Assessment of Heavy Metal Contamination of Agricultural Soil around Dhaka Export Processing Zone (DEPZ), Bangladesh: Implication of Seasonal Variation and Indices
Assessment of Heavy Metal Contamination of Agricultural Soil around Dhaka Export Processing Zone (DEPZ), Bangladesh: Implication of Seasonal Variation and Indices
复制标题
DOI：
10.3390/app2030584
复制
发表时间：
2012-09-01
影响因子：
2.7
通讯作者：
Akbor, Mohammad Ahedul
中科院分区：
文献类型：
--
作者：
Rahman, Syed Hafizur;Khanam, Dilara;Akbor, Mohammad Ahedul
在过去的几十年里，强烈的城市化、大规模的工业化和空前的人口增长导致了环境质量的下降。由于金属的毒性和在生物群中积累的能力，土壤污染是一个严重的问题。本研究利用不同的指数，即地质累积指数（i -geo）、污染因子（C-f(i)）、污染程度（C-d）、改良污染程度（mC(d)）和污染负荷指数（PLI），评估了达卡出口加工区（DEPZ）附近农业土壤在干湿季节的重金属污染。从土壤表层采集样品，采用原子吸收分光光度计（AAS）进行分析。干季和湿季金属平均浓度的变化趋势分别为As > Fe > Hg > Mn > Zn > Cu > Cr > Ni > Pb > Cd和As > Fe > Mn > Zn > Hg > Cu > Ni > Cr > Pb > Cd。由于雨季的季节性降雨、稀释等径流的影响，土壤上层金属被一定程度地冲出，因此雨季各指数值均低于旱季。Igeo结果显示，干湿季节研究区砷和汞分别为重度和中度污染。根据C-f(i)，土壤Zn、Cr、Pb、Ni为中度污染，Cu为重度污染，as、Hg为重度污染。干季和湿季分别为Hg > As > Cu > Zn > Ni > Cr >Pb > Fe > Mn > Cd和As > Hg > Cu > Cd > Zn > Ni >Pb > Fe > Mn。干季和湿季的mC(f)值分别为575.13和244.44，表明污染程度极高。两个季节的C-d值都与非常高的污染程度有关。PLI结果表明，在两个季节都应立即采取干预措施改善污染。金属的主要来源包括废水处理厂的流出物、周围工业设施以及农业活动产生的处理过和未经处理的废水。保护农业土壤是研究区面临的巨大挑战，这需要工业现代化，从而提高废水的回收和循环利用。在本工作中提出的指标分析可以作为当代毒理学研究的一个里程碑。
Intense urbanization, large scale industrialization and unprecedented population growth in the last few decades have been responsible for lowering environmental quality. Soil contamination with metals is a serious concern due to their toxicity and ability to accumulate in the biota. The present work assessed the heavy metal contamination of agricultural soil in the close vicinity of the Dhaka Export Processing Zone (DEPZ) in both dry and wet seasons using different indices viz., index of geoaccumulation (I-geo), contamination factor (C-f(i)), degree of contamination (C-d), modified degree of contamination (mC(d)) and pollution load index (PLI). Samples were collected from the surface layer of soil and analyzed by Atomic Absorption Spectrophotometer (AAS). The trend of metals according to average concentration during the dry and wet seasons was As > Fe > Hg > Mn > Zn > Cu > Cr > Ni > Pb > Cd and As > Fe > Mn > Zn > Hg > Cu > Ni > Cr > Pb > Cd, respectively. Because of seasonal rainfall, dilution and other run-off during the wet season, metals from the upper layer of soil were flushed out to some extent and hence all the indices values were lower in this season compared to that of the dry season. Igeo results revealed that the study area was strongly and moderately contaminated with As and Hg in the dry and wet seasons respectively. According to C-f(i), soil was classified as moderately contaminated with Zn, Cr, Pb and Ni, considerably contaminated with Cu and highly contaminated with As and Hg. The general trend of the mean C-f(i). was Hg > As > Cu > Zn > Ni > Cr > Pb > Fe > Mn > Cd and As > Hg > Cu > Cd > Zn > Ni >Pb > Fe > Mn in dry and wet seasons, respectively. The mC(f) values in the dry and wet seasons were 575.13 and 244.44 respectively indicating an ultra high degree of contamination. The C-d values in both seasons were associated with a very high degree of contamination. PLI results indicated immediate intervention to ameliorate pollution in both seasons. The main sources of metals included effluents from wastewater treatment plants, treated and untreated wastewater from surrounding industrial establishments as well as agricultural activities. Protecting the agricultural soil is a formidable challenge in the study area, which requires modernization of industries, thereby improving the recovery and recycling of wastewater. Indices analysis presented in the present work could serve as a landmark for contemporary research in toxicology.