Purpose

The aim of the study was to (1) investigate the distributions of sulfur (S), iron (Fe), and phosphorus (P) in coastal surface sediments under the stresses of high salinity and heavy metals; (2) identify potential sources and the environmental geochemical process of S–Fe mineral accumulation; and (3) elucidate the coupling mechanisms of S–Fe–P in coastal sediments under environmental stresses.

Materials and methods

The distributions of reduced inorganic sulfur (RIS), inorganic P, and reactive Fe (RFe) in surface sediments in two coastal rivers with heavy metals and high salinity (~50 psu, brine drainage) and in offshore areas in the Bohai Sea were investigated.

Results and discussion

Pyrite sulfur (CRS) was the predominant fraction of RIS in two rivers (Jiaolai River (JL), 56%; Jiehe River (JH), 72%), whereas acid volatile sulfur (AVS) dominated RIS in their offshore sediments (L, 66%; J, 45%). RFe(II) dominated RFe in JH (70%) and JL (66%), while RFe(III) dominated the fractions in their offshore areas (53%). Coastal surface sediments under the stresses of high salinity and heavy metals were dominated by HCl-P (Ca-bound P) and NaOH-P (Fe- and Al-bound P), respectively.

Conclusions

Accumulated Fe sulfide was limited by elemental sulfur (ES) availability under high salinity, while it was limited by total organic carbon (TOC) availability when the river was heavily polluted. High salinity produced sulfide-dominated environments, which could reduce the NaOH-P and facilitate HCl-P immobilization. However, the presence of heavy metals resulted in Fe-dominated environments, which could promote metal sulfides formation and increase the NaOH-P fixation.

中文翻译：

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高盐度和重金属胁迫下沿海河流表层沉积物中S–Fe–P的耦合机制

目的

本研究的目的是（1）研究高盐度和重金属胁迫下沿海表层沉积物中硫（S），铁（Fe）和磷（P）的分布；（2）确定潜在的来源和S-Fe矿物积累的环境地球化学过程；（3）阐明了环境胁迫下沿海沉积物中S–Fe–P的耦合机制。

材料和方法

研究了两条重金属，高盐度（〜50 psu，盐水排泄）的沿海河流和渤海近海地区表层沉积物中还原态无机硫（RIS），无机磷和反应性铁（RFe）的分布。 。

结果和讨论

黄铁矿硫（CRS）是两条河流中RIS的主要组成部分（焦来河（JL），56％; he河（JH），72％），而酸性挥发性硫（AVS）在其近海沉积物中主要是RIS（L， 66％； J，45％）。RFe（II）在JH（70％）和JL（66％）中占主导地位，而RFe（III）在其离岸地区的馏分中占主导地位（53％）。高盐度和重金属胁迫下的沿海表层沉积物分别以HCl-P（Ca结合的P）和NaOH-P（Fe-和Al结合的P）为主。

结论

在高盐度下，累积的硫化铁受元素硫（ES）可用性的限制，而当河流受到严重污染时，则受总有机碳（TOC）可用性的限制。高盐度产生了以硫化物为主的环境，这可以减少NaOH-P并促进HCl-P的固定。然而，重金属的存在导致了以铁为主的环境，这可能促进金属硫化物的形成并增加NaOH-P的固定。