Exhibit HHHH Environmental Health Perspectives Vol. 83, pp. 39-68, 1989 Principles and Problems of Environmental Pollution of Groundwater Resources with Case Examples from Developing Countries B. C. E. Egboka,* G. 1. Nwankwor,t 1. P. Orajaka,* and A. 0. Ejiofor* The principles and problems of environmental pollution and contamination are outlined. Emphasis is given to case examples from developing countries of Africa, Asia, and Latin America with a comparative analysis to developed countries. The problems of pollution/contamination are widespread in developed countries but are gradually spreading from the urban to rural areas in the developing countries. Great efforts in research and control programs to check pollution-loading into the environment have been made in the industrialized countries, but only negligible actions have been taken in developing countries. Pol- lutants emanate from both point and distributed sources and have adversely affected both surface water and groundwaters. The influences of the geologic and hydrologic cycles that exacerbate the incidences of pollution/contamination have not been well understood by environmental planners and managers. Profes- sionals in the different areas of pollution control projects, particularly in developing countries, lack the integrated multiobjective approaches and techniques in problem solving. Such countries as Nigeria, Kenya, Brazil, and India are now menaced by pollution hazards. Appropriate methods of control are hereby suggested. Introduction for research to combat and control widespread pollu- tants and contaminants. Volumes of these pollutants/ Environmental pollution and contamination are be- contaminants are produced yearly through natural and coming a common occurrence in parts of the developing anthropogenic activities such as industrial activities, ag- world. It is difficult to distinguish precisely between ricultural practices, waste disposal systems, etc. High- pollution and contamination. In modern hydrogeologic level, medium-level, and low-level wastes in solid, liq- literature, pollution is regarded as occurring in such uid, or gaseous forms are released into the environment high dosages or concentrations that it renders the pol- at discrete intervals or on a continuous basis. These luted medium very hazardous or highly deleterious to pollutants may be physical, chemical, biochemical, bi- biota. Contamination may occur to a lesser magnitude ological, or microbiological in nature. They may have when compared to pollution, but it also may render the short or long half-lives in the environment. They have contaminated medium unusable or make it slightly haz- continued to damage many environments of the indus- ardous to life. Many urban and rural areas of the de- trialized countries, having defied many painstaking con- veloped or industrialized world have been adversely af- trol programs (1,2). Many urban centers of developing fected by large-scale pollution and contamination, countries are now also similarly threatened. Unfortu- resulting in losses of human, material and financial re- nately, these poor countries lack the necessary exper- sources. In many American, European, and Asiatic tise and funds to wage any meaningful war against pol- countries, huge amounts of money are spent annually lution, which continues to spread unabated. Parts of the environment currently being polluted *Water Resources and Environmental Pollution Unit, Department include the atmosphere, pedosphere, hydrosphere, lith- of Geological Sciences, Anambra State University of Technology, P.M.B. 5025, Awka Campus, Awka, Nigeria. osphere, and biosphere. This paper shall focus on pol- tSchool of Applied and Natural Sciences, Federal University of lution/contamination of the hydrosphere, with particu- Technology, P.M.B. 1526, Owerri, Nigeria. lar emphasis on the groundwater regime, and pollution tDepartment of Applied Microbiology, Anambra State University incidences in developing countries. The scope shall em- of Technology, P.M.B. 5025, Awka Campus, Awka, Nigeria. brace Address reprint requests to B. C. E. Egboka, Water Resources sources and types of pollution/contamination, and Environmental Pollution Unit, Department of Geological Sci- processes generating them, implications of geology/hy- ences, Anambra State University of Technology, P.M.B. 5025, Awka drogeology, and pollution dynamics and mechanisms. Campus, Awka, Nigeria. Potentials of groundwater pollution in developing coun- 40 EGBOKA ET AL. tries vis-a-vis the developed ones shall be outlined, high- Table 1. Point sources of pollution and contamination. lighting their health hazards. Relevant suggestions for combating pollution more effectively shall be made. The Type of pollution Examples Sewage disposal systems