In toxicology this is commonly referred to as dose-response or "the dose makes the poison". This book is not a comprehensive survey of hazardous chemicals, but uses everyday examples to illustrate the principles of toxicology.
Acknowledgments
In regulating our consumption of caffeine, we apply the most fundamental principle of toxicology: dose-response. As we will see in a subsequent chapter, caffeine is an excellent example of how we consciously or unconsciously apply the principles of toxicology.
Toxicology and you
Looking at the world through the lens of toxicology offers a very interesting perspective on current, historical and personal events. The purpose of Small Dose Toxicology is to build on our intuitive understanding of toxicology and make it a basis for professional and comfortable application of toxicology principles.
Contents
Everyday examples of toxicology
A more contemporary definition of toxicology is the study of the adverse (unwanted or harmful) effects of chemical and physical agents on living organisms. The 'Principles of Toxicology' chapter provides an overview of the principles of toxicology, while subsequent chapters delve deeper into specific topics.
Toxicological resources
Unfortunately, much of the in-depth medical or highly scientific information is not very accessible. CDC is recognized as the lead federal agency for protecting the health and safety of the people of the United States.
Introduction
While these principles may form much of the foundation of toxicology, when it comes to any specific substance, controversy is likely. Exploring these principles is an essential first step before considering their application to any specific substance.
Principles of toxicology
Routes of exposure and absorption
In fact, carbon monoxide binds to hemoglobin in blood cells better than oxygen, so exposure can cause Other agents such as lead can accumulate in bone instead of calcium.
Metabolism, distribution, and excretion
Half-life is a measure of the time a drug remains in the body before it is metabolized and eliminated. The half-life of lead in the blood is measured in days, while that in bone is measured in years.
Slide Presentation2.9 Summary
The principles of toxicology are summarized as follows: dose-response, risk = hazard × exposure and individual sensitivity. And finally, I hope that beyond the basics of toxicology, you'll find that toxicology is both fun and informative.
Toxic agents
Alcohol
Dossier
Liver effects are dose-related; the more you consume the greater the effects. Early on there is an accumulation of fat in the liver as a result of alcohol metabolism.
Introduction and history
Beer Fact – Dark porter beers were developed in London, England in 1722 to feed potters and hard workers. An Irish brewer named Guinness refined this process in the late 1700s to produce a beer that still bears his name.
Biological properties
Another factor in determining blood alcohol concentration and thus the effects of alcohol is gender. The mechanisms of action of alcohol's effects on the nervous system remain unclear.
Caffeine
Dossier
Perhaps the best book to combine both historical and health aspects of caffeine is The World of Caffeine – The Science and Culture of the World's Most Popular Drug by Bennett Alan Weinberg and Bonnie K. 1475 Co Constantinople – the world's first coffee house 1528 Ch Cocoa was brought to Spain by Hernando Cortés 1600s Co Coffee enters Europe and moves quickly to Americas 1600s Ch Chocolate drinks introduced in Europe.
PURINE XANTHINE
More information and references 4.8 Recommendation and conclusions
Reducing exposure
This FDA document provides information on caffeine during pregnancy and advises "pregnant women to eliminate caffeine from their diet". The US National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction in 1998. effects on reproduction and development caused by substances to which humans may be exposed.
Company website dedicated to "Exploring remote regions of the world to provide the best True Tea".
Nicotine
- Dossier Name: nicotine
- Case studies
- Health effects
- Biological properties
- Recommendation and conclusions5.7 Regulatory standards
- More information and references
- Dossier – insecticides Use: kill insects
Workers who use tobacco products are less likely to suffer from GTS due to tolerance to the effects of nicotine. Journal of Christopher Columbus, October 15, 1492 The habit of using tobacco is directly related to the biological effects of nicotine. Acute effects of nicotine poisoning include nausea, vomiting, salivation, diarrhea, dizziness, mental confusion, and weakness.
The health effects of nicotine cannot be completely separated from the effects of cigarettes as a whole.
Pesticides
- Dossier – herbicides Use: kill or injure plants
- Introduction and history
- Reducing exposure6.6.4 Other
- Dossier Name: lead (Pb)
Only a very small amount of pesticide is needed in the animal's blood to kill the flea. Significant increases in pesticide use occurred with advances in synthetic chemistry and our understanding of biology. Although rarely used in the United States, paraquat is still widely used in developing countries.
NAWQA provides an assessment of US water use and pesticide use in United States streams, rivers, and groundwater.
Lead
Health effects
Currently, there appears to be no safe level of lead exposure for the developing child. At high levels of lead exposure, the brain will swell (encephalopathy), possibly resulting in death. In 1979, a study by Needleman showed that even low levels of lead exposure would reduce children's school performance.
The fact that children are more sensitive to the effects of lead exposure is illustrated in Figure 7.2.
Reducing exposure
The next best thing is to be aware of the potential sources of lead and act accordingly. If the house is old, it may contain pipes or solder joints with lead or fixtures with a high concentration of lead. Small children are hand-to-mouth and will ingest significant amounts of lead from dust alone.
If you handle and then eat lead, whatever you touch with your hands will contain a small amount of lead.
Dossier – inorganic mercury Name: mercury (Hg) (inorganic)
Mercury
- Dossier – organic mercury
- Case studies
- Biological properties8.4.2 Organic mercury
- Regulatory standards8.7.2 Organic mercury
Mercury exists in various forms with very different properties; therefore, each section of this chapter is divided into inorganic mercury – the common silvery liquid – and organic mercury (usually methylmercury – Hg-CH3) which is generated from mercury and accumulates in some commonly consumed fish species. The history of mercury's use by humans demonstrates our struggle to balance and understand the usefulness of this compound and its harmful effects on humans and the environment. Elemental mercury has been used for over a hundred years in mercury-silver amalgam preparations to repair dental caries.
