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Nature reflects our nature degradation and their effects . Journal of Wetlands Ecology , 4 , 83-101 .
Sheng , L ., Zong-xiang , G ., Huai-yu , Y ., & Zheng-yong , Y . ( 2009 ). Evaluation of cultural service value of aquaculture pond ecosystem : A case study in a water conservation area of Shanghai . Yingyong Shengtai Xuebao , 20 ( 12 ).
Shrestha , R . R . ( 2009 ). Rainwater harvesting and groundwater recharge for water storage in the Kathmandu Valley . ICIMOD Newsletter , 56 , 27-30 .
Tandan , P . K . ( 2016 , May 12 ). Valley groundwater level drastically down . The Himalayan Times . Retrieved from https :// thehimalayantimes . com / nepal / valley-groundwater-level-drastically /
Sandeep Hada Masters in Sustainable Development Kathmandu University
Jenisha Rai Bachelors of Arts in Social Work and Major English
Master in Sustainable Development
DDT and History of Bald Eagle Decline
Bald Eagle , a national emblem of the United States since 1782 is found with a historic range from Alaska and Canada to Northern Mexico . Great Lake state , Florida , The Pacific Northwest , The Greater Yellow stone area Chesapeake Bay region has a significant population of Bald Eagle . Bald eagles are believed to breed for a lifetime . They breed at a very early age of 4 or 5 years which means that it can produce a large number of offspring in its whole life span of 15-30 yrs . in wild . Hence , produces around 36 eggs in its whole lifetime . The oldest known Bald Eagle in the wild was 39 years old . However , it was in a verse of extinction 20 years ago . Accumulation of the DDT in fish , that makes up most of the eagle ’ s diet was a major cause of the decline in its population . Besides that , habitat destruction , illegal shooting , overexploitation triggered a decline in the population of Bald Eagle .
When Bald Eagle was adopted as a National bird of the United States , there were around 10,000 nesting eagles ( Tomera , 2001 ). Soon after DDT was made available for public sale in 1945 AD for household and agricultural pesticide number suddenly declined to 412 nesting eagles . DDT was first synthesized by a German Chemist Zeidler in 1874 AD which was widely used to combat lice , to control malaria and typhus among civilians and troops in the second half of World War II ( DDT and its derivatives . Environmental Health Criteria ., 1969 ). No sudden effect of DDT was seen among the soldiers because unlike the other HC , DDT in powder form is not absorbed by the skin . Later in 1939 , its insecticide property was discovered by Paul Muller for which he was awarded a Nobel Prize . Since then over 200
66 Year Book of Environmental Science