A stretch from beneficial
What are pharmaceuticals?
Category of pollution:
The sources are rather simple, all medications, most cosmetics, and most personal health products (certain shampoos, conditioners, soap, toothpaste, mouth wash, etc) lead to PPCP pollution.
According to http://www.epa.gov/ppcp/basic2.html
- Prescription and over-the counter therapeutic drugs
- Veterinary drugs
- Sun-screen products
- Diagnostic agents
- Nutraceuticals (e.g., vitamins)
Sources of PPCPs:
- Human activity
- Residues from pharmaceutical manufacturing (well defined and controlled)
- Residues from hospitals
- Illicit drugs
- Veterinary drug use, especially antibiotics and steroids
This drawing shows the pathway between homes and septic or municipal sewage facilities.
Agribusiness and Business
This drawing shows some of the contributions of sewage, biosolids and farms to PPCPs in the environment.
Discarding unused drugs and personal care products down the toilet is a common but poor disposal method.
Agribusiness and Business
"Studies have shown that pharmaceuticals are present in our nation's waterbodies. Further research suggests that certain drugs may cause ecological harm. More research is needed to determine the extent of ecological harm and any role it may have in potential human health effects. To date, scientists have found no evidence of adverse human health effects from PPCPs in the environment.
Reasons for concern:
- Large quantities of PPCPs can enter the environment after use by individuals or domestic animals.
- Sewage systems are not equipped for PPCP removal. Currently, there are no municipal sewage treatment plants that are engineered specifically for PPCP removal or for other unregulated contaminants. Effective removal of PPCPs from treatment plants varies based on the type of chemical and on the individual sewage treatment facilities.
- The risks are uncertain. The risks posed to aquatic organisms, and to humans are unknown, largely because the concentrations are so low. While the major concerns have been the resistance to antibiotics and disruption of aquatic endocrine systems (the system of glands that produce hormones that help control the body's metabolic activity) by natural and synthetic sex steroids, many other PPCPs have unknown consequences. There are no known human health effects from such low-level exposures in drinking water, but special scenarios (one example being fetal exposure to low levels of medications that a mother would ordinarily be avoiding) require more investigation.
- The number of PPCPs are growing. In addition to antibiotics and steroids, over 100 individual PPCPs have been identified (as of 2007) in environmental samples and drinking water.
Should we be worried about ecological and/or human health?
Studies have shown that pharmaceuticals are present in some of our nation's waterbodies. Further research suggests that there may be some ecological harm when certain drugs are present. To date, no evidence has been found of human health effects from PPCPs in the environment."
- The effects of PPCPs are different from conventional pollutants. Drugs are purposefully designed to interact with cellular receptors at low concentrations and to elicit specific biological effects. Unintended adverse effects can also occur from interaction with non-target receptors.
- Environmental toxicology focuses on acute effects of exposure rather than chronic effects.
- Effects on aquatic life are a major concern. Exposure risks for aquatic organisms are much larger than those for humans. Aquatic organisms have:
- continual exposures
- multi-generational exposures
- exposure to higher concentrations of PPCPs in untreated water
- possible low dose effects
- Effects may be subtle because PPCPs in the environment occur at low concentrations. There's a need to develop tests that detect more subtle end-points. Neurobehavioral effects and inhibition of efflux pumps are two examples. Subtle effects that accumulate may be significant.
- There are little aquatic/terrestrial toxicology data for PPCPs. There is substantially more data available for pesticides. For example, brief exposure of salmon to 1 ppb of the insecticide diazinon is known to affect signaling pathways (via olfactory disruption), leading to alteration in homing behavior (with obvious implications for predation, feeding, and mating). There's concern that low doses of PPCPs may also have effects.
- There are many drug classes of concern:
- antibiotics which are actively being researched
- estrogenic steroids
- antidepressants. Profound effects on spawning and other behaviors in shellfish can occur with antidepressant selective serotonin reuptake inhibitors (SSRIs).
- calcium-channel blockers. Dramatic inhibition of sperm activity in certain aquatic organisms can be effected by calcium-channel blockers.
- antiepileptic drugs (e.g., phenytoin, valproate, carbamazepine) have potential as human neuroteratogens, triggering extensive apoptosis in the developing brain, leading to neurodegeneration.
- multi-drug transporters (efflux pumps). Possible significance of efflux pump inhibitors (EPIs) in compromising aquatic health.
- musk fragrances are bioaccumulative and persistent
- genotoxic drugs (primarily used at hospitals)"
Residence Time and Treatment:
Some PPCPs are easily broken down and processed by the human body or degrade quickly in the environment, but others are not easily broken down and processed, so they enter domestic sewers. Excretion of biologically unused and unprocessed drugs depends on:
- individual drug composition (certain excipients -- i.e., inert ingredients -- can minimize absorption and therefore maximize excretion)
- ability of individual bodies to break down drugs (this ability depends on age, sex, health, and individual idiosyncrasies)
Because they dissolve easily and don't evaporate at normal temperatures or pressure, PPCPs make their way into the soil and into aquatic environments via sewage, treated sewage sludge (biosolids), and irrigation with reclaimed water."