de Janeiro City (Brazil). A total of 22 samples were collected between March and August 2005 by means of a high volume PM10 sampler. The particulate matter contained in the filters was extracted ultrasonically with dichloromethane. The extracts were later analyzed by gas chromatography coupled to a mass spectrometer (GC/MS). The individual concentrations of PAHs ranged between the detection limit and 0.386 ng m^?3. The PAHs concentrations observed in this study were towards the lowest end of the range of values reported for other European locations and also lower than values obtained for South America. PAHs concentrations and molecular ratios showed that light cars seem to be the main contributors to PM10 emissions, but diesel vehicles are clearly minor emission sources and industrial contributions should not be disregarded until more data are obtained.     

Topographic controls of landslides in Rio de Janeiro: field evidence and modeling

Landslides are common features in the Serra do Mar, located along the southeastern Brazilian coast, most of them associated with intense summer storms, specially on the soil-mantled steep hillslopes around Rio de Janeiro city, where the favelas (slums) proliferated during the last few decades. On February 1996, hundreds of landslides took place in city of Rio de Janeiro triggered by intense rainstorms. Since then, many studies have been carried out in two experimental river basins in order to investigate the role played by the topographic attributes in controlling the spatial distribution of landslides inside them. Landslide scars and vegetation cover were mapped using aerial photographs and field observations. A detailed digital terrain model (4 m² resolution) of the basins was generated from which the main topographic attributes were analyzed, producing maps for slope, hillslope form, contributing area and hillslope orientation. By comparing these maps with the spatial distribution of the landslide scars for the 1996 event, a landslide potential index (LPI) for the many classes of the different topographic attributes was defined. At the same time, field experiments with the Guelph permeameter were carried out and a variety of scenarios were simulated with the SHALSTAB model, a process-based mathematical model for the topographic control on shallow landslides. The results suggest that most of the landslides triggered in the studied basins were strongly influenced by topography, while vegetation cover did affect landslide distribution. Between the topographic attributes, hillslope form and contributing area played a major role in controlling the spatial distribution of landslides. Therefore, any procedure to be used in this environment towards the definition of landslide hazards need to incorporate these topographic attributes.     

Natural disaster in the mountainous region of Rio de Janeiro state,Brazil: Assessment of the daily rainfall erosivity as an early warning index

Rainfall erosivity is defined as the potential of rain to cause erosion. It has great potential for application in studies related to natural disasters, in addition to water erosion. The objectives of this study were: i) to model the R_day using a seasonal model for the Mountainous Region of the State of Rio de Janeiro (MRRJ); ii) to adjust thresholds of the R_day index based on catastrophic events which occurred in the last two decades; and iii) to map the maximum daily rainfall erosivity (R_maxday) to assess the region's susceptibility to rainfall hazards according to the established R_day limits. The fitted R_day model presented a satisfactory result, thereby enabling its application as a R_day estimate in MRRJ. Events that resulted in R_day > 1500 MJ ha^?1.mm.h^?1. day^?1 were those with the highest number of fatalities. The spatial distribution of R_maxday showed that the entire MRRJ has presented values that can cause major rainfall. The R_day index proved to be a promising indicator of rainfall disasters, which is more effective than those normally used that are only based on quantity (mm) and/or intensity (mm.h^?1) of the rain.     

Heavy metal contamination of the marine biota along the Rio de Janeiro coast,SE-Brazil

A survey is presented on the heavy metal contamination of benthic organisms of the Rio de Janeiro coast, SE Brazil. Metal concentrations were different depending on major pollution sources, element, and species analyzed. The highest concentrations of Zn and Cd occurred in moderately industrialized Sepetiba Bay, while Cu presented its highest content in areas receiving urban wastes. The metals Pb, Ni and Mn did not show any difference among areas. The highest concentration of metals, regardeless of site, occurred in barnacles and oysters, due to the high filtering capacity of these organisms, while the lowest concentrations of all metals occurred in algae species.     

