Is the water "polluted"?

Today, I will be looking into a study on water pollution. What are the sources of water pollution? What are the indicators to define how “polluted” is the water?

River Sabarmati is one of the biggest and major river of Gujarat that runs through two major cities of Gujarat (a state in the western part of India) (Lodrick, 2014), Gandhinagar and Ahmedabad and finally meets the Gulf of Khambhat (GoK) in the Arabian Sea.

Gujarat is one of the highly industrialized states of India with a strong web of pharmaceutical, petrochemical, textile, automotive, energy, chemical, and other industries. Many of these industries release partially or untreated effluents to the adjoining rivers like the Sabarmati. 

Figure 1 Location of River Sabarmati

Source: (Google Map)

The study of this paper was conducted to evaluate the water quality of this river, as it could possibly be one of the major sources for filling up Kalpasar, the proposed man-made freshwater reservoir supposed to be the biggest one in the world. The Kalpasar would be supplying water for irrigation to 10.54 lakh hectare land in 39 talukas of 6 districts of Saurashtra region; hence the water quality of upstream has the impact on it.

There were total of 9 sampling stations covering 163 km stretch of the river from upstream of Gandhinagar city to Vataman near Sabarmati estuary. (Haldar, et al., 2013)

Figure 2 Nine Sampling Points of the Study

Source: (Haldar, et al., 2013)

	S1	S2	S3	S4	S5	S6	S7	S8	S9
Water temp (°C)	20	19	22	20	27	29	25	25	26.5
pH	8.2	9.2	8.4	8.4	6.8	7.9	8.6	8.9	8.4
Turbidity (NTU)	8.61	41.9	141	3.77	248	48.9	55.7	27.4	74.7
TSS (mg/L)	3.4	29	118	196	9	58	23.2	16.4	40.8
DO (mg/L)	9.44	8.33	8.25	9.73	ND	ND	ND	3.6	ND
BOD (mg/L)	0.91	3.58	2.26	1.32	191.5	42.61	45.8	3.3	50.4
Phenol (μg/L)	17.3	56.2	166.7	70.6	95.4	136.6	250.25	24	57.75
PHC (mg/L)	9.2	8	9.2	3.8	13.8	10.2	235.4	253.2	277.2
TDS (ppt)	0.8	3.7	0.3	0.2	1.9	1.9	2.2	2	1.7
Chloride (g/L)	0.07	1.21	0.21	0.14	0.28	0.43	0.47	0.41	0.35
Salinity (‰)	0.12	1.99	0.25	0.23	0.47	0.70	0.88	0.77	0.67
NO2(mg/L)	0.005	0.015	0.003	0.001	0.005	0.004	0.03	0.02	0.04
NO3(mg/L)	0.046	0.035	0.007	0.005	0.005	0.003	0.02	0.04	0.04
TN (mg/L)	0.12	0.11	0.26	0.04	0.16	0.29	1.8	1.36	1.24
NH4(mg/L)	0.02	0.06	0.12	0.05	0.76	0.45	0.67	0.7	0.49
TP (mg/L)	0.16	0.27	0.25	0.15	0.54	0.38	0.71	0.57	0.6
PO4(mg/L)	0.004	0.03	0.07	0.02	0.24	0.11	0.24	0.23	0.21

Table 1 Tested Result for Different Water Parameters

Source: (Haldar, et al., 2013)

Some of the water parameters discussed:

1.  Dissolved oxygen (DO): DO is the dissolved oxygen which aquatic life breath in. (Kwok, 2011)

·    The higher level of DO at S1 to S4 indicated the high re-aeration rate and rapid aerobic oxidation of biological substances.

·    DO was undetectable in water samples of stations S5 to S7 and S9, indicating that water quality at these stations was not suitable for drinking, outdoor bathing and propagation of wild life according to the classification of Central Pollution Control Board (CPCB) (Annexure I Water Quality Criteria (CPCB) ).

