Environmental xenobiotic

Last updated

Environmental xenobiotics are xenobiotic compounds with a biological activity that are found as pollutants in the natural environment.

Contents

Pharmaceuticals

Pharmaceutical drugs are chemicals used for the alteration, diagnosis, prevention and treatment of disease, health conditions or structure/function of the human body. Some pharmaceutically active compounds (PhACs) can enter the environment by one route or another as the parent compound or as pharmacologically active metabolites. Drugs are developed with the intention of having a beneficial biological effect on the organism to which they are administered, but many such compounds all too often pass into the environment where they may exert an unwanted biological effect. [1]

For many years PhACs have been all but ignored as environmental researchers concentrated on the well known environmentally dangerous chemicals that were/are largely used in agriculture and industry. But with increasing technology to help in the separation and identification of multiple compounds in a mixture, PhACs and their effects have received increasing attention. [2] PhACs have not (until relatively recently) been seen as potentially toxic because regulations associated with pharmaceuticals are typically overseen by human health organizations which have limited experience with environmental issues. [3]

Nearly all categories of pharmaceuticals including pain killers (analgesics and anti-inflammatory), antibiotics (antibacterial), anticonvulsant drugs, Beta-blockers, blood lipid regulators, X-ray contrast media, cytostatic drugs (Chemotherapy), oral contraceptives, and veterinary pharmaceuticals among many others have been found in the environment. [4]

Sources and origins

PhACs can be entered into the environment in two main ways; direct and indirect. Indirect sources are PhACs that have performed their biologically intended effect and are passed onto the environment in either their complete or a modified state.

PhAC's can be discharged directly by manufacturers of the pharmaceuticals or effluents from hospitals. However with increasing regulation by local, state and federal regulating agencies, direct discharge is becoming much less of an issue. [5]

There are also several indirect sources of PhACs into the environment. One common indirect source of PhACs into the environment is the passing of antibiotics, anesthetics [6] and growth promoting hormones [7] by domesticated animals in urine and manure. This is often stored in large pits before being pumped and applied to fields as fertilizers where many of the PhACs can be washed away by rainfall to aquatic environments.

Family pets can also be an indirect source of PhACs into the environment. [8]

Most of the PhACs in the environment however come from human sources. A direct human source is leachate from a landfill. Often the pharmaceuticals that are located in landfills are found in their original, most chemically active state.

Most pharmaceuticals are administered and passed through the human body in one of three ways:

  1. Metabolized partially or completely within the body and made inactive (Ideal)
  2. Partially metabolized and passed through the system
  3. Passed through the body unmodified (Worst Case Scenario). In any manner PhACs are then passed to sewage treatment plants (STPs), where facilities are designed to break down natural human waste by microbial degradation. However, many PhACs are of very complex structure and are incompletely broken down in STPs before they are passed into the environment. [9]

Fate in environment

Once PhACs are entered into the environment they suffer one of three fates:

  1. Biodegradation into carbon dioxide and water.
  2. Undergo some form of degradation and form metabolites.
  3. Persist in the environment unmodified. The amount of the compound that is broken down depends on several factors such as bioavailability and compound structure among many others.

Effects

Because PhACs have come into the limelight relatively recently their effects on the environment are not completely understood. PhACs are also not generally intended to come in contact with the environment, and therefore are not typically tested environmentally prior to release. Therefore several tests are required to determine the different mechanisms and side effects of PhACs in the environment making testing largely impractical. [10]

Many PhACs have very broad modes of action in humans. Similar, subtle reactions may occur in organisms in the environment that are not easily seen by humans. Highly specific mechanisms in humans may solicit profound effects at extremely low concentrations. Many effects may not necessarily be readily detectable and lead to ecological change that would be erroneously attributed to natural change. [11] This said there are several effects that have been identified in the literature.

One long term, possibly irreversible effect is microbiological resistance to antibiotics (antibiotic resistance). Some bacteria may be able to survive when administered antibiotics (especially at low concentrations). [12] Those colonies will multiply and produce new colonies that are resistant to that particular antibiotic and will not succumb the next time antibiotics are administered. Because rivers and streams are ever flowing objects they are an ideal pathway for antibiotics to reach bacteria and therefore provide a source and reservoir for resistant strains to develop and establish themselves. [13]

Another recent discovery is endocrine disruptors. Endocrine disruptors can replace or disturb the balance of hormones within an organism and have been found to be occurring in waters with a concentration in the ng/L level for certain compounds. Some possible effects of endocrine disruptors are male and female sterility, feminization of males, masculinization of females and abnormal testes growth among many others. The exact pathway of occurrence of endocrine disruptors is not completely certain, however several pathways have been proposed. [14]

Typically PhACs are found in low concentrations, (<1 ug/L) making acute toxicity effects fairly unlikely. However, because of their continual input to the environment it is possible for chronic toxicity effects to occur. One major area of concern with several compounds being present at low levels at the same time is what happens when the compounds mix? It is possible and truly likely that these mixtures will have additive, neutralistic or synergistic effects. But again testing would be both time consuming and very expensive to test all of the combined effects.

