Location: Commodity Utilization ResearchTitle: Effects of soil amendments on cadmium transfer along the lettuce-snail food chain: Influence of chemical speciation
|WANG, YI-MIN - Hohai University|
|TANG, DOU-DOU - Hohai University|
|ZHANG, XIAO-HUI - Hohai University|
|YUAN, XU-YIN - Hohai University|
|LI, MING - Hohai University|
|CHEN, YAO-ZU - Hohai University|
Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2018
Publication Date: 8/31/2018
Citation: Wang, Y.-M., Tang, D.-D., Zhang, X.-H., Uchimiya, M., Yuan, X.-Y., Li, M., Chen, Y.-Z. 2019. Effects of soil amendments on cadmium transfer along the lettuce-snail food chain: Influence of chemical speciation. Science of the Total Environment. 649:801-807.
Interpretive Summary: Cadmium is toxic to edible crops including lettuce, and accumulates in the ecological food chain. Following important questions were investigated in this study: (1) how would different forms of cadmium (chemical speciation) impact its transfer up the food chain? (2) could soil amendments mitigate (1) and if so, what is the mechanism? To address those questions, this paper investigated the soil-lettuce-snail ecological food chain in the presence of biochar and apatite soil amendments. Results indicated the importance of solubility-limiting phases and translocation (movement of cadmium in lettuce cellular components) on bioavailability and trophic transfer of cadmium.
Technical Abstract: Cadmium (Cd) trophic transfer along the soil-plant-snail food chain was investigated using the root bags-based pot experiments. Two amendments (corn straw biochar and µHAP) were investigated on Cd (0, 2.5, and 5 mg/kg soil) bioavailability in soils, chemical distribution in plant cells, and accumulations in snail tissues. After 60 d, both the CaCl2 extractable Cd (CdCaCl2,rhizo) and total Cd accumulation in lettuce were reduced in the biochar/µHAP amended soils. Moreover, biochar has a greater capacity to reduce the toxicity-sensitive associated Cd contents (CdFi+Fii) of lettuce at 2.5 mg Cd/kg soil, while µHAP significantly decreased the contents of CdFi+Fii in the high Cd soil (5.0 mg/kg soil). For all treated soils, µHAP generates the highest reduction in the chain transfer associated Cd (CdFi+Fii+Fiii) contents in the lettuce shoots, which is better correlated with the CdCaCl2,rhizo (r2 > 0.70, p < 0.001). Cd bio-magnification phenomenon (TFs>1) in the soil-lettuce system is also decreased with the soil Cd bioavailability affected by amendments. After 15d snail feeding, snail viscera has the dominant Cd accumulation (~90%), followed by the soft tissues and shells. µHAP has a higher reduction in snail Cd accumulation in comparison with biochar. Distributions of Cd in snail tissues are correlated with CdFi+Fii+Fiii (total r2 = 0.832; viscera r2 = 0.835; soft tissue r2 = 0.771). It could be suggested that CdFi+Fii+Fiii in shoots might be responsible for the transfer ability of Cd along the lettuce-snail chain. Moreover, the TFs calculated from the CdCaCl2,rhizo contents in soil rather than the total Cd contents indicated a bio-magnification phenomenon of Cd along the soil-snail soft tissues. Established quantitative relationships could be used to predict the bioavailability and transfer of Cd in the terrestrial food chain in the presence of amendments.