Model for the Assessment of Seawater Environmental Quality Based on Multiobjective Variable Fuzzy Set Theory

Table 4

Results of the variable fuzzy comprehensive evaluation of seawater quality in the Qingdao dumping area (1985–2003).

Year	COD	OIL	DO	Inorganic nitrogen	PO4-P	Cu	Pb	Zn	Cd	Variable fuzzy evaluation model
										Average	Evaluation grade
1985	0.45	0.038	8.73	1.26	0.31	0.49	4.13	2.715	0.13	1.30	I
1991	0.89	0.015	7.86	25.9	6.82	0.36	5.7	9.8	0.17	1.33	I
1997	0.65	0.0745	7.76	77.3	14.96	4.74	1.28	42.5	0.07	1.59	II
2000	1.54	0.021	9.17	94.42	15.75	2.98	0.86	13.7	0.18	1.14	I
2002	0.48	0.024	7.99	65.7	6.5	2.04	1.49	11.16	0.28	1.11	I
2003	0.72	0.039	7.64	102	6.9	4.30	2.25	41.54	0.19	1.64	II