Screening of rhizobacteria isolated from maize (Zea mays L.) in Rio Grande do Sul State (South Brazil) and analysis of their potential to improve plant growth

Plant growth-promoting rhizobacteria (PGPR) are considered to have a beneficial effect on host plants and may facilitate plant growth by different mechanisms. In this work, the influence of different soil types on the bacterial diversity and the stimulatory effects of selected PGPR on two cultivars of maize were investigated. A set of 292 strains was isolated from the roots and rhizosphere soil of maize cultivated in five different areas of the Rio Grande do Sul State in Brazil. 16S rDNA-PCR-RFLP and 16S rDNA partial sequencing were used for identification, and the Shannon–Weaver index was used to evaluate bacterial diversity. We evaluated the ability of each isolate to produce indole acetic acid (IAA), siderophores and solubilize phosphates. On the basis of multiple PGP traits, six isolates were selected to test their potential as plant growth-promoting rhizobacteria on maize plants. In both the roots and the rhizospheric soil of maize, the dominant bacterial genera identified were Klebsiella and Burkholderia. IAA producers were distributed widely among isolates, regardless of the sampling site. Approximately 42% of the isolates exhibited at least two attributes, and 24% showed all three PGP traits. Three strains, identified as Achromobacter, Burkholderia, and Arthrobacter, were effective as PGPR in both of the cultivars evaluated.     

Interdependence of air,water, and soil pollution control strategies in a power plant and a kraft mill

An analysis of cross-media (air, water, and soil) emissions resulting from various control strategies is necessary in the evaluations of emission standards as well as control strategies. This paper presents such analysis on seven control strategies for a coal-fired power plant and ten control strategies for a kraft pulp and paper mill. The data illustrated include uncontrolled and controlled emissions to all three environmental media as well as power requirement, and capital and operating costs.     

Carbon Fluxes from Different Pools in a Mined Area under Reclamation in Minas Gerais State,Brazil

Despite the benefits of grass cultivation and organic fertilization in mining areas undergoing reclamation, these practices may be associated to CO₂ emissions and soil organic matter (SOM) losses by priming effect. In the present study, we evaluated the changes on SOM pools and C–CO₂ emissions in a bauxite‐mined area under reclamation fertilized with poultry litter (PL) (0, 10, 20, and 40 Mg ha⁻¹) and cultivated with Brachiaria brizantha . Increases of about 3·5 times in the soil labile C were observed 1 year after experiment establishment. High C–CO₂ fluxes and a significant positive priming effect were observed in the presence of B. brizantha , increasing native C mineralization by nearly 4·9 times. Nevertheless, no net soil C loss was detected, probably because of the C inputs derived from B. brizantha , which offset these losses. In fact, the grass increased total organic C by 45% when fertilized with 40 Mg PL ha⁻¹. The data obtained suggest that the cultivation of B. brizantha fertilized with PL can be a promising option for rapid recovery in SOM in areas under reclamation. Copyright © 2016 John Wiley & Sons, Ltd.     

Removal of trace metals from wastewater during long-term storage in seasonal reservoirs

The removal of five metals (Cu, Zn, Cr, Pb, Al) was studied in two reservoirs in series used for the seasonal storage of wastewater effluents for irrigation. The evaluation was made by two methods: (1) an anual budget which includes inputs and outputs and. (2) sediment traps. The concentrations of metals were reduced between 20 and 75%, to the base level found in unpolluted groundwater in the region. The amount of Pb was reduced in 5%, Cu in 10%, Al in 30%, Cr in 50%, and Zn in 90%. Sedimentation has an irregular pattern due to the effect of wind induced longshore and rip-currents. The release of bottom sediments in the outflow means a direct release of trace metals and other settling pollutants and clogging particles. It is recommended to take the effluents for irrigation from the uppermost water layer, to avoid strong outflow rates which may drag out part of the sediments by hydraulic turbulence, and to locate the outlet away from the dominant wind axis. The main tools to improve the removal of trace metals in seasonal reservoirs are not the control of the age distribution of the effluents and/or the loading of the reservoirs, but the proper location, design and flow rate of the outlet.     

