John E.L. Maddock

Biogeochemistry of a hypersaline lagoon east of Rio de Janeiro, Brazil

Abstract Biogeochemical processes in sediments, algal mats, and surface and interstitial waters of a hypersaline ecosystem are described. Analyses of the main anions and cations, identification of mineral phases and microbiological investigations elucidate the mechanisms of a unique biogeochemical system. The potential of hypersaline environments for interdisciplinary research is discussed.

Nitrous oxide emission from soil of the Mata Atlantica, Rio de Janeiro State, Brazil

Emissions of nitrous oxide by the soils of the Mata Atlantica subtropical forest were measured, on 21 days spread over one year, using a static chamber technique with natural flux calculation from nonlinear curves of chamber concentration versus time. The average of measured fluxes was 4.8 ng N Cm−2h−1 (n = 131). Emission rates increased by an order of magnitude during and after rainfall, and a mean flux from this environment, weighted for mean weather conditions, was estimated as 3.6 ng N cm−2h−1. These fluxes are comparable to others reported for humid tropical forests, among the highest for any environment.

Environmental risk increase due to heavy metal contamination caused by a copper mining activity in Southern Brazil

The Camaquã Copper Mines (CCM) were the main sulphide deposit in Southern Brazil and have been in operation from last century to 1996. To evaluate water contamination and environmental risk increase by heavy metals from mining operations, two points on the João Dias Creek were sampled (Station 1, background area and Station 2, contaminated area). Mining activity increased the natural weakly heavy metal fluxes by approximately 5424 kg. (approximately 60%) of the total metal flux, 1542 kg. (approximately 49%) of dissolved and 3881 kg (approximately 66%) of particulate metal flux. Total metal flux of anthropic origin was mostly due to Fe followed by Cu > Zn > Mn whereas Cd, As and Pb fluxes were negligible. The potential human health hazards and risk assessment related to daily intake of water from João Dias Creek are mostly due to Mn and should be of concern for the contaminated area. The ingestion of water from station 2 represents incremental risks of 130% and 59% respectively, considering the non-carcinogenic and the carcinogenic effects. The real increase of human health hazards may be greater than those related to the total concentrations since Mn and As dissolved concentrations were 5.5 and 2.0 higher than acceptable, respectively.

A Practical Method to Internalize Environmental Impacts into Cost-Benefit Analysis

Governments and managers have generally conducted inadequate cost-benefit analysis (CBA) by failing to incorporate environmental impact costs. This is not a straightforward task, owing to the intangibility, in monetary terms, of most environmental goods and services. By means of a theoretical example, we present a practical approach to correct cost-benefit analysis for environmental externalities that do not need natural resource valuations. The theoretical example is based on ventures that potentially pollute river waters. However, we think that the methodological approach presented here may be used to internalize (in monetary terms) the costs of negative external impacts on the environment, which may result from any type of venture or project.

Absorption of metals by benthic microbial mats and sediments of Lagoa Vermelha, Brazil

Abstract Lagoa Vermelha provides a small scale model Sabkha Environment, conviniently situated near Rio de Janeiro. This paper presents the results of laboratory experiments on the absorption of copper from solution by sediments and microbial material from this lake, and discusses the permeation of solutions through this material. The laboratory study of naturally occurring materials represents a departure from previous approaches, where either field studies of the natural system, or investigations of totally synthetic laboratory analogues have been undertaken. The results have been used to test the previously postulated theory of mineralogenesis in microbial mats.

