Application Of PXRF In The Measurement And Analysis Of Heavy Metal Concentrations In Mushrooms In Mining Areas

In recent years,heavy metal pollution caused by mining and smelting activities has threatened the environment and organisms.Using the ability of bio-enrichment of heavy metal elements can achieve the purpose of reducing pollution,which is of great significance to the ecological restoration of the surrounding mining areas.Many studies have shown that mushrooms have a strong ability to accumulate heavy metals.This paper mainly studies the application of Portable X-ray fluorescence spectroscopy（PXRF）in the measurement and analysis of heavy metal concentrations in mushrooms in the mining area.Sample preparation methods for mushroom samples were summarized based on previous studies and several major factors affecting PXRF readings were systematically evaluated through experiments.In the case of compaction,the change of sample density has little effect on PXRF results.The effect of sample thickness on the readings should be the effect of the mass of the sample per unit area on the PXRF readings.Experimental results showed that as the mass of the sample per unit area increased,the PXRF readings decreased following a power-law distribution.The PXRF reported concentrations for Fe and Zn will not change significantly when the mass per unit area reached 0.65 g/cm² and 0.66 g/cm² respectively.The mass attenuation coefficient valuesμ_netof iron and zinc were 7.09 cm²/g and 6.98 cm²/g,respectively.The PXRF readings decreased significantly as the moisture content of the mushroom sample increases.A linear regression calibration model was established to correct for matrix effect by considering all affecting factors.The verification results showed that the linear regression correction model improved PXRF data quality and realized quantitative analysis of mushroom samples.Based on the above sample pretreatment method and calibration model,PXRF was used to measure the element concentrations in mushrooms in the mining area.The excess rates of concentrations for Cu and As in mushrooms around the mining area are both 100%,and the concentrations for Cu and As in the Cortinarius collinitus Fr.were enriched,much higher than that in soils.Differences in heavy metals in mushrooms in different locations indicate the source of pollution（mining activities）.Differences in heavy metals in mushrooms in different locations indicate the source of pollution（mining activities）.This paper confirmed the feasibility of using PXRF to ascertain by measuring the element content around the mining area,to determine the pollution level,delineate the pollution range,and to trace the source of the pollution.It was also found that the Cortinarius collinitus Fr.in the mushroom had a strong enrichment ability for copper and arsenic.On the one hand,it can guide the identification of weak anomalies on the surface,and on the other hand,it has important significance for the restoration of heavy metals in the soil of the mining area.PXRF has the advantages of simple sample preparation,multi-element determination,rapid analysis,good reproducibility and non-destructive analysis,and finally realized the evaluation of heavy metal pollution and ecological risks in mining areas.