Snapshot Herbicide

Introduction
Pesticides are found as common contaminants in soil, air and water, and on non-target vegetation in our urban landscapes. Once there, they can damage plants and animals from micro-organisms and beneficial soil insects, non-target plants, fish, birds and other wildlife. Table 1 summarizes the adverse effects on non-targets of some herbicides commonly used in urban areas.

Table 1. organisms harmful effects of certain herbicides on non-target

Source: Sanders, 1969

Fish
When pesticides contaminate the water, they can be harmful to fish that live there. Insecticides can be especially toxic to fish. Chlorpyrifos, a common contaminant of urban streams, 18 is very toxic to fish, and caused Fishkill in waterways near treated fields or buildings.1 2 Diazinon, also commonly found in urban streams , 18 is very toxic to many species of fish, including salmon.3 herbicides can be toxic to fish. According to the EPA, studies show that trifluralin, an active ingredient in the instant weed-killer, "is very highly toxic to fish hot and cold." It 4 was also demonstrated in a series of different tests to cause vertebral deformities in fish.5 oryzalin, the active ingredient Surflan, is also "very toxic" herbicide Roundup fish.6 The Ronstar and are also highly toxic to fish.7, 8 The toxicity of Roundup is probably due to the high toxicity of the inert ingredients of a product. In addition to direct acute toxicity, some herbicides may produce sublethal effects on fish that reduce their chances of survival and threaten the population as a whole. Glyphosate or glyphosate-containing products may cause sublethal effects such as erratic swimming and labored breathing, which increases the likelihood of fish being eaten.9, 10 herbicides 2,4-D caused physiological stress reactions of the sockeye, 11 and reduces the capacity to collect food for rainbow trout .12

Other aquatic animals and plants
Besides fish, other marine and fresh water are threatened by pesticide contamination. 2,4 - D or 2,4-D containing products were found to be harmful to newts, 13 frogs, 14 crabs, crustaceans 15, 16 and other aquatic species.17, 18 herbicides trifluralin is moderately to highly toxic to aquatic invertebrates and highly toxic to estuarine and marine organisms such as shrimp and mussels. Diuron is also very toxic to aquatic invertebrates.19 Since herbicides are designed to kill plants, it is logical that the water contamination with herbicides could have devastating effects on aquatic plants. In one study, oxadiazon was found to significantly reduce algae growth.20 algae is a grassroots organization in the food chain of aquatic ecosystems. Studies concerned with the impact of the herbicides atrazine and alachlor on algae and diatoms in rivers have shown that even at relatively low levels, the chemicals the damaged cells, blocked photosynthesis and growth retardation in various ways.20 another important class of organisms is the cyanobacteria. Cyanobacteria live in aquatic environments and soils, and play a crucial role in fixing nitrogen, helping plants convert atmospheric nitrogen into nitrate compounds that plants can use. Trifluralin has been found to inhibit the growth of two common cyanobacteria at all levels of application.21

Insects and spiders
In addition to killing insects "harmful", insecticides obviously have the potential to harm non-target insects including beneficial natural predators and pollinators. Less obvious, herbicides can also be harmful to beneficial insects. One study showed that exposure to freshly dried Roundup (glyphosate) has killed more than 50 percent of three species of insects: a parasitoid wasp, a lacewing and a ladybug. More than 80 percent of a fourth species, a predator.