当前世界环境

Introduction

The brick kiln industries occupy a very significant place in the unorganised sector, confined mainly to rural and semi –urban areas. Small and medium sized traditional brick kilns are growing in cities of developing countries around the globe supplying the urban population with cheap construction material.¹Fired clay brick is one of the most important building materials in the country. There are no reliable estimates of brick makers in India. The current (2001) annual brick production in the country is estimated at 140 billion bricks. The number of brick producing units in the country is estimated to exceed 100,000.²There are around 50,000 brick kilns in the whole of country.³Brick kiln industry has its own unique characteristic like instability, short duration and poor technology. In Cachar brick kiln industry is a major employer of unskilled and semi-skilled labours. In brick kiln industry work is a seasonal activity and occurs largely between October to May and remains shut down during monsoon period.⁴Though the brick fields of Cachar are playing a vital role in economic development of the region, at the same time we cannot ignore the pollution risks associated with the brick fields. There are several environmental impacts of brick kiln of which the major problems are land degradation, water quality loss, deterioration and air pollution. Due to degradation of top soil layer from the agricultural land ultimately the eroded soil goes to the nearby aquatic system through catchment channels. Water reflect its ecological potential and sustenance quality by it biological, chemical and physical characteristics. Now a days due to increasing anthropogenic influences in and around the catchment area of the aquatic systems causes large extent of nutrient enrichment in the aquatic systems and leads to deterioration in water quality. The brick industries highly affects the physico-chemical and biological properties of aquatic systems.⁵In Ujjain (India) high pollution levels in Kshipra river near these industries has been noticed, which could be possibly due to leaching of compounds from raw materials used in brick industries.⁶This observation is also made in this paper. The present research paper highlights the variation in physico-chemical properties in aquatic bodies present near the brick kiln industries and comparison with the ponds of Chatla floodplain wetland. In the Chatla floodplain wetland the presence of different types of habitats like fisheries, beels, ponds, inlets and outlets make an unique hydrology here and maintain the ecological balance among rivers, streams and floodplains.

Materials and Methods

For water sampling three stations Bariknagar, Silcoorie and Natun bazaar have been selected which have brick kiln industries, then three ponds from the vicinity of each brick kilns i,e. 18 sites (A1,A2,A3,B1,B2,B3,C1,C2,C3,D1,D2,D3E1,E2,E3,F1,F2,F3) were chosen randomly,⁶control sites (A4,B4,C4,D4,E4,F4) have been selected away from the brick kilns ( 10-15 kms) and 3 sites (G1,G2,G3) were selected from Chatla floodplain wetland in Cachar district for comparison.⁷Water samples have been collected using standard methods.^8,9Samples were collected on bi-monthly basis for one year. To study the impact of these industries on the aquatic bodies physico–chemical properties of like WT, pH, EC, Transparency, TA, DO, FCO₂, Nitrate and Phosphate was analyzed by using Standard Methods.^8,9

Results

一项调查是为了了解砖process and to select the sites in brick kiln industry to study its impact on the aquatic bodies. The results of different physico-chemical parameters are depicted in the (Table.1,2). Values show mean and SD for different sites studied during January to December 2014.The study shows the value of WT ranged from 19.8ºC to 26.5ºC. WT was higher in site F2 and lower in site D4 which was a control site. The value of water transparency ranged from 2.4 cm to 18.2 cm and was found higher in site C4 and lower in site F2. pH indicates acidic and basic nature of water. In the present study the average pH value recorded was 4.5 to 7.1. pH value was lower in C3 and higher in site B4. The average range of EC recorded was 13 µs/cm to 119 µs/cm. EC was recorded maximum in brick kiln affected site C2 and minimum in site G2 which was in Chatla wetland. The DO values ranged between 2.8-12.3 mgl^-1. DO of water samples was found maximum in site C4 whereas site B1 exhibits least concentration of DO. The FCO₂value of the water bodies varied between 3.35-18.1 mgl^-1. Maximum level of FCO₂was observed in C2 and minimum level in E4. The average range of TA recorded was 14.3-54.3 mgl^-1. Higher value of TA was recorded in site F4 and lower value in site C3 near brick kiln industry. The value of Nitrate content recorded was between 0.15 mgl^-lto 1.14 mgl^-l. Nitrate level was found maximum in site B3 and minimum in site B4. The values of Phosphate content ranged between 0.14-1.37 mgl^-1. Phosphate level was observed high in site C1 and low in site F4 near brick kiln.

