Long-term stability and risk assessment of copper and cadmium in a smelter-impacted soil treated by four amendments

ABSTRACT

In an effort to address public concerns of the long-term stability and ecological risk reduction of Cu and Cd in a farmland located at the Guixi, Jiangxi Province, China, containing ∼ 800 mg kg⁻¹ Cu and 0.8 mg kg⁻¹ Cd soil, were treated in situ by attapulgite, apatite, montmorillonite and lime at the rate: 10, 10, 10 and 4 g kg⁻¹ soil, respectively. Field experiment consisted of 2 × 3-m plots arranged in a randomised complete block design with each treatment. Soil and plant samples were collected in sixth years post-treatments and analysed for Cu and Cd bioaccessibility, chemical fraction and Cu, Cd concentration in plant tissue. The results indicated that the apatite and lime treatments significantly reduced bioaccessible and exchangeable fractions Cu and Cd in the soil at sixth years post the treatments. Cu and Cd concentration in plant tissue was positively related to the bioaccessibility of Cu and Cd. The treatment used 10 g apatite kg⁻¹ soil appeared to be most effective for overall risk reduction. The Cu and Cd stabilisation and risk reduction by the apatite treatments were accomplished by the induced transformation of labile Cu and Cu species to relatively insoluble forms. This study illustrated that in situ Cu and Cd stabilisation by apatite would be long-term and ecologically safe, which could safeguard human health and ecosystem from Cu and Cd contamination in mining areas.

KEYWORDS:

• Copper
• cadmium
• contamination
• in situ remediation
• risk assessment
• sustainability

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Lei Xu obtained Ph.D. in soil science and he is a researcher and teacher at Nanyang Normal University, Nanyang, PRC.

Hongbiao Cui obtained Ph.D. in soil science and he is a researcher and teacher at Anhui University of Science and Technology, Huainan, PRC.

Xiangyu Xing obtained Master's degree in English linguistics and she is a researcher and teacher at Nanyang Normal University, Nanyang, PRC.

Zhimin Du obtained Ph.D. in soil science and she is a researcher at Henan Academy of Sciences Institute of Biology Co., Ltd, Zhengzhou, PRC.

Jiani Liang obtained Master's degree in soil science and she is a researcher at Institute of Soil Science, Chinese Academy of Science, Nanjing, PRC.

Xuebo Zheng obtained Ph.D. in soil science and he is a researcher at Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, PRC.

Lunguang Yao obtained Ph.D. in soil science and he is a researcher and teacher at Nanyang Normal University, Nanyang, PRC.

Jing Zhou obtained Ph.D. in soil science and he is a researcher and teacher at Institute of Soil Science, Chinese Academy of Science, Nanjing, PRC.

Additional information

Funding

The authors acknowledge the PhD special project of Nanyang Normal University (2018ZX018), Chinese Academy Of Agricultural Sciences (2015BAD05B01), National Natural Science Foundation of China (41571461, 41601340, 41701361), Scientific Research And Service Platform Fund Of Henan Province (2016151) and the fund of scientific and technological innovation team of water ecological security for water source region of mid-line of south-to-north diversion project Henan province (17454).