Accumulation and output of heavy metals by the invasive plant Spartina alterniflora in a coastal salt marsh

Spartina alterniflora is a foreign introduced species and has far-reaching effects on salt marsh ecosystems, particularly on the biogeochemical cycle of heavy metals. To ascertain whether the invasive plant Spartina alterniflora Loisel is a source of metals in the environment, we determined the bimonthly concentrations of heavy metals, chromium(Cr), lead(Pb), copper(Cu), zinc(Zn),and manganese(Mn), in the roots, stems, and leaves of S. alterniflora from a typical semidiurnal tidal zone in the coastal area of northern Jiangsu Province, China. Based on the measurements, we calculated annual metal primary accumulation and output. To calculate the annual output of heavy metals from S. alterniflora, a new method that calculates the annual rate of biomass loss and decomposition was developed. The annual primary accumulation of Cr, Pb, Cu, Zn, and Mn was 19.08, 84.19, 63.74, 442.58, and774.66 mg m~(-2), respectively, and the annual output from S. alterniflora to the surrounding environment was 4.01, 18.09, 14.00, 97.11,and 164.28 mg m~(-2), respectively. Spartina alterniflora only provides temporary storage, and its absorption of heavy metals could be used to remediate contaminated soil and for phytomining. The heavy metals released by S. alterniflora to the environment cannot be ignored; thus, S. alterniflora should be considered a source of metal contamination. Therefore, when we evaluate the remarkable ability of certain plant species to concentrate metals in their tissues, the balance between heavy metal accumulation and output should be considered.     

Mercury Accumulation in Sediments of a Mangrove Ecosystem in SE Brazil

The Hg accumulation in sedimentary environments of a mangrove ecosystem in Sepetiba Bay, SE Brazil, was investigated. These environments include sediments of a mangrove forest, the main tidal creek that drains the forest, and the bare seaward-edge mud flat adjacent to forest and tidal creek. Maximum Hg concentration peaks in sediments from the mud flat (184 ng g^-1), tidal creek (98 ng g^-1), and mangrove forest (60 ng g^-1) correspond to enrichment factors of 6.1, 3.3, and 2.0 above the estimated average background level, respectively. Average inventories of Hg excess (background-corrected) concentrations were substantiallydifferent between environments, decreasing from mud flat sediments (5.2 mg m^-2) to creek sediments (3.3 mg m^-2)to mangrove forest sediments (0.9 mg m^-2). Mercury concentration profiles indicated a consistently higher accumulation of Hg in surface layers of mud flat and tidal creeksediments, whereas mangrove forest sediments showed a higher Hgaccumulation in root-rich subsurface layers, in agreement with an enrichment of Fe and organic matter contents. While Hg distribution in mud flat and tidal creek sediments appears to belargely affected by contamination, its distribution in mangrove forest substrate appears to be greatly affected by root-sedimentinteractions. Mercury levels in the study site were comparable tothose observed in coastal sediments under moderate Hg contamination at local and regional scales. Results indicate thatsedimentary environments surrounding the mangrove forest retain most of the anthropogenic Hg reaching the ecosystem. Since tidal waters have been previously demonstrated as the main source of metals to the site, it is suggested that the Hg retention in mudflat sediments precede and may avoid a higher Hg accumulation inlandward environments.     

Accumulation of atmospherically deposited metals in Wetland soils of Sudbury,Ontario

Concentrations of Cu, Ni, Fe, and Mg in soil/sediment material from 25 wetlands in the Sudbury, Ontario, region decline logarithmically with increasing distance from several ore smelters. Total Cu and Ni reach concentrations potentially toxic to plant life in soil/sediment material near the smelters. Despite random variation in soil/sediment pH and Eh, NH₄OAc extractable Cu, Ni and Fe, and DTPA extractable Cu Ni and Mg show the same pattern as total Cu, Ni, Fe, and Mg. The failure of DTPA extractable Fe to show the same pattern as total Fe may be due to the inadequacy of the DTPA soil test when testing Fe in acid soils. Soil/sediment organic C content increases with distance from the smelters, but is unrelated to pH or Eh.