Table 1: Effect of Brick kiln industry on water quality (Mean±SD) Click here to View table

Table 2: Water quality in aquatic bodies at control sites (Mean±SD) Click here to View table

Discussion

Water temperature of an aquatic body shows very close association with ambient temperature¹⁰and plays important role in metabolism of different organisms. In the present study increase in WT might be due to the emissions of heat from the kilns which slightly raise the water temperature in nearby aquatic systems which is very much comparable with the heat losses from other brick kilns of the country.¹¹During the study water is more turbid in affected site which might be due to dumping of ashes, extraction of sand and cutting of land that causes high silt content in water from the catchment areas.¹²The high turbidity might be responsible for high level of water temperature in the aquatic bodies near brick kiln industry because the suspended particles absorb the heat from the sunlight making the water warm.^13,14Measurement of pH indicates the level of acidic and basic nature of the aquatic system. During the study pH was slightly acidic in some of the affected sites which might be due to leaching of some elements or acidic substances into the water bodies from the vicinity of the brick kilns.⁶However fluctuations in pH is also related with input loads of pollutants in the aquatic systems.¹⁵EC的波动可能是由于波动s in total dissolved solids and salinity.¹⁶Water conductivity is mainly attributed to the dissolved ions liberated from the decomposed plant matter¹⁷and input of organic and inorganic waste.¹⁸DO shows inverse relationship with both water temperature and free carbon dioxide^16,19,20. Free CO₂in water originates from the respiration of aquatic biota and decomposition of organic matter which reacts with water and form carbonic acid that lowers the pH.²¹High level of FCO₂might be due to increased rate of decomposition of organic matter in the lower level of the aquatic system. High level of TA is followed by high level of pH. Utilization of CO₂from HCO₃for photosynthesis by algae may increase the amount of TA in water body.²²Algae and other plants use nitrate as a source of food which might have caused reduction in nitrate concentration of the water body. The concentration of Nitrate plays an important role for primary production.²³Lack of Phosphate is often the chief cause of poor productivity of water. Presence of organic matter had increased the level of phosphate. Natural waters having a phosphorous content more than 0.2 mgl^-1(PO₄) are likely to be quite productive.²⁴The low value of Nitrate and Phosphate might be due to lower input of pollutants in the aquatic bodies.²⁵

Conclusion

Thus, the present study clearly reveals the extent of aquatic degradation at the aquatic bodies in the brick kiln industry area. The data obtained clearly shows the extent of contamination at the study sites near the brick kiln industry which leads to deterioration and degradation of water quality. It directly affects the sustainability of the biotic components in the ponds and causes ecological imbalance in a particular aquatic ecosystem. The results show urgency to restore the chemical, physical and biological restoration of these aquatic bodies. So, it is very essential to adopt some mitigation measures and to implement appropriate regulatory measures regarding the maintenance of environment and also important to follow several conservation strategies to prevent the ecological imbalance which affects the hydrological cycles and finally disturbs the food chain and food web in the aquatic bodies near the brick kiln industries.

Acknowledgment

The first author is grateful to the Dept. of Ecology and Environmental Science, Assam University, Silchar for providing the necessary infrastructure and laboratory facilities throughout the tenure of the research work. The author also likes to acknowledge Dst/Inspire, Government of India, Ministry of Science and Technology for providing financial assistance to carry out the research work.