Common pharmaceutically active compounds found in the environment

Analgesics (anti-inflammatory and antipyretic)

  1. Acetaminophen
  2. Acetylsalicylic Acid
  3. Diclofenac
  4. Codeine
  5. Ibuprofen

Antibiotics

  1. Macrolide Antibiotics
  2. Sulfonamides
  3. Fluoroquinolones
  4. Chloramphenicol
  5. Tylosin
  6. Trimethoprim
  7. Erythromycin
  8. Lincomycin
  9. Sulfamethoxazole
  10. Trimethoprim

Anticonvulsant

  1. Carbamazepine
  2. Primidone

Beta-blockers

  1. Metoprolol
  2. Propanolol
  3. Betaxolol
  4. Bisoprolol
  5. Nadolol

X-ray media

  1. Iopromide
  2. Iopamidol
  3. Iohexol
  4. Diatrizoate

Cytostatics (chemotherapy drugs)

  1. Cyclophosphamide
  2. Mycophenolic acid
  3. Ifosfamide
  4. Bicalutamide
  5. Epirubicin

Steroids and hormones

  1. 17α-ethinylestradiol
  2. Mestranol
  3. 19-norethisterone

Related Research Articles

Medication substance used to diagnose, cure, treat, or prevent disease

A medication is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management.

Phthalate ester of phthalic anhydride

Phthalates, or phthalate esters, are esters of phthalic anhydride. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC).

Triclosan chemical compound

Triclosan is an antibacterial and antifungal agent present in some consumer products, including toothpaste, soaps, detergents, toys, and surgical cleaning treatments. It is similar in its uses and mechanism of action to triclocarban. Its efficacy as an antimicrobial agent, the risk of antimicrobial resistance, and its possible role in disrupted hormonal development remains controversial. Additional research seeks to understand its potential effects on organisms and environmental health.

Prescription drug licensed medicine that is regulated by legislation to require a medical prescription before it can be obtained

A prescription drug is a pharmaceutical drug that legally requires a medical prescription to be dispensed. In contrast, over-the-counter drugs can be obtained without a prescription. The reason for this difference in substance control is the potential scope of misuse, from drug abuse to practicing medicine without a license and without sufficient education. Different jurisdictions have different definitions of what constitutes a prescription drug.

Endocrine disruptor Chemicals that can interfere with endocrine or hormonal systems at certain doses

Endocrine disruptors are chemicals that can interfere with endocrine systems at certain doses. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders. Any system in the body controlled by hormones can be derailed by hormone disruptors. Specifically, endocrine disruptors may be associated with the development of learning disabilities, severe attention deficit disorder, cognitive and brain development problems; deformations of the body ; breast cancer, prostate cancer, thyroid and other cancers; sexual development problems such as feminizing of males or masculinizing effects on females, etc.

Bisphenol A chemical compound

Bisphenol A (BPA) is an organic synthetic compound with the chemical formula (CH3)2C(C6H4OH)2 belonging to the group of diphenylmethane derivatives and bisphenols, with two hydroxyphenyl groups. It is a colorless solid that is soluble in organic solvents, but poorly soluble in water (0.344 wt % at 83 °C).

Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of their persistence, POPs bioaccumulate with potential adverse impacts on human health and the environment. The effect of POPs on human and environmental health was discussed, with intention to eliminate or severely restrict their production, by the international community at the Stockholm Convention on Persistent Organic Pollutants in 2001.

Nonylphenol family of organic compounds

Nonylphenols are a family of closely related organic compounds composed of phenol bearing a 9 carbon-tail. Nonylphenols can come in numerous structures, all of which may be considered alkylphenols. They are used in manufacturing antioxidants, lubricating oil additives, laundry and dish detergents, emulsifiers, and solubilizers. These compounds are also precursors to the commercially important non-ionic surfactants alkylphenol ethoxylates and nonylphenol ethoxylates, which are used in detergents, paints, pesticides, personal care products, and plastics. Nonylphenol has attracted attention due to its prevalence in the environment and its potential role as an endocrine disruptor and xenoestrogen, due to its ability to act with estrogen-like activity. The estrogenicity and biodegradation heavily depends on the branching of the nonyl sidechain. Nonylphenol has been found to act as an agonist of the GPER (GPR30).

A biological target is anything within a living organism to which some other entity is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets are proteins and nucleic acids. The definition is context-dependent, and can refer to the biological target of a pharmacologically active drug compound, the receptor target of a hormone, or some other target of an external stimulus. Biological targets are most commonly proteins such as enzymes, ion channels, and receptors.

Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.

Environmental hazard

An environmental hazard is a substance, a state or an event which has the potential to threaten the surrounding natural environment / or adversely affect people's health, including pollution and natural disasters such as storms and earthquakes.