This release led to widespread human methylmercury exposure and toxicity in the 1950s and 1960s and led to our understanding of mercury cycling in the environment, biomethylation, and food chain transport today.
Arsenic
- Dossier
- Health effects
- Biological properties
- Recommendation and conclusions9.7 Regulatory standards
- More information and references
High levels of arsenic in local soil or rock contaminate the local water supply. In the United States, the federal government has struggled for years to set standards for arsenic in drinking water. It was subsequently discovered that many of these wells have high levels of arsenic in the water.
In the United States, federal agencies are debating tough arsenic drinking water standards, which would limit the amount of arsenic in municipal wells.
Metals
Toxicologically important metals10.2.8 Zinc (Zn)
Absorption is increased when associated with low levels of dietary iron or calcium. Some plants, such as tobacco, can even concentrate cadmium from low levels in the soil. In the 1970s, studies showed that even low exposure to lead was harmful to the developing nervous system.
Exposure to organic cans can cause brain swelling and cell death in the nervous system.
Medically important metals10.3.11 Tin (Sn)
It is generally present in the environment and appears to be an essential element for some plant life and bacteria. Lithium was first used in 1949 to treat manic-depressive illness, but was not used in the United States until 1970 due to concerns about its toxicity. Blood lead levels are reduced when the lead displaces the calcium to bind with EDTA and is then excreted in the urine.
Heavy metals and heavy metal antagonists. eds) Goodman & Gilman's The Pharmacological Basis of Therapeutics, 9th ed.
Solvents
- Dossier
- Biological properties
- More information and references 11.8 Recommendation and conclusions
- Reducing exposure
- Dossier – nonionizing radiation
Common occupational exposure to n-hexane is from degreasing agents, which usually contain a mixture of solvents. Some people find the effects of solvents on the nervous system to be desirable and deliberately inhale (sniff) solvents to induce a form of intoxication. As noted above, repeated exposure to high levels of solvents causes permanent brain damage.
Inhalation of solvents is particularly dangerous because of the rapid exchange in the lungs and rapid access to the nervous system.
Radiation
- Dossier – ionizing radiation
- Introduction and history
- Biological and physical properties
- Health effects 12.5.3 Radiation units
- Reducing exposure
- Recommendation and conclusions 12.8.1 Standards for radiation exposure
- More information and references
UV radiation stimulates the production of the pigment melanin, which absorbs UV radiation and protects skin cells from damage. This period also led to a growing understanding of the potential harmful effects of radiation exposure. Our knowledge of the effects of radiation has gradually evolved from the tragic experiences of the last century.
We evolved in an environment of natural radiation from the solar energy of the sun to radioactive elements.
Animal and plant toxins
- Dossier – animal toxins Name: animal venoms and poisons
- Dossier – plant toxins
- Introduction and history13.3.3 Mushroom poisoning
- Animal toxins
- Plant toxins
- Recommendation and conclusions
- More information and references
- Dossier
Jimson weed, part of the belladonna family of plants, is a common weed in North America. The classification of a substance as a toxin tends to be in the eye of the beholder. We have become dependent on many of the substances produced by animals and plants.
The venom is a complex mixture that contains serotonin, a neurotransmitter, but lacks many of the other protein-degrading enzymes.
Persistent environmental contaminants
Introduction and history14.2.1 Lindane dumping site
Birds of prey are at the top of the food chain where they accumulate and concentrate DDT. Many early pesticides, and certainly metals, do not degrade or degrade very slowly in the environment. Animals at the top of the food chain, such as polar bears and beluga whales, routinely have PCB fat levels above 6 ppm.
The use of many persistent chemical pesticides was restricted or even banned in some countries.
Reducing exposure 14.4 Health effects
Importation and production banned in US, use banned in 1988 Pesticides – organochlorine – bioaccumulative – used to control mosquitoes Importation and production banned in US in 1972. Pesticides – organochlorine – bioaccumulative – insecticide on fruit – analogue of DDT – but very degradable toxic to aquatic life, including fish. Pesticides - organochlorine - bioaccumulations - fungicide used in seeds Most use ceased in 1965, but is a by-product of solvent production. Metal – widely distributed in the environment when used as a gasoline additive and in paint.
Pesticide - organochlorine - bioaccumulates - used as a substitute for DDT In the United States, 3.7 million pounds were produced in 1978.
More information and references
This site contains information on the use of pesticides in the US, both as contaminants and crops. The site contains information about the history and use of lindane and information about efforts to ban the use of lindane in Europe. WTC provides information on model pesticide policies, home use pesticide alternatives, information on persistent chemical pollutants, and much more.
The site has maps and information about pollutants in the Arctic. 2000) Safe and Effective Use of Plant Protection Products in Developing Countries, CABI Publishing, CAB International, Wallingford, Oxon, UK, 163 pp. 1998).
Targets of toxic agents
Introduction
Neurotoxicology
As a result, neurotoxicology evolved in the 1970s to advance our understanding of the effects of chemicals on the nervous system. Neurotoxicity or a neurotoxic effect - an adverse change in the chemistry, structure, or function of the nervous system following exposure to a chemical or physical agent. Voluntarily and involuntarily, we are exposed to a range of chemicals that affect the nervous system.
Alcohol, while having a predictable effect on the pregnant mother, can be disastrous for the developing baby's nervous system.
