INTRODUCTION: Environmental geology is the application of geologic concepts to problems created by human activities and their effects on the physical environment. The geologic hazards which are the result of human activities on the environment are brought about by the action of internal and external forces which are responsible for the relative movement of the earth as well as the changes in landscape. These forces could be in the form of tectonic forces (internal) or mass wasting and erosion (External).
GEOLOGIC HAZARDS/ENVIRONMENTAL HAZARD IN
THE STUDY AREA
The study area is underlain by hard and well consolidate rock mass. The rapid alteration of the limestone due quarrying may have favoured processes that initiate geologic and environmental hazards.
However, due to collapse of the company (Nigercem) that is mining the limestone in the study area major geologic and environmental hazards are no more experienced in the study area during the period of this work. But information gathered from people of the area shows that the have experience some of the geologic hazards during those days when the company (Nigercem) was operational.
Some of the geologic hazards that have been experienced by the people of the study area include particulate matter, flooding, mining activity and landslides and slumps.
The mining of limestone has led to the excavation of the top soil in order to harness the economic minerals at the subsurface. These activity develops noise pollution and also depreciates agricultural land which can led to loss of farm land causing reduction in the quantity and quality of agricultural products produced by the people of the area.
The mapped area is predominantly underlain by shales and limestone. These rocks being impermeable do not allow free percolation of Water during rainy season. Thus, such land surfaces become water logged. The water logged surface makes accessibility difficult and also creates breading sites for mosquitoes.
LANDSLIDES AND SLUMPS
To ensure successful mining of limestone it involves blasting of rocks. The large rock mass has to be disintegrate using explosives. The blasting of rocks (Explosives) creates seismicity which can lead to landslide and even failure of houses around the area as well as sources of terror to wildlife.
ENVIRONMENTAL IMPACT AND REMEDIES ON ENVIRONMENTAL GEOLOGY
All these above geologic hazards have made some impact on some components ofthe environment such as the air, soil, and socio-economic lives of the host communities.
The air around the quarry is impacted by the smokes and noises of the fleet of vehicles and explosives used for the operation. Another source of pollution is the particulate matters released from the quarry.
Government can enact laws to control the reckless blasting of rocks in order to control air pollution.
The abandoned mine pits and excavation have rendered much land useless for agriculture and human habitation and also serve as dead trap for people that are not aware. Another source of contamination on the soil is poor disposal of wastes generated from the industry.
To minimize these impacts, wastes should be properly segregated and taken to designated dump areas and government can make a policy mandating the mining company to reclaim each operational site to its original state after mining.
Mining in this area require large work force. The communities in the map area are exposing to such hazards as uncontracted marriages and production of illegal children. Diseases such as malaria arising from mosquito bites and infection of the respiratory organs due to inhalation of smoke and other particulate matters in the atmosphere and failure of houses around the quarry.
However, positive impact includes employment opportunity for the people of the area and provision of social amenities like electricity, health Centre, good roads and water boreholes by the company for the host communities.
Some remedies to the geologic hazards is that the villagers should be educated on the need to embark on construction of standard houses at certain distances away from the mining sites. Good surface drainage system and roads should be constructed in the flood prone areas.
However, these geologic hazards occurs mostly during the period when the company (NIGERCEM) was operational but during the period of this mapping exercise the geologic hazards were not noticed due to collapse of the company over 11-12 years ago. But it was gathered from the people of the area that they have experience those environmental hazards in years past when the company was working.