Gold Mining in the Peruvian Amazon: Global Prices, Deforestation, and Mercury Imports

Many factors such as poverty, ineffective institutions and environmental regulations may prevent developing countries from managing how natural resources are extracted to meet a strong market demand. Extraction for some resources has reached such proportions that evidence is measurable from space. We present recent evidence of the global demand for a single commodity and the ecosystem destruction resulting from commodity extraction, recorded by satellites for one of the most biodiverse areas of the world. We find that since 2003, recent mining deforestation in Madre de Dios, Peru is increasing nonlinearly alongside a constant annual rate of increase in international gold price (∼18%/yr). We detect that the new pattern of mining deforestation (1915 ha/year, 2006–2009) is outpacing that of nearby settlement deforestation. We show that gold price is linked with exponential increases in Peruvian national mercury imports over time (R2 = 0.93, p = 0.04, 2003–2009). Given the past rates of increase we predict that mercury imports may more than double for 2011 (∼500 t/year). Virtually all of Peru's mercury imports are used in artisanal gold mining. Much of the mining increase is unregulated/artisanal in nature, lacking environmental impact analysis or miner education. As a result, large quantities of mercury are being released into the atmosphere, sediments and waterways. Other developing countries endowed with gold deposits are likely experiencing similar environmental destruction in response to recent record high gold prices. The increasing availability of satellite imagery ought to evoke further studies linking economic variables with land use and cover changes on the ground

Mapping and monitoring lakes in the Brazilian Pantanal wetland using synthetic aperture radar imagery

1. The Pantanal wetland in South America is being threatened by human development, such as the construction of hydropower dams in the upper Paraguay River and the Hydrovia. The consequences of these developments are difficult to predict, but will potentially cause irreversible loss of habitat and biodiversity. 2. Radar satellite imagery can be used to establish baseline information that is crucial for monitoring changes in this region. In the case of the Pantanal, the pixel spacing of the imagery is a major concern if the goal is to count, map, and monitor lakes. To address this, Radarsat and JERS-1 data were acquired and used to produce a series of coarser-resolution images in order to understand the capabilities of the various resolutions to map Pantanal lake ecosystems. The simulations included resolutions of the existing JERS-1 mosaics (100m resolution) and the proposed ALOS/PALSAR mosaics (50m resolution). 3. Using the 15 in data it was found that in the Nhecolandia region of the Pantanal, only about 7% of lakes have an area larger than 0.2 km(2), 47% have an area larger than 0.05 km(2), and 50% are smaller than 0.05 km(2). Therefore, it is important to consider the substantial number of lakes smaller than 0.05 km(2). 4. The size of the errors in determining lake area depends on lake size, lake shape, and the image pixel spacing - long and small lakes have greater errors, and 100m resolution images show unacceptable errors. The error in estimating lake area associated with the pixel spacing of the Radarsat ScanSAR image is 12.5% and 25%, and for the proposed mosaics of ALOS/PALSAR it is 30% and 47% for lakes larger and smaller than 0.05 km 2 respectively. Therefore, based on simulated results, the spatial resolution of the observing SAR was an important determining factor in the capacity to discriminate small lakes in the Pantanal. Copyright (c) 2007 John Wiley & Sons, Ltd.17327728

SAR-based estimates of the size distribution of lakes in Brazil and Canada: a tool for investigating carbon in lakes

1. The size of lakes and the size distribution of lakes are important parameters controlling lake function, and how lakes interact with landscapes, the atmosphere and ecosystems. A baseline digital database of lakes could be used to improve understanding of lake function, to extrapolate lake information to regional and global scales, and as a basis for detecting future changes to lakes. 2. This paper examines the capabilities of synthetic aperture radar (SAR) imagery produced by the Japanese Earth Resources Satellite (JERS-1) to map the number and size distribution of lakes in western Arctic Canada, Central Canada and the Pantanal (Brazil). 3. For the Arctic and Pantanal, the total area found within one lake size category increases towards smaller lakes. The opposite was 2 true for the area in Central Canada. The number of lakes in the smallest size category, 0.01 to 0.1 km, was underestimated for all regions owing to the resolution of the mosaics - 100 x 100 m. The number of large lakes in the Pantanal was over-estimated through confusion with intermittent floodways that are scrubby grasslands and bare sand in the dry season and which exhibit low backscattering and therefore appear dark like lakes. 4. The lake distributions were combined with existing data to produce preliminary 2 regional estimates of carbon accumulation. Lakes may accumulate as much as 1.7 and 1.3 t C km(-2) yr(-1) for the Arctic Canadian and Central Canadian areas, respectively. No estimates were produced for the Pantanal because there are no applicable data on carbon accumulation rates available for that region. Copyright (c) 2007 John Wiley & Sons, Ltd.17328930

The role of smelter emissions and element remobilization in the sediment chemistry of 99 lakes around the Horne smelter, Quebec

Ninety-nine lakes were sampled at varying distances up to 75 km from the Horne smelter at Rouyn-Noranda, Quebec, to study the influence of the smelter versus other factors on metal concentrations in lake sediments. Most of these lakes he within the Abitibi Greenstone Belt, a zone of extensive base metal and gold mineralization and the focus of a mining and smelting economy for almost a century. Lake sediment cores, c. 25 cm long, were collected and sampled at the top (0-2 cm) and the bottom (18-20 cm) to capture sediment that was deposited after the smelter was in operation ('post-industrial') and well before the mining and smelting activity was started ('pre-industrial'). Additionally, nine cores were sampled in 1 cm increments to depths of up to 50 cm to study temporal patterns and potential element remobilization in detail. The cores were analysed for an extensive suite of elements. This paper focuses on those elements that are emitted by the smelter for which there are records of emissions through time, namely As, Cd, Cu, Pb and Zn. A spatial statistical approach - a logistic model of metal content versus distance from the smelter - was used investigate the relationship of sediment chemistry with smelter emissions and other possible influences. Using Cu as a representative proxy for the other emitted metals, this analysis demonstrates that elements are enriched in lake sediments by a factor of about three times around the smelter, that the impact of the smelter is detectable in lakes to a distance of at least 50 km, and that there is no obvious association between sediment Cu concentration and bedrock geology, land-use, lake pH, or lake morphometry Oake area/lake catchment area). The nine lakes studied in detail show enrichment towards the sediment-water interface (SWI) and relatively steady concentrations below depths of c. 10 cm. However, depth profiles do not match changes in the magnitude of smelter emissions through time, nor do they match changes in emission chemistry (element ratios) through time. Element ratios do generally move towards the chemistry of the emissions, suggesting smelter influence, but do not do so predictably. For example, (i) trends in the Cu/Pb ratio continue to the very bottom of cores into material deposited hundreds of years before industrialization, and (ii) proximity to the smelter does not lead to greater similarity between sediment and emission chemistry. These results suggest that significant element remobilization is occurring and that it differs from lake to lake and from element to element. We conclude that lakes within 50 km of the smelter have elevated metal concentrations in their near-surface sediments due to stack emissions but, due to element cycling and mobility, it is difficult to quantitatively determine the magnitude of metal increase attributable to the smelter. We also suggest that due to upward remobilization, the duration of industrial metal enrichments in surface sediments (the residence time) may be increased, thereby making surface enrichments more persistent than would be predicted by the sedimentation rate.64170018720