2-Butoxyethanol Chemical compound

2-Butoxyethanol is an organic compound with the chemical formula BuOC2H4OH (Bu = CH3CH2CH2CH2). This colorless liquid has a sweet, ether-like odor, as it derives from the family of glycol ethers, and is a butyl ether of ethylene glycol. As a relatively nonvolatile, inexpensive solvent, it is used in many domestic and industrial products because of its properties as a surfactant, though it is a known respiratory irritant and suspected human carcinogen and has been shown to be associated with increased rates of obesity.

Triclocarban chemical compound

Triclocarban is an antibacterial chemical once common in, but now phased out of, personal care products like soaps and lotions. It was originally developed for the medical field. Although the mode of action is unknown, TCC can be effective in fighting infections by targeting the growth of bacteria such as Staphylococcus aureus. Additional research seeks to understand its potential for causing antibacterial resistance and its effects on organismal and environmental health.

Triphenyl phosphate chemical compound

Triphenyl phosphate (TPhP) is the chemical compound with the formula OP(OC6H5)3. This colourless solid is the ester (triester) of phosphoric acid and phenol. It is used as a plasticizer and a fire retardant in a wide variety of settings and products.

Ecotoxicity potential for biological, chemical or physical stressors to affect ecosystems

Ecotoxicity, the subject of study of the field of ecotoxicology, refers to the potential for biological, chemical or physical stressors to affect ecosystems. Such stressors might occur in the natural environment at densities, concentrations or levels high enough to disrupt the natural biochemistry, physiology, behavior and interactions of the living organisms that comprise the ecosystem.

Environmental impact of pharmaceuticals and personal care products effects of drugs on the environment

The environmental effect of pharmaceuticals and personal care products (PPCPs) is currently being widely investigated. PPCPs include substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. More than twenty million tons of PPCPs are produced every year. PPCPs have been detected in water bodies throughout the world. The effects of these chemicals on humans and the environment are not yet known, but to date there is no scientific evidence that they affect human health.[2]

Environmental impacts of cleaning agents are the consequences of chemical compounds in cleaning products. Cleaning agents can be bioactive with consequences ranging from mild to severe. Developmental and endocrine disruptors have been linked to cleaning agents. Green cleaning is an approach to redress or address the problems associated with traditional cleaning agents.

Environmental persistent pharmaceutical pollutant

The term Environmental persistent pharmaceutical pollutants (EPPP) was first suggested in the nomination in 2010 of pharmaceuticals and environment as an emerging issue in a Strategic Approach to International Chemicals Management (SAICM) by the International Society of Doctors for the Environment (ISDE). The occurring problems from EPPPs are in parallel explained under environmental impact of pharmaceuticals and personal care products (PPCP). The European Union summarizes pharmaceutical residues with the potential of contamination of water and soil together with other micropollutants under “priority substances”.

Galaxolide chemical compound

Galaxolide is a synthetic musk with a clean sweet musky floral woody odor used in fragrances. It is one of the musk components that perfume and cologne manufacturers use to add a musk odor to their products. Galaxolide was first synthesized in 1965, and used in the late 1960s in some fabric softeners and detergents. High concentrations were also incorporated in fine fragrances.

Antiandrogens in the environment have become a topic of concern. Many industrial chemicals, including phthalates and pesticides exhibit antiandrogen activity in animal experiments. Certain plant species have also been found to produce antiandrogens. In animal studies, environmental antiandrogens can harm reproductive organ development in fetuses exposed in utero as well as their offspring.

References

  1. ↑ Halling-Sorensen et al. 1998. Occurrence, fate, and effects of pharmaceutical substances in the environment-A Review. Chemosphere 36: 357-393
  2. ↑ Daughton and Ternes. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environmental Health Perspectives 117:907-938.
  3. ↑ Jones et al. 2001. Human pharmaceuticals in the aquatic environment. Environmental Technology 22: 1383-1394
  4. ↑ Heberer. 2002. Occurrence, fate and removal of pharmaceutical residues in the aquatic environment- A review of recent research data. Toxicology Letters 131: 5-17.
  5. ↑ Heberer. 2002. Occurrence, fate and removal of pharmaceutical residues in the aquatic environment- A review of recent research data. Toxicology Letters 131: 5-17.
  6. ↑ Daughton and Ternes. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environmental Health Perspectives 117:907-938.
  7. ↑ Bound and Voulvoulis. 2004. Pharmaceuticals in the aquatic environment- A comparison of risk assessment strategies. Chemosphere 56: 1143-1155.
  8. ↑ Daughton and Ternes. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environmental Health Perspectives 117:907-938.
  9. ↑ Daughton and Ternes. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environmental Health Perspectives 117:907-938.
  10. ↑ Daughton and Ternes. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environmental Health Perspectives 117:907-938.
  11. ↑ Daughton and Ternes. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environmental Health Perspectives 117:907-938.
  12. ↑ Jorgenson and Halling-Sorensen. 2000. Drugs in the Environment. Chemosphere 40: 691-699.
  13. ↑ Jones et al. 2001. Human pharmaceuticals in the aquatic environment. Environmental Technology 22: 1383-1394
  14. ↑ Jorgenson and Halling-Sorensen. 2000. Drugs in the Environment. Chemosphere 40: 691-699.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.