Changes of Heavy Metal Content in Sediments at Haizhou Bay and Risk Assessment

Abstract

This research studied the six heavy metal contents, their distribution and the level of pollution in sediments at Haizhou Bay in 2009 and 2014. It was found that the content of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) accounted for the major factors in the sediments at Haizhou Bay. The content of major pollutants presented a declining trend from south to north, and the Pb-intensive area moved from the southern waters of the study area in 2009 to the northern waters of Ganyu Port in 2014. Analysis of the pollution load index shows that the study area suffers from medium-level pollution; the most polluted area was the waters around the estuary of Dragon-King River in 2009 and Ganyu Port in 2014, which meant that development of the port had significant impact on the heavy metal contents. Assessment based on the geo-accumulation index shows that Pb pollution deteriorated and Cd pollution abated slightly over the past 5 years. Analysis of comprehensive potential risk index indicates that the ecological risk of the study area from 2009 to 2014 was at the low-medium level, with Cd being the major contributor to the risks.

Comprehensive Assessment and Potential Ecological Risk of Trace Element Pollution (As, Ni, Co and Cr) in Aquatic Environmental Samples from an Industrialized Area

“…In general, As concentrations observed in sediments from Algeciras Bay were similar than those found in Cadiz Bay, where the values ranged from 6.77 to 14.48 mg/kg and 1–2 times higher than the ones found in other ecosystems from China, such as the Jiaozhou Bay and Haizhou Bay [ 56 , 58 , 59 ]. However, they are 24–25 times below the levels found in the Ría de Huelva, where As concentrations ranged from 85.1 to 615.4 mg/kg [ 38 , 39 ].…”

“…Ni and Cr values in Algeciras Bay were above the concentrations found in other ecosystems, such as the Galician coast (affected by the oil spill from the tanker Prestige in November 2002), where Ni was found in the range 1.04–16.2 mg/kg [ 60 ], the Bohay Bay in China, where these metal concentrations ranged from 23.4 to 52.7 mg/kg for Ni and from 60.1 to 224.5 mg/kg for Cr [ 61 ] and other ecosystems, such as the Jiaozhou Bay and Haizhou Bay in China [ 56 , 58 , 59 ] or the Todos los Santos Bay in Brazil [ 62 ]. Morillo et al, 2007 found 3.7–5.0 times lower levels of Ni in Cadiz Bay (2.2–39.3 mg/kg) and up to 2 times lower in the same area of Algeciras Bay (16–100 mg/kg) [ 15 ].…”