Global Mercury Emissions from Gold and Silver Mining     

Lacerda  L.D. 《Water, air, and soil pollution》1997,97(3-4):209-221

Mercury has been used in gold and silver mining since Roman times. With the invention of the "patio" process in Spanish colonial America, silver and gold were produced in large scale, mostly in the Americas but also in Australia, Southeast Asia and even in England. Mercury released to the biosphere due to this activity may have reached over 260,000 t from 1550 to 1930, when silver reserves in Spanish colonial America were nearly exhausted and Hg-amalgamation was replaced by the more efficient cyanidation process. Exceptional increases in gold prices and the worsening of social-economic conditions in the third world in the 1970's, resulted in a new gold rush in the southern hemisphere, involving over 10 million people in all continents. Presently, Hg amalgamation is used as a major technique for gold production in the South America especially the Amazon, China, Southeast Asia and in some African countries. Mercury inputs to the environment from this activity may reach up to 460 t.yr- 1. Compared with other anthropogenic Hg sources, gold mining is presently responsible for approximately 10% of the global anthropogenic Hg emissions, but has never been included in global models of Hg cycling in the biosphere. Further, most of the Hg released to the biosphere through gold and silver mining during the last 500 years, roughly 300,000 t, may still participate in the global Hg cycle through remobilization from abandoned tailings and other contaminated areas.  相似文献   

Evolution of Mercury Contamination in Brazil     

Lacerda  L.D. 《Water, air, and soil pollution》1997,97(3-4):247-255

This paper reviews the history of Hg contamination in Brazil by characterizing and quantifying two major sources of Hg emissions to the environment: industrial sources and gold mining, industry was responsible for nearly 100% of total Hg emissions from the late 1940's to the early 1970's, when efficient control policies were enforced, leading to a decrease in emissions. Gold mining, on the other hand was nearly insignificant as a Hg source up to the late 1970's, but is presently responsible for over 80% of total emissions. Presently, over 210 t of Hg are released into the environment in Brazil annually. Nearly 170 t come from gold mining operations. 17 t come from chlor-alkali industry and 10 t come from all other industrial uses. Emissions to the atmosphere are the major pathway of Hg releases to the environment and reach over 160 t.yr-1 with approximately 136 t.yr-1 from gold mining.  相似文献   

Varying Nitrogen Concentrations to Optimize Basic Seed Potato Minitubers Production in a Three-Phase Hydroponic System     

Jaime Barros da Silva Filho  Paulo Cezar Rezende Fontes  Hermínia Emília Prieto Martinez  Jose Soares de Lacerda  Paulo Roberto Cecon  Milton E. McGiffenJr 《American Journal of Potato Research》2018,95(6):687-695

In hydroponics, nutrient management is the limiting factor to obtaining optimal production, and nitrogen (N) is the key component to consider when optimizing nutrient management in these types of systems. The objective of this study is to evaluate different combinations of N fertilizer concentrations in order to optimize the yield of basic seed potato minitubers in a three-phase hydroponic system. Treatments consisted of five combinations of N concentrations, applied before and after 21 days after plant transplant as follows, respectively: 1) 13 and 13, 2) 13 and 0, 3) 13 and 7.8, 4) 13 and 16, and 5) 13 and 26 mmol L^?1. Propagation was performed by transplanting 3–4 cm potato plantlets cv. Agata from sprouts. There were significant effects of N treatments on all measured variables (root, leaf, stem, and plant dry weight and minituber number and weight). To obtain the maximum minituber number yield, 9.51 minitubers/plant, corresponding to 67 minitubers/m², post 21-day adjusted N concentration was 18.4 mmol/L. Treatment 4 promoted higher basic seed potato minituber yield in a three-phase hydroponic system.  相似文献   

Canine cell line,IPC‐366, as a good model for the study of inflammatory breast cancer          下载免费PDF全文

S. Caceres  L. Peña  L. Lacerda  M. J. Illera  P. J. de Andres  R. A. Larson  H. Gao  B. G. Debeb  W. A. Woodward  J. M. Reuben  J. C. Illera 《Veterinary and comparative oncology》2017,15(3):980-995

Inflammatory breast cancer (IBC) is an aggressive type of cancer with poor survival in women. Inflammatory mammary cancer (IMC) in dogs is very similar to human IBC and it has been proposed as a good surrogate model for study the human disease. The aim was to determine if IPC‐366 shared characteristics with the IBC cell line SUM149. The comparison was conducted in terms of ability to grow (adherent and nonadherent conditions), stem cell markers expression using flow cytometry, protein production using western blot and tumorigenic capacity. Our results revealed that both are capable of forming long‐term mammospheres with a grape‐like morphology. Adherent and nonadherent cultures exhibited fast growth in vivo. Stem cell markers expressions showed that IPC‐366 and SUM149 in adherent and nonadherent conditions has mesenchymal‐like characteristics, E‐cadherin and N‐cadherin, was higher in adherent than in nonadherent cultures. Therefore, this study determines that both cell lines are similar and IPC‐366 is a good model for the human and canine disease.  相似文献   

Severe Hemorrhagic Syndrome After Lonomia Caterpillar Envenomation in the Western Brazilian Amazon: How Many More Cases Are There?     

João Hugo A. Santos  Sâmella S. Oliveira  Eliane C. Alves  Iran Mendonça-da-Silva  Jacqueline A.G. Sachett  Antonio Tavares  Luiz Carlos Ferreira  Hui Wen Fan  Marcus V.G. Lacerda  Wuelton M. Monteiro 《The Forestry Chronicle》2017,28(1):46-50

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Protected areas and native freshwater bivalves are not in the same place in south-east Brazil     

Igor Christo Miyahira  Maria Cristina Dreher Mansur  Luiz Eduardo Macedo de Lacerda  Isabela Cristina Brito Gonçalves  Glauco Gil Sant'Anna  Sonia Barbosa dos Santos 《水产资源保护:海洋与淡水生态系统》2023,33(1):102-114

1. Bivalves are important components of freshwater ecosystems; however, they are also one of the most threatened animal groups, especially members of the order Unionida. The main threats to freshwater bivalves are habitat modification and invasive species. Protected areas are a common way to minimize impacts and preserve native species, but they are rarely designated with a focus on freshwater invertebrates.
2. The main goal of this article was to describe the distribution of freshwater bivalves in the state of Rio de Janeiro, and the relationship between these species and bioclimatic areas, land use and protected areas.
3. Five native and two invasive bivalve species have been reported in Rio de Janeiro. They occur mainly in bioclimatic areas related to the Paraíba do Sul River and Campista Lowlands. The few records of bivalves inside protected areas are in areas of sustainable use that offer a lower level of protection, and frequently in sympatry with invasive bivalves.
4. Thus, the established protected areas in Rio de Janeiro are not adequately effective for freshwater bivalve conservation, and some species remain under threat even within them. Freshwater bivalves thus remain largely unprotected in the state.
5. The development of new protected areas and management plans should consider other faunal groups that are usually ignored, such as freshwater bivalves, to achieve more inclusive and effective protection.

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