Chen Te-Hao, Gross Jackson A, Karasov William H
Department of Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Environ Toxicol Chem. 2006 May;25(5):1383-9. doi: 10.1897/05-356r.1.
Northern leopard frogs (Rana pipiens) were exposed to environmentally relevant concentrations of lead in water (3, 10, and 100 microg/L as lead nitrate) from the embryonic stage to metamorphosis. Survival, growth, deformity, swimming ability, metamorphosis, and lead tissue concentrations were evaluated. Tadpole growth was significantly slower in the early stages (Gosner stages 25-30) in 100 microg/L treatment. More than 90% of tadpoles in the 100 microg/L treatment developed lateral spinal curvature, whereas almost all the tadpoles in the other groups were morphologically normal. Spinal deformity was associated with abnormal swimming behavior. Maximum swimming speed of tadpoles in the 100 microg/L treatment was significantly lower than that in the other groups. No significant effect of lead exposure was found on percentage metamorphosis, snout-vent length, mortality, and sex ratio of metamorphs. Time to metamorphosis was delayed in 100 microg/L treatment. Lead tissue concentrations in the tadpoles ranged from 0.1 to 224.5 mg/kg dry mass, were positively related to lead concentrations in the water, and fell within the range of tissue concentrations of wild tadpoles found in previous studies. According to our results, the current U.S. Environmental Protection Agency freshwater-quality chronic criterion for lead (2.5 microg/L) is appropriate to protect northern leopard frog larvae.
从胚胎期到变态期，将北美豹蛙（林蛙）暴露于水中与环境相关浓度的铅（以硝酸铅计为3、10和100微克/升）中。评估了存活率、生长、畸形、游泳能力、变态以及铅组织浓度。在100微克/升处理组中，蝌蚪在早期阶段（戈斯纳25 - 30期）的生长显著较慢。100微克/升处理组中超过90%的蝌蚪出现脊柱侧弯，而其他组几乎所有蝌蚪形态正常。脊柱畸形与异常游泳行为有关。100微克/升处理组蝌蚪的最大游泳速度显著低于其他组。未发现铅暴露对变态百分比、吻肛长度、死亡率和变态后的性别比例有显著影响。100微克/升处理组的变态时间延迟。蝌蚪体内铅组织浓度范围为0.1至224.5毫克/千克干重，与水中铅浓度呈正相关，且落在先前研究中野生蝌蚪组织浓度范围内。根据我们的结果，美国环境保护局目前的铅淡水水质慢性标准（2.5微克/升）适合保护北美豹蛙幼体。