Soil Respiration and Carbon Storage of an Acrisol Under Forest and different Cultivations in rio de Janeiro State, Brazil

Soil respiration rates of a clay-loam textured Acrisol under different uses (Atlantic forest, manioc, horticulture and pasture) from Rio de Janeiro State were measured. The relationship between carbon dioxide (CO2) emissions and soil physico-chemical properties were investigated. Rates of CO2 emission of two sites (Atlantic forest and horticulture) were also evaluated in different seasons in 1997 and 1998. In the forest site, monthly means of measured respiration rates showed good correlation with soil temperature in the range 19.6–24.1°C (r2 = 0.89). In the horticulture site, no change was observed with soil moisture alone, in the range 3.0–13.2 wt%. In the horticulture soil, even when the surface soil was very dry, respiration rates increased in the hot, wetter summer but remained higher than the mean flux from forest soil. The CO2 emission flux of the Acrisol under different use showed good correlation with soil temperature (r2 = 0.72) and moisture (r2 = 0.61).

Avaliação do risco ambiental e comportamento geoquímico de metais em área impactada por resíduos industriais em Queimados (RJ).

Areas contaminadas por metais podem configurar serio risco a saude publica e ao meio ambiente. No final da decada de 1980 foi instalado um patio de estocagem provisoria de residuos industriais perigosos na area da empresa Centro Tecnologico de Residuos (CENTRES), no municipio de Queimados, RJ. A gestao inadequada destes residuos proporcionou um grande impacto ambiental ao solo da regiao. Entao, em 2009 foram amostrados solos desta empresa para que fossem avaliadas a mobilidade, toxicidade, biodisponibilidade e risco ambiental de Cd, Cr, Cu, Ni, Pb e Zn utilizando extracao sequencial para o fracionamento geoquimico (BCR), determinando-se as concentracoes destes metais por ICP OES. A soma de todas as fracoes geoquimicas mostraram que a amostra P1 e severamente contaminada por Zn, que as amostras P5 e P5.1 sao contaminadas por Cu, Ni, Pb e Zn, que a amostra P5.2 e contaminada por Ni, Pb e Zn e que a amostra P6 possui concentracoes de Ni que ultrapassam o valor de investigacao industrial preconizado pela legislacao brasileira. Geralmente, o Cd, o Ni e o Zn se mostraram como os metais mais moveis, devido ao enriquecimento das suas concentracoes na fracao soluvel e trocavel do solo (F1). O Pb so se mostrou altamente soluvel e trocavel em amostras de solos que foram severamente contaminadas com este metal. Por outro lado, o Cu e o Cr se mostraram pouco moveis, preferindo estar adsorvidos a fracao oxidavel do solo (F3) ou ao residuo (R) que contem a matriz silicatica e oxi-hidroxidos de alta cristalinidade. Finalmente, o codigo de avaliacao de risco (RAC) se mostrou uma ferramenta limitada ao superestimar o risco ambiental do Cd e do Ni e subestimar o do Cu.

Soil Fauna Communities and Soil Attributes in the Agroforests of Paraty

We conducted the present study in Paraty, southeastern Brazil, in areas under different management regimes and plant cover. The study comprised two different agroforestry systems (AFS-1 and AFS-2), a secondary forest, and a cassava monoculture. We aimed at assessing the effects of land use on the soil fauna and its relationship with soil chemical (pH, Al, Ca, Mg, P, K, carbon, and organic matter) and microbiological attributes (soil microbial biomass carbon - SMB-C, soil respiration – SR, metabolic quotient - qCO2, microbial biomass carbon - C-mic). During winter, AFS-2 showed higher abundance of microphagous, saprophagous, and total individuals than the other areas. AFS-1 and the forest showed an increased abundance of Formicidae and phytophagous groups from winter to summer. The soil fauna and community structure showed that the studied agroforests are under regeneration, becoming more similar to the native forest, where ecological processes are considered efficient.

Relationships between Simultaneous Methane, Nitrous Oxide and Carbon Dioxide Fluxes and Surface Soil Humidity and Temperature in the Mata Atlântica Subtropical Forest, Brazil

Monitoring and other observations have shown that the chemical composition of the atmosphere is suffering modifications, and climate modelling predicts that the average temperature of the planet’s surface and lower atmosphere should increase by 1.5 to 4.5 °C by the middle of 21st century. Current opinion is that increases in atmospheric CO2, CH4 and N2O concentrations, especially by human action, are the cause of this effect.