EnS 115 Module 1

By 202380261

Published: Jul 27, 2026
Pages: 29

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UNIVERSITY & SECST STATE
OverviewIn this course, the basic concepts, methods, and approaches in environmental toxicology will be introduced. Natural and synthetic chemicals commonly encountered in the air, water, and soil will be discussed regarding their occurrence, fate and transport, and toxicological effects on ecological species and humans. Case studies will be used to illustrate the complexity of environmental toxicology issues. New trends in chemical toxicity testing will be discussed. Contaminants of emerging concerns such as pharmaceutical and personal care products and engineered nanomaterials will also be introduced. This module will introduce you to environmental toxicology. Specifically, the topics include the definition and scope of toxicology, brief history of toxicology, dose-response relationships, sources of toxic compounds, and the movement of toxicants in the environment.
Learning ObjectivesAfter going through in this module, you should be able to: ➤ define important terms in environmental toxicology;
Initial ActivityI want to know if you have any idea/ knowledge about Environmental Toxicology. First, I know that Secondly, I know that Finally, I know that Please write something about this topic: Environmental Toxicology
DiscussionI. DEFINITION AND SCOPE A. DEFINITION OF TERMS
DiscussionI. DEFINITION AND SCOPE A. DEFINITION OF TERMS
DiscussionI. DEFINITION AND SCOPE A. DEFINITION OF TERMS
DiscussionI. DEFINITION AND SCOPE A. DEFINITION OF TERMS
Target tissueDiscussion I. DEFINITION AND SCOPE
DiscussionI. DEFINITION AND SCOPE B. SCOPE OF TOXICOLOGY
DiscussionI. DEFINITION AND SCOPE B. SCOPE OF TOXICOLOGY
DiscussionI. DEFINITION AND SCOPE B. SCOPE OF TOXICOLOGY
DiscussionII. BRIEF HISTORY OF TOXICOLOGY ➤ 1500 BC: The Ebers Papyrus is among the oldest written documentation of medicines in the ancient world. It is the oldest known ancient Egyptian medical scroll, dating back to a period between 1550 and 1500 BC.
DiscussionII. BRIEF HISTORY OF TOXICOLOGY ➤ 1939: DDT: Recognized as insecticide by the Swiss scientist Paul Hermann Müller, who was awarded the 1948 Nobel Prize in Physiology and Medicine. Banned in 1972.
DiscussionII. BRIEF HISTORY OF TOXICOLOGY Did you know?
DiscussionIII. DOSE-RESPONSE RELATIONSHIPS The first recognition of the relationship between the dose of a compound and the response elicited has been attributed to Paracelsus. His statement includes not only that all substances can be toxic at some dose, but that “the right dose differentiates a poison from a remedy," a concept that is the basis for pharmaceutical therapy.
Page 17Dose Discussion
DiscussionIII. DOSE-RESPONSE RELATIONSHIPS A typical dose-response curve is shown in Figure 3, which plots the relationship between the toxicant dose and the health effects.
Threshold DoseDiscussion III. DOSE-RESPONSE RELATIONSHIPS
DiscussionIV. SOURCES OF TOXIC COMPOUNDS Everything in the environment is made out of chemicals. These chemicals can either be naturally occurring or synthetic. Both types can be toxic to living organisms; thus natural chemicals can also cause negative effects. Just because they are "natural," does not mean that they are safe.
DiscussionV. MOVEMENT OF TOXICANT IN THE ENVIRONMENT Chemicals released into the environment rarely remain in the form, or at the location, of release.
DiscussionV. MOVEMENT OF TOXICANT IN THE ENVIRONMENT Lipophilic Toxicants
DiscussionV. MOVEMENT OF TOXICANTS IN THE ENVIRONMENT The transport of chemical toxicants can occur through both aquatic and terrestrial food chains, although in the former, higher members of the chains, such as fish, can accumulate large amounts of toxicants directly from the medium.
DiscussionV. MOVEMENT OF TOXICANTS IN THE ENVIRONMENT In order for a chemical substance to have any effect, it must first enter the body. Living organisms can ingest them, inhale them, or absorb them through their skin (Figure 7). They may also travel inside the body via mucous in the nose, eye, or ear canals. These pathways are termed routes of exposure.
DiscussionV. MOVEMENT OF TOXICANTS IN THE ENVIRONMENT Toxicokinetics
DiscussionV. MOVEMENT OF TOXICANTS IN THE ENVIRONMENT Acute toxic effects
DiscussionV. MOVEMENT OF TOXICANTS IN THE ENVIRONMENT Categories of Toxic effects
DiscussionV. MOVEMENT OF TOXICANTS IN THE ENVIRONMENT Categories of Toxic effects
ReferencesCourse References Dekant W. & Vamvakas S. 2004. Toxicology. In Ullmann's Encyclopedia of Industrial Chemistry, (Ed.). https://doi.org/10.1002/14356007.b07_155.pub2

