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.
Key facts. 1  Arsenic is naturally present at high levels in the groundwater of a number of countries. 2  Arsenic is highly toxic in its inorganic form. 3  Contaminated water used for drinking, food preparation and irrigation of food crops poses the greatest threat to public health from arsenic.t is highly toxic in its inorganic form. People are exposed to elevated levels of inorganic arsenic through drinking contaminated water, using contaminated water in food preparation and irrigation of food crops, industrial processes, eating contaminated food and smoking tobacco.