Land disposal of dredged sediments from an urbanized tropical lagoon: toxicity to soil fauna.

Urban tropical lagoons are commonly impacted by silting, domestic sewage and industrial wastes and the dredging of their sediments is often required to minimize environmental impacts. However, the ecological implications of land disposal of dredged sediments are still poorly investigated in the tropics. Aiming to contribute to filling this gap, an ecotoxicological evaluation was conducted with dredged sediments from Tijuca Lagoon (Rio de Janeiro, Brazil) using different lines of evidence, including soil and sediment characterization, metal determination, and acute and avoidance bioassays with Eisenia andrei.

A picture of artisanal and small-scale gold mining (ASGM) in Brazil and its mercury emissions and releases.

This study presents a picture of ASGM in Brazil and prospective numbers on mercury emissions and releases in 2016, when the country declared production of about 90 tonnes of gold, of which circa 25 tonnes came from ASGM. However, it is also necessary to consider the illegal production of ASGM which is estimated to vary between 10% and eight times more than the legal production. The proposed method included: organization of spatial data on legal ASGM output, stakeholder identification and meetings, mercury metallurgical balance, quantitative measurement of mercury in the atmosphere and qualitative social aspects such as the miners' economic dependence on the managers and scenarios of illegal ASGM annual production.

Chemical and ecotoxicological indicators for evaluating the treatment of coal mining wastes.

This paper consists of the evaluation in regards to the ecotoxicological effectiveness of a treatment applied to a coal mining waste. The treatment consisted of separating the particles based on gravimetric concentration in spirals, generating three fractions: heavy, intermediate, and light, with high, moderate, and low pyrite content, respectively. The intermediate fraction represents the larger disposal volume of the waste on soils.

Ecological risk assessment of metal and hydrocarbon pollution in sediments from an urban tropical estuary: Tijuca lagoon (Rio de Janeiro, Brazil).

Urban tropical lagoons are often impacted by eutrophication, metal, and polycyclic aromatic hydrocarbon (PAH) contamination, but the toxicity of their bottom sediments is still poorly investigated in South America. Aiming to contribute to filling this gap, a sediment quality assessment was conducted in the Tijuca Lagoon (Rio de Janeiro, Brazil) using different lines of evidence (LOEs) including sediment characterization, determination of metals and PAHs, and acute toxicity testing with burrowing amphipods (Tiburonella viscana). Mud and organic matter contents played a crucial role in contaminant distribution along the lagoon.

Gold mining tailing: Environmental availability of metals and human health risk assessment.

The gold ore from sulfide minerals is, in general, ore dressed by means of nine stages among which stand out flotation and cyanidation. The residues of these steps, containing potentially toxic elements, such as As, Cd, Cr, Mn, Zn and Pb disposed of tailings dams, which might be a source of environmental contamination if not suitably disposed and/or in cases of accidents and overflows. Sequential extraction schemes (SES) have been used to estimate the potential environmental availability of contaminants from environmental matrices and, lately, from residues.

Metal pollution in surface sediments from Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil): Toxic effects on marine organisms.

The Rodrigo de Freitas Lagoon (RFL - Rio de Janeiro, RJ, Brazil) is a highly polluted and eutrophic lacustrine system, which has been often used for the practice of aquatic sports, including during the 2016 Summer Olympic Games. This study proposes the evaluation of metal concentrations in surface sediments from the RFL before and after urban interventions performed for the 2016 Olympics, as well as their toxicity to the benthic amphipod Tiburonella viscana and embryos of the sea-urchin Echinometra lucunter. Metal concentrations determined in 2017 were significantly higher than those obtained in 2015 (especially Cu, Cd and Ni), suggesting that the interventions performed to fulfill the requirements of the Olympics increased metal contents in sediments.

Spatial variability and seasonal toxicity of dredged sediments from Guanabara Bay (Rio de Janeiro, Brazil): acute effects on earthworms.

The toxicity of dredged sediments from Guanabara Bay (Rio de Janeiro, Brazil) was evaluated using acute bioassays with Eisenia andrei and metal determination. The sediments were collected in August 2014 (winter) and February 2015 (summer) and in five areas distributed along the Bay: Port of Rio de Janeiro, Port of Niterói, Meriti River mouth, Iguaçu River mouth, and the Environmental Protection Area (APA) of Guapimirim. The sediments were mixed with a ferralsol (a representative Brazilian tropical soil) in proportions varying between 0 (pure soil) and 30%.

Mass balance of arsenic fluxes in rivers impacted by gold mining activities in Paracatu (Minas Gerais State, Brazil).

Arsenic (As) is a dangerous and carcinogenic element and drinking water is its main pathway of human exposure. Gold mines are widely recognized as important sources of As pollution. This work proposes the assessment of As distribution along watersheds surrounding "Morro do Ouro" gold mine (Paracatu, southeastern Brazil).

Information sources, awareness and preventive health behaviors in a population at risk of Arsenic exposure: The role of gender and social networks.

