Tox Topic


Threshold of Toxicological Concern

Level of Exposure
  Estimating Potential for Harm:  The Threshold of Toxicological Concern  Background Whether it’s a man-made or a naturally occurring chemical, we don’t always have a lot of data on its potential toxicity.  Some of these chemicals can occur at very low levels in nature or in products.  But given our ever-increasing ability to measure very low amounts of chemical exposure we have a need to be able to make judgements about potential for harm and prioritizing which chemicals need further toxicity studies.  So how does a toxicologist go about prioritiz...

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Methanol Toxicity

Methanol, sometimes called wood alcohol, is the simplest of the class of chemicals chemists call alcohols.  Ethanol, the spirit many enjoy in beer, wine, and cocktails, is closely related.  Both can be made naturally when yeast ferment the natural chemicals in grains and fruits.  And like all chemicals, both can be toxic when you are exposed to too much.  But, when you consume methanol, the way your body metabolizes it makes it much more toxic than ethanol.  Methanol poisonings were common during the Prohibition Era of the 1920’s and 30’s because methanol was ...

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Mixing Cleaners – Just Don’t!

bleach and ammonia
Introduction: Mixing two different cleaning products will double the power to disinfect your home, right?  Everyone knows that bleach kills viruses and bacteria and rubbing alcohol is great at removing grime, so why not mix the two and kill two birds with one stone?  Here is why – many cleaning products contain chemicals that when mixed with each other can form extremely toxic compounds.  According to the American Association of Poison Control Centers, accidental exposures to chlorine gas from mixing bleach and acid occurred 2,284 times in 2017.  This Tox Topic was ...

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How Safe is this Drug? 

Therapeutic Index
As discussed in its own Tox Topic, and referred to in many others, a fundamental premise of toxicology is that “the dose makes the poison.” This observation dates back almost 500 years ago to the Swiss physician Paracelsus who wrote “The right dose differentiates a poison from a remedy.”  As a physician Paracelsus knew that it was important to not give too much of a drug.  But how much is too much, and how do we help ensure that we have a clear picture of the difference between the dose it takes to provide a benefit and the dose it takes to cause harm? To help do ...

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What’s a GMO?

gmo
Few things spark alarm in enlightened consumers more than the subject of GMO’s—or Genetically Modified Organisms, particularly if related to the food they eat and feed their family.  Because of this fear, consumers can find numerous products sold with a specific label of “GMO-Free” or Non GMO Project Verified.  While an internet  search reveals numerous definitions for GMO, this tox-topic will define them the way many non-scientists think of them.  Specifically, GMO is a term used to describe a plant, animal, or microorganism that has had its genetic material ...

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Basics of Dose-Response

Introduction: You have just moved into your dream house and discover a secret room which you hadn’t noticed before and which escaped the notice of your home inspection. Once you gain access, you discover numerous amber colored bottles with the traditional skull and crossbones logo emblazoned upon the bottles. You’re rightfully concerned.  Is your house now contaminated and are you at risk to live there?  This Tox Topic was developed to help you understand how to think about potential exposure to chemicals.  By understanding these key concepts, you’ll be better ...

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Hazard vs Risk

Many people find it confusing when toxicologists and others talk about hazard versus risk.  To many, they seem to mean the same thing.  They don’t, and assuming they do can lead people to unnecessarily fear ingredients and other chemicals.  This tox topic is intended to help you understand the differences between hazard and risk and why knowing the difference is important to your health and your effort to keep yourself and your family safe from harmful exposures. Let’s start with definitions. Hazard:  A potential source of danger/harm.  A hazard evaluation ...

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Human Health Risk Assessment

The woman in this photo may not know she risks harming her unborn baby's health by smoking while pregnant. Or she understands that, but she is taking that risk because she is addicted to smoking cigarettes.  Risk assessments are applied to many things we encounter in our daily lives including life-saving drugs, food additives, cosmetics, household cleaning products, pesticide residues in foods, and countless other environmental agents.   This Tox Topic briefly explains some basics of human health risk assessment.   TEF’s “Is It Safe? Evaluating Chemical Risk” ...

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What is Toxicology?

The Society of Toxicology defines toxicology as the study of the adverse effects of chemical, physical, or biological agents on people, animals, and the environment.  Toxicologists are scientists trained to investigate, interpret, and communicate the nature of those effects.   Most toxicologists focus on chemical agents, although some are experts about harmful effects of physical agents such as radiation.  Toxicology is an interdisciplinary science, integrating information from biology and virtually all of its subspecialties (e.g., genetics, endocrinology and molecular ...

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Occupational Safety and Health

Anyone that has been in a high school chemistry laboratory has no doubt noticed the numerous postings stressing laboratory safety.  While there are both physical and chemical hazards in these laboratories, it’s toxicologists that provide information involving hazardous chemicals.  The chemistry lab is a short term experience for the student, but it’s the workplace for the instructor.  Indeed, potentially hazardous chemicals are used in many workplaces. In 1973, Stellman and Daum called the “workplace” a battleground in the war against poisonous chemicals and ...

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