Reference

1. Bandyopadhyay Performance of the Selected Clusters of Small and Medium Industries in India in the Post-Reform Period – An Overview.Journal of Scientific & Industrial Research ,60, 220-231(2001)
2. Maithel S., Johri R., Kumar A., and Vasudevan Pollution Reduction and Waste Minimization in Brick Making. Tata Energy Research Institute, Habitat Place, Lodhi Road, New Delhi (2002)
3. Gupta Informal labour in brick kiln: Need for regulation. Economic and political weekly 2(3),282-92, (2003)
4. Molankal Gangabhushan. Health Status of Women Brick Kiln Labourers: A Case Study.Health Action.23, 32-35, (2003)
5. Uprety B. Environmental Aspects of the Brick Factory. Chief, Environment Assessment Section and Biodiversity Section Ministry of Forests and Soil Conservation Kathmandu, Nepal. http://people.exeter.ac.uk/rwfm201/cbbia/downloads/grants/Annex3CsW.pdf
6. Khan R., Rahman K., Rouf A.J.M., Sattar G.S., Oki Y., and Adachi T. Assessment of degradation of agricultural soils arising from brick burning in selected soil profiles.Journal of Environmental Science and Technology4, 471-480, (2007)
7. Khan R., and Vyas H. A Study Of Impact Of Brick Industries On Environment And Human Health In Ujjain City (India).Journalof Environmental Research And Development2,421(2007)
8. APHA (American Public Health Association). Standard methods for examination of water and waste water analysis, 21st edn. Washington, DC (2005)
9. Trivedi R.K., and Goel P.K. Chemical and biological methods of water pollution studies. Environmental Publications, Karad, India, 251(1984)
10. Munawar M. Limnological studies of fresh water ponds of Hyderabad , India.Hydrobioligia36(1), 127-162, (1970)
11. Maithel S., Uma R., Kumar R., and Vasudevan N. Energy Conservation and Pollution Control in Brick Kilns. Tata Energy Research Institute, Habitat Place, Lodhi Road, New Delhi, (1999)
12. Bandyopadhyay S., Ghosh K., Saha S, Chakravorti S., and De S.K. Status and Impact of Brick Fields on the River Haora, West Tripura.Inst. Indian Geographers35,277-280, (2013)
13. Tiwari Assessment of physcio-chemical status of Khanpura Lake,Ajmer in relation to its impact on public health.Eco. Env. and Cons, 11(3-4),491-493, (2005)
14. Mishra M.K., Mishra N., and Pandey D.N. An assessment of physic-chemical characteristics of Bhamka Pond, Hanumana, Rewa District, India. International Journal of Innovative Research in Science, Engineering and Technology, 2,1781-1788, (2013)
15. Sahu B.K., Rao R.J., and Behera S.K. Studies of some physic-chemical characteristics of Ganga river water (Rishikesh-Kanpur) within twenty four hours during winter, 1994.Env. & Cons.1(1-4),35-38 (1995)
16. Boyd E. Water Quality in Warm Water Fish Ponds. Craftmaster Printers, Inc. Opelika, Alabama, (1981)
17. Sarwar K., and Irfan-Ul-Majid. Abiotic features and diatom population of Wular Lake, Kashmir.Ecol.Env. & Cons3(3), 121-122 (1997)
18. Wright Seasonal Variation in water Quality of a West African river ( R. Jong in Sierra Leone).Reveued. Hydrobiologie Tropicale. 15(3), 193-199(1982)
19. Ali M., Salam A., and Hussain M.Z. Effect of seasonal variations on physic-chemical parameters of Zaidi fish farm. Punjab Univ.J Zool9,53-58 (1994)
20. Salam A., Ali M., Khan B.A., and Rizvi S. Seasonal changes in physico-chemical parameters of river Chenab Muzaffar Garh, Punjab, Pakistan.J Bio Sci. 4, 299-301(2000)
21. Wurts W.A., and Durborow R.M. Interections of pH, carbon dioxide, alkalinity, and hardness in fish ponds. Southern Regional Aquacultural Centre Publication No.464, (1992) http://www2.ca.uky.edu/wkrec/Interactions pHEtc.PDF
22. Durrani A. Oxidative Mineralization of Plankton with its Impact of Eutrophication of Bhopal. (1993)
23. Bisht S., Ali G., Rawat D.S., and Pandey N.N. Physico-chemical behaviour of three different water bodies of sub –tropical Himalayan region of India.J Ecol Nat Environ. doi:10.5897/JENE12.087 Ph.D. Thesis. Barakatullah University, Bhopal, M.P. (2013)
24. Jhingran g .鱼和金融中间人heries of India. Hindustan Publishing Corporation (India), Delhi, (1988)
25. Clarke F.W. The data of Geochemistry (5^th版)。公牛。美国Geol.Survey。770.美国。Govt.Printing office, Washington D.C. 841(1924).