Acidification, heavy metal mobility and nutrient accumulation in the soil-plant system of a revegetated acid mine wasteland.
A revegetation program was established at an extreme acidic and metal-toxic pyrite/copper mine wasteland in Guangdong Province, PR China using a combination of four native grass species and one non-native woody species. It was continued and monitored for 2 y. The emphasis was on acidification, metal mobility and nutrient accumulation in the soil-plant system. Our results showed the following: (i) the acid-forming potential of the mine soils decreased steadily with time, which might be due to plant root-induced changes inhibiting the oxidization of sulphide minerals; (ii) heavy metal extractability (diethylene-triamine-pentaacetic acid-extractable Pb and Zn) in the soils increased with time despite an increase in soil pH, which might be attributed to soil disturbance and plant rhizospheric processes, as well as a consequence of the enhanced metal accumulation in plants over time; and (iii) the vegetation cover increased rapidly with time, and plant development accelerated the accumulation of major nutrients (organic matter, total and ammonium-N, and available P and K). The 2-y field experiment demonstrates that direct seeding/planting of native plant species in combination with lime and manure amelioration is a practical approach to the initial establishment of a self-sustaining vegetation cover on this metalliferous and sulphide-bearing mine wasteland. However, heavy metal accumulation in the soil-plant system should be of great concern, and long-term monitoring of ecological risk must be an integral part of such a restoration scheme.
Yang
Sheng-Xiang
SX
School of Life Sciences and State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275, PR China.
Liao
Bin
B
Li
Jin-tian
JT
Guo
Tao
T
Shu
Wen-Sheng
WS
D000143:Acids / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002244:Carbon / Q000032:analysis / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D008906:Mining; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry; D063245:Plant Development; D010944:Plants / Q000737:chemistry*; D011188:Potassium / Q000032:analysis / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000032:analysis / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
D000143:Acids; D019216:Metals, Heavy; D000644:Quaternary Ammonium Compounds; D012989:Soil Pollutants; D010758:Phosphorus; D002244:Carbon; D011188:Potassium