Showing posts with label bioaccumulation. Show all posts
Showing posts with label bioaccumulation. Show all posts

Tuesday, September 9, 2014

What is Biogas & How Do We Make It? INFOGRAPHIC

Biogas systems provide economic, energy, and environmental benefits for farms, businesses, and communities. These systems enable the capture and use of methane while also addressing waste management and nutrient recovery needs, finds the Biogas Opportunities Roadmap, released by the Obama Administration.
If its full potential was realized, a cost-effective biogas industry could produce enough energy from the livestock sector to power 1 million average American homes.

Biogas is primarily a mixture of methane and carbon dioxide produced by the bacterial decomposition of organic materials in the absence of oxygen. Depending on the source of organic matter, biogas typically contains 50-70% methane, 30-40% carbon dioxide, and trace amounts of other constituents, such as hydrogen sulfide, hydrogen, nitrogen, and siloxanes.

Methane is both a potent greenhouse gas and a valuable source of energy. Today, methane accounts for nearly 9% of domestic greenhouse gas emissions. Thirty six percent of these emissions come from the agricultural sector, equivalent to over 200 million tons of carbon pollution. While methane’s lifetime in the atmosphere is much shorter than carbon dioxide, it is more efficient at trapping radiation. Pound for pound, the comparative impact of methane on climate change is over 20 times greater than carbon dioxide over a 100-year period.

This Biogas Opportunities Roadmap builds on progress made to date to identify voluntary actions that can be taken to reduce methane emissions through the use of biogas systems and outlines strategies to overcome barriers to a robust biogas industry in the United States. It supports the U.S. dairy industry’s voluntary 2008 goal to reduce its greenhouse gas emissions by 25% by 2020.

Learn more:
Check out a fact sheet about the Biogas Opportunities Roadmap.

Content Courtesy: 1sun4all

Thursday, July 24, 2014

Bioaccumulation and Biomagnification

Heavy metals (mercury, lead, cadmium), pesticides and herbicides (such as DDT) and endocrine-disrupting chemicals (PCB’s and BPA’s) do not readily biodegrade. These are fat-soluble substances that are stored in organisms and are not quickly broken down by bacteria or other decomposers. Bioaccumulation is the process by which persistent pollutants accumulate in the fatty tissues of organisms. These pollutants are absorbed at a greater rate than they are released and therefore build up within the individual organism. Biomagnification is the process by which persistent pollutants increase in concentration up a food chain. So secondary and tertiary consumers have higher concentrations than producers and primary consumers.

This phenomena has been observed with DDT, causing the thinning of eggshells in raptors, such as the threatened Peregrine Falcon. Rachel Carson, a marine biologist and conservationist,  made the American public aware of the environmental problems caused by synthetic pesticides, such as DDT, in her famous book, “Silent Spring”. DDT is now prohibited in most developed countries.

Mercury has been shown to bioaccumulate in marine food webs, affecting higher order consumers, such as dolphins, sharks and swordfish. As such, Food Standards of Australia and New Zealand recommend that the intake of certain types of fish is limited.

Content Courtesy : vceenviroscience