Pakzad Hamid Reza, Pasandi Mehrdad, Yeganeh Siavash, Lahijani Hamid Alizadeh Ketek
Department of geology, Faculty of Science, University of Isfahan, Isfahan, Iran.
Iranian National Institute for Oceanography, Tehran, Iran.
Environ Monit Assess. 2016 May;188(5):303. doi: 10.1007/s10661-016-5302-7. Epub 2016 Apr 21.
Sampling of the offshore seabed sediments of southwestern part of the Caspian Sea was carried out by gravity corer in order to study heavy metal concentration and the physicochemical factors controlling their distribution in the fine-grained fraction. The grain size distribution, amount, and type of clay minerals, total organic carbon (TOC) content, and Eh-pH of the sediments were determined. The average concentrations of the heavy metals in ppm are Mn (563), Cu (207.5), Sr (187), Zn (94), Pb (26.3), Ni (14.5), Co (11.5), Cd (2.56), and Ag (1.04) in their order of abundances. Co and Zn mostly indicate increase in silt-size fraction of the sediments suggesting their probable detrital provenance but the Mn, Ni, Cu, Sr, Pb, Cd, and Ag concentrations show a similar trend to distribution of the clay-size fraction. The concentrations of Mn, Co, and Cd increase with increase in the TOC content but the Cu, Pb, Ni, Ag, and Sr concentrations decrease with increase of the TOC content. The amounts of Zn, Cu, Sr, Pb, Cd, and Ag increase with increase in the CaCO3 content. The calculated enrichment factor indicates that the sediments are very strong to extremely enriched in Ag, significantly enriched in Cu and Cd, and depleted to mineral for Pb, Sr, Co, Ni, and Zn. Variations of the Cu, Sr, Cd, Ag, and Pb concentrations are similar to the clay and CaCO3 distributions.
为了研究里海西南部近海海底沉积物中重金属浓度以及控制其在细颗粒部分分布的物理化学因素，使用重力取芯器对该区域进行了采样。测定了沉积物的粒度分布、粘土矿物的数量和类型、总有机碳（TOC）含量以及沉积物的氧化还原电位（Eh）和pH值。以ppm计的重金属平均浓度依次为：锰（563）、铜（207.5）、锶（187）、锌（94）、铅（26.3）、镍（14.5）、钴（11.5）、镉（2.56）和银（1.04）。钴和锌大多表明沉积物粉砂级部分含量增加，表明它们可能来自碎屑源，但锰、镍、铜、锶、铅、镉和银的浓度与粘粒级部分的分布趋势相似。锰、钴和镉的浓度随TOC含量的增加而增加，但铜、铅、镍、银和锶的浓度随TOC含量的增加而降低。锌、铜、锶、铅、镉和银的含量随碳酸钙含量的增加而增加。计算得出的富集因子表明，沉积物中银的富集程度为极强到极高，铜和镉显著富集，而铅、锶、钴、镍和锌则贫化至矿物质。铜、锶、镉、银和铅浓度的变化与粘土和碳酸钙的分布相似。
