Aspectos da biogeoquímica do mercúrio em lagos na planície costeira do Rio Grande do Sul

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2006.No ambiente aquático um dos mais perigosos contaminantes é o mercúrio.A contaminação por mercúrio na cadeia trófica em ambientes aquáticos pode ser severa e persistente, uma das principais fontes de contaminação por mercúrio em humanos através da cadeia alimentar são os peixes. Nesse estudo:- Foram mensurados os níveis de mercúrio em três lagos no extremo sul do Brasil e avaliou-se a relação entre mercúrio na precipitação atmosférica total, material particulado no ar, material particulado na água dos lagos, sedimentos, solo e água subterrânea as margens dos lagos, plantas aquáticas, molusco aquático e peixes de áreas próximas às fontes de emissão de mercúrio (áreas: industrial e suburbana) e distante das fontes de mercúrio (área de reserva natural).- Foram mensurados os níveis de mercúrio em vinte e sete espécies de peixes de quatro ambientes (lago fechado, lago aberto, estuário, marinho). Simulou-se o aporte de mercúrio atmosférico para os lagos, através de um experimento. No qual adicionou-se poeira contaminada por mercúrio em tanques contendo: peixe, sedimento e plantas aquáticas. As concentrações de mercúrio no sedimento e nas plantas aquáticas não demonstraram variação entre os lagos. Em molusco, água subterrânea, e material particulado na água dos lagos apresentam diferença muito pequena entre as três áreas estudadas. No entanto, o nível de mercúrio na precipitação atmosférico nesses lagos estudado apresentou aumento com a proximidade da fonte industrial. Mercúrio no tecido de peixe geralmente aumenta ao longo do mesmo gradiente, mas varia com o nível trofico. A concentração de mercúrio em peixe pode estar diretamente relacionada com a concentração de mercúrio na deposição atmosférica nesses lagos fechados. Foram encontradas altas concentrações de mercúrio em peixes do lago fechado na área suburbana, em relação ao lago aberto, estuário e oceano. Em todos os ambientes, as espécies piscívoras apresentaram maior valor de mercúrio no tecido do que as espécies não piscívoras. A simulação do processo de contaminação por mercúrio através do depósito das precipitações atmosféricas na superfície da água em laboratório demonstrou acumulação progressiva de mercúrio nas plantas aquáticas e no sedimento.Mercury is one of the most hazardous contaminant in aquatic environment. Mercury contamination in aquatic environment food webs can be severe and persistent, and fish are a major source of mercury contamination in humans across food web. In this study: - Was measured mercury levels at three lakes in southern Brazil and assessed relationships between mercury in atmospheric precipitation, particulate matter in lake water, sediment, soil near the lake, groundwater, aquatic plants, aquatic mollusc and fish tissues at sites close to (industrial and suburban areas) and distant from (protected conservation area) sources of mercury emissions. - Mercury levels are measured in twenty-seven fish species from four sites (close lake, open lake, estuary, marine). Was simulated the input of mercury at atmosphere from lake, through the experiment. In this experiment to add the dust contamination with mercury in pools contained: fish, sediments and aquatic plants. Also assessed relationship between mercury in fish species and their trophic habits. Mercury concentrations in sediment and aquatic plants did not significant variation among lakes. In aquatic mollusc, groundwater and particulate matter in lake water has small difference between the three sites. In contrast, mercury in precipitation at the study lakes increased with proximity to industrial sources. Mercury in fish tissue generally increased along the same gradient, but also varied with trophic level. Atmospheric mercury deposition to these closed lakes may be directly linked to concentrations in fish. Was finding the highest mercury concentration in fish from close lake in relation than open lake, estuary and ocean. In every site the piscivorous species present more mercury in tissue than species non-piscivorous. The simulation of process of mercury contamination through the deposition of atmospheric precipitation in the water surface in laboratory demonstrates progressive mercury accumulation in aquatic plants and sediment

Mercury in freshwater, estuarine, and marine fishes from Southern Brazil and its ecological implication

