Mashiatullah Azhar, Chaudhary Muhammad Zaman, Ahmad Nasir, Ahmad Nisar, Javed Tariq, Ghaffar Abdul
Isotope Applications Division, Pakistan Institute of Nuclear Science & Technology (PINSTECH), Islamabad, Pakistan,
Environ Monit Assess. 2015 May;187(5):249. doi: 10.1007/s10661-015-4467-9. Epub 2015 Apr 14.
This paper is an attempt to compare the pollution status in two sediment cores, one from a polluted site (Ghizri Creek) and another from a relatively unpolluted site (Sandspit). Sediment cores (45 cm in length) from coastal locations were characterized in terms of grain size, sediment composition, pH, organic matter, calcium carbonate, and metal element contents. Metal elements, including Al, Ca, Cr, Co Cu, Fe, K, Mg, Mn, Ni, Pb, V, Ti, and Zn, were determined using PIXE. Grain size analysis and sediment composition demonstrated a sandy nature of both cores. Acidic trend in sediment core I was predominant from bottom to top, whereas neutral pH was observed throughout core II. TOC values varied in the range of 1.23-2.68 and 1.14-2.60% in core I and core II, respectively; however, there was an increasing trend in TOC level from bottom to top. The values of enrichment factor for Zn, Cu, Co, Ni, Pb, and Cr were slightly higher in core I than core II. The average geo-accumulation index values for core I and core II showed that sediments were moderately Co- and Pb-polluted but not polluted with Mg, Al, Ca, K, Cr, Cu, Fe, Mn, Ni, Ti, V, and Zn. The degree of contamination was however considerably higher in core I relative to core II. The pollution load index values, although showing an increasing trend from bottom to top in both cores, overall rendered the marine sediment pollution free. The metal toxicology results demonstrated that heavy metal pollution, except Cr, may pose low to moderate risk to marine biota. The sum of toxic unit values however indicated that sediment core I was relatively more polluted than that of core II.
本文旨在比较两个沉积物岩芯的污染状况，一个来自污染场地（吉兹里溪），另一个来自相对未受污染的场地（桑德皮特）。对来自沿海地区的沉积物岩芯（长度为45厘米）进行了粒度、沉积物成分、pH值、有机质、碳酸钙和金属元素含量方面的表征。使用质子激发X射线发射（PIXE）测定了包括铝、钙、铬、钴、铜、铁、钾、镁、锰、镍、铅、钒、钛和锌在内的金属元素。粒度分析和沉积物成分表明两个岩芯均为砂质。沉积物岩芯I从底部到顶部以酸性趋势为主，而岩芯II全程观察到pH值呈中性。岩芯I和岩芯II的总有机碳（TOC）值分别在1.23 - 2.68%和1.14 - 2.60%范围内变化；然而，TOC水平从底部到顶部呈上升趋势。岩芯I中锌、铜、钴、镍、铅和铬的富集因子值略高于岩芯II。岩芯I和岩芯II的平均地积累指数值表明，沉积物受到中度钴和铅污染，但未受到镁、铝、钙、钾、铬、铜、铁、锰、镍、钛、钒和锌的污染。然而，岩芯I的污染程度相对于岩芯II要高得多。污染负荷指数值虽然在两个岩芯中都显示出从底部到顶部的上升趋势，但总体上表明海洋沉积物未受污染。金属毒理学结果表明，除铬外，重金属污染可能对海洋生物群构成低到中度风险。然而，毒性单位值的总和表明沉积物岩芯I比岩芯II污染更严重。