Sewage lagoons primary objective is to review the general incidences of Septic systems environmental pollution/contamination in relation to the Cesspools effects of pedology and geology in close association with Barnyards/feed lots the dynamics of the hydrologic cycle. Proper under- Surface waste disposal sites Landfills/garbage dumps Surface waste dumps standing of sources and types of pollutants/contami- Underground waste disposal sites Storage tanks (low-, medium-, nants and their genesis and hydrodynamics would help high-level wastes) determine the appropriate control measures to be con- Pit latrines, tunnels, trenches, sidered for the situation. The goal is to contribute to caves better control methods. It is believed that present con- Waste subsurface injections Spills, washings, and intrusions Oil/gas/waste spills trol methods in parts of the world lack the depth of Auto workshop washings understanding required. In addition, many ofthese con- Research/laboratory washings trol efforts seem to be uncoordinated. Developing na- Seawater/saltwater intrusions tions still at the threshold of widespread pollution/con- Mining sources Acid mine drainages tamination could learn from the costly mistakes of the Gas explosions/seepages Mine dumps and gangue deposits industrialized nations and hence take the necessary ac- Tunnels/excavations outflows tions to protect their environments. Natural mineral/ore deposits Saline ponds/lakes The natural processes and anthropogenic activities Hot springs/mineralized waters that generate pollutants/contaminants are many and Anhydrite/pyrite deposits/ varied, and so are their sources. The natural processes evaporites include products of soil and gully erosion, physicochem- ical weathering and mass wasting, sediment transport, floods, volcanic eruptions, seawater intrusions, etc. The Table 2. Distributed sources of pollution and contamination (1). manmade ones include industrial, agricultural, sewage Source Examples wastes and lagoons, garbage dumps and barnyards, Agriculture Cropland mining wastes, etc. Pasture and rangeland These pollutants/contaminants in one way or the Irrigated land other via the cycle reach the groundwater Wood land hydrologic Feed lots systems to pollute/contaminate them. Through the cir- Silviculture Growing stock culation of water within the hydrologic cycle, pollutants Logging on the ground surface are transferred through the soil Road building zone into the aquifer horizons where they damage po- Construction Urban development Highway construction table water supplies. To reduce degradation of these Mining Surface water supplies, a comprehensive management strategy Underground is required, as discussed later. The present control tech- Terrestrial (many and scattered) Landfills niques with regard to pollution and contamination haz- Dumps Utility maintenance Highways and streets ards, particularly in developing countries, need to be Deicing greatly improved. Priority and concern are not shown Urban run-off Floods and snowmelt adequately by government authorities, and hence, ap- Precipitation Rainfall, snowfall, etc. propriate planning and management strategies to check Background sources Native forests pollution are generally absent. The expertise or req- Prairie land, etc. uisite manpower may be lacking. Funds for basic re- search may not be provided. Environmental protection laws or edicts may be nonexistent and where available (4). Point sources of pollution can be geometrically de- are rarely enforced. These have exacerbated the fined and the dimensions amenable to mathematical spreading phenomenon of many pollutants/contami- analysis in assessing pollution loads and rates of dis- nants in many developing countries. In this review, nec- charge determined. Point sources of pollution may as- essary suggestions for improvement of this situation sume any geometrical shape such as circular, triangular, shall be given. spherical, etc. The areal sources of pollutants/contam- inants or leachates are comparatively smaller, easily mappable, and readily distinguishable. However, where Sources and Types of Pollutants/ the input/output load functions from point sources into Contaminants the hydrogeologic environment are continuous, the pol- luted/contaminated area may eventually become wide- The two main sources of pollutants/contaminants are spread. Distributed sources of pollutants/contaminants point sources (Table 1) and distributed sources (2) (Ta- are much more widespread and can rarely be geomet- ble 2). Pollutants/contaminants from the two sources rically defined as precisely as a point source. Hence, it may be released continuously (3) or at discrete intervals is more difficult to subject the input/output source to GROUNDWATER POLLUTION IN DEVELOPING COUNTRIES