سمية المبيدات ودراستها

Toxicology Book (Project)

• This book is a project on toxicology, specifically focused on pesticide toxicology.
• It discusses toxicology's history, including early knowledge of poisons, from ancient civilizations to modern times.
• Paracelsus (1493-1541) is credited with establishing the dose-response relationship, stating "All substances are poisons; there is none that is not a poison. The right dose differentiates a poison and a remedy."
• Toxicology is defined as the study of harmful effects of substances on living organisms, including potential effects across generations, and it encompasses both apparent and internal harm.
• Pharmacology, the study of drug interactions with living organisms, forms a key link with toxicology.
• Toxicology's association with other biological fields (biochemistry, physical chemistry, physiology, morphology, pathology) is emphasized, highlighting its broad interdisciplinary nature.
• Pesticide toxicology, cosmetic agent toxicology, and toxicology of food additives are distinct subfields within this broad area of study.

Introduction

• Toxicology is recognized since 1900.
• Human knowledge of poisons dates back millennia.
• Shen Nung (2696 BCE) was a figure in early Chinese medical knowledge, who's work is connected with early identification of poisons
• The Ebers Papyrus describes numerous toxic substances and their medical applications dating back to circa. 1500 BCE.
• Socrates (470-399 BCE) died by poison.
• Cleopatra (69-30 BCE) reportedly conducted experiments with plant and animal-derived poisons.
• Paracelsus (1541-1493) founded the concept of dose-response.

Pesticide Toxicity

• Pesticides are a major group of toxins extensively used in agriculture to control pests.
• Types include insecticides for insects, nematicides for nematodes, acaricides for mites, herbicides for weeds, and fungicides for fungi.
• Pesticides toxicology focuses on studying reciprocal impacts between these compounds and diverse environmental factors.

Treatment Methods

• Various methods exist to expose test animals to pesticides, varying by the study's target and the chemical properties of the pesticide.
• Topical application involves dissolving the pesticide in a suitable volatile solvent.
• Injection method uses a carrier such as propylene glycol or peanut oil, targeting specific body cavities.
• Dipping method is used for insects that are challenging to expose.
• Contact method or residual exposure involves exposing an environment to the pesticide.
• Leaf-dipping method tests pesticide effects on specific insects.
• Grain fumigation method examines pesticide impact on stored goods.
• Oral application tests involves feeding the animal the pesticide.

Toxicity Effects

• Pesticide effects can be reversible (resolve with removal) or irreversible (lasting).
• Primary effects manifest at the site of exposure.
• Secondary effects persevere after the substance is eliminated.
• Latent effects appear later.
• Toxicity depends on dose, strength, and duration of exposure to a given chemical.
• Pharmacodynamic and pharmacokinetic relationships play critical roles.

Distribution of Pesticides

• Pesticides' movement within organisms involves absorption, distribution, and biological transformation in organs, determining the site of action and its impact.
• The interaction between the toxic substance and the organism is described in terms of dose-dependent response.
• The rate and extent of absorption, distribution, and excretion processes in the body influence the toxicity and severity of adverse effects.

Specific Pesticide Groups (e.g., Organochlorines, Organophosphates, Pyrethroids, etc.)

• Each class of pesticide has unique properties and modes of action influencing their toxicology.
• Special attention is given to the mechanisms by which they affect the nervous system.
• Detailed descriptions of various pesticide types and their relationship to toxicity effects are provided.

Resistance to Pesticides

• Insect resistance to pesticides arises due to genetic modifications, enabling tolerance to pesticide treatment.
• Various mechanisms underlie this, including changes to metabolic pathways that degrade pesticides.
• Resistance can be considered a phenomenon that impacts efficacy of the original method used for pest control.
• Behavioral resistance, penetration resistance, and metabolic resistance are discussed as contributing factors.
• Genetic factors, evolutionary factors, and practical considerations connected to pesticide application are discussed.

يستكشف هذا الاختبار الموضوعات المتعلقة بدراسة سمية المبيدات وتأثيراتها على الكائنات الحية. يتناول الأسئلة كيفية عمل المبيدات، والمخاطر المرتبطة بها، بالإضافة إلى العمليات البيولوجية المتورطة في هذا المجال. هذا الاختبار مثالي للطلاب والمختصين في علوم البيئة والصحة.