For dry-type transformers having a 220 [degrees] C insulating system and a winding hot-spot temperature of 220 [degrees] C, and with no unusual operating conditions present, the 20-yr life expectancy is a reasonable time frame.he 80 [degrees] C transformer requires operation at 75% or more of full load for a 2-yr payback, and at 100% load to payback in 1 yr over the 150 [degrees] C transformer.
Exposure to arsenic through drinking water is a great threat to human health. Arsenic is a carcinogen and its consumption can negatively affect the gastrointestinal tract and cardiac, vascular and central nervous systems.
Inorganic arsenic (arsenate and arsenite salts) are more harmful than organic arsenic exposure. Organic arsenic is 500 times less harmful than inorganic arsenic, and is a minor problem compared to the groundwater situation which affects many millions of people.hus although arsenic poisoning can be related to human activities such as mining and ore smelting, the most serious problems are natural, resulting from water wells drilled into aquifers that have high concentrations of arsenic.