Centro de Investigaciones Biológicas del Noroeste SC, Instituto Politécnico Nacional No 195, Col Playa Palo de Santa Rita sur, 23096, La Paz, Baja California Sur, Mexico.
Environ Sci Pollut Res Int. 2020 Dec;27(36):45755-45766. doi: 10.1007/s11356-020-10392-0. Epub 2020 Aug 15.
Raptors as top predators have been used as effective sentinels of environmental stressors in agricultural areas worldwide. Pollutants in agricultural areas have negative effects on top predator populations. Biomarkers such as erythrocyte nuclear abnormalities have been used as an effective measure of genotoxicity caused by exposure-particularly short-term exposure-to pollutants. We took blood samples from 54 wild specimens of American kestrel (Falco sparverius) captured in an agricultural area in Valle de Santo Domingo, Baja California Sur, Mexico in the autumns of 2018 and 2019 (n = 25) and the winters of 2019 and 2020 (n = 29). We prepared and examined blood smears to look for erythrocyte abnormalities as a means to evaluate genotoxicity. The number of abnormality types and the total frequency of abnormalities (MNs and NAs: notched, symmetrically or asymmetrically constricted, displaced, or indented nuclei) per 10,000 erythrocytes were calculated for all the specimens. We found a high frequency of abnormalities in numerous individuals, similar to those found in raptors from highly polluted areas. The best-fit generalized linear model for the number of abnormality types included season-of-the-year as the main significant predictor; the model for the total frequency of abnormalities included season and wing chord, an indicator of body size and health condition, as significant predictors. MNs frequencies were significantly related to season; NAs frequencies were related to season, wing chord length, and coverage of native vegetation around the area where the birds were captured. Abnormalities observed in the autumn closely coincide with the time when agrochemicals are applied in the area, mainly after the rains and during hot spells in late summer and early autumn. Small-sized kestrels showed higher frequencies of NAs, with an additional impact if native vegetation had been cleared for agriculture; this suggests both that resident birds are more exposed, and the observed genotoxicity has a local origin. These results, together with the ecological and physiological characteristics of the American kestrel suggest that this charismatic and widely distributed species might constitute a suitable biomonitor of genotoxicity in rural landscapes.
猛禽作为顶级掠食者，已被广泛用于监测全球农业地区的环境胁迫因子。农业地区的污染物会对顶级掠食种群产生负面影响。红细胞核异常等生物标志物已被用作暴露于污染物（尤其是短期暴露）引起遗传毒性的有效衡量标准。我们从 2018 年和 2019 年秋季（n=25）以及 2019 年和 2020 年冬季（n=29）在墨西哥南下加利福尼亚州圣地亚哥山谷的一个农业区捕获的 54 只野生红隼（Falco sparverius）中采集了血液样本。我们制备并检查了血涂片，以寻找红细胞异常，以此评估遗传毒性。我们计算了所有样本中每 10,000 个红细胞的异常类型数量和总异常频率（MN 和 NA：有切迹、对称或不对称收缩、移位或凹陷的核）。我们发现许多个体中存在高频率的异常，与来自高度污染地区的猛禽相似。异常类型数量的最佳拟合广义线性模型包括年季作为主要显著预测因子；总异常频率的模型包括季节和翼展，这是身体大小和健康状况的指标，作为显著预测因子。MN 的频率与季节显著相关；NA 的频率与季节、翼展长度以及鸟类被捕获区域周围原生植被的覆盖情况有关。秋季观察到的异常与该地区施用农用化学品的时间大致吻合，主要是在雨后以及夏末初秋的炎热时期。小型红隼的 NA 频率更高，如果原生植被被清除用于农业，频率会更高；这表明居留鸟类受到的影响更大，并且观察到的遗传毒性具有本地来源。这些结果，以及红隼的生态和生理特征表明，这种迷人且分布广泛的物种可能是农村景观遗传毒性的合适生物监测器。
