Influence of multi-industrial activities on trace metal contamination: an approach towards surface water body in the vicinity of Dhaka Export Processing Zone (DEPZ)

Abstract

Industrial wastewater discharged into aquatic ecosystems either directly or because of inadequate treatment of process water can increase the concentrations of pollutants such as toxic metals and others, and subsequently deteriorate water quality, environmental ecology and human health in the Dhaka Export Processing Zone (DEPZ), the largest industrial belt of 6-EPZ in Bangladesh. Therefore, in order to monitor the contamination levels, this study collected water samples from composite effluent points inside DEPZ and the surrounding surface water body connected to effluent disposal sites and determined the environmental hazards by chemical analysis and statistical approach. The water samples were analysed by inductively coupled plasma mass spectrometry to determine 12 trace metals such as As, Ag, Cr, Co, Cu, Li, Ni, Pb, Se, Sr, V and Zn in order to assess the influence of multi-industrial activities on metal concentrations. The composite effluents and surface waters from lagoons were characterized by a strong colour and high concentrations of biochemical oxygen demand, chemical oxygen demand, electrical conductivity, pH, total alkalinity, total hardness, total organic carbon, Turb., Cl(-), total suspended solids and total dissolved solids, which were above the limit of Bangladesh industrial effluent standards, but dissolved oxygen concentration was lower than the standard value. The measurement of skewness and kurtosis values showed asymmetric and abnormal distribution of the elements in the respective phases. The mean trend of variation was found in a decreasing order: Zn > Cu > Sr > Pb > Ni > Cr > Li > Co > V > Se > As > Ag in composite industrial effluents and Zn > Cu > Sr > Pb > Ni > Cr > Li > V > As > Ag > Co > Se in surface waters near the DEPZ. The strong correlations between effluent and surface water metal contents indicate that industrial wastewaters discharged from DEPZ have a strong influence on the contamination of the surrounding water bodies by toxic metals. The average contamination factors were reported to be 0.70-96.57 and 2.85-1,462 for industrial effluents and surface waters, respectively. The results reveal that the surface water in the area is highly contaminated with very high concentrations of some heavy/toxic metals like Zn, Pb, Cu, Ni and Cr; their average contamination factors are 1,460, 860, 136, 74.71 and 4.9, respectively. The concentrations of the metals in effluent and surface water were much higher than the permissible limits for drinking water and the world average concentrations in surface water. Therefore, the discharged effluent and surface water may create health hazards especially for people working and living inside and in the surrounding area of DEPZ.

Assessment of Heavy Metal Contamination of Agricultural Soil around Dhaka Export Processing Zone (DEPZ), Bangladesh: Implication of Seasonal Variation and Indices

“…The observed Zn and Cr concentrations in studied soil around DEPZ probably comes from construction materials in the form of alloys for protective coating for iron and steel. These metals are also used in the industries of DEPZ pigment and reducing agents; cotton processing, soldering and welding flux; rubber industry, glass, enamels, plastics, lubricants, cosmetics, pharmaceuticals, agents for burns and ointments [40]. Both metals were unevenly distributed in the study area (Figure 4).…”

Influence of Soil Chemistry and Plant Physiology in the Phytoremediation of Cu, Mn, and Zn

“…The continuous application of various Cu-based products such as pesticides, fertilizers and animal fodder has resulted in increased Cu concentrations in agricultural soils well above the European guideline limit of 100 mg kg −1 (Arthur et al, 2012). Furthermore, Cu is a by-product in several industry and mining processes (Ahmed et al, 2012;Testiati et al, 2013).…”

“…It is a major component of alloys, batteries, automobile equipment, pipes, and household devices, and it is used as catalyst in the production of rubber, pigments, plastic, lubricants, and pesticides (Wilkinson et al, 2011). Despite the usual low concentrations of Zn in soil, the content of this element can rise to several thousands of mg kg −1 due to anthropogenic activities such as agricultural practices and industry and mining activities (Ahmed et al, 2012;Buccolieri et al, 2010). Water pollution by Zn is more notable near industry zones due to waste discharges.…”

“…Several significant sources, such as fertilizers, sewage sludge, manure, agrochemicals and industrial by-product wastes, have contributed to the increased Cu, Mn and Zn levels observed in soil and water (Ahmed et al, 2012;Arthur et al, 2012;Buccolieri et al, 2010;Hu et al, 2009;Testiati et al, 2013).…”

Arsenic Contamination of Water-Soil-Crop System in an Industrial Area of Bangladesh

“…Various industries like textile, dyeing of plastics, metal fabrications, paints, lather, tanning, semiconductor goods, etc. are the major source of As and other heavy metals in the wastewater of Bangladesh (Ahmed et al, 2012). Continuous irrigation with As containing wastewater is quite responsible for increased As concentration in soil (Das et al, 2004).…”