Abstract The degradation of tropical coastal lagoon systems in urban areas of the least developed countries has been associated with an increase in impermeable areas and poor domestic sewage treatment, increasing land-based runoff of nutrients and suspended solids from catchments. This study aimed to assess the biogeochemical changes caused by human interventions through the analysis of the spatial distribution of sedimentary phosphorus (P) and its mass balance in the Itaipu lagoon, located on the east coast of the state of Rio de Janeiro. Human intervention in the Itaipu lagoon system has caused severe imbalances in biogeochemical cycles over the past decades. Watercourses have been channeled to normalize the hydrological regime and increase hydraulic energy, improving sediment transport capacity. In this context, the increase in runoff from the coastal urban basin into the Itaipu lagoon has buried an increasing amount of phosphorus in the sediment. Recently, a regional increase in storm events caused a series of landslides and floods, which have been reported as possible consequences of global climate change. In recent decades, the synergy between landslides and river channeling has increased TP loads, accelerating phosphorus settling and changing P spatial distribution in surface sediments. This has accelerated siltation of the lagoon with an accumulation of nutrients and organic matter, leading in some cases to sediment anoxia. The lagoon has undergone strong eutrophication, changing its trophic state from meso- to hypertrophic in less than 30 years, even though P loads are not as high as in other coastal lagoons. Our findings confirm that human intervention impacts nutrient loads, which in turn disrupt the balance of biogeochemical cycles, compromising coastal water resources. This leads to the collapse of ecosystem services, another step towards degrading planetary boundaries.

Abstract The atmospheric dispersion atmospheric plume of the metropolitan region and neighborhoods of the city of Rio de Janeiro was investigated through elemental analyzes (Na, K, Al, Mn, Pb, Ni, Cr) and stable lead isotopes in two epiphytes; the lichen Parmotrema crinitum (Ach.) and the bromeliad Tillandsia usneoides (L.). All the elements had lower concentrations in epiphytes than in rocks of the local geological basement, with the exception of K, which was similar to rocks. This behavior was attributed to the nutritional essentiality and abundance of this element in the environment. The concentrations of Na, Pb and the 206Pb/207Pb and 208Pb/206Pb ratios indicated the presence of spatial gradients in the path (a) sea shore → continent, and (b) urban center → farmlands. These patterns were associated with the mesoscale atmospheric circulation regime, in which, during the arrival of cold fronts, air masses from the metropolitan region of Rio de Janeiro are transported towards the mountainous region of Teresópolis, which acts as a barrier to the dispersion of pollutants. The bromeliad Tillandsia usneoides and the lichen Parmotrema crinitum were linked to Na and Pb atmospheric levels, respectively.

Resumo A Lagoa de Araruama (Rio de Janeiro) é conhecida por sua beleza cênica e recursos naturais, fatores que permitiram a expansão econômica da região. A atividade turística e a especulação imobiliária foram determinantes para o desenvolvimento urbano dos municípios adjacentes nas últimas décadas. Utilizando dados secundários e o referencial teórico a Ecologia Política e da Educação Ambiental Crítica, buscou-se avaliar as correlações entre o processo de desenvolvimento das cidades as margens da Lagoa e o seu impacto sobre a qualidade ambiental deste ecossistema. A evolução dos parâmetros estudados ao longo dos últimos anos demonstrou que o desequilíbrio do desenvolvimento sustentável na região prejudicou a saúde do corpo hídrico. A elevada taxa de introdução artificial de água doce e de efluentes domésticos e industriais, sem o tratamento adequado, sobrecarregou o sistema lagunar; prejudicando, assim, toda a economia adjacente.

Abstract The Araruama Lagoon (Rio de Janeiro) is known for its scenic beauty and natural resources, factors that have led to the economic expansion of the region. In recent decades, tourism and property speculation have been key to the urban development of the municipalities surrounding this Lagoon. Using secondary data and a theoretical framework based on Political Ecology and Critical Environmental Education, this article seeks to analyze the correlations between the development processes of the towns surrounding the Lagoon and the impact of these processes on the environmental quality of its ecosystem. In recent years, the evolution of parameters studied revealed that the imbalance in terms of the sustainable development of the region has damaged the health of this body of water. Large quantities of fresh water, as well as domestic and industrial effluents discharged without appropriate treatment in the Lagoon, have overloaded the ecological system, with negative effects for the entire economy in the surrounding area.

