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Role of the floodplain lakes in the methylmercury distribution and exchanges with the Amazon River,Brazil

Journal of Environmental Sciences 2018年第6期30卷 24-40页

作者： Poliana Dutra Maia laurence maurice Emmanuel Tessier David Amouroux Daniel Cossa Patricia Moreira-Turcq Henri Etcheber Universidade de Brasilia-Faculdade UnB Planaltina Area Universitaria n. 1-Vila Nossa Senhora de Fatima Planaltina 73300-000 Brasilia DF Brazil Geosciences Environnement Toulouse (GET) Observatoire Midi Pyrenees Universite de Toulouse CNRS IRD14 Avenue Edouard Belin F-32400 Toulouse France CNRS/Univ Pau & Pays Adour Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Materiaux UMR5254 F-64000 Pau Prance Universite Grenoble Alpes CP 40700 F-38058 Grenoble Cedex 9 France EPOC UMR 5805 Universite de Bordeaux I Av. des Facultes F-33405 Talence France

Seasonal variability of dissolved and particulate methylmercury（F-MeHg, P-MeHg） concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005–2006, to understand the MeHg exchanges between these aquatic systems. In the oxic white water lakes, with neutral pH, high F-MeHg and P-MeHg concentrations were measured during the rising water stage（0.70 ± 0.37 pmol/L, n = 26） and flood peak（14.19 ± 9.32 pmol/g, n = 7） respectively, when the Amazon River water discharge into the lakes was at its maximum. The lowest mean values were reported during the dry season（0.18 ± 0.07 pmol/L F-MeHg, n = 10 and 1.35 ± 1.24 pmol/g P-MeHg, n = 8）, when water and suspended sediments were outflowing from the lakes into the River. In these lakes,the MeHg concentrations were associated to the aluminium and organic carbon/nitrogen changes. In the black water lakes, with acidic pH and reducing conditions, elevated MeHg concentrations were recorded（0.58 ± 0.32 pmol/L F-MeHg, n = 16 and 19.82 ± 15.13 pmol/g PMeHg, n = 6）, and correlated with the organic carbon and manganese concentrations. Elevated values of MeHg partition coefficient（4.87 〈 Kd〈 5.08 log（L/kg） indicate that MeHg is mainly transported associated with the particulate phase. The P-MeHg enrichment detected in all lakes suggests autochthonous MeHg inputs from the sediments into the water column. The MeHg mass balance showed that the Curuai floodplain is not the source of P-MeHg for the Amazon River.

关键词： Methylmercury Water Sediment Amazon River Floodplain lakes

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玻利维亚亚马孙河流域上贝尼河的汞污染

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AMBIO－人类环境杂志 1999年第4期28卷 302-306页

作者： laurence maurice-Bourgoin Irma Quiroga Jean Loup Guyot Olaf Malm 刘乃隆 ORSTOM French Scientific Research Institute for Development by Cooperation CP 9214 La Paz Bolivia 拉巴斯大学 ORSTOM French Scientific Research Institute for Development by CooperationCP 09747 70001-970 Brasilia DF Brazil 里约热内卢联邦大学生物物理学研究所中国地质出版社

小规模采金业,特别是一些从本世纪70年代开始蓬勃兴起这种采金业的热带地区(例如亚马孙河流域),由于汞齐法造成的汞污染是一项受到日益关注的环境问题。这项问题的研究工作在巴西早已开展多年,而玻利维亚这方面的资料尚缺。本文论述了... 详细信息

小规模采金业,特别是一些从本世纪70年代开始蓬勃兴起这种采金业的热带地区(例如亚马孙河流域),由于汞齐法造成的汞污染是一项受到日益关注的环境问题。这项问题的研究工作在巴西早已开展多年,而玻利维亚这方面的资料尚缺。本文论述了亚马孙河流域一条玻利维亚河系中由水、鱼和人头发所测出的汞污染情况。从鱼和食用食肉鱼类的人头发中都发现了高浓度的汞。食用鱼对健康的潜在危险明显存在于采金活动下游的居民,而在矿区本身却不明显。

关键词：贝尼河汞污染玻利维亚亚马孙河流域水样分析

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Prognostic Factors and Survival of Laryngeal Cancer in Cameroon

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International Journal of Otolaryngology and Head & Neck Surgery 2021年第1期10卷 30-42页

作者： Jean Paul Engbang maurice Mpessa laurence Essama Samad Abdel Mohamadou Louis Richard Njock Faculty of Medicine and Pharmaceuticals Sciences The University of Douala Douala Cameroon Douala Laquintinie Hospital Douala Cameroon Douala General Hospital Douala Cameroon

Background: Laryngeal cancer is a major cause of morbidity and mortality worldwide. It is ranked worldwide as the second ENT cancer with 238,000 new cases and 106,000 deaths each year. In Africa, data on the prognostic factors and the survival of this pathology remain quite limited. Objective: To study the prognostic factors of laryngeal cancer and the survival of patients with laryngeal cancer in Yaoundé and Douala. Methods and Materials: We performed an analytical, longitudinal (retrospective) study over a period from January 1, 2009 to December 31, 2018 including all patients with histologically proven laryngeal cancer, at the ENT, oncological, anatomopathological, radiotherapy and surgery Department of three reference health structures in the cities of Douala and Yaoundé (Laquintinie Hospital and General Hospital of Douala, General Hospital of Yaounde). The data collected were recorded and analyzed by SPSS version 25 and Excel 2013 statistical computer software. Survival was determined by the Kaplan Meier method and the search for prognostic factors was carried out using the Cox proportional hazards model. The significance level was p = 0.05. Results: We selected 80 patients whose vital status we knew and who had been followed up after histological evidence. The sex ratio was 5.66. The median age at cancer diagnosis was 62 years old. 60 (75%) were exposed to tobacco, 52 (65%) had alcohol-tobacco poisoning. The Center and Littoral regions were the most represented with 37.5% and 48.8% respectively. Dysphonia was present in 98.8% of patients. The histological type encountered was squamous cell carcinoma in 78 patients;in the majority of cases the cancer was diagnosed at stage IV and the glottis was the most frequent site (86.2%). The median overall survival was 1.41 with 95% CI [1.08 - 1.74]. The overall survival rates at 1 year, 3 years, 5 years and 8 years were 70%, 18%, 3% and 1.5%, respectivel

关键词： Laryngeal Cancer Prognostic Factors Survival Cameroon

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Prognostic Factors and Survival of Laryngeal Cancer in Cameroon

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International Journal of Otolaryngology and Head & Neck Surgery（耳鼻喉） 2021年第1期

作者： Jean Paul Engbang maurice Mpessa laurence Essama Samad Abdel Mohamadou Louis Richard Njock

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