Gujarat Pollution Control Board (GPCB) also performed DO analysis at Sabarmati River and they reported the depletion of DO in the downstream of the river associated with the increase in pollution. (Haldar, et al., 2013) DO is an indicator of pollution because the degradation of organic pollutants decrease the level of DO. (Shifflett)

   

2.  Biochemical Oxygen Demand (BOD): BOD measures the amount of oxygen required or consumed for the microbiological decomposition (oxidation) of organic material in water. (BIOCHEMICAL OXYGEN DEMAND IN WATER BODIES)

·    Acceptable BOD values (<3 mg/l in Indian standard) were observed at stations S1, S2, S3, S4, and S8.

·    Significant high values of 191 mg/l BOD were recorded at station S5, followed by 45.8 and 42.6 mg/l at stations S7 and S6, respectively. The possible reason behind the high BOD is mixing of wastewater from the discharge of effluents from city/towns and industries.

A trend of slight decrease in BOD was observed in the downstream sites, which might be due to the dilution of river water with seawater during high tide. Comparatively, lower BOD values at upstream sampling stations (S1 to S4) than downstream sites clearly suggested the anthropogenic stress over Sabarmati River from Ahmedabad to Vataman.

BOD and DO have significant relationship and directly indicate load of organic pollutants in surface waters.

  

 3.  Total and differential bacterial load:  Bacterial such as Vibrio, coliforms and Streptococcus were measured in the study.  These organisms pose human health hazards. (Palaniappan, et al., 2010)

·    Sampling stations S1 to S4 showed very low total as well as differential bacterial counts.

·    However, there was a drastic increase in total as well as differential bacterial counts at stations S5 and S6 and same trend was noticed for other three downstream stations. (Haldar, et al., 2013)

Table 2 Comparison of Test Result to Different Standards and Rivers (only part of the results are shown)

Source: (Haldar, et al., 2013)

In conclusion, several small and medium-scale industrial estates located nearby the river catchment area are contributing towards the river water pollution. Average concentrations of various components in the Sabarmati River water were comparatively higher than those in different rivers. The data revealed that water at the downstream of the river is not fit for any domestic application. The paper discussed and proved the tremendous influence of anthropogenic activities in the Sabarmati River.

In this study, we could notice the different water parameters were tested and analysed because they are important living condition to aquatic life and human health. There were also correlation between the different water parameters such as the relationship between DO and BOD.

The difference of parameter between different sampling points could be explained by the nearby land use of the sampling points. To determine how “polluted” was the river, the study was compared the different parameters with the standards limit of India and other rivers in the world.

Works Cited

Annexure I Water Quality Criteria (CPCB) . (n.d.). Retrieved 31 August, 2014, from Maharashtra Pollution Control Board: http://mpcb.gov.in/images/pdf/WaterQuality0709/AnnexureI_WQ.pdf

BIOCHEMICAL OXYGEN DEMAND IN WATER BODIES. (n.d.). Retrieved 31 August, 2014, from United Nations: http://www.un.org/esa/sustdev/natlinfo/indicators/methodology_sheets/freshwater/biochemical_oxygen_demand.pdf

Haldar, S., Mandal, S. K., Thorat, R. B., Goel, S., Baxi, K. D., Parmer, N. P., et al. (6 December, 2013). Water pollution of Sabarmati River—a Harbinger to potential disaster. India.

Kwok, C. (2011). Your First Guide to Water Quality Monitoring in Singapore. Retrieved 31 August, 2014, from ABC Waters Learning Trails: http://www.abcwaterslearningtrails.sg/web/files/PUB_WQM.pdf

Lodrick, D. O. (5 May, 2014). Gujarat. Retrieved 31 August, 2014, from Encyclopedia Britannica Logo: http://global.britannica.com/EBchecked/topic/249059/Gujarat

Palaniappan, M., Gleick, P. H., Allen, L., Cohen, M. J., Christian-Smith, J., Smith, C., et al. (March, 2010). Clearing the Waters A focus on water quality solutions. Retrieved 31 August, 2014, from United Nations Environment Programme: http://www.unep.org/PDF/Clearing_the_Waters.pdf

Shifflett, S. D. (n.d.). Water Quality Indicators: Dissolved Oxygen. Retrieved 31 August, 2014, from Water and Sustainability: http://www.unc.edu/~shashi/TablePages/dissolvedoxygen.html