Shipyards impact on estuarine environments because of the use of antifouling paints and petroleum products, which release trace metals that may remain in their bioavailable or labile form. Regardless of its importance, the relation between continuous input of trace metals (hotspot area) and their availability in the water column has been scarcely studied. This study evaluated seasonal variations in the concentrations of labile fractions of metals in shipyards located in estuarine areas on the Brazilian subtropical coast. These fractions were determined by the Diffuse Gradients in Thin Films (DGT) technique. Maximum labile fraction concentrations of Cr (0.3 μg L⁻¹), Ni (2.2 μg L⁻¹) and V (2.0 μg L⁻¹) are directly related to (i) their specific source: antifouling paints (for Cr), metal and steel alloys (for Cr and Ni) and petroleum products (for V), besides (ii) periods of intensive traffic and vessel repair. Additionally, variations in labile fractions of Ni and V in the Patos Lagoon estuary were influenced by salinity, which is known to affect metal desorption from surface sediments in resuspension events. Even though Cr is affected by the same processes, it is available as Cr(III) and does not represent any ecological risk in the study areas. Although the areas under study are affected by variations in physical and chemical conditions, shipyards were effectively hotspots of trace metals in their labile fraction in various estuarine systems in southeastern and southern Brazil. Thus, they represent areas where Ecological Risk Assessment, mainly of V, should be carried out.

由于使用了防污涂料和石油产品，造船厂对河口环境产生了影响，这些防污涂料和石油产品释放出可能以其生物利用度或不稳定形式保留的痕量金属。不管其重要性如何，很少研究痕量金属的连续输入（热点区域）与其在水柱中的可用性之间的关系。这项研究评估了位于巴西亚热带海岸河口地区的船厂中金属不稳定成分浓度的季节性变化。这些分数是通过薄膜中的扩散梯度（DGT）技术确定的。铬（0.3微克升最大不稳定分数浓度^-1），镍（2.2微克大号^-1）和V（2.0微克大号^-1）与（i）特定来源直接相关：除（ii）繁忙的交通和船只维修期间外，防污漆（用于Cr），金属和钢合金（用于Cr和Ni）和石油产品（用于V）。另外，Patos Lagoon河口中不稳定的Ni和V分数的变化受盐度的影响，已知盐度会在重悬事件中影响金属从表层沉积物中的脱附。即使铬受相同的过程影响，它也可以作为Cr（III）的形式使用，并不代表研究区域的任何生态风险。尽管研究区域受物理和化学条件的变化影响，但船厂实际上是巴西东南部和南部各种河口系统中不稳定部分中的微量金属的热点。因此，它们代表了生态风险评估，