Estuaries are considered receptors of various contaminants released into the environment, including Polycyclic Aromatic Hydrocarbons (PAH), a ubiquitous contaminant. In this study, the response of subtidal macrofauna in the polyhaline zone of three tropical estuaries was analyzed using a taxonomic approach, multimetric indices, and functional traits, to three different levels of PAH. The estuaries presented distinct degrees of contamination, with PAH directly correlated with mud percentage and organic matter. The considerable variation in granulometry found in the three studied estuaries may indicate complex hydrodynamics, with very different sedimentary characteristics. The community structure showed typical estuarine characteristics, with low diversity and high dominance. The macrofauna was distinct among estuaries, with no shared dominant species and with several species occurring just in one site, with different compositions, although other parameters of the community structure were similar. The AMBI and functional indices performed better than taxonomic indices in separating the areas with different impacts. In the analyzed communities, the functional traits approach demonstrated consolidated patterns in the estuarine environment, such as the predominance of opportunistic species, generally of smaller size and detritivore/depositivore, under conditions of pollution by the organic load. Local characteristics, such as the predominance of suspensivore organisms and relatively more mobility in areas with higher hydrodynamics, provide insight into the community's behavior on natural and anthropogenic stressors. The multivariate taxonomic and functional analyses were complementary, emphasizing the importance of integrating them in these environments diagnosis. Stressed environments need information from the entire data set for a correct assessment of the community.

河口被认为是释放到环境中的各种污染物的受体，其中包括普遍存在的污染物多环芳烃（PAH）。在这项研究中，使用分类学方法，多指标指标和功能性状，分析了三个热带河口多盐带下潮汐大型动物对三种不同PAH的响应。河口呈现出不同程度的污染，PAH与泥浆百分比和有机物直接相关。在三个研究河口中发现的粒度变化很大，这可能表明流体动力学复杂，沉积特征也大不相同。群落结构具有典型的河口特征，多样性低，优势度高。大型动物在河口之间是不同的，尽管群落结构的其他参数相似，但没有共有的优势种，并且只有一个地点出现了几种，组成不同。在区分具有不同影响的区域时，AMBI和功能指数的表现优于分类指数。在被分析的社区中，功能特征方法证明了在河口环境中的整合模式，例如在有机物污染的条件下，机会主义物种占优势，通常是较小的物种和破坏性/沉积性物种。局部特征，如悬臂生物的优势以及在水动力较高的地区相对较多的流动性，使人们能够深入了解社区在自然和人为压力源下的行为。多变量分类学和功能分析是互补的，强调了将它们集成到这些环境诊断中的重要性。压力大的环境需要来自整个数据集的信息，以便对社区进行正确的评估。