Uncertainty in soil metal element measurements and its key influencing factors
Soil testing is the cornerstone of data for the Third National Soil Condition Census.However,the presence of measurement errors introduces uncertainty and affects the reliability of the results.To enhance the quality of testing outcomes,an evaluation of uncertainty was conducted for total chromium,manganese,copper,zinc,nickel,molybdenum,cadmium and lead in the survey,focusing on the factors that influence the magnitude of uncertainty.The findings indicated that the key components of uncertainty in soil metals measurements stem from the mass concentration of the digestion solution(ρ),and the measurement repeatability(R).The uncertainty introduced by ρ could be reduced by appropriate establishing a linear range for the standard curve to ensure thatρ was as close as possible to the highest point of the curve;using a standard curve with a higher Pearson correlation coefficient(r);employing more mass concentration points to establish standard curves and increasing the number of instrument signal acquisitions.The uncertainty introduced by R could be reduced by improving measurement precision.Through optimization,the uncertainty range for total cadmium was reduced from(0.365±0.126)mg·kg-1(k=2)to(0.365±0.030)mg·kg-1(k=2).For the screening value of 0.4 mg·kg-1,the reducing uncertainty led to more accurate and reliable results in the conformity assessment of total cadmium in soils.This study clarified the key components of uncertainty affecting the measurement of soil metals,providing a theoretical reference for laboratories to effectively control the measurement uncertainty of soil metals,reduce the dispersion of test results,and enhance the quality level of the outcomes.
soil metal elementsthe key components of uncertaintystandard curve calibrationmeasurement repeatabilityconformity assessment
万方数据
维普
