Cadmium-109 whole-body and internal biokinetics were experimentally investigated in critically endangered diamond sturgeon Acipenser gueldenstaedtii after uptake from water or food, in fresh (FW) and brackish (BW; 9‰) salinities typical of the Caspian Sea. Whole-body rates of uptake of ¹⁰⁹Cd from water and subsequent depuration were quantified over 14 and 28 days, respectively. Uptake was greater in FW than BW by a factor of 2.4, but depuration rates were similar in both salinities. In contrast, for the dietary (chironomid) exposure pathway ¹⁰⁹Cd assimilation efficiencies (AEs) were higher in BW (13%) compared to FW (9.5%). Head (including gills) or digestive tract were major repositories of ¹⁰⁹Cd following aqueous and dietary exposures, respectively, including both uptake and depuration phases. The point-of-entry of ¹⁰⁹Cd into the body was also a major and persistent determiner of its subsequent internal distribution. For aqueous exposures, the internal distributions of ¹⁰⁹Cd changed appreciably during depuration with increased activity concentrations in some body components, which again varied with salinity. Increased salinity appreciably enhanced the percentage distributions and activity concentrations of ¹⁰⁹Cd in the liver, kidney and digestive tract, which are typically most pathologically altered by elevated Cd exposure. For dietary exposure, increased salinity also enhanced ¹⁰⁹Cd activity concentrations in most body components. The results repeatedly indicate the important role of salinity in the whole-body and internal biokinetics of ¹⁰⁹Cd in A. gueldenstaedtii, a representative of both a phylogenetically distinct and most endangered family of fishes.

在里海典型的淡水（FW）和咸水（BW；9‰）盐度下，对极度濒危的钻石鲟Acipenser gueldenstaedtii从水或食物中摄取后的镉-109全身和内部生物动力学进行了实验研究。分别在 14 和 28 天内对全身从水中吸收¹⁰⁹ Cd 的速率和随后的净化进行量化。 FW 的吸收量比 BW 高 2.4 倍，但两种盐度的净化率相似。相比之下，对于饮食（摇蚊）暴露途径¹⁰⁹ Cd 同化效率 (AE)，BW (13%) 高于 FW (9.5%)。头部（包括鳃）或消化道分别是水接触和饮食接触（包括吸收和净化阶段）^{109 Cd 的主要储存库。 109} Cd 进入体内的点也是其随后内部分布的主要且持久的决定因素。对于水暴露， ¹⁰⁹ Cd的内部分布在净化过程中发生明显变化，某些身体成分的活性浓度增加，这又随盐度的变化而变化。盐度的增加明显增强了肝脏、肾脏和消化道中¹⁰⁹ Cd的百分比分布和活性浓度，这些区域通常因 Cd 暴露的增加而发生最明显的病理改变。对于饮食暴露，盐度的增加也提高了大多数身体成分中^{109 Cd 的活性浓度。结果反复表明盐度在}A. gueldenstaedtii的全身和内部¹⁰⁹ Cd生物动力学中发挥重要作用，A. gueldenstaedtii是系统发育独特且最濒危的鱼类家族的代表。