Resumen La Laguna de Araruama, situada en la costa del estado de Río de Janeiro, es conocido por su belleza escénica y los recursos naturales, y permitieron que la región expandir económicamente. El turismo y la especulación inmobiliaria fueron la clave para el desarrollo urbano de los municipios adyacentes en las últimas décadas. El presente estudio intenta una evaluación de las correlaciones entre los procesos de desarrollo de las ciudades relacionadas con la laguna de Araruama y su impacto en la calidad ambiental de este ecosistema. Se basa en una revision de la literatura e usada la teoria Política Ecología teórica y Educación ambiental crítica. La evolución de los parámetros estudiados en los últimos años ha demostrado que el desequilibrio del desarrollo sostenible en la región deterioro la salud de la masa de agua. La alta tasa de introducción artificial de agua dulce y aguas residuales domésticas e industriales, sin tratamiento adecuado, ha sobrecargas el sistema lagunar; causando, por ello, un perjuicio a toda la economía circundante.

Os metais traço apresentam grande toxicidade quando presentes em teores elevados nos organismos humano e animal. No ambiente aquático, alguns elementos formam compostos orgânicos que bioacumulam nos tecidos de organismos vivos. Os moluscos bivalves se destacam, pois possuem grande participação na dinâmica de contaminantes metálicos no ambiente marinho devido à capacidade de concentrá-los em níveis mais elevados que na água. Os mexilhões são moluscos bivalves que constituem bons indicadores de biodisponibilidade de metais, sendo amplamente utilizados como biomonitores em ecossistemas aquáticos. No Brasil, a espécie de mexilhão Perna perna é o mais cultivado devido à importância na alimentação de grande parte da população das regiões costeiras. Portanto, o consumo de mexilhões pode representar um risco à saúde humana quando proveniente de locais contaminados com metais traço, o que reforça a importância de se conhecer os teores desses elementos nos ambientes que fornecem alimento ao Homem. Devido à constante busca pela qualidade ambiental associada à utilização do mexilhão P. perna como biomonitor e como alimento, é importante conhecer o panorama de contaminação do território nacional a fim de auxiliar na prevenção de intoxicação por metais traço pelo consumo desse molusco por grande parte da população brasileira.

Trace elements are considered toxic in high levels for human and animal organisms. In aquatic environment, some elements can form organic compounds and tend to bioaccumulate in organisms tissues. Bivalve mollusks participate on the metallic contaminants dynamics in aquatic environment due to capacity in concentrate trace elements in their soft tissues in higher levels than in water. Mussels are mollusks widely used as bioindicators of trace metal pollution in coastal areas because they can accumulate various elements as filter-feeders. In Brazil, Perna perna is one of the most commonly consumed bivalve mollusks and the most cultivated in coast regions. Therefore, the consumption of mussels may be a potential risk for human health, which enhances the importance to know trace metal levels in environment that provides food to humans. Due to constantly search for environmental quality and the use of mussels as food and often employed to monitor metal pollution in sea, it is of great interest and importance an overview of metallic contamination in national territory to assist in prevention of intoxication by trace elements.

O presente estudo teve por objetivo avaliar a qualidade da água na área do Emissário de Esgoto de Icaraí (ISEO). A amostragem foi realizada durante o inverno e o verão, e as amostras de água foram analisada quanto ao oxigênio dissolvido, pH, temperatura, salinidade, nutrientes inorgânicos dissolvidos (NID), seston, matéria orgânica particulada (MOP) e pigmentos. Os resultados mostraram que a química da água apresenta variações temporal e espacial. Grande variabilidade foi também observada nas razões C:N:P do MOP (Agosto, 112:30:1; Dezembro, 59:11:1) e nas concentrações de NID. As concentrações de clorofila-a e amônia (4.5 µg L-1 - 71.2 µg L-1, e 0.20 µM - 52,6 µM, respectivamente) caracterizam a área do ISEO como eutrófica. A dispersão do material não é efetiva em certas condições oceanográficas.

The present study aimed to evaluate the water quality of the Icaraí Sewage Outfall (ISEO) area. Sampling was conducted during winter and summer, and water samples were analyzed for dissolved oxygen, pH, temperature, salinity, dissolved inorganic nutrients (DIN), seston, particulate organic matter (POM), and pigments. Results showed that the water chemistry of the area suffers temporal and spatial variation. Great variability was also seen in the C:N:P ratios of POM (August, 112:30:1; December, 59:11:1) and in the DIN concentrations. Chlorophyll-a and ammonium concentrations (4.5 µg L-1 - 71.2 µg L-1, and 0.20 µM - 52,6 µM, respectively) characterized the ISEO area as eutrophic. The dispersal of the material was not effective under certain oceanographic conditions.