Invertebrates herbicide toxicity

Diuron An herbicide used as a weed killer. Persists in ground water and highly toxic to aquatic invertebrates. 

Chlorophenoxy herbicides are moderately toxic to nontarget species. Some of the commercial products are highly toxic to aquatic invertebrates and other beneficial nontarget plants. 

FIFRA microcosm experimental unit. An example of a microcosm experimental unit designed to test the effects of a herbicide on an aquatic environment. This particular setup does not include fish since the predatory effects would tend to hide lower trophic level effects upon the invertebrate populations. Typically, a FIFRA microcosm experiment includes fish species, especially when acetylcholinesterase inhibitors or other toxicants particularly effective against animal species are tested. 

Indirect effects are the potential impacts of the toxicants due to the disruption of the ecosystem, apart from direct impacts upon the ecosystem components. The elimination of photosynthetic organisms in a pond by a herbicide will eventually eliminate the invertebrate herbivores and the fish that rely upon them as a food source. 

Six imidazolinones are commercially available. These herbicides have extremely low toxicity or are non-toxic to mammals, birds, invertebrates and fish [36]. The crops on which these herbicides are registered and whether or not they are applied to foliage or to the soil is determined by the structure of the chemical (Table 2.3.2). When applied to the foliage of plants, a non-ionic surfactant or oil adjuvant is required for maximum activity. The addition of either urea or another form of nitrogen can also increase herbicidal activity. 

The toxicity rating can be evaluated on an array of species including plants, invertebrates, vertebrates, or human exposure. While these degradates may be less phytotoxic to both crop and weed species, their toxicity to other species may increase, decrease, or remain similar to the original herbicide. 

Butafenacil is known to be eye, skin and respiratory tract irritant in humans [262]. It also demonstrated very high toxic effect to algae, and moderate toxicity to fish, aquatic invertebrates and honeybees. For Benzfendizone and Flufenpyr-ethyl, no reports on toxic effects are available. Acute mammalian toxicology smdies of Saflufenacil indicate that herbicide has low toxicity for mammals after ingestion, dermal exposure or inhalation. It is not an irritant for eyes and skin and does not act as a sensitizer. 

---