In this study, we measured the mercury concentration in 27 different fish species with high commercial value. Samples were taken from a region characterized by the diversity of aquatic environments. Mercury concentration in marine fish species varied from 30.4 to 216 ng g−1, while in estuarine species, it varied from 12.4 to 60.3 ng g−1. Compared to mercury concentration in marine species, none of the specimens from estuarine environment has reached a mercury concentration of 100 ng g−1.However, mercury concentrations in species from the freshwater Patos lagoon are remarkably higher (15.3 to 462 ng g−1) than those from the estuarine or marine region. Even though mercury concentrations in these fish species did not exceed the maximum level (500 ng g−1) allowed by WHO for human consumption, they represent the main food source for sea birds and mammals coming from South Pole during their migration period

Trophic analysis of female mangrove crabs at two sites from Southeastern Brazil (Rio de Janeiro)

The mangrove crab Ucides cordatus (Linnaeus, 1763) is a burrowing crab with an important role in mangrove nutrient cycling. The species holds major socioeconomic importance, generating yield for traditional and low-income populations. Despite its ecological and economic importance, there are few experiments in Brazil applying stable isotope tools to trophic crab classification, and even fewer considering females in the reproductive period. Females have different energy demands than males; studies examining C and N can reveal details regarding the differences. Hence, the present study is the first analysis of the δ 13C, δ 15N, and the C/N ratio in ovigerous females of two populations from Southeastern Brazil (Caceribu River - Guanabara Bay and Gargaú mangrove - Paraiba do Sul River secondary estuary). The Caceribu mangrove is larger and is located in one of the most impacted bays in the world. In the Paraiba do Sul River region, the mangrove swamp is about ten times smaller, has a substantially lower population in the surrounding area, and is more influenced by agricultural activities. The δ 13C analysis confirmed mangrove leaves as their main food source. The significant δ 13C variation between the Guanabara and Paraiba do Sul estuary populations can be related to differences in food availability and nutritional value. However, the δ 15N values can be related to the ingestion of other food items during the breeding season as well as the influence of anthropogenic mangrove degradation. At both study sites, the δ15N values were higher than those observed in other mangrove crab populations and other herbivorous species. Significant (p < 0.05) isotopic differences were found among populations, suggesting variations in biogeochemical cycles that may be related to different environmental conditions between the sites

Egg release and initial development of caligus sp. (copepoda: caligidae) parasite of captive juvenile flounder paralichthys orbignyanus (teleostei: paralichthyidae)

Submitted by EDUARDO PENA ([email protected]) on 2012-08-24T12:28:47Z No. of bitstreams: 1 OVOPOSIÇÃO E DESENVOLVIMENTO INICIAL DE Caligus sp. (COPEPODA CALIGIDAE).pdf: 122880 bytes, checksum: 288864d3fb3790d3096892f1fbccc0bf (MD5)Approved for entry into archive by Gabriela Silva da Rosa([email protected]) on 2013-09-08T11:59:27Z (GMT) No. of bitstreams: 1 OVOPOSIÇÃO E DESENVOLVIMENTO INICIAL DE Caligus sp. (COPEPODA CALIGIDAE).pdf: 122880 bytes, checksum: 288864d3fb3790d3096892f1fbccc0bf (MD5)Made available in DSpace on 2013-09-08T11:59:27Z (GMT). No. of bitstreams: 1 OVOPOSIÇÃO E DESENVOLVIMENTO INICIAL DE Caligus sp. (COPEPODA CALIGIDAE).pdf: 122880 bytes, checksum: 288864d3fb3790d3096892f1fbccc0bf (MD5) Previous issue date: 2002Fêmeas ovígeras de Caligus sp. foram coletadas em juvenis do linguado Paralichthys orbignyanus (Valenciennes, 1839) capturados na Praia do Cassino (Rio Grande – RS) e mantidos em cativeiro no Laboratório de Maricultura da FURG. As fêmeas de Caligus sp. foram mantidas em placas de Petry com o objetivo de acompanhar a ovoposição e o desenvolvimento das fases larvais livres. O comprimento médio das fêmeas, excluindo as cerdas das lâminas caudais, foi de 3,58 ± 0,28mm (média ± desvio padrão). Foi verificado que a diferenciação dos embriões ocorre cerca de 20h após a postura, a primeira eclosão entre 21-25h e o tempo para atingir o estágio de copepódito foi estimado em 20h. Foram produzidas 31,5 ± 3,6 larvas por fêmea, sendo sua sobrevivência até o estágio de copepódito igual a 46,3 ± 14,3%. Imediatamente após a eclosão foi observada a reposição dos sacos ovígeros e a eclosão dos ovos do segundo par de sacos ovígeros ocorreu 50h após o início da sua formação. Este segundo lote de ovos foi produzido com as fêmeas em jejum e na ausência de machos. Os resultados deste trabalho sugerem a existência de um elevado potencial de infestação de juvenis de P. orbignyanus por Caligus sp., indicando a importância da elaboração de protocolos profiláticos que permitam o controle desta parasitose e assim evitar possíveis perdas em sistema de cultivo intensivo de linguado.Ovigerous females of Caligus sp. were collected from juvenile flounder Paralichthys orbignyanus (Valenciennes, 1839) captured at Cassino Beach (Rio Grande – RS) and kept in captivity in the Mariculture Laboratory (FURG). Fifteen females were kept in Petry dishes in order to observe egg release and development of free-swimming larvae. The average length of females, excluding anal setae, was 3.58 ± 0.28mm (average ± standard deviation). Differentiation of embryos occurred in 20h and larvae hatched between 21-25h. The elapsed time from hatching to the copepodid stage was estimated as 20h. The average number of nauplii I produced per female was 31.5 ± 3.6, and survival to the copepodid stage was found to be 46.3 ± 14.3%. The second pair of egg sacs, was observed immediately after the first eggs had hatched. Hatching began 50h after the emergence of the second pair of egg sacs. It is important to note that the production of the second pair of egg sacs was achieved in the absence of males and of food. Results of this work suggest a high potential for infestation of juvenile flounder P. orbignyanus by Caligus sp. Therefore, a prophylactic protocol should be established to control this parasite and avoid losses that might occur in intensive flounder culture

Ovoposição e desenvolvimento inicial de caligus sp. (copepoda: caligidae) parasita de juvenis do linguado paralichthys orbignyanus (teleostei: paralichthyidae) em cativeiro

Fêmeas ovígeras de Caligus sp. foram coletadas em juvenis do linguado Paralichthys orbignyanus (Valenciennes, 1839) capturados na Praia do Cassino (Rio Grande – RS) e mantidos em cativeiro no Laboratório de Maricultura da FURG. As fêmeas de Caligus sp. foram mantidas em placas de Petry com o objetivo de acompanhar a ovoposição e o desenvolvimento das fases larvais livres. O comprimento médio das fêmeas, excluindo as cerdas das lâminas caudais, foi de 3,58 ± 0,28mm (média ± desvio padrão). Foi verificado que a diferenciação dos embriões ocorre cerca de 20h após a postura, a primeira eclosão entre 21-25h e o tempo para atingir o estágio de copepódito foi estimado em 20h. Foram produzidas 31,5 ± 3,6 larvas por fêmea, sendo sua sobrevivência até o estágio de copepódito igual a 46,3 ± 14,3%. Imediatamente após a eclosão foi observada a reposição dos sacos ovígeros e a eclosão dos ovos do segundo par de sacos ovígeros ocorreu 50h após o início da sua formação. Este segundo lote de ovos foi produzido com as fêmeas em jejum e na ausência de machos. Os resultados deste trabalho sugerem a existência de um elevado potencial de infestação de juvenis de P. orbignyanus por Caligus sp., indicando a importância da elaboração de protocolos profiláticos que permitam o controle desta parasitose e assim evitar possíveis perdas em sistema de cultivo intensivo de linguado.Ovigerous females of Caligus sp. were collected from juvenile flounder Paralichthys orbignyanus (Valenciennes, 1839) captured at Cassino Beach (Rio Grande – RS) and kept in captivity in the Mariculture Laboratory (FURG). Fifteen females were kept in Petry dishes in order to observe egg release and development of free-swimming larvae. The average length of females, excluding anal setae, was 3.58 ± 0.28mm (average ± standard deviation). Differentiation of embryos occurred in 20h and larvae hatched between 21-25h. The elapsed time from hatching to the copepodid stage was estimated as 20h. The average number of nauplii I produced per female was 31.5 ± 3.6, and survival to the copepodid stage was found to be 46.3 ± 14.3%. The second pair of egg sacs, was observed immediately after the first eggs had hatched. Hatching began 50h after the emergence of the second pair of egg sacs. It is important to note that the production of the second pair of egg sacs was achieved in the absence of males and of food. Results of this work suggest a high potential for infestation of juvenile flounder P. orbignyanus by Caligus sp. Therefore, a prophylactic protocol should be established to control this parasite and avoid losses that might occur in intensive flounder culture

Impacts of a tailings dam failure on water quality in the Doce river: The largest environmental disaster in Brazil

Background: On November 5, 2015, the Fundão Dam, owned by Samarco Mineração SA, experienced a catastrophic failure, releasing approximately 55 to 62 million m3 of mining ore waste into the Doce River. This event had severe consequences as the Doce River serves as a vital source of water and food for numerous communities. Objective: Evaluate the spatiotemporal distribution of water parameters before, during, and after the failure of the Samarco tailings dam, with the goal of support the management and restoration of water quality. The study utilizes a long historical series of data from 1997 to 2018. Methodology: In this study, data from 13,916 measurements of variables including HCO3−, Mg2+, Ca2+, SO42−, pH, EC, and metal(oids) such as Fe, Mn, As, Cu, Ba, Pb, Zn, Cd, Cr, and Ni were compiled. These measurements were collected from 1997 to 2018 to investigate the impact of the dam rupture. Results: The dam failure resulted in an increase in high turbidity events and total suspended solids (TSS), leading to a decline in water quality. The Kruskal-Wallis test revealed a homogenization effect along the river watershed caused by the accident, particularly for Pb, Ni, Cd, Cr, and coliforms. Additionally, there was a change in the seasonal distribution of PO43−, NH4+, Na+, SO42−, and Zn. The factor analysis identified four main factors: i) HCO3−, Mg2+, Ca2+, SO42−, pH, and electrical conductivity (37.55%) were indicative of weathering processes from lithotypes; ii) Fe+Mn and the metal(oids) (As, Cu, Ba, Pb, Zn, Cd, Cr, and Ni) (15.89%) were associated with ore waste and regional geology; iii) total coliforms, NO3−, NH4+, and PO43− (9.39%) were linked to anthropogenic influences in the river; and iv) K+, Na+, and Cl− (8.22%) represented the impact of domestic and industrial sewage discharge as well as the marine environment in the lower sector of the Doce River. Conclusion: The dam rupture significantly altered water quality in the Doce River, particularly in relation to metal(oids), three years after the disaster. The presence of ore waste in the bottom sediments creates an environmental liability as it can be remobilized by human activities or extreme weather events, further impacting water quality

RISCOS DE INGESTÃO DE FLÚOR: ESTUDO DE CASO PARA ÁGUA MINERAL DO INTERIOR DO ESTADO DO RIO DE JANEIRO

O consumo de flúor presente em águas superficiais e subterrâneas é uma prática comum em diversos países. Além de abordar a temática controversa quanto ao consumo do flúor, este artigo apresenta um estudo de caso de avaliação de risco à saúde humana pelo consumo de águas fluoretadas, provenientes do Parque de Águas Minerais, localizado na região Centro-Sul do Estado do Rio de Janeiro. As concentrações de flúor foram medidas entre outubro de 2014 e agosto de 2015 em três poços de água mineral e em seus respectivos fontanários, sendo as fontes denominadas popularmente de Fonte Alcalina Terrosa Cálcica, Alcalina Terrosa Ferruginosa e Alcalina Terrosa Magnesiana. Foi avaliada a possibilidade de haver riscos para o desenvolvimento de fluoroses e aumento de fraturas ósseas nas populações consumidoras. Esta pesquisa modelou a ingestão diária dessas águas com flúor por receptores residenciais dos tipos: bebês, infantes, crianças, adolescentes e adultos. Foi constatado que os grupos de bebês e infantes podem estar mais sujeitos a riscos crônicos para o desenvolvimento de fluorose dentária na fonte de água mineral Alcalina Terrosa Magnesiana. Recomenda-se que a água mineral dessa fonte não seja consumida pelos grupos de crianças