使用氯进行水的补救，自古以来就是一种全球性的做法。为了达到上述目的而使用氯的主要想法是降低微生物的致病形式对健康的总体风险，这些微生物在饮用水场所和水源中普遍存在，从而成为治疗过程的积极组成部分(Tang & Xie, 2016)。尽管这一策略非常重要，但在饮用水来源中仍然存在一些不受欢迎的副产品(Smith et al.， 2016)。这些不良产品通常出现在饮用水供应中，最常分别被称为产品消毒(DBPs)。当氯与未经处理的原水中的天然有机物(NOM)接触时，就会发生化学反应，导致三卤甲烷(THMs)和卤乙酸(HAAs)的形成(Melo et al.， 2016)。因此，由于化学反应而形成的各种类型或类别的氯化产品据说对生物和人类的健康造成严重和不利的影响。它们进入食物链，影响环境的各种生物组成。在世界各地不同国家进行的不同类型的毒理学研究已经确定了不同数量的产品或CBPs氯化反应(Melo et al.， 2016)。哈斯是CBPs的活性成分，具有高度的致突变性和致癌性。它们造成不利的威胁，因为它们损害了生物体的生殖和发育方面。接下来有关论文代写-饮用水副产品氯化的危害分析如下：
A number of epidemiological studies conducted in this field have confirmed and suggested that the enhanced risk of cancer and other fatal diseases as a result of mutagenic factors is largely due to the by-products present in potable drinking waters (Plewa & Wagner, 2016). The DBPs, as outlined by various researchers, have enhanced carcinogenic properties compared to THMs and HAAs as per the animal studies conducted worldwide (Righi et al., 2014). They further enhance cancer and other life threatening disease risk and interfere with the normal reproductive biology of living organisms thus altering it. The various commonly available nine types of HAAs in chlorinated drinking water samples are MCA (monochloroacetic acid ), DCA (dichloroacetic acid, Cl2CHCOOH), TCA (trichloroacetic acid, Cl3CCOOH), MBA (monobromoacetic acid, BrCH2COOH),DBA (dibromoacetic acid, Br2CHCOOH), Bromochloroacetic acid (BrCl2AA), Bromodichloroacetic acid (BrClAA), Chlorodibromoacetic acid (Br2ClAA),and Tribromoacetic acid (Br3AA) respectively (Ali et al., 2014). Since the HAAs are identified to pose serious risks to health of living organisms, the environment protection agency (EPA) has set a permissible range for these harmful by-products in potable waters (Teh & Li., 2015). The maximum level of permissible contaminant which has been fixed by the EPA has been levelled at0.080mg/L for the THMs and 0.060mg/L for the five different classes of HAAs which include MCA, DCA, TCA, MBA, and DBA respectively.
The formation of HAAs in water is largely dependent upon the ways in which the different operational procedures are conducted in the various water treatment plants (WTPs), with regard to dose of chlorine, the time of contact between the dissolved organic matter and chlorine and other physical parameters like pH of water, temperature and other related conditions (Righi et al., 2014). Furthermore, it has been suggested by numerous researchers that the amount and percentage of HAAs formed in water could vary from place to place with regard to geographical environment and seasons of nature where these water bodies or resources are located (Melo et al., 2016).
HAAs, similar to the different THMs, are found to be an active constituent of drinking water along with chlorine. Researchers have pointed out the fact that irrespective of the water source or water body, HAAs and THMs happen to be the largest classes of DBPs that are present in water which have been treated with chlorine. In order to control the percentage of DBP in finished drinking water facility, it is extremely essential to have a thorough understanding of the aspects leading to DBP formation along with speciation (Plewa & Wagner, 2016). As the measurement of total organic halogen (TOX) can be considered to be a standard for water quality measurement, it is extremely important to be aware regarding the percentage of specific and individual levels of HAAs, as a measure of the total organic halogen(TOX) under a series of different experimental set ups (Legay et al., 2011).
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