Spry D J, Wiener J G
Ontario Ministry of the Environment, Water Resources Branch, 135 St. Clair Avenue West, Toronto, Ontario M4V 1P5, Canada.
Environ Pollut. 1991;71(2-4):243-304. doi: 10.1016/0269-7491(91)90034-t.
Fish in low-alkalinity lakes having pH of 6.0-6.5 or less often have higher body or tissue burdens of mercury, cadmium, and lead than do fish in nearby lakes with higher pH. The greater bioaccumulation of these metals in such waters seems to result partly from the greater aqueous abundances of biologically available forms (CH(3) Hg(+), Cd(2+), and Pb(2+)) at low pH. In addition, the low concentrations of aqueous calcium in low-alkalinity lakes increase the permeability of biological membranes to these metals, which in fish may cause greater uptake from both water and food. Fish exposed to aqueous inorganic aluminum in the laboratory and field accumulate the metal in and on the epithelial cells of the gills; however, there is little accumulation of aluminum in the blood or internal organs. In low-pH water, both sublethal and lethal toxicity of aluminum has been clearly demonstrated in both laboratory and field studies at environmental concentrations. In contrast, recently measured aqueous concentrations of total mercury, methylmercury, cadmium, and lead in low-alkalinity lakes are much lower than the aqueous concentrations known to cause acute or chronic toxicity in fish, although the vast majority of toxicological research has involved waters with much higher ionic strength than that in low-alkalinity lakes. Additional work with fish is needed to better assess (1) the toxicity of aqueous metals in low-alkalinity waters, and (2) the toxicological significance of dietary methylmercury and cadmium.
pH值为6.0 - 6.5或更低的低碱度湖泊中的鱼类，其体内或组织中的汞、镉和铅含量往往高于附近pH值较高湖泊中的鱼类。这些金属在这类水体中更大程度的生物累积，部分原因似乎是在低pH值条件下，生物可利用形态（CH(3)Hg(+)、Cd(2+)和Pb(2+)）在水中的丰度更高。此外，低碱度湖泊中水体钙浓度较低，会增加生物膜对这些金属的通透性，这在鱼类中可能导致从水和食物中摄取更多的金属。在实验室和野外环境中，接触水体无机铝的鱼类会在鳃的上皮细胞内和细胞表面累积这种金属；然而，血液或内脏中铝的累积量很少。在低pH值水中，无论是亚致死毒性还是致死毒性，在实验室和野外研究中均已在环境浓度下清楚地得到证实。相比之下，最近测量的低碱度湖泊中总汞、甲基汞、镉和铅的水体浓度，远低于已知会对鱼类造成急性或慢性毒性的水体浓度，尽管绝大多数毒理学研究涉及的水体离子强度比低碱度湖泊中的要高得多。需要对鱼类开展更多研究，以更好地评估：（1）低碱度水体中金属的毒性；（2）膳食甲基汞和镉的毒理学意义。
