Wastewater is used water draining out of homes and industries that contains a wide variety
of chemicals, debris and microorganisms. It contains large amounts of solid waste, dissolved organic matter and toxic chemicals that pose a health risk. It is composed of all the materials
that flow from household plumbing systems, including washing water, toilet waste, bathing
water, domestic wastewater, ground, surface and atmospheric waters that enter the sewage
system (Prescott et al., 2005; Talaro, 2005; and Prescott et al., 2008). Pharmaceutical
wastewaters are liquid waste generated by the pharmaceutical industries during the process
of drugs manufacturing. The steps involved in the compounding of drugs generate air
emission, liquid waste and solid waste (Ulamen and Robert, 2006).
Among such wastes discharged as partially treated or untreated in Nigeria are
pharmaceutical wastewaters. Drugs are designed to stimulate a physiological response in
human, animals, bacteria and other organisms (Kummerer, 2003). Many pharmaceuticals
and personal care products (as well as their metabolites and byproducts) can enter the
environment and finally the food chain following ingestion or application by the user or
administration to domestic animals. Aquatic environment serves as the major ultimate
receiving end for these chemicals, of which little is known with respect to their actual
or potential adverse effects. During the past decade, concern has grown about the adverse
effect that the use and disposal of pharmaceuticals might potentially have on human and
ecological health (Kummerer, 2003). In the last 15 to 20 years, there have been several
reports of pharmaceuticals in the environment: human and veterinary drugs were detected
in river water and even in drinking water (Richardson and Bowron, 1985; and Halling-
Sorensen et al., 1998). Although reported levels are very low, effects were observed, with
a noteworthy example being hormone disruption in fish due to the presence of estrogens
in the environment. Drug substances may reach the environment via use or disposal.
Patients will usually excrete a drug or its metabolites, which will then pass on to a sewage
treatment plant. There, it may be (partially) degraded, it may absorb to the sludge or
it may remain in the effluent. After processing in the sewage treatment plant, the sludge
is usually incinerated, but it may also be spread on the land and then leach into the
soil and eventually into the groundwater. In the case of disposal, depending on the route
(drain, household or industrial waste), pharmaceutical wastewater may enter the
groundwater and surface water via a sewage treatment plant or by leaching from a land
fill site (Halling-Sorensen et al., 1998).
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