Canadian Water Quality Index (CWQI) provides protection for freshwater life promoting healthy ecosystems and safeguarding human health. Biological Diatom Index (BDI) was developed to indicate the ecological status and water quality of freshwater systems. This paper evaluates the relations between the two different indices. During rising and falling, water samples were taken in the Curuai Floodplain, Brazil. CWQI was calculated using 14 physicochemical parameters and 1 microbiological parameter. The limits were established according to freshwater quality conditions and standards based on water use classes 1 and 2 determined in CONAMA 357 legislation and British Columbia. Canadian Water Quality Index categorization ranged from "marginal" to "excellent," most sampling units were "good" (71%), followed by "fair" (12%) and "excellent" (12%) water quality. Total phosphorus (38 times), chlorophyll a (20), dissolved oxygen (10), and total organic carbon (10) were the parameters that presented the most non-compliance values. Encyonema silesiacum (14%), Gomphonema parvulum (13%), and Navicula cryptotenella (12%) were the main taxa in the rising period, while G. lagenula, E. silesiacum, and Fragilaria capucina were the main taxa during the falling period. BDI ranges from I to V water quality classes. We observed "poor" to "very good" ecological status, with most sampling units "moderate" (52%) and "good" (29%). Water quality for class 2 was better than water quality for class 1, as the limits of the parameters evaluated were more restrictive in class 1 than in class 2 and the predominant uses of water require a higher degree of water purity. The biological index based on diatoms was the most restrictive index whose water classes and categorizations have shown an ecological status that could threaten the protection of aquatic communities on the Curuai floodplain. We suggest the combined use of both indices-physicochemical and biological for water quality assessment in this type of environment.

中文翻译：

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在巴西亚马逊河泛滥平原的水质评估中，基于附生硅藻组合的生物指标比物理化学指标更具限制性。

加拿大水质指数（CWQI）为保护淡水生命，促进健康的生态系统和维护人类健康提供了保护。开发了生物硅藻指数（BDI）来指示淡水系统的生态状况和水质。本文评估了两个不同指标之间的关系。在上升和下降期间，在巴西的库鲁艾洪泛区采集了水样。使用14个理化参数和1个微生物学参数计算CWQI。根据CONAMA 357立法和不列颠哥伦比亚省确定的用水等级1和等级2，根据淡水质量条件和标准确定限值。加拿大水质指数的分类范围从“边际”到“优秀”，大多数抽样单位是“好”（71％），其次是“一般” （12％）和“优秀”（12％）的水质。总磷（38倍），叶绿素a（20），溶解氧（10）和总有机碳（10）是代表最不合格值的参数。上升时期的主要分类群为灰耳线虫（14％），小孢子菌（13％）和隐孢子虫（12％），而下降时期的主要分类群为紫花革兰，大叶大肠杆菌（E. silesiacum）和角荚菜（Fragilaria capucina）。 。BDI的水质等级从I级到V级。我们观察到从“差”到“非常好”的生态状况，大多数采样单位为“中等”（52％）和“良好”（29％）。2级水质优于1级水质 因为评估的参数限制在第1类中比在第2类中更为严格，并且主要使用水需要更高的水纯度。基于硅藻的生物指标是限制性最强的指标，其水质和分类显示其生态状况可能威胁对库鲁艾河漫滩的水生生物群落的保护。我们建议在这种类型的环境中结合使用物理化学指标和生物指标来进行水质评估。