Columbia Environmental Research Center, US Geological Survey, Columbia, Missouri, USA.
Department of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, New York, USA.
Environ Toxicol Chem. 2023 Jul;42(7):1529-1541. doi: 10.1002/etc.5631. Epub 2023 May 17.
Nitrate concentrations have been rising in surface waters over the last century and now frequently exceed drinking water standards and environmental safety benchmarks globally. Health-wise, these trends are concerning because nitrate has been shown to disrupt endocrine function and developmental outcomes. The present study investigated potential sublethal effects of nitrate on developing fathead minnows. Fish were exposed from fertilization through 21 days postfertilization (dpf) to environmentally relevant concentrations of nitrate (0, 2, 5, 10, 25, or 100 mg/L NO -N as NaNO ). Nitrate effects on hatch timing, heart rate and rhythm at 3 dpf, growth through 21 dpf, swim bladder inflation timing and size, scoliosis, pericardial edema, and mortality were assessed. Because adding NaNO increases water conductivity, two conductivity controls were included to match the ionic strength of the 10- and 100-mg/L NO -N treatments. Increasing nitrate delayed posterior swim bladder (PSB) inflation in a dose-dependent manner, with possible inhibition of anterior swim bladder (ASB) inflation at higher doses, although nitrate did not affect swim bladder size. Conversely, nitrate did not affect hatch timing or cardiac endpoints at 3 dpf or induce pericardial edema or scoliosis, although there was a noted brood effect on these latter defects. As was observed with increasing nitrate, higher ion concentrations in the conductivity controls caused dose-dependent increases in fish body size at 21 dpf. Increased ionic strength also hastened ASB inflation independently of nitrate. As in other published studies, the observed delay in PSB inflation suggests that nitrate disrupts the thyroid axis and warrants further investigation. In addition, the present study supports the need for conductivity controls in nitrate toxicity studies to distinguish nitrate-specific effects. Environ Toxicol Chem 2023;42:1529-1541. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.
在过去的一个世纪里，地表水中的硝酸盐浓度不断上升，现在在全球范围内经常超过饮用水标准和环境安全基准。从健康角度来看，这些趋势令人担忧，因为硝酸盐已被证明会破坏内分泌功能和发育结果。本研究调查了硝酸盐对发育中的黑头呆鱼的潜在亚致死影响。从受精到受精后 21 天（dpf），鱼暴露于环境相关浓度的硝酸盐（0、2、5、10、25 或 100mg/L 作为 NaNO 的硝酸盐-N）中。评估了硝酸盐对孵化时间、3 dpf 时的心率和节律、21 dpf 时的生长、鳔充气时间和大小、脊柱侧凸、心包水肿和死亡率的影响。由于添加 NaNO 会增加水的电导率，因此包含了两个电导率对照，以匹配 10-和 100-mg/L NO -N 处理的离子强度。硝酸盐以剂量依赖的方式延迟了后鳔（PSB）充气，在较高剂量下可能抑制了前鳔（ASB）充气，尽管硝酸盐不影响鳔大小。相反，硝酸盐在 3 dpf 时不影响孵化时间或心脏终点，也不引起心包水肿或脊柱侧凸，但这些缺陷在后代中存在明显的窝效应。与硝酸盐增加一样，电导率对照中较高的离子浓度导致 21 dpf 时鱼体大小呈剂量依赖性增加。增加离子强度也独立于硝酸盐加速了 ASB 充气。与其他已发表的研究一样，PSB 充气延迟表明硝酸盐破坏了甲状腺轴，需要进一步研究。此外，本研究支持在硝酸盐毒性研究中进行电导率对照，以区分硝酸盐的特异性影响。环境毒理化学 2023；42:1529-1541。2023 年出版。本文是美国政府的一项工作，在美国属于公有领域。
