The Distributions Of The Major Pollutants And Assessment Of Environment Quality In The Guangzhou Sea Area

Material fluxes were surveyed in the four sections of the four east outlets (Humen, Jiaomen, Hongqimen and hengmen) once a month from January, 2004 to December, 2004. Seawater samples for studying the nutrients and heavy metals were collected from 17 stations in the Guangzhou sea area once a month from August, 2003 to August, 2004. The monitoring parameters included ammonium (NH₄⁺-N), nitrite (NO_<sup>--N), nitrate (NO₃^--N), phosphate (PO₄^3--P), silicate (SiO₃^2--Si), chemical oxygen demand (COD), mercury (Hg), zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), arsenic (As), water temperature, salinity and dissolved oxygen (DO).According to the method of period fluxes, the fluxes of major pollutants were estimated from the four east outlets. The results showed that the fluxes of DIN, NH₄⁺-N, NO₂^--N, NO₃^--N, PO₄^3--P, COD, Hg, Zn, Cd, Pb, Cu and As were 126.50×10⁴t/a, 5.02×10⁴t/a, 15.11×10⁴t/a, 106.34×10⁴t/a, 4.30×10⁴t/a, 178.66×10⁴t/a, 18.75t/a, 5029.21t/a, 241.00t/a, 471.23t/a, 1564.05t/a and 2403.19t/a, respectively. The seasonal variation pattern of the fluxes represented higher values in the flood period than that in the drought period. The highest flux was recorded in Humen, then in Jiaomen and Hongqimen, successively, the lowest in Hengmen. Compared with the fluxes in 1985 and 1995, these of all major pollutants increased remarkably in the investigated period. The correlations between major pollutant contents, the flows and their fluxes from the four east outlets were analyzed. The results showed that there were very significant correlations between their fluxes and flows were, and significant corretations between fluxes of DIN, NO₃^--N, PO₄^3--P, COD, Hg, Cd, Pb, As and their contents.In the Guangzhou sea area, the annual average concentrations of dissolved inorganic nitrogen (DIN), phosphorus (PO₄^3--P) and silicate (SiO₃^2--Si) were 1.63 mg/L, 0.043 mg/L and 2.59 mg/L, respectively. Amongst them, 66.55% DIN was NO₃^--N and 20.19% DIN was NH₄⁺-N. Comparing with other estuaries around the world, the concentrations of DIN and SiO₃^2--Si were much higher while the concentration of PO₄^3--P was of average level. DIN, PO₄^3--P and SiO₃^2--Si decreased gradually from inner bay to outer bay, from nearshore to offshore. This distribution pattern was mainly a result of the industrial discharge, domestic and agriculture sewage from the east four outlets. Due to the terrestrial sewage from...