Exploration into the Development of"Integration of Production and Education"in Vocational Education in China

In order to further clarify the function and important value of the integration of production and education for the development of vocational education,this paper combed the development context of the integration of production and education in China's vocational education from three dimensions:policy evolution,research evolution and practice promotion.Studies have shown that the integration of production and education,as a distinctive type characteristic of vocational education in China,has experienced four stages of evolution in policy:the period of combination of production and education,the preparation and presentation period,the full implementation period and the in-depth promotion period,and the initially-constructed institutional system reflects developmental characteristics.In academic research,there are obvious policy-driven characteristics.The theoretical framework tends to be perfect,and the concept connotation and promotion path are gradually getting clear,but the research on regional promotion modes is slightly insufficient.The empirical research is weak,and the operability of countermeasure research is not strong.Moreover,the problem of discussing integration based on education is more prominent.In practice and promotion,the characteristic of the integration of production and education is gradually highlighted and deepened in terms of talent training,school-running system and school-running mode,and the carriers and contents of the integration of production and education are gradually enriched.

Evaluation of the potential risks of heavy metal contamination in rice paddy soils around an abandoned Hg mine area in Southwest China

To assess the potential ecological and health risks of trace elements(Hg,Cd,As,Mn,Sb,Pb,Cu,Ni,Cr,and Zn),a total of 138 soil samples from rice paddies were collected during the rice harvest season in the Wanshan mining area,Guizhou Province,Southwest China.Factors of the pollution load index(PLI),geo-accumulation index(I-Geo),enrichment factor(EF),and risk index(RI)were determined.High concentrations of Hg,Sb,As,Zn,Cd,Cu,and Mn were observed in the soils.The PLI,I-Geo,and EF results all showed high levels of contamination by Hg and Sb and moderate levels of contamination by As,Pb,Zn,Cu,Cd,and Mn.There was no significant contamination from Ni and Cr.The RI was very high,with Hg as the dominant pollutant,as expected,indicating that the historical large-scale Hg mining,as well as artisanal mining,has had a significant impact on the Wanshan area.Moreover,coal combustion,manganese factories,and the use of agrochemicals by the local population could also have an impact on the soil through the introduction of heavy metal loads.To address the current state of contamination,pollutant remediation and the regulation control of the anthropogenic activities in Wanshan are urgently needed.

Mercury speciation, bioavailability and risk assessment on soil–rice systems from a watershed impacted by abandoned Hg mine-waste tailings

Mercury(Hg) is a global pollutant and can be accumulated in the food chain, posing exposure risks to humans. In this study, rice plants and corresponding rhizosphere soil samples were collected from a watershed of the Wawu River Basin that is heavily impacted by historic Hg mining and retorting activities. Total mercury(THg)and methylmercury(MeHg) in rice grains, as well as other tissues and soil samples, were measured. Five soil Hg fractions, as well as soil parameters, were also determined.The results show that the average concentrations of THg and MeHg in rice grains were 14 ± 7.0 lg kg^(-1) and7.2 ± 4.0 lg kg^(-1). Soil organic-bound(Hg-o) and strong complex-bound(Hg-s) were the main Hg fractions,accounting for 44% of the total. To estimate the Hg–ligand interaction in the soils, soil-N/Hg(R = 0.451, p \ 0.05),-S/Hg(R = 0.372, p \ 0.1), and-OM/Hg ratio(R = 0.320,p \ 0.5) with MeHg_(soil) were observed with significant positive correlations, indicating that the formation of Hg–OM, Hg–N–OM or Hg–S–OM complexes could prevent Hg(II) from methylation in soils. The significant positive correlations of the-N/Hg ratio,-S/Hg ratio and-OM/Hg ratio with MeHg in rice tissues suggested that Hg methylation and MeHg demethylation occurred throughout the rice paddy ecosystem. The estimated MeHg daily intake(EDI) was 0.075 ± 0.041 lg kg^(-1) bw d^(-1) and was lower than the RfD level of 0.1 lg kg^(-1) bw d^(-1) recommended by the US EPA. However, approximately 29% of the hazardous index(HI) of MeHg in grain exceeded 1, posing a potential threat to local populations, particularly pregnant women and children.