Source identification and comprehensive apportionment of the accumulation of soil heavy metals by integrating pollution landscapes, pathways, and receptors.

Existing source apportionment methods for soil heavy metals fail to identify the actual landscapes related to pollutant sources and quantify their contributions to the accumulation of soil heavy metals. In this work, we propose a new source identification and apportionment approach for soil heavy metal accumulation by integrating pollution landscapes, pathways, and receptors. Datasets for soil lead (Pb) concentrations in Daye city, China, which was sampled in 2018, were used. First, based on the spatial distribution of Pb, the source landscapes were identified using GeoDetector and spatial analysis methods. Second, a source landscape apportionment model (SLAM) was developed considering both atmospheric deposition and surface runoff as diffusion pathways. Third, considering soil properties and topography as receptor attributes, ordinary least squares (OLS) and geographically weighted regression (GWR) models were employed to further adjust the soil Pb accumulation at receptor locations. The results showed that SLAM followed by the GWR model (SLAM-GWR) had the highest fitting accuracy. Then, the spatial distributions and ranges of contributions of each identified source landscape to Pb accumulation through different pathways were obtained. Finally, the advantages and disadvantages of the proposed approach were discussed.

[The standardization of genetic terms--I. Of the same name with different definition phenomenon].

The phenomenon of same term with different definitions exists widely in genetic teaching courses. The present paper was aiming at analyzing and discussing these problems. For example, the terms such as Y-linked inheritance, sex-limited inheritance, sex-influenced inheritance, haploid, polyploid and cumulative effect expression are very confused and chaotic in meaning, even mutually contradictory. This involves the accuracy of nomenclature. We presumed that the term of Y-linked inheritance cannot confuse with that of sex-limited inheritance, and that though the sex-limited factor and the sex-influenced inheritance gene are both located on autosome with some distance, but they are still different. Haploid refers to the gametophyte chromosome number an individual has, but does not equate to monoploid. Also we thought that polyploid represented the basic number of chromosome, such as triploid indicated for 3x. And, the cumulative effect refers to mutual accumulation function between the exponential quantitative characters of relevant genes.