Water Quality
Introduction
As an old saying goes: water is the source of life. Without water, all species will die out especially human beings, because water is not only the main component of the body, of which over 60% is made by water, but also has many physiological functions. Researches have proved that once the bodies are lack 15% of water, their lives will seriously threaten. Owing to the importance of water and its worldwide contamination concerns, water quality referring to the characteristics of physics and chemistry and biology and ingredients of water is valued no matter in the domestic or outside areas. In the article, two typical regions China and Great Lakes are given to discuss the water quality and something related to it, because emerging pollution is usually reported along with the big economic progression.
A History of water pollution in China
Songhua river water pollution incident is termed as one of the most serious contamination o
f water in China due to un-estimable loss and effect of thousands of people (Hou, Y., & Zhang, T. Z. 2009). On 13th November, 2005, a diphenyl workshop of petrochemical company located in Jilin province was exploded, which resulted in some 100 tons of benzene (benzene, nitrobenzene, etc.) flowing into the Songhua river, which led a fearful water pollution and affecting countless lives of people along the river including 5 dead, 1 missing and nearly 70 injured due on 14th November. The explosion created an 80-kilometer-long slick of pollutants across the Songhua river which passed through the city of Harbin, leading an absence of water for 5 days. Additionally, Russia had expressed concern about the impact of water pollution from the Songhua river (Russia calls it the Amur), because the river is on the border between China and Russia. On 23th November, the State Environmental Protection Administration seriously criticized it as a major water pollution incident through the media.
The Basin of Songhua River in the northeast is major agricultural areas producing soybeans, corn, sorghum and wheat since the ancient times. Meanwhile, Songhua river is
a large freshwater fishery, famous for abundance of carp, grass carp, catfish and mandarin fishes etc. However, this incident caused a series of hazardous issues. First, water is badly polluted, according to Water quality monitoring recordwater pollutions, Benzene (maximum limit of 108 times), nitrobenzene (maximum limit of 29.1 times), aniline, xylene and other benzene organic pollutants are main hazards, due to their toxicity. Moreover, owing to high stability, density and solubility of nitrobenzene in water, a long period of time are needed to recover once the water is suffering its pollution. Additionally, volatility of benzene and its compounds such as nitrobenzene and xylene makes the air toxic as a small amount of those easily escapes from the water into the air. More than that, a fast-flowing river can aggravate this phenomenon. Of course, the ecosystems there are contaminated at the same time, let alone soil pollution both in China and Russia although there is not official date to evaluate how bad it is. It is worth mentioning that people without pollution awareness were still cutting ice to catch fish after announcements had been widely aired.
The toxicity of benzene and compounds containing benzene is strong, trace can be lethal
for species especially human beings. The International Centre for Research on Cancer (IARC) has identified them as carcinogens. Inhalation, gastrointestinal and skin absorption with large amounts of benzene can cause acute and chronic benzene poisoning because of the formation of phenol in vivo. Benzene produces paralytic action to central nervous system, causing acute poison of which symptoms are manifested as headache, nausea, vomiting, confusion, loss of consciousness, coma, convulsions, etc. Severe cases may result in death due to paralysis of the central system. While, prolonged exposure to benzene is likely to cause neurasthenic syndrome as well as chromosome aberrations, damage the bone marrow and blood corpuscle reduction, which are exactly the pre-sign of leukemia, even aplastic anemia. Worse still, scientists have found that the incubation period of benzene in the body can be as long as 12 to15 years, thus it constantly suppresses the immune system and allows the various diseases to take advantage.
For Fear of its potential hazards, the government administrations have taken the strictest means to manage this emergency. Pollution detections are foremost，which decide the fo
llowing methods should be taken. At present, gas chromatography (GC) (Patil, S. S., & Shinde, V. M. 1988) and high performance liquid chromatography (HPLC) (Astier, A. 1992) are widely used to distinguish nitrobenzene and aniline organic compounds in water, with scores of advantages including simple operation, high separation efficiency, fast analysis speed and high detection sensitivity etc. Meanwhile, these methods with low detection cost and high accuracy are true for xylene detection although there is no unified testing standard for it in China (Astier, A. 1992). As for chlorobenzene compounds, gas chromatography - mass spectrometry is deemed as a most common method particularly for the detection of trace concentrations of chlorobenzene compounds (Wang, Y., & Lee, H. K. 1998).