The spatial limits for the ecological evaluation of impacts were defined based on the following two important considerations.

i. Study area limits as dictated by environmental guidelines and legislative provisions for environmental assessment of industrial projects.

ii. The potential of the project in contributing to the existing level of contamination of the physical and biological components of the environment.

As per the existing guidelines (MoE&F, 1984) in respect of industrial projects listed in schedule I of EIA Notification, the observations for ecological assessment need to be made within 25 km radial zone. Subsequent Notification (MoE&F, June 1999) for Draft
Rule stipulate specific distances for location of industries designated wetland areas, protected areas and highway and rail projects. The proposed project does not fall in any of the categories of conservation areas designated above within the stipulated distances. The information required in the environmental questionnaire for industries (MoE&F, 1999) for perusal in the initial scrutiny of the environmental aspects of the projects demand assessment of floral, faunal values within 7 km pf the periphery of the project.

The following design features of the proposed project are other considerations for setting the boundaries for the study.

• The proposed project site for DHPU is located within the existing BRPL complex which is an established industry in the area now for more than two decades.
• The objective of the project is to upgrade the product quality by reducing the sulphur content of the diesel products of the refinery.
• Liquid sulphur obtained in the process shall be solidified in the sulphur yard and the solid sulphur thus obtained shall be dispatched through trucks for various commercial uses.
• The liquid effluents generated in DHPU shall be sent to the existing WWTP for treatment and disposal.
• The fuel gas generated in DHPU shall be consumed internally.
• No additional land infrastructure storage and transport facilities is proposed as the proposed unit would use the BRPL's existing facilities.

Considering the facts given above, the spatial limits of the impacts cannot be visuaiised the area beyond the 10 km radial zone of the proposed project. Even the natural life sustaining systems and the specific land uses that are more sensitive to industrial impacts, because of their specific nature and extent of fragility are not expected to be receptors of impacts in the area beyond 10 km radial zone. Hence for the purpose of this study , a 10 km radial zone from the existing BRPL complex has been delineated as the study area (Fig. 3).