Tetanus, also known as lockjaw, is an infection characterized by muscle spasms. In the most common type the spasms begin in the jaw and then progress to the rest of the body. These spasms usually last a few minutes each time and occur frequently for three to four weeks.etanus occurs in all parts of the world but is most frequent in hot and wet climates where the soil contains a lot of organic matter. In 2013 it caused about 59,000 deaths â down from 356,000 in 1990. Description of the disease by Hippocrates exists from at least as far back as the 5th century BCE.
The water resources of China are affected by both severe water quantity shortages and severe water quality pollution. A growing population and rapid economic development as well as lax environmental oversight have increased water demand and pollution.
Nutrient pollution. Nutrient pollution, a form of water pollution, refers to contamination by excessive inputs of nutrients. It is a primary cause of eutrophication of surface waters, in which excess nutrients, usually nitrogen or phosphorus, stimulate algal growth. Sources of nutrient pollution include surface runoff from farm fields and pastures, discharges from septic tanks and feedlots, and emissions from combustion.