Barquero J I, Hidalgo J J, Esbrí J M, Higueras P, García-Ordiales E
Instituto de Geología Aplicada, Universidad de Castilla-La Mancha, Pl. Manuel Meca 1, 13400, Almadén, Ciudad Real, Spain.
Escuela de Ingeniería Minera e Industrial de Almadén, Pl. Manuel Meca 1, 13400, Almadén, Ciudad Real, Spain.
Environ Geochem Health. 2024 Dec 23;47(1):27. doi: 10.1007/s10653-024-02326-3.
The food chain of the Valdezogues River system is at considerable risk due to the presence of mercury in the environment and to intense bioaccumulation and biomagnification processes in some fish species, particularly in piscivorous. Moreover, the presence of mercury in fish is a reliable indicator of the presence of its most toxic form, methylmercury. Of interest is that selenium, when present together with mercury in food, represents a significant decrease in the risks related to the ingestion of methylmercury. This study presents the concentrations of total mercury, methylmercury, selenium, and other elements in Micropterus salmoides from a transect of the Valdeazogues River. This water course cuts across the Almadén mining district, which has been the most important producer of this element for over 2000 years. Results highlight the highest total- and methylmercury concentrations ranging between 0.47 and 7.61 mg kg ww for total mercury, and with methylmercury representing between 79.7 and 92.1% of total mercury. These are the highest concentrations in the element ever found in this species. Seven sampling sites were examined along a 34 km long transect of the river, starting at an open pit lake corresponding to a decommissioned Hg mine (El Entredicho open pit, isolated from the river course), with the rest of the sites located downstream. Concentrations of mercury are the highest in this open pit lake and decrease steadily downstream. Concentrations of selenium are also high to very high, ranging between < 2.5 and 11.4 mg kg ww. The Se/Hg molar ratio, as well as the HBV index, show values indicating low risk, except for specimens of low size/age from the most highly Hg contaminated site considered in this study. The rest of the potentially toxic elements (Se, As, Pb, Zn, Sb and Cu) show no concerning values even though the area is heavily populated with decommissioned polymetallic mines.
由于环境中汞的存在以及某些鱼类物种，特别是食鱼性鱼类中强烈的生物累积和生物放大过程，瓦尔德索格斯河系统的食物链面临着相当大的风险。此外，鱼类中汞的存在是其毒性最强的形式——甲基汞存在的可靠指标。有趣的是，当硒与汞同时存在于食物中时，与摄入甲基汞相关的风险会显著降低。本研究呈现了瓦尔德阿佐格斯河一个断面的小口黑鲈中总汞、甲基汞、硒和其他元素的浓度。这条水道横穿阿尔马登矿区，在过去2000多年里，该矿区一直是这种元素的最重要产地。结果突出显示，总汞和甲基汞的最高浓度范围为：总汞为0.47至7.61毫克/千克湿重，甲基汞占总汞的79.7%至92.1%。这些是该物种中该元素有史以来发现的最高浓度。沿着这条34公里长的河流断面检查了七个采样点，起点是一个对应于已退役汞矿的露天矿湖（埃尔恩特雷迪乔露天矿，与河道隔离），其余采样点位于下游。汞浓度在这个露天矿湖中最高，向下游稳步下降。硒浓度也很高到非常高，范围在<2.5至11.4毫克/千克湿重之间。硒汞摩尔比以及乙肝病毒指数显示的值表明风险较低，但本研究中考虑的汞污染最严重地点的小尺寸/低龄标本除外。其余潜在有毒元素（硒、砷、铅、锌、锑和铜）即使该地区布满了退役的多金属矿，也没有显示出令人担忧的值。
