
ET
Apr 17, 2004, 2:24 PM
Post #20 of 28
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quote]"Esteban" writes: I'm thinking all hospital waste including blood products etc. Isn't it possible dangerous stuff could be mixed with rainwater and go down through the soil to the water table? I mean how else does the aquifer get re-generated? With such vaguely expressed fears ("all hospital waste", "dangerous stuff") I can only offer an answer in a broad form. Medical waste generally ceases to be a significant risk when it loses recognizable form. Direct contact with blood or other bodily fluids offers the risk of exposure to whatever pathogens may be present in the blood or fluid. Blood remains intact in a vial, needle, or syringe and continues to carry this risk. Expose blood to large quantities of air, such as if it was dumped into a field, and proteins and structures start to degrade and pathogenic microorganisms start to die off. A similar activity is seen when blood is dumped into water. Neither of the two big fear factors, the Human Immunodeficiency Virus (HIV) and the Hepatitis B Virus (HBV) survive for any significant period when placed into water, which is why to this day, hospitals and laboratories in the US are continued to be allowed to dump bulk blood into the standard sanitary sewer system without pretreatment (blood in vials is disposed of in the vials as medical waste to reduce the handling and associated risk of exposure). Beyond blood, you'll find that medical waste regulations in the US are only in part intended to assure that such items as needles, syringes, used dressings, and tissue specimens are sterilized before being disposed of with other municipal wastes. The other significant component of the regulations are to force the wastes to be rendered unrecognizable, so that when they wash up on a beach in New Jersey, or are found in a roadside ditch in the vicinity of the landfill they don't cause major public outcry, concern, and/or newspaper pictures. To this end the regulations are extended to veterinary and laboratory wastes with similar appearances not because of any significant exposure risks to humans, but because they could be confused with medical waste and make the 6 PM news. Aquifers are recharged ("re-generated") through the percolation of groundwater though a solid medium such as rock. This percolation can take years to centuries, and can serve to both filter and age out pathogenic microorganisms. Direct connections between groundwater and aquifers only tends to occur in either fractures and man-made penetrations such as around improperly installed wellshafts, and tend to affect the "shallow" aquifers directly beneath the water table. If drawn from the ground municipal potable water supplies are typically drawn from the deeper aquifers which are more protected and require longer percolation times and distances. I've never seen an aquifer being described as a "potable aquifer".
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