Effects of PASP/NTA and TS on the phytoremediation of pyrene-nickel contaminated soil by Bidens pilosa L.

Bidens pilosa L. (B. pilosa) is considered as an effective phytoremediation plant. In this study, polyaspartic acid (PASP), aminotriacetic acid (NTA) and tea saponin (TS) was combined with B. pilosa. to strengthen the phytoremediation efficiency. The removal rate of pyrene reached 95.8% with B. pilosa alone. The release of Ni in NTA and NTA-TS treatments was 20-30 times than untreated contaminant soil. The Ni concentration in roots of B. pilosa increased by 63.1% and 58.6% in PASP and PASP-TS treatments, respectively. The Ni concentration in leaves of B. pilosa increased by 55.9% and 186% in NTA and NTA-TS treatments, respectively. The growth of B. pilosa was significantly promoted in PASP and PASP-TS treatments. PASP, NTA and TS significantly promoted soil microbial activities. The results showed that B. pilosa was beneficial to pyrene removal. PASP and NTA had positive effects on absorption of Ni by B. pilosa.