Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz (UESC), Ilhéus, BA, 45662-900, Brazil.
Departamento de Ciências Exatas e Tecnológicas, Universidade Estadual de Santa Cruz, Ilhéus, BA, 45662-900, Brazil.
Environ Monit Assess. 2018 Jan 8;190(2):68. doi: 10.1007/s10661-017-6420-6.
Nitrogen enters estuaries mostly through fluvial discharge and tide, although anthropogenic sources are known to influence the amount of this element in these aquatic ecosystems. Thus, the objective of this work was to verify which river (Cachoeira, Fundão, and/or Santana) exerts greater influence on the distribution of dissolved N forms (Dissolved Organic Nitrogen and Dissolved Inorganic Nitrogen = NH/NH, NO, and NO) along a tropical urbanized estuarine system in northeastern Brazil. The studies estuarine system lies with in urban municipality, and the upper portion of the Cachoeira river estuary receives the treated effluent from this municipality through a sewage treatment station and untreated effluents from nearby villages. The selected sampling stations were located near the outfall of the rivers in the estuaries to the treatment plant and the villages. Of all the nitrogen forms, dissolved organic nitrogen (DON) prevailed in the estuarine system, followed by nitrate (NO) as the main inorganic form. The highest concentrations were recorded in the fluvial portion and upper estuary of Cachoeira river in the dry season. Based on the N concentrations found in the estuarine system, Cachoeira river has the greatest anthropogenic influence due to the amount of untreated effluents from the villages and treated effluents from the sewage treatment plant (STP) in the upper portion of the estuary.
氮主要通过河流排放和潮汐进入河口，尽管人为来源已知会影响这些水生态系统中该元素的数量。因此，这项工作的目的是验证哪个河流（Cachoeira、Fundão 和/或 Santana）对沿巴西东北部热带城市化河口系统中溶解氮形式（溶解有机氮和溶解无机氮=NH/NH、NO 和 NO）的分布施加更大的影响。该研究的河口系统位于城市自治市内，Cachoeira 河口的上游部分通过污水处理站接收该自治市的处理废水和附近村庄的未经处理的废水。选择的采样站位于河口的河流出海口附近的处理厂和村庄。在所有氮形式中，溶解有机氮（DON）在河口系统中占优势，其次是硝酸盐（NO）作为主要的无机形式。在旱季，在 Cachoeira 河的河流部分和上游河口处记录到的浓度最高。根据河口系统中发现的 N 浓度，由于村庄的未经处理的废水和河口上游污水处理厂（STP）的处理废水的数量，Cachoeira 河受到最大的人为影响。
