Ubufakazi bokuqhuma kwe-Shenhai
Ngokuvamile, inqubo ihamba nxazonke 20 izinsuku. I-Petroleum asphalt ivamise ukukhombisa ubuthi obuphansi, ngokuyinhloko ikhipha ama-hydrocarbon anephunga elimnandi. Ngokuphambene, itiyela lamalahle, ecebile ku-volatiles ehlobene ne-benzene, inobuthi kakhulu.
Nakuba lezi zinto zinobuthi ngokwemvelo, ukuchayeka okubalulekile ngokuhamba kwesikhathi ngokuvamile kuyadingeka ukuze kubonakale imiphumela enobuthi.