Simultaneous Speciation Analysis of Trace Heavy Metals (Cu, Pb, Cd and Zn) in Seawater from Sishili Bay, North Yellow Sea, China

Abstract

Different species of trace heavy metals (HMs) in seawater samples were simultaneously analyzed by anodic stripping voltammetric method, an analytical technique that does not require sample pre-concentration or the addition of reagents. The effects of the crucial parameters, deposition potential and time, on the determination of HMs were investigated. Concentrations of the total dissolved, dissolved active, and dissolved inert HMs were obtained through different analysis processes. The three species of Cu, Pb, Cd and Zn in seawater samples collected in different locations across Sishili Bay, North Yellow Sea, China were studied. The relative concentration of the dissolved active Cu, Pb, Cd and Zn in the total dissolved concentrations is 59.0%, 69.6%, 87.3% and 84.1%, respectively. The concentrations of different HMs species in Sishili Bay could be affected by the discharged effluent, sea current, and uptake of marine organism.

Species, Spatial-Temporal Distribution, and Contamination Assessment of Trace Metals in Typical Mariculture Area of North China

“…The concentrations of different species of Cu, Pb, Cd, and Zn in seawater samples were determined by ASV, which imposes detection limits of 28.87, 1.06, 2.97, and 12.70 ng L −1 , respectively (Han et al, 2018). Seawater samples were pretreated, as shown in Figure 2.…”

“…Dissolved reactive TM concentrations were obtained via direct electrochemical detection of the filtered samples. Filtered samples (10 mL) were placed into the voltammetric cell and DO was removed with high-purity nitrogen for 5 min; then, the dissolved reactive TM concentration was obtained by ASV (Han et al, 2018). Dissolved inert TMs were obtained via the difference between total dissolved TMs and dissolved reactive TMs (Florence, 1986).…”

“…The detailed parameters of the differential pulse voltammetry were as follows: deposition time was 60 s, deposition potential was −1.15 V, initial potential was −1.15, termination potential was 0.02 V, sweep rate of 0.03 Vs −1 , and the peak positions of Cu, Pb, Cd, and Zn were −0.17, −0.41, −0.58, and −1.0 V, respectively (Han et al, 2018). The accuracy and reliability of the method have been verified in certified reference materials (CASS-6 and NASS-6) (Han et al, 2018).…”

“…These dissolved TMs can be subdivided into total dissolved TMs, dissolved reactive TMs, and dissolved inert TMs. The total dissolved TM concentration is the sum of the dissolved reactive TM and the dissolved inert TM (Han et al, 2018). So far, environmental measurements have only established the total concentration of target metals in samples (Kot and Namiesńik, 2000), which was proved to be inadequate for assessing their bioavailability, behavior, and toxicity (Huang et al, 2003;Adnívia et al, 2016).…”

“…As a mariculture area, it is very important to investigate the pollution level of seawater, especially the metal levels. Although various studies investigated TMs in seawater (Nimmo et al, 1989;Meng et al, 2008;Mao et al, 2009;Tian et al, 2009;Wang et al, 2012;Su et al, 2015Su et al, , 2016Su et al, , 2017Han et al, 2018), little information is available on the spatialtemporal distributions and species of TMs. However, studying the spatial-temporal distributions and species of TM is helpful to achieve a better understanding of the TM pollution degree in seawater and provides effective data support for aquaculture.…”