Heavy metals in apple orchard soils and fruits and their health risks in Liaodong Peninsula, Northeast China

The heavy metal pollution of soils, resulting from long-term fertilizing activity, is becoming serious in many countries, endangering ecological safety and human health. This study employed inductively coupled plasma-mass spectrometry (ICP-MS) to investigate concentrations of eight heavy metal elements (Cd, Hg, As, Pb, Cr, Cu, Ni, and Zn) in five apple orchard soil profiles after five different cultivation durations, one modern intercropping farmland soil profile, and one natural soil profile from Baishui County, Southeast Chinese Loess Plateau. The potential risk associated with the presence of heavy metals in the soils was assessed by the single-factor pollution index (Pi), Nemerow comprehensive index (NCI), and potential ecological risk index (RI). Results showed that the average concentrations of Cr, Ni, As, Pb, and Hg in the farmland soil were higher than those in the apple orchard soils. The average concentrations of Ni, Cu, As, and Hg in the apple orchard soils reached the highest after 25 years of cultivation. The results imply that concentrations of heavy metals will increase with increasing cultivation time. The farmland soil had the highest NCIs, while the NCIs of the apple orchard soils also increased with cultivation time. Compared with the quality standards of pollution-free orchards and green food production areas, all Pis and NCIs were less than 1 and 0.7, respectively, indicating that the soils were in healthy condition. The RI results also suggest that the soils have a low ecological risk (RI < 150). Although the potential ecological risk is currently low, predicting and reducing heavy metal input should be considered.

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Ecological Risk Assessment and Contamination History of Heavy Metals in the Sediments of Chagan Lake, Northeast China

Water ◽

10.3390/w13070894 ◽

2021 ◽

Vol 13 (7) ◽

pp. 894

Author(s):

Panfeng Liu ◽

Chaojie Zheng ◽

Meilan Wen ◽

Xianrong Luo ◽

Zhiqiang Wu ◽

...

Keyword(s):

Heavy Metals ◽

Principal Component Analysis ◽

Ecological Risk ◽

Surface Sediment ◽

Northeast China ◽

Principal Component ◽

Potential Ecological Risk ◽

210Pb Dating ◽

History Of ◽

Chagan Lake

The study deals with the spatio-temporal distribution of heavy metals in the sediments of Chagan lake, Northeast China. The pollution history of heavy metals is studied simultaneously through the 210Pb dating method by analyzing the characteristic of As, Hg, Cd, Cr, Ni, Cu, Pb, and Zn concentration-depth profiles. The potential ecological risk index (RI) and geo-accumulation index (Igeo) were used to evaluate the contamination degree. Principal component analysis (PCA), based on the logarithmic transformation and isometric log-ratio (ilr) transformed data, was applied with the aim of identifying the sources of heavy metals. The element concentrations show that the heavy metals are enriched in the surface sediment and sediment core with a varying degree, which is higher in the surficial residue. The results of Igeo indicate that the Cd and Hg in the surface sediment have reached a slightly contaminated level while other elements, uncontaminated. The results of RI show that the study area can be classified as an area with moderate ecological risk in which Cd and Hg mostly contribute to the overall risk. For the sediment core, the 210Pb dating results accurately reflect the sedimentary history over 153 years. From two evaluation indices (RI and Igeo) calculated by element concentration, there is no contamination, and the potential ecological risk is low during this period. The comparative study between raw and ilr transformed data shows that the closure effect of the raw data can be eliminated by ilr transformation. After that, the components obtained by robust principal component analysis (RPCA) are more representative than those obtained by PCA, both based on ilr transformed dataset, after eliminating the influence of outliers. Based on ilr transformed data with RPCA, three primary sources could be inferred: Cr, Ni, As, Zn, and Cu are mainly derived from natural sources; the main source of Cd and Hg are associated with agricultural activities and energy development; as for Pb, it originated from traffic and coal-burning activities, which is consistent with the fact that the development of tourism, fishery, and agriculture industries has led to the continuous increasing levels of anthropogenic Pb in Chagan Lake. The summarized results and conclusions will undoubtedly enhance the governmental awareness of heavy metal pollution and facilitate appropriate pollution control measures in Chagan Lake.

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