Hellenic Centre for Marine Research, Institute of Oceanography, P.O. Box 2214, 71003 Heraklion, Crete, Greece; Biology Department, University of Crete, Voutes Campus, 70013 Heraklion, Crete, Greece.
IMDEA Water Institute, Science and Technology Campus of the University of Alcalá, Avenida Punto Com 2, 28805, Alcalá de Henares, Madrid, Spain.
Sci Total Environ. 2021 Apr 10;764:142843. doi: 10.1016/j.scitotenv.2020.142843. Epub 2020 Oct 8.
Chemical residues released from aquaculture farms may persist in the environment and may pose adverse ecological effects. The aim of this study was to assess the pollution status of marine sediments underneath or close to aquaculture farms in the Eastern Mediterranean Sea, the factors that affect the elemental distribution, and the exceedance of environmental quality standards and factors. To this end, surface sediment samples were collected (underneath fish cages, at 25 m distance and from a reference station) from 48 fish farms in Greece with variable environmental and geochemical characteristics. The content of 29 metals and major and trace elements, and three antibiotics (oxytetracycline, florfenicol, and flumequine), was determined in the sediment samples. Most of the elements found in the sediments originated from geological sources and their concentrations were close to Earth's Crust content. Below and close to fish farm cages, the sediment was enriched with P, Cu, Zn, Mo, and Cd mainly due to the aquaculture biosolid deposition, and changes in environmental conditions (increased organic matter, low redox potential). Cr and As were found to exceed twice the upper threshold limit of the available sediment quality guidelines in 13.5% and 7.3% of sampling stations, respectively. The potential ecological risk of V, Cr, Mn, Co, Ni, Cu, Zn, As and Pb was found to be low in the sediment close to fish cages except for Cd, which may pose a moderate to considerable risk in 12.5% of sampled fish farms. However, the estimated risks for this metal may be influenced by the high background levels found in the investigated areas. This study also shows that the occurrence of antibiotics in sediments below fish farms in the Eastern Mediterranean Sea is very sparse (i.e., only flumequine was found in two farms) and concentration levels are relatively low.
水产养殖场释放的化学残留物可能会在环境中持续存在，并可能对生态产生不利影响。本研究的目的是评估东地中海地区水产养殖场下方或附近海洋沉积物的污染状况、影响元素分布的因素、以及超过环境质量标准和因素的情况。为此，从希腊具有不同环境和地球化学特征的 48 个水产养殖场采集了表层沉积物样品（在鱼类养殖笼下方、25 米距离处和参考站）。在沉积物样品中测定了 29 种金属和主要及微量元素，以及三种抗生素（土霉素、氟苯尼考和氟甲喹）的含量。沉积物中发现的大多数元素来自地质来源，其浓度接近地球地壳的含量。在鱼类养殖场笼下方和附近，由于水产养殖生物固体的沉积以及环境条件的变化（增加了有机物、降低了氧化还原电位），沉积物中 P、Cu、Zn、Mo 和 Cd 得到了富集。在 13.5%和 7.3%的采样点，Cr 和 As 的含量分别超过可用沉积物质量指南上限阈值的两倍。在靠近鱼类养殖笼的沉积物中，V、Cr、Mn、Co、Ni、Cu、Zn、As 和 Pb 的潜在生态风险被认为较低，除了 Cd 之外，在 12.5%的采样养殖场中，Cd 可能构成中度到相当大的风险。然而，对这种金属的估计风险可能受到调查区域高背景水平的影响。本研究还表明，在东地中海地区水产养殖场下方的沉积物中，抗生素的出现非常稀少（即在两个养殖场中仅发现了氟甲喹），且浓度相对较低。
