Chapter 45 - Aquatic Toxicity of Carbamates and Organophosphates

Abstract

The chapter focuses on the toxicity of organophosphates (OPs) and carbamates (CMs) on aquatic system. There are many routes by which pesticides can reach the aquatic environment: surface runoff and sediment transported from treated soil; industrial waste discharged from factory effluents; direct application as aerial spray or granules to control pests inhabiting water; spray drift from normal agricultural operation; and municipal waste discharge. Runoff is generally considered to represent the major movement of pesticides in the aquatic environment. During runoff, pesticides remain suspended in the runoff water and are transported to the aquatic ecosystem. During runoff, pesticides may be adsorbed on the eroding soil particles suspended in runoff water. Heavy rainfall immediately after application of pesticides has a higher potential for pesticide transport. The effects of pesticides on aquatic life may be acute, resulting in mass mortality of fishes, chronic changes in their behavior, or reduction in survival, growth, and reproduction. Pesticides in general are also toxic to many nontarget organisms and cause ecological imbalance by indiscriminate killing of aquatic insects, worms, and mollusks by contaminating soil and water, thereby disturbing the general ecosystem. The distribution of pesticides in water influences the pathway of biological uptake. The quantity accumulated by each biological entity is dependent on the chemical properties of pesticides, and the physiology and behavior of organisms. The determination of pesticide contents in water, organic substrates, sediments, and animal tissues depends on the chemical methods.