Abstract: Regional ecological risk assessment (RERA) covers the assessments of m ultiple risk sources, receptors, and endpoints, while the selection of assessmen t indices is quite complicated, being a hotspot in regional environment manageme nt research. Domestic and international researches on RERA revealed that three p rocesses in RERA are of vital, i.e., risk probability assessment measured by ris k probability index, status and value assessment of ecosystem at regional scale indicated by ecological index, and vulnerability assessment of each ecosystem in a region under risk measured by vulnerability index. The main problems in the e stablishment of RERA index system are the strong subjectivity and poor comparabi lity, and thus, the index system should be set up in the three key processes und er the principles of objectivity, integration, hierarchy, and comparability. Due to the fact that the status and value assessment of ecosystem is most complicat ed, the index system should be formulated by compulsory and optional components to increase the comparability of RERA results between regions.

Key words: engineering carbon nanomaterials, chemical transformation, photodegradation, biodegradation.