Pecologix Political Ecology Blotter » rivers

Dam Yangtze?

A. Cherson — Sat, 05 May 2012 00:17:29 +0000

Last month, preparatory work began on the Xiaonanhai Dam, with more projects to follow. Within a few years, the Jinsha will slow to a sluggish pace and its temperature will drop as a series of large hydropower dams release cold bottom water from their reservoirs into the river. For species already threatened by the Three Gorges Dam downriver, ecologists say, the new dams will take away their last refuge. Last year, the central government solidified plans to increase China’s reliance on non-fossil fuel energy from the 2010 level of 8% to 15% of the energy mix by 2020. Nearly two-thirds of that target will come from hydropower—an increase on par with adding nearly one Three Gorges Dam a year. Ecologists say China’s hydropower push will threaten already-taxed ecosystems in the upper Yangtze.

doi: http://dx.doi.org/10.1126/science.336.6079.288

Effects of Ibuprofen on hematological, biochemical and enzymological parameters of blood in an Indian major carp, Cirrhinus mrigala

A. Cherson — Sat, 28 Apr 2012 14:11:47 +0000

In the present investigation, the most commonly used pharmaceutical drug Ibuprofen (IB) was exposed to an Indian major carp Cirrhinus mrigala under static bioassay method to estimate its toxicological effects for a period of 35 days. The median lethal concentration (LC 50) of IB to the fish C. mrigala for 24 h was found to be 142 ppm. In sublethal treatment (1/10th of LC 50 24 h value, 14.2 ppm), a significant decrease in erythrocyte (RBC), mean cellular hemoglobin concentration (MCHC) and plasma protein levels were observed throughout the study period when compare to that of their respective controls. In contrast, haemoglobin (Hb), hematocrit (Hct), mean cellular volume (MCV), mean cellular hemoglobin (MCH), leucocyte (WBC), plasma glucose and alanine transaminase (ALT) levels were increased in this study period. On the other hand, a mixed trend was noticed in aspartate aminotransaminase (AST) enzyme activity. Alterations of these parameters can be effectively used as potential biomarkers in monitoring of IB toxicity in the aquatic organisms.

http://dx.doi.org/10.1016/j.etap.2012.02.005

No related posts.

New York City Will Use Green Infrastructure to Mitigate Combined Sewage Overflows

A. Cherson — Mon, 16 Apr 2012 14:09:06 +0000

The New York State Department of Environmental Conservation and New York City Department of Environmental Protection announced an agreement on an enforcement order to improve the overall water quality in New York Harbor waters. Under this agreement, the city will invest approximately $187 million during the next three years and an estimated $2.4 billion of public and private funding during the next 18 years to install green infrastructure technologies to manage stormwater before it enters the city’s combined sewer system. The city maintains the flexibility to prioritize green investments in areas that will benefit most from the resulting reductions in combined sewer overflows.

Groundbreaking Agreement Will Use Green Infrastructure to Improve Water Quality in New York Harbor – NYS Dept. of Environmental Conservation

Landscape controls on total and methyl Hg in the upper Hudson River basin, New York, USA

A. Cherson — Sat, 31 Mar 2012 14:35:08 +0000

Approaches are needed to better predict spatial variation in riverine Hg concentrations across heterogeneous landscapes that include mountains, wetlands, and open waters. We applied multivariate linear regression to determine the landscape factors and chemical variables that best account for the spatial variation of total Hg (THg) and methyl Hg (MeHg) concentrations in 27 sub-basins across the 493 km2 upper Hudson River basin in the Adirondack Mountains of New York. THg concentrations varied by sixfold, and those of MeHg by 40-fold in synoptic samples collected at low-to-moderate flow, during spring and summer of 2006 and 2008. Bivariate linear regression relations of THg and MeHg concentrations with either percent wetland area or DOC concentrations were significant but could account for only about 1/3 of the variation in these Hg forms in summer. In contrast, multivariate linear regression relations that included metrics of (1) hydrogeomorphology, (2) riparian/wetland area, and (3) open water, explained about 66% to >90% of spatial variation in each Hg form in spring and summer samples. These metrics reflect the influence of basin morphometry and riparian soils on Hg source and transport, and the role of open water as a Hg sink. Multivariate models based solely on these landscape metrics generally accounted for as much or more of the variation in Hg concentrations than models based on chemical and physical metrics, and show great promise for identifying waters with expected high Hg concentrations in the Adirondack region and similar glaciated riverine ecosystems.

doi: http://dx.doi.org/10.1029/2011JG001812

Reduced river discharge intensifies phytoplankton bloom

A. Cherson — Thu, 29 Mar 2012 16:16:43 +0000

► Indian estuaries receive huge nutrients from land drainage and agricultural fields ► Light limitation and fast flushing prevents potentially intense phytoplankton bloom ► Reduced discharge promotes intense bloom by enhancing stability and stratification ► Changing climate and more dam construction may potentially reduce discharge

http://dx.doi.org/10.1016/j.marchem.2012.01.005

No related posts.

Past and future trends in grey water footprints of anthropogenic nitrogen and phosphorus inputs to major world rivers

A. Cherson — Sun, 25 Mar 2012 20:51:43 +0000

The grey water footprint (GWF) is an indicator of aquatic pollution. We calculate past and future trends in GWFs related to anthropogenic nitrogen (N) and phosphorus (P) inputs into major rivers around the world. GWFs were calculated from past, current and future nutrient loads in river basins using the Global NEWS model. We present water pollution levels (WPLs), deduced from GWFs for more than 1000 rivers. The calculated GWFs and WPLs of the different river basins show a large variation among different periods. WPL values generally increased between 1970 and 2000. For the year 2000 about two-thirds of the basins have WPL values exceeding 1 for N or P, indicating that the pollution assimilation capacity has been fully consumed. Even though the other rivers have a WPL < 1, this does not guarantee that at sub-basin level or within particular periods of the year no eutrophication exists. High WPLs are generally found in rivers in tropical–subtropical areas. For dissolved organic N and P, the problems are located mostly in the southern hemisphere. The results indicate that many rivers may become more polluted with dissolved N and P in the future.

http://dx.doi.org/10.1016/j.ecolind.2011.10.005