Environmental Hazard of Tea garden belt in Jalpaiguri District, West Bengal
Deforestation:
The Terai or Duars are covered with forests. The swampy wet land helps to grow natural forest. But increasing population and requirements of foods force to change the land use pattern of this region. Forests are also being damaged to establishing tea gardens. Mainly two types of hazards cause deforestation. That is-
Due to the shifting of river deforestation occurred here. Shifting of river Jaldhaka devastated nearly 50% of Tundu forest and Tundu Tea Garden. Shifting of river Diana deforested the Western part of this river i.e., Diana forest. During 1960’s shifting of river Torsha to Buri Torsha caused huge damages to Chilapota forest. In the foothills region shifting and changing course of river Torsha damages a huge portion of Reti forest near Jaigaon. Man-made Hazards: On the other hand, man made hazards also causes deforestation in this region. In the name of development, and requirements of cultivable lands- huge forest area is damaged for this purpose. In this regard we took the example of Baikunthapur forest, which is now just a shadow of the past. Deforestation of huge area causes ecological imbalances in this region and changing weather condition is the result of this. Soil Erosion: Due to natural and man-made hazards erosion of top soil is a major problem of this region. Erosion of soil mainly occurred due to human interference. In the name of so called development, for constructing roads in hilly region, detonators are often used for blasting stones or part of hills, which causes loosening and cracking of stones and ultimately causes severe landslide and sleeps. Unscientific spreading of human habitation is also a big factor for soil erosion. To meet the demand of greater population in the hills, terrace cultivation of paddy with the help of flow irrigation is adopted. This process washed out the cementing material, which bonds the stone. It is experienced that hill flow irrigation project areas are often followed by severe sleeps. Adding to this unscientific dolomite mining in Bhutan and neighboring Sub-Himalayan hills causes erosion of soil in heavy amount. It is true, that due to some natural process soil erosion occurs but interference of human activities increases its margin heavily. So, it is high time necessary steps should be taken before any calamity can take place. Ground and surface Water Quality: Ground and surface water quality monitoring is the process of regular study of parameters related to ground and surface water. It helps determining the quality trend and hence the threshold values for the restoration of water quality to its normal. Different factors those affect the water quality are physical, chemical and socio- economic parameters of the area. The water quality is differing in circumference of tea garden belts than other area of the district. Using GIS, the database on water quality, the relationship between water quality parameters with land use (tea garden, non tea garden and drainage networks) have been asserted and graphically presented (Fig 1). 
About eleven water quality parameters, the physical parameters temperature and total dissolve solid and chemical parameters PH, Total hardness, conductivity, Sulphate (SO4), Phosphate (PO4), Chlorite, Bio-carbonate, Sodium, Calcium and BOD are studied from their pre-monsoon and post-monsoon period. In monsoon period all water quality parameters are more than non-monsoon period. Total dissolve solid, Sulphate, Sodium, PH ,BOD and other parameter are more than the permissibility limit (WHO) in the tea garden area . The contamination of surface water and groundwater pollution can result from the large-scale application of fertilizers, pesticides and agrochemicals in tea garden area. Unwanted elements and others excess elements easily leach out though high permeable and porosity soil, which are easily contaminated with ground water. The ground water model described the first, shallow aquifer that is directly exposed to tea garden region, which is the major cause of contamination. The major driving forces include the spatially distributed recharge from huge rainfall in hilly region depending on land use, infiltration or exfiltration from and to the river and the pumping of groundwater in shallow wells that constitute the majority of small domestic wells. Spatially varying characteristics of the aquifer and land use are directly taken from GIS. Another problem of water quality in the north-eastern part (Birpapa, Dhupguri, Kalchini Blocks) of district due to the unscientific excavation of dolomites mine at Bhutan border that effect fall on the drinking and irrigation system in this region cause the hardness of water is increased though soluble of excess of carbonate, bi-carbonate in the water system which is deceased the fertility of tea and agric-land. Excessive levels of Sulphate, TDS, BOD, PH and Bi-carbonate and other water quality parameters that can pose a long-term health hazard such as Diarrhoea, Malaria, and others water-bone diseases are the major problem of tea garden area. Waste tea garden management is one of the cause of health hazard because do not have any concrete platform of drinking tube wells. All environmental hazards directly or indirectly effect of the health condition of tea garden belts compare to other part of district. The Diarrhoea, Malaria, and others water-bone disease are ‘Acute Problem’ of the tea garden belts in the monsoon period in every years (Table -1).
The GIS database used for relationship of health condition with land use and other spatial and non-spatial data of the district, which show positive relationship with poor health condition and tea garden belts than other part of district. The primary causes of the poor health are –
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