Pesticides vertebrates

Many pesticides cause endocrine disruption in vertebrate and invertebrate species at concentrations that are not overtly metabolically toxic. The insect growth inhibitor diflubenzuron can affect the reproduction, development and behaviour of estuarine crustaceans at concentrations of just lOmgP (reviewed... 

A formidable array of compounds of diverse structure that are toxic to invertebrates or vertebrates or both have been isolated from plants. They are predominately of lipophilic character. Some examples are given in Figure 1.1. Many of the compounds produced by plants known to be toxic to animals are described in Harborne and Baxter (1993) Harborne, Baxter, and Moss (1996) Frohne and Pfander (2006) D Mello, Duffus, and Duffus (1991) and Keeler and Tu (1983). The development of new pesticides using some of these compounds as models has been reviewed by Copping and Menn (2000), and Copping and Duke (2007). Information about the mode of action of some of them are given in Table 1.1, noting cases where human-made pesticides act in a similar way. 

Herbicides constitute a large and diverse class of pesticides that, with a few exceptions, have very low mammalian toxicity and have received relatively little attention as environmental pollutants. Much of the work in the held of ecotoxicology and much environmental risk assessment has focused on animals, especially vertebrate animals. There has perhaps been a tendency to overlook the importance of plants in the natural world. Most plants belong to the lowest trophic levels of ecosystems, and animals in higher trophic levels are absolutely dependent on them for their survival. 

Walker, C.H. (1981). The correlation between in vivo and in vitro metabolism of pesticides in vertebrates. Progress in Pesticide Biochemistry 1, 247-286. 

CL95 = 0.008-0.28 qgg ). Diazinon concentrations in earthworm samples were higher p < 0.005) in PA orchards, where rainfall was frequent, than in the more arid WA orchards. This difference also existed for live captured earthworms from PA and WA p < