Rio Doce Acoustic Surveys of Fish Biomass and Aquatic Habitat.

Following the failure of the Fundão mine tailings dam in Brazil, approximately 32 million cubic meters of Fe ore tailings were released into the downstream riverine system. The postevent monitoring surveys implemented the use of noninvasive acoustic methods to improve the understanding of the fish biomass distribution patterns and aquatic habitat condition of the impacted reaches of the Rio Gualaxo do Norte, Rio do Carmo, and Rio Doce. The primary focus of the program was to collect hydroacoustic measurements of fish biomass, which was accompanied by sonar imaging of aquatic habitats using high-resolution side scan and downward imaging sonar at each site visited. The biannual surveys began in April 2017 and were fundamentally a multiple control-impact design because before data (prior to the dam failure event) were not available. Up to 22 sites were visited for each survey, including reservoir and river sites. Results indicate similar levels of instream habitat between control and impact river and reservoir sites. Average volumetric biomass was not significantly different between impact sites and their corresponding controls in the August 2018 survey (latest to date). Preliminary temporal analysis of the biomass data set collected indicates that either stable or increasing levels of biomass are detected at tailings impacted sites within the Rio Doce. Integr Environ Assess Manag 2020;16:615-621. © 2020 Hydrobiology QLD Pty Ltd. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Após o rompimento da barragem de rejeitos da mina do Fundão no Brasil, cerca de 32 milhões de metros cúbicos de rejeitos de minério de Fe foram libertados no sistema fluvial a jusante. Monitoramentos pós-evento foram implementados com a utilização de métodos acústicos não invasivos visando ampliar a compreensão dos padrões de distribuição da biomassa de peixes e condições dos habitat aquáticos em trechos impactados do Rio Gualaxo do Norte, Rio do Carmo e Rio Doce. A aquisição de medições hidroacústicas sobre a biomassa de peixes foi o foco principal do programa, seguido pela obtenção de imagens dos habitats aquáticos através da utilização de um sonar de varredura lateral de alta resolução e um sonar de imagem vertical, em cada local visitado. Os levantamentos de campo semestrais tiveram início em Abril de 2017 e seu design amostral foi baseados na concepção "trechos controle - trechos impactados" uma vez que não existem dados disponíveis para o período anterior ao evento (rompimento da barragem). Em cada levantamento foram visitados até 22 pontos de amostragem, incluindo vários reservatórios e rios. Os resultados indicaram níveis de habitat similares entre os pontos controle e impacto, de rios e reservatórios. No monitoramento mais recente (Agosto/2018) a biomassa volumétrica média não foi significativamente diferente entre os locais de impacto e os seus correspondentes pontos controles. A análise temporal preliminar do conjunto de dados sobre a biomassa indicou níveis estáveis ou crescentes deste parâmetro nos locais impactados pelos rejeitos, no Rio Doce. Integr Environ Assess Manag 2020;16:615-621.

Spring Melt and the Redistribution of Organochlorine Pesticides in the Sea-Ice Environment: A Comparative Study between Arctic and Antarctic Regions.

Complementary sampling of air, snow, sea-ice, and seawater for a range of organochlorine pesticides (OCPs) was undertaken through the early stages of respective spring sea-ice melting at coastal sites in northeast Greenland and eastern Antarctica to investigate OCP concentrations and redistribution during this time. Mean concentrations in seawater, sea-ice and snow were generally greater at the Arctic site. For example, α-HCH was found to have the largest concentrations of all analytes in Arctic seawater and sea-ice meltwater samples (224-253 and 34.7-48.2 pg·L-1 respectively compared to 1.0-1.3 and <0.63 pg·L-1 respectively for Antarctic samples). Differences in atmospheric samples were generally not as pronounced however. Findings suggest that sea-ice OCP burdens originate from both snow and seawater. The distribution profile between seawater and sea-ice showed a compound-dependency for Arctic samples not evident with those from the Antarctic, possibly due to full submersion of sea-ice at the former. Seasonal sea-ice melt processes may alter the exchange rates of selected OCPs between air and seawater, but are not expected to reverse their direction, which fugacity modeling indicates is volatilisation in the Arctic and net deposition in the Antarctic. These predictions are consistent with the limited current observations.

