Grey Correlative Assessment of Marine Environmental Quality in Shenzhen Bay

Grey system theory is widely used in various environmental quality assessments for the grey characteristic of environmental system. In this paper, according to grey theory, a grey correlative model which is variable weights and based on water chemistry and productivity indicators is constructed to evaluate the marine environmental quality of Shenzhen Bay. The results show that the sea water quality of Shenzhen Bay is in IV class and beyond the III class management objective for water quality in Shenzhen Bay, indicating the sea water has been seriously polluted. The overall trend of pollution is that the inside is greater than the mouth of the bay; Shenzhen side is greater than Hong Kong side; and the most polluted area are estuaries and docks, suggesting that the pollution of land-based sources is the main reason for water quality damage. The results are not only accordance with that of the fuzzy comprehensive evaluation, but also can further rank the assessment objects, and the grey correlative assessment is reliable and could be used for marine environmental quality assessment.