Laboratório de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos, Departamento de Oceanografia, Universidade Federal de Pernambuco, CEP 50740-550 Recife, Brazil.
Laboratório de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos, Departamento de Oceanografia, Universidade Federal de Pernambuco, CEP 50740-550 Recife, Brazil.
Sci Total Environ. 2019 Feb 15;651(Pt 1):1199-1218. doi: 10.1016/j.scitotenv.2018.09.276. Epub 2018 Sep 22.
Estuarine pollution imposes rapid, increasing and lasting environmental modifications. In the present review, especial attention is given to estuaries in South America (SA), where legislation, policies and actions to guarantee environmental quality remain ineffective. There, the majority of estuaries face uncontrolled occupation of its margins by urban and industrial centres, agriculture and aquaculture expansion, water extraction and flow control. The lack of basic sanitation and poor environmental management (including territories within Marine Protected Areas) often lead to hydrological alterations, high nutrient loads, and the presence and dynamics of pollutants (nutrient loads, persistent organic pollutants (POPs), metals and plastic debris) along the entire estuarine ecocline. Organic enrichment has increased dissolved oxygen consumption, with wide spatio-temporal variability along latitudes and estuarine gradients. The toxicity, biogeochemistry and availability of metals and POPs depend on the annual fluctuations of salinity, water renewal, dissolved oxygen levels, suspended particulate loads, sediment mobility, grain size and composition at the sink. Plastic debris from land sources are widespread in estuaries, where they continue to fragment into microplastics. River basins are the main contributors of plastics to estuaries, whose transportation and accumulation are subjected to interannual water flow variations. Although some systems seems to be in a better condition in relation to others around the world (e.g. Goiana and Negro estuaries), many others are among the most modified worldwide (e.g. Guanabara Bay and Estero Salado System). We propose that, estuarine conservation plans should consider year-round fluctuations of the ecocline and the resulting cycles of retention and flush of environmental signals and their influence on trophic webs over the whole extent of estuarine gradients.
河口污染会造成快速、持续且持久的环境变化。在本次综述中，我们特别关注南美洲的河口，那里的立法、政策和保护环境质量的行动仍然收效甚微。在这些河口，大多数都面临着城市和工业中心、农业和水产养殖业的无节制扩张、水资源开采和水流控制等问题，导致其边缘地区失控。缺乏基本的卫生设施和不良的环境管理（包括海洋保护区内的区域）往往会导致水文变化、养分负荷增加，以及污染物（养分负荷、持久性有机污染物（POPs）、金属和塑料碎片）的存在和动态变化，这些情况沿着整个河口生态梯度都有发生。有机物的富集增加了溶解氧的消耗，其在时空上的变化具有很大的变异性，这种变化与纬度和河口梯度有关。金属和 POPs 的毒性、生物地球化学特性和可用性取决于盐度、水更新、溶解氧水平、悬浮颗粒物负荷、沉积物流动性、汇点处的颗粒大小和组成的年度波动。来自陆地的塑料碎片在河口广泛存在，在那里它们继续碎裂成微塑料。河流流域是塑料进入河口的主要来源，其运输和积累受到年际水流变化的影响。尽管一些系统与世界其他地区相比（例如，瓜纳巴拉湾和内格罗河口）的状况似乎更好，但许多其他系统是世界上受人为影响最大的河口之一（例如，圣罗莎河口和埃斯特罗·萨拉多河口系统）。我们建议，河口保护计划应考虑生态梯度全年的波动，以及由此产生的环境信号的滞留和冲洗周期及其对整个河口梯度中营养网络的影响。