Air-Seawater Exchange of Organochlorine Pesticides in the Southern Ocean between Australia and Antarctica.

This study contributes new data on the spatial variability of persistent organic pollutants in the Indian-Pacific sector of the Southern Ocean and represents the first empirical data obtained from this region in 25 years. Paired high-volume atmospheric and seawater samples were collected along a transect between Australia and Antarctica to investigate the latitudinal dependence of the occurrence and distribution of legacy organochlorine pesticides (OCPs) and the current use pesticide chlorpyrifos in the Southern Ocean. Dissolved ΣHCH and dieldrin concentrations decreased linearly with increasing latitude from 7.7 to 3.0 and from 1.0 to 0.6 pg·L(-1), respectively. There was no consistent trend observed in the latitudinal profile of atmospheric samples; however, some compounds (such as dieldrin) showed reduced concentrations from 7.5-3.4 to 2.7-0.65 pg·m(-3) at the highest latitudes south of the Polar Front. Chlorpyrifos was found in samples from this area for the first time. Estimated air-seawater fugacity ratios and fluxes indicate a current net deposition between -3600 and -900, -6400 and -400, and -1400 and -200 (pg·m(-2)·d(-1)) for γ-HCH, dieldrin, and chlorpyrifos, respectively. These findings suggest that, under current climatic conditions, the Southern Ocean reservoir in the Indian-Pacific sector serves as an environmental sink rather than a source of OCPs to the atmosphere.

On the formulation of environmental fugacity models and their numerical solutions.

Multimedia models based on chemical fugacity, solved numerically, play an important role in investigating and quantifying the environmental fate of chemicals such as persistent organic pollutants. These models have been used extensively in studying the local and global distribution of chemicals in the environment. The present study describes potential sources of error that may arise from the formulation and numerical solution of environmental fugacity models. The authors derive a general fugacity equation for the rate of change of mass in an arbitrary volume (e.g., an environmental phase). Deriving this general equation makes clear several assumptions that are often not articulated but can be important for successfully applying multimedia fugacity models. It shows that the homogeneity of fugacity and fugacity capacity in a volume (the homogeneity assumption) is fundamental to formulating discretized fugacity models. It also shows that when using the fugacity rather than mass as the state-variable, correction terms may be necessary to accommodate environmental factors such as varying phase temperatures and volume. Neglecting these can lead to conservation errors. The authors illustrate the manifestation of these errors using heuristic multimedia fugacity models. The authors also show that there are easily avoided errors that can arise in mass state-variable models if variables are not updated appropriately in the numerical integration scheme. Environ Toxicol Chem 2016;35:2182-2191. © 2016 SETAC.

[Cholera in a Paris resident with no history of travel. A case report]. / Choléra autochtone à Paris. Une observation.

BACKGROUND: Cases of imported cholera are frequently observed, but cholera almost never occurs in subjects who have never travelled to an endemic area. In the last 30 years, 4 cases have been reported. We report an indigenous case diagnosed in Paris in September 1996. CASE REPORT: The patient was hospitalized for severe dehydration and acute renal failure. Cultures of a fecal specimen grew Vibrio cholerae O1 Ogawa serotype. An epidemiological study was conducted to identify the vehicle and mode of contamination and suggested that this case was associated with the consumption of fresh sorrel imported from West Africa. No other cases were identified in contacts of the patient. DISCUSSION: Asymptomatic carriage of V. cholerae is rare. However, air travel has allowed people to arrive in non-endemic areas during the incubation period. The agent may also be transported in contaminated foods. Cholera should be suspected in all adults presenting acute watery diarrhea with severe dehydration. History taking should also look for risk exposure and these patients should be systematically asked about possible exposures.