The population of Paracatu is at risk of Arsenic (As) exposure associated with long-term exploration of the largest open pit gold mine in Brazil. As part of the interdisciplinary research "The Paracatu project: Arsenic environmental contamination and human health risks assessment in Paracatu-MG", carried out between 2011 and 2013, we used data disaggregated by gender to identify the sources of As-related information being accessed by inhabitants of Paracatu and to examine if access to these sources was correlated to awareness of As health effects and adoption of behaviors to reduce risk of As exposure. Semi-structured, face-to-face interviews were carried out with 460 participants (294 women and 166 men) to collect data on respondent's socio-demographic characteristics, use of mass media and social communication networks as sources of information on As issues, the trustworthiness of these information sources, awareness of As health effects, and adoption of behaviors to reduce As exposure.

Hydrogeochemistry of arsenic pollution in watersheds influenced by gold mining activities in Paracatu (Minas Gerais State, Brazil).

The aim of this study is to evaluate total arsenic (As) concentrations in drinking water (main pathway of human exposure) and its hydrogeochemical controls in the "Morro do Ouro" gold mine region, which is the largest gold mine in Brazil, characterized by gold-arsenopyrite association. Arsenic concentration was generally below the detection limit (LOD < 0.5 μg L(-1)).

Human exposure and risk assessment associated with mercury contamination in artisanal gold mining areas in the Brazilian Amazon.

Mercury (Hg) contamination is an issue of concern in the Amazon region due to potential health effects associated with Hg exposure in artisanal gold mining areas. The study presents a human health risk assessment associated with Hg vapor inhalation and MeHg-contaminated fish ingestion, as well as Hg determination in urine, blood, and hair, of human populations (about 325 miners and 321 non-miners) from two gold mining areas in the Brazilian Amazon (São Chico and Creporizinho, Pará State). In São Chico and Creporizinho, 73 fish specimens of 13 freshwater species, and 161 specimens of 11 species, were collected for total Hg determination, respectively.

Ecotoxicological assessment of a dredged sediment using bioassays with three species of soil invertebrates.

The ecotoxicity of a dredged sediment from the Guanabara Bay (Rio de Janeiro, RJ, Brazil) was evaluated using reproduction tests with Eisenia andrei, Folsomia candida and Enchytraeus crypticus, and avoidance and feeding inhibition tests with Folsomia candida. The sediment was mixed with artificial soil to obtain the following doses: 1.25, 2.

Disposal of dredged sediments in tropical soils: ecotoxicological evaluation based on bioassays with springtails and enchytraeids.

Metal reference values established in Brazilian legislation for terrestrial disposal of dredged sediments and soil quality were derived for temperate regions. To evaluate the adequacy of such metal reference values to tropical soils, the ecotoxicity of a dredged sediment (from the Guanabara bay, Rio de Janeiro, Brazil) was investigated in two local soils (ferralsol and chernosol) by performing avoidance and reproduction tests using Folsomia candida and Enchytraeus crypticus. Test doses consisted of 0 %, 1.

Mercury contamination in alligators (Melanosuchus niger) from Mamirauá Reservoir (Brazilian Amazon) and human health risk assessment.

Mercury (Hg) concentrations in muscles of wild alligators (Melanosuchus niger) from the Mamirauá Reservoir (a reference area in the Brazilian Amazon) and the human health risks associated with its consumption were assessed. The mean Hg concentration in alligator muscles was 0.407 ± 0.

Disposal of dredged sediments in tropical soils: ecotoxicological effects on earthworms.

The upper limit concentrations of metals established by international legislations for dredged sediment disposal and soil quality do not take into consideration the properties of tropical soils (generally submitted to more intense weathering processes) on metal availability and ecotoxicity. Aiming to perform an evaluation on the suitability of these threshold values in tropical regions, the ecotoxicity of metal-contaminated dredged sediment from the Guanabara Bay (Rio de Janeiro, Brazil) was investigated. Acute and avoidance tests with Eisenia andrei were performed with mixtures of dredged sediment with a ferralsol (0.

Relationship between mercury concentrations in the blood with that in the muscle of four estuarine tropical fish species, Rio de Janeiro State, Brazil.

The aim of this work was to assess the relationship between mercury concentrations in the blood with that in muscle for non-invasive mercury contamination assessment in fish. At Ribeira Bay were collected 198 fishes of 4 species (Genidens genidens, Arius luniscutis, Haemulon steindachneri, Micropogonias furnieri). At Guanabara Bay were collected 84 fishes of 2 species (Genidens genidens, Micropogonias furnieri).

Mercury contamination in fish from gold mining areas in Indonesia and human health risk assessment.

This study investigates the effects on fish and assesses human health hazards from mercury released in two gold mining areas in Indonesia: Tatelu (North Sulawesi Province) and Galangan (Katingan District, Central Kalimatan Province). In Tatelu, 154 fish specimens of 10 freshwater species were collected, as well as five marine species from the fish market. The mean concentration of total mercury in muscles of freshwater fish from this area was 0.