地质封存CO_2泄漏对蚯蚓的毒性效应

二氧化碳捕集与封存技术(CO_2 capture and storage, CCS)是当前国际上公认的CO_2减排的有效措施,但封存在地下的CO_2仍然因为各种不稳定因素存在泄漏风险,对土壤环境及土壤生态系统产生威胁。选择赤子爱胜蚓为研究对象,通过模拟高浓度CO_2对蚯蚓形态与生理变化的影响,探究CCS泄漏所产生的土壤高浓度CO_2对蚯蚓的毒性效应。研究表明,土壤高浓度CO_2使蚯蚓出现生殖环带肿大、尾部串珠以及断尾等外部形态变化,皮肤和刚毛受到损伤并且表皮发生褶皱等现象;随着CO_2浓度的增加以及暴露时间的延长,蚯蚓的死亡率不断增加,土壤高浓度CO_2对蚯蚓的7 d和14 d半致死浓度分别为26.39%和17.78%;蚯蚓体腔细胞溶酶体中性红保留时间(NRRT)减少。因此,蚯蚓有望作为监测CO_2泄漏的指示生物,NRRT可作为识别CO_2泄漏的敏感指标。

Toxic Effects of CO2 Leakage from Geological Storage on Earthworms

CO₂ capture and storage (CCS) is currently recognized as an effective measure to reduce carbon dioxide emissions in the world. However, the CO₂ stored underground has the risk of leakage because of various unstable factors, posing a threat to the soil environment and soil ecosystem. In this study, Eisenia fetida was selected as the research object. By simulating the effects of high concentration of CO₂ on the morphology and physiological changes of earthworms, the toxic effects of high concentration of CO₂ on the earthworms caused by CCS leakage were explored. The results showed that the high concentration of CO₂ in the soil caused earthworms to have external morphological changes such as clitellum swelling, tail beading and tail breaking; skin and setae were damaged and epidermis was wrinkled. With the increase of CO₂ concentration and the extension of exposure time, the mortality rate of earthworms increased continuously. The median lethal concentrations of 7 d and 14 d for high concentration CO₂ soil were 26.39% and 17.78%, respectively, and the lysosomal membrane neutral red retention time (NRRT) of granulocytes decreased. Therefore, earthworms are expected to be used as indicators of monitoring CO₂ leakage, and NRRT can be used as a sensitive biomarker for CO₂ leakage.