Wang Xizhi, Liu Yuanyuan, Liu Bin
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China.
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China.
J Hazard Mater. 2023 Sep 15;458:132052. doi: 10.1016/j.jhazmat.2023.132052. Epub 2023 Jul 11.
Chromite ore processing residue (COPR) keeps releasing Cr(VI) over time, and the mixing of residual COPR into soil makes the remediation of COPR-contaminated sites challenging. In this study, a sample of COPR and two soil profiles were collected from a typical historical COPR-contaminated site, and the vertical migration of Cr(VI) and COPR particles in contaminated soil was simulated in the laboratory. Cr(VI) was detected in the upper layer of the field samples at thousands of milligrams per kilogram even after decades of aging, and it can be leached out and migrate vertically deep into the surrounding soil and groundwater. In the COPR-containing soil, more diverse hydrated minerals of brownmillerite were produced than the COPR in the open air on the site. Minerals with high Cr content in COPR-containing soils have a relatively high proportion of particles smaller than 10 µm. COPR particles smaller than 5 µm were found to have migrated downward into the deep soil. During simulated one-year of precipitation, 578.9 mg Cr(VI)/kg was leached from COPR, while 35.5% of the COPR particles smaller than 5 µm had the potential to migrate vertically. The management of COPR particles should be emphasized during risk management or remediation of COPR-contaminated sites.
铬铁矿加工残渣（COPR）会随着时间的推移持续释放六价铬，而将残留的COPR混入土壤使得对受COPR污染场地的修复具有挑战性。在本研究中，从一个典型的历史COPR污染场地采集了一份COPR样本和两个土壤剖面，并在实验室中模拟了六价铬和COPR颗粒在污染土壤中的垂直迁移。即使经过数十年的老化，在现场样本的上层仍检测到每千克数千毫克的六价铬，并且它可以被淋滤出来并垂直迁移到周围土壤和地下水中。在含有COPR的土壤中，与现场露天的COPR相比，生成了更多样化的水化石榴石矿物。含有COPR的土壤中高铬含量的矿物具有相对较高比例的小于10微米的颗粒。发现小于5微米的COPR颗粒已向下迁移到深层土壤中。在模拟的一年降水期间，从COPR中淋滤出578.9毫克六价铬/千克，而小于5微米的COPR颗粒中有35.5%有可能垂直迁移。在对COPR污染场地进行风险管理或修复期间，应强调对COPR颗粒的管理。
