Earthworm activities weaken the immobilizing effect of biochar as amendment for metal polluted soils

Wang, Jie; Shi, Liang; Zhang, Xinzhe; Zhao, Xuan; Zhong, Kecheng; Wang, Shengxiao; Zou, Jianwen; Shen, Zhenguo; Chen, Yahua

doi:10.1016/j.scitotenv.2019.133729

Cited by 32 publications

(12 citation statements)

References 53 publications

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“…47 Similarly, after 28 days, the immobilization effect of biochar was weakened with 15-E. fetida in 450 g soil and earthworm activities significantly reduced soil pH by 0.1−0.19 unit. 48 However, more studies showed that the effects of earthworm activities were to increase rather than decrease the soil pH. 30,35,42 In the present study, no significant effects on soil pH was observed.…”

Section: Resultscontrasting

confidence: 48%

“…Changes in metal fractionation showed that the exchangeable and reducible Cd, Pb, and Zn fractions increased while the oxidizable and residual fractions of the same metals decreased with the earthworm’s inoculation assessed by the BCR sequential extraction procedure . Also, the fractions of Cd, Pb, and Zn bound to carbonates were significantly reduced with the significantly increased exchangeable fractions as affected by earthworm activities, while no significant effect on other forms was observed with the Tessier’ sequential extraction scheme . Thus, in the present study, the U bioavailability in soil was increased by earthworm activities and the U uptake and accumulation in Indian mustard and sunflower were promoted.…”

Section: Resultssupporting

confidence: 42%

“…31 Also, the fractions of Cd, Pb, and Zn bound to carbonates were significantly reduced with the significantly increased exchangeable fractions as affected by earthworm activities, while no significant effect on other forms was observed with the Tessier' sequential extraction scheme. 48 Thus, in the present study, the U bioavailability in soil was increased by earthworm activities and the U uptake and accumulation in Indian mustard and sunflower were promoted.…”

Section: Resultsmentioning

confidence: 47%

“…31 Moreover, after 28-days exposure, only 31.7−36.7% of E. fetida was found alive irrespectively with biochar addition, and a significant amount of earthworms' weight was lost. 48 Our previous study observed that amendments (lime, hydroxyapatite, biochar, and organic fertilizer) had no significant effects on the death rate and fresh weight loss of E. fetida in a mildly Cdcontaminated soil (0.73 mg kg −1 ), 35 whereas the compost increased the cocoon and juvenile production of E. fetida when subjected to a Cu/As-contaminated soil in Chile. 50 Nonetheless, the application of cattle manure benefited the state of earthworms in DU-contaminated soils, which eventually facilitated the phytoremediation process.…”

Section: Resultsmentioning

confidence: 93%

“…In fact, the mortality rate of E. fetida reached as high as ∼83.3% after 33-days cultivation in a heavily lead–zinc mine-contaminated soil that even worms were fed, and alternatively, the survival rate was increased with the application of EDTA . Moreover, after 28-days exposure, only 31.7–36.7% of E. fetida was found alive irrespectively with biochar addition, and a significant amount of earthworms’ weight was lost . Our previous study observed that amendments (lime, hydroxyapatite, biochar, and organic fertilizer) had no significant effects on the death rate and fresh weight loss of E. fetida in a mildly Cd-contaminated soil (0.73 mg kg –1 ), whereas the compost increased the cocoon and juvenile production of E. fetida when subjected to a Cu/As-contaminated soil in Chile .…”

Section: Resultsmentioning

confidence: 97%

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Earthworm Enhanced Phytoremediation of U in Army Test Range Soil with Indian Mustard and Sunflower

Guo

Proctor

Larson

et al. 2022

ACS Earth Space Chem.

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Wars and military testing have resulted in the depleted uranium (DU) contamination of military proving grounds. In the present study, a pot experiment was conducted to explore the effects of earthworms on the uranium phytoremediation process. Effects of cattle manure and Eisenia fetida on biomass and U accumulation of plants, U solubility, and pH in soil were investigated using DU-contaminated soil from Yuma Proving Ground in Arizona, U.S. Results showed that the growth of plants was promoted with the addition of cattle manure and earthworms, which was more obvious for sunflowers. Moreover, the U accumulation was significantly enhanced by earthworms and cattle manure, with a 68.5% (Indian mustard) and 85.0% (sunflower) increase in the cattle manure plus earthworm treatments, and the removal efficiencies of U were correspondingly improved. No significant effect on soil pH was observed, while the soil water extractable U was increased by 84.9–87.8% in the earthworm treatments. Moreover, after the 4-week cultivation, cattle manure benefited the survival of earthworms and slightly increased their average fresh weight in DU-contaminated soil. Therefore, this study concludes that earthworms combined with agricultural organic wastes was an alternative approach to effectively remediate DU-contaminated soils in firing ranges.

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