Abstract:
In this study, the aged refuse, collected from Xingou municipal solid waste landfill of Taiyuan, was screened and classified into five samples with different particle-size (900~300, 300~150, 150~105, 105~90, and 90~0 μm), and then used to prepare leachate. Following this, several physical and chemical indexes were analyzed, and the effects on the growth and developmental of barley seedlings and zebrafish embryos were investigated. The results indicate that pH value decreased with the decrease of particle-size of aged refuse, conversely, electrical conductivity, CODCr, total salt and total nitrogen showed negative correlation with the particle-size. Furthermore, the germination, root length and shoot length of barley seedlings were inhibited by the aged refuse samples, and the effects were significantly negatively correlative with particle-size, especially for the smallest particle-size (90~0 μm). For the leachate of 90~0 μm aged refuse sample, the germination rate of barley seeding was 39.74%, 56.38% and 59.81% of control group after 1 d-, 2 d- and 3 d-exposure; the root length decreased to 57.08%, 48.33% and 41.66% of control and the shoot length decreased to 66.60%, 64.79% and 61.65% of control after 3 d-, 5 d- and 7 d-treatment. Similarly, the aged refuse leachate of different size of particles adversely affected embryonic growth and development, and the actions showed a significantly negative correlation with the particle size. The leachate of 90~0 μm aged refuse caused the most significant alterations on coagulation, abnormal blood circulation, hatchability, pericardial edema and spinal deformation of zebrafish embryos, and reached 40.28%, 50.00%, 51.39%, 31.94% and 29.17%, respectively. These findings imply that aged refuse could lead to the growth inhibition and developmental risk on barley seedlings and zebrafish embryos in a particle-size dependent manner, and the smallest particle-size sample (90~0 μm) showed the most serious injuries.