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Discussion

II. BRIEF HISTORY OF TOXICOLOGY

➤ 1500 BC: The Ebers Papyrus is among the oldest written documentation of medicines in the ancient world. It is the oldest known ancient Egyptian medical scroll, dating back to a period between 1550 and 1500 BC.

➤ 400-250 BC: the surviving medical works of Hippocrates, Aristotle, and Theophrastus, all include some mention of poisons;

➤ 3 BC: Nicander of Colophon (Greek poet) - author of two treatises on poison: Theriaca ( deals with the bites of venomous snakes, spiders, and scorpions, and how to remedy them) and Alexipharmica (enumerates additional animal, vegetable, and mineral poisons, including aconite, white lead, hemlock, and opium, together with their symptoms and specific remedies). The cures are almost always herbal and often include olive oil as an emetic to induce vomiting. ➤ 50 AD: Dioscorides, a Greek employed by the Roman emperor Nero, wrote the earliest surviving attempt to classify plants according to their toxic and therapeutic effects. His classification of poisons into plant, animal, and mineral groups provided a framework for future toxicologists to build upon;

➤ 131-200: Galen. He was the first physician to use the pulse as a sign of illness;

➤ 1493-1541: Paracelsus laid the groundwork for the later development of modern toxicology by recognizing the importance of the dose-response relationship. His famous statement "All substances are poisons; there is none that is not a poison. The right dose differentiates a poison and a remedy.. His belief in the value of experimentation was also a break with earlier tradition. ➤ 1700: Bernardino Ramazzini (Italian) published Diseases of Workers which led to his recognition as the father of occupational medicine. Hei focused on workers' health problems; ➤ 1775: Sir Percival Pott recognized that the high rate of scrotal cancer among chimney sweeps in England was linked to their exposure to soot;

➤ 1761: John Hill reported the correlation of nasal cancer and snuff use (nasal snuff causing cancer of the nose);

➤ 1787-1853: Mateu Joseph Bonaventura Orfila i Rotger, a Spanish chemist, is generally regarded as the father of modern toxicology. He clearly identified toxicology as a separate science and, in 1815, published the first book devoted exclusively to toxicology. An English translation in 1817 was entitled A General System of Toxicology or, A Treatise on Poisons, Found in the Mineral, Vegetable and Animal Kingdoms, Considered in Their Relations with Physiology, Pathology and Medical Jurisprudence. He established basic principles of modern medicine and pharmacology;

➤ 1833: Alfred Nobel: Swedish chemist, engineer, innovator, armaments manufacturer and the inventor of dynamite.

➤ 1840: James Marsh: Chemist developed and perfected the Marsh test for arsenic. The improved Marsh test used forensically for the first during the trial of Marie Lafarge.

➤ 1847: Ascansio Sobrer: Italian chemist, discovered nitroglycerine in 1847, a powerful explosive and vasodilator. Alfred Nobel was his student.