Study On The Contents Of Rare Earth Elements In Cereals,Vegetables And Fruits Of A Rare Earth Ore Area,Shandong Province

BackgroundRare earth elements include 15 lanthanide elements in the periodic table ? B Group, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and scandium and yttrium which has similar electronic structure and chemical properties. Usually lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium are called light rare earth elements and Gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium are called heavy rare earth elements. China is the world's most resource-rich countries of rare earth and So far China's rare earth reserves, production and export are the first in the world and application of rare earth also ranked second in the world. In the 1970s, China used light rare earth elements in agriculture and make crop yield increased, varieties improved and achieved significant economic benefits. Since the mining of rare earth, the widespread of rare earth elements as fertilizer and the widely used in medicine, the environmental pollution of rare earth is getting worse. The potential impact on human health of rare earth has attracted wide attention.ObjectiveThe major objective were to obtain the contents of rare earth elements in cereals, vegetables, and fruits in the mining and non-mining area and compare the differences of rare earth elements between mining and non-mining area.Subjects and methods5 km around rare earth minerals is defined as the study area and 5 km away from the area is defined as the control area. In the study area, five village were selected as close as possible to the rare earth mine and five village were also selected in the control area.The households within villages were randomly selected. All samples were grown themselves. The investigator should understand the characteristics of samples being collected and sampling requirements. The sampling should be completed by two or more persons at the same time and paste the sample labels. Samples should be delevered to the laboratory for testing as soon as possible. The testing was conducted by inductively coupled plasma mass spectrometry. Because the data is skewed distribution, Wilcoxon signed-rank tests were performed for statistical analysis..Results1. Rare earth oxides in cerealsThe total content of rare earth oxides (REOs) for cereals from mining area was (269.74±423.57) ?g·kg-1, and the median was 101.84 ?g·kg-1; while, for non-mining area, the total REOs was (386.60±941.46) ?g·kg-1, and the median was 69.09 ?g·kg-1. Differences between cereals from mining area and non-mining area were not statistically significant (P>0.05). The contents of REOs in different cereals had obvious differences. The content of total REOs of cereals from mining area decline in sequence from wheat, soybean, corn. For mining area, the difference of REOs between wheat and corn is statistically significant; for non-mining area, the differences of REOs between wheat and corn and corn and soybean are statistically significant.2. Rare earth oxides in vegetablesThe total contents of REOs for vegetables from mining area were (1555.76±10328.00) ?g/kg, while, for non-mining area, the total REOs were (82.07?g·kg-1252.22) ?g/kg. Differences between mining area and non-mining area were statistically significant (P<0.05). The contents of REOs in different vegetables had obvious differences. The content of total REEs decline in sequence from leaf vegetables, root vegetables, leguminous vegetables, solanaceous vegetables, gourd vegetables.3. Rare earth oxides in fruitsThe total content of REOs for fruits from mining area was (19.50±29.20) ?g/kg, and the median was 12.06?g/kg. while, for non-mining area, the total REOs in fruits was (168.43±521.88)?g/kg, and the median was 18.96?g/kg. Differences between mining area and non-mining area were statistically significant (P<0.05). Differences of REOs in stone fruits between mining area and non-mining area were statistically significant (P<0.05).4. Comparison of rare earth elements in grain, vegetables, fruits opare from mining area/non-mining areaThe differences between cereals and vegetables, cereals and fruits, and vegetables and fruits are statistically significant for mining area. The differences between cereals and vegetables and cereals and fruits are statistically significant for non-mining area, but, the difference between vegetables and fruits is not statistically significant.Conclusion1. Differences between cereals from mining area and non-mining area were not statistically significant. The content of total REOs of cereals from mining area decline in sequence from wheat, soybean, corn.2. Differences between vegetables from mining area and non-mining area were statistically significant. The content of total REOs decline in sequence from leaf vegetables, root vegetables, leguminous vegetables, solanaceous vegetables, gourd vegetables.3. Differences between fruits from mining area and non-mining area were not statistically significant. Differences of REOs in stone fruits between mining area and non-mining area were statistically significant.4. The differences between cereals and vegetables, cereals and fruits, and vegetables and fruits are statistically significant for mining area. The differences between cereals and vegetables and cereals and fruits are statistically significant for non-mining area, but, the difference between vegetables and fruits is not statistically significant.