Centro de Estudos do Ambiente e do Mar (CESAM), Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal; Estação de Biologia Marinha do Funchal, Departamento de Biologia, Universidade da Madeira, 9000-107 Funchal, Portugal.
Environ Pollut. 2017 Dec;231(Pt 1):123-133. doi: 10.1016/j.envpol.2017.07.103. Epub 2017 Aug 8.
Microplastics are widespread in aquatic environments and can be ingested by a wide range of organisms. They can also be transferred along food webs. Estuaries and other tidal wetlands may be particularly prone to this type of pollution due to their particular hydrological characteristics and sewage input, but few studies have compared wetlands with different anthropogenic pressure. Furthermore, there is no information on microplastic transfer to secondary intertidal consumers such as shorebirds. We analysed intertidal sediments, macroinvertebrates and shorebirds, from three important wetlands along the Eastern Atlantic (Tejo estuary, Portugal; Banc d'Arguin, Mauritania and Bijagós archipelago, Guinea-Bissau), in order to evaluate the prevalence and transfer of microplastics along the intertidal food web. We further investigated variables that could explain the distribution of microplastics within the intertidal areas of the Tejo estuary. Microfibers were recorded in a large proportion of sediment samples (91%), macroinvertebrates (60%) and shorebird faeces (49%). μ-FTIR analysis indicated only 52% of these microfibers were composed of synthetic polymers (i.e. plastics). Microfiber concentrations were generally higher in the Tejo and lower in the Bijagós, with intermediate values for Banc d'Arguin, thus following a latitudinal gradient. Heavier anthropogenic pressure in the Tejo explains this pattern, but the relatively high concentrations in a pristine site like the Banc d'Arguin demonstrate the spread of pollution in the oceans. Similar microfiber concentrations in faeces of shorebirds with different foraging behaviour and similar composition of fibres collected from invertebrate and faeces suggest shorebirds mainly ingest microfibers through their prey, confirming microfiber transfer along intertidal food webs. Within the Tejo estuary, concentration of microfibers in the sediment and bivalves were positively related with the percentage of fine sediments and with the population size of the closest township, suggesting that hydrodynamics and local domestic sewage are the main factors influencing the distribution of microfibers.
微塑料广泛存在于水生环境中，可被多种生物摄入。它们也可以沿着食物链转移。河口和其他潮汐湿地由于其特殊的水文特征和污水输入，可能特别容易受到这种类型的污染，但很少有研究比较具有不同人为压力的湿地。此外，关于微塑料向二级潮间带消费者（如滨鸟）转移的信息也很少。我们分析了来自东大西洋三个重要湿地（葡萄牙的特茹河口、毛里塔尼亚的阿尔金浅滩和几内亚比绍比热戈斯群岛）的潮间带沉积物、大型无脊椎动物和滨鸟，以评估微塑料沿潮间带食物网的传播情况。我们进一步研究了可能解释特茹河口潮间带地区微塑料分布的变量。在很大一部分沉积物样本（91%）、大型无脊椎动物（60%）和滨鸟粪便（49%）中记录到微纤维。μ-FTIR 分析表明，这些微纤维中只有 52%由合成聚合物（即塑料）组成。微纤维浓度在特茹河较高，在比热戈斯群岛较低，阿尔金浅滩居中，因此呈现出纬度梯度。特茹河口较高的人为压力解释了这种模式，但在像阿尔金浅滩这样原始的地方相对较高的浓度表明了污染在海洋中的传播。不同觅食行为的滨鸟粪便中的微纤维浓度相似，从无脊椎动物和粪便中收集到的纤维组成相似，这表明滨鸟主要通过其猎物摄入微纤维，证实了微纤维沿潮间带食物网的转移。在特茹河口，沉积物和双壳类动物中的微纤维浓度与细沉积物的百分比以及最近城镇的人口规模呈正相关，这表明水动力和当地生活污水是影响微纤维分布的主要因素。
