Water quality appraisal of Keti Bandar and Shah Bandar creeks of Indus delta, Sindh, Pakistan

Abstract

a b s t r a c tThe present research investigation deals with the assessment of pollution status in the Indus delta creek system. This manuscript advocates the physicochemical, bacteriological characteristics and heavy metal pollution in the creek system. In the present investigation, the pH, salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD), chlorophyll, cyanide, oil and grease, total phosphate, phenol, Kjeldahl nitrogen and total organic carbon (TOC) values were recorded from 36 sampling sites during 6 field surveys conducted in 2011-2013. The creek water samples were also analyzed for their heavy metal contents (As, Cd, Cr, Pb, Ni and Zn). The bacteriological parameters included in the study were total coliform count (TCC), total fecal coliform count (TFC), and total fecal streptococci (TFS). These parameters were determined as per methods described in reference [12]. Salinity of water samples ranged between 15 and 32 ‰ while pH ranged from 7.2 to 7.6. High salinity values indicated the progression of seawater into the creek system. The mean DO was low with a range of 4.2-5.7 mg/L. Low DO concentration was due to high BOD 5 (range 10-78 mg/L) while COD ranged from 320 to 1,334 mg/L. High BOD 5 load is mainly due to organic pollution coming from nearby human settlements. The mean chlorophyll-a content was 0.114 mg/L. Interestingly, higher chlorophyll-a concentration was observed near the mangroves area. The mean cyanide concentration was high, though the source of cyanide could not be traced that needs further study. Oil and grease content of water was also substantial, mainly originated from faulty boats operated in the area. Excessive concentration of oil and grease could be deleterious to marine life forms. The concentration of phosphate ranged between 2.1 and 4.6 mg/L mainly attributed to the agriculture runoff. Phenol concentration was not high (0.01-0.08 mg/L) and, therefore, could not be responsible for adverse environmental implications. The mean concentrations of total Kjeldahl nitrogen and TOC were 59.27 and 4.97 mg/L, respectively. The concentrations of heavy metals in the samples were found to be in the order Zn > Ni > Pb > As > Cr > Cd. The bacterial load was exceptionally higher in all the samples in terms of organisms of public health importance that is mainly attributed to domestic wastewater originated from nearby squatter settlements. In essence, the present study disclosed that the creeks of Indus delta are likely to be polluted mainly because of anthropogenic sources. The continuous accumulation of pollutants in the creek area may have severe ecological and health implications.

Climate Vulnerability Index of the Coastal Subdistricts of Badin, Sindh, Pakistan

“…Since rising temperatures have already affected the natural resources in the area, particularly the agriculture sector, the livelihood opportunities in the area have become limited . The decline of the Indus deltaic region is mostly due to diminished downstream flow, which has resulted in seawater encroaching over 1,700 km2 of the delta over the last five decades (Alamgir et al, 2017). The groundwater and soils in coastal areas are becoming salinized, rendering them useless for agriculture, resulting in an involuntary migration of the local population.…”

“…For instance, damage to agricultural crops , livestock and water resources is widely reported (reference missing). A climate change scenario changed the outlook of the environmental factors in the coastal areas of Sindh, thus affecting the livelihood, natural resources, and other sectors of life (Alamgir et al, 2017). Climate variability in the coastal areas of Sindh has been widely studied in association with its impacts (e.g., floods, cyclone, drought).…”

“…Pakistan. The region has been exposed to the consequences of climate change in the last two decades (Alamgir et al, 2017). The objective of the study was to identify and compare the vulnerabilities in the light of coastal communities expose to climate change.…”