Aquatic Pollution and Coastal Management

Unit 4 : Pesticide pollution

4.7.The ecological impacts of pesticides
The ecological effects of pesticides (and other organic contaminants) are varied and are often inter-related. Effects at the organism or ecological level are usually considered to be an early warning indicator of potential human health impacts. The major type of effects are listed below and will vary depending on the organism under investigation and the types of pesticide. Different pesticides have markedly different effects on aquatic life which makes generalization very difficult. The important point is that many of these effects are chronic (not lethal) and are often not noticed by casual observers, yet have consequences for the entire food chain.

• Death of the organism.
• Cancers, tumours and lesions on fish and animals
• Reproductive inhibition or failure
• Suppression of immune system
• Disruption of endocrine (hormonal) system
• Cellular and DNA damage
• Teratogenic effects (physical deformities such as hooked beaks on birds)
• Poor fish health marked by low red to white blood cell ratio, excessive slime on fish scales and gills, etc.
• Intergenerational effects (effects are not apparent until subsequent generations of the organism)
• Other physiological effects such as egg shell thinning