Effect of humic acid on seedling growth and trace metal accumulation of pak choi (Brassica chinensis L.) cultivated on molybdenum slag-spiked soil

• Published in: Environmental science and pollution research international Vol. 28; no. 5; pp. 6122 - 6131
• Main Authors: Chen, Dong, Meng, Zhong-wen, Chen, Yi-ping
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2021; Springer Nature B.V
• Subjects: Accumulation; Acids; Antioxidants; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Brassica; Brassica rapa chinensis; Cadmium; Calcareous soils; Catalase; Chlorophyll; Copper; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Food safety; Health risk assessment; Health risks; Heavy metals; Humic acids; Humic Substances; Lead; Leaf area; Malondialdehyde; Manganese; Metals; Molybdenum; Peroxidase; Quotients; Research Article; Risk assessment; Seedlings; Seedlings - chemistry; Slag; Soil; Soil Pollutants - analysis; Soils; Superoxide dismutase; Trace metals; Waste Water Technology; Water Management; Water Pollution Control; Zinc; Industrial slag; Antioxidant enzyme; Calcareous soil; Trace metal; Soil amendment; Health risk
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-10929-3

The growth performance and trace metal accumulation of pak choi ( Brassica chinensis L.) were investigated to evaluate the ameliorative effect of humic acid on molybdenum (Mo) slag-spiked calcareous soil. Calcareous soil spiked with 5.0% (w/w) slag was amended with humic acid derived from leonardite from 0 to 5.0% (w/w). With increasing application rate, humic acid enhanced the antioxidative capacity of pak choi seedling, as indicated by increases in the activities of antioxidant enzymes (superoxide dismutase, catalase, and peroxidase) and a decrease in malondialdehyde content; humic acid application also increased total chlorophyll content, leaf area, seedling height, and fresh biomass of pak choi. These stimulation effects started to decrease above 2.5–5.0% application of humic acid. The contents of trace metals (Cu, Mn, Zn, As, Cd, and Pb) in the aboveground part of pak choi seedling generally decreased at low rates (0.5% and 1.0%), and then increased with higher rates (2.5% and 5.0%) of humic acid application. Health risk assessment of trace metals based on target hazard quotient (THQ) suggested that consuming pak choi grown on these soils is safe. Low rate (0.5%) of humic acid reduced the potential health risk, while high rates (2.5% and 5.0%) accumulated trace metals and increased health risk. Humic acid could be added to Mo slag-spiked calcareous soil for the yield and food safety of pak choi, but the overuse of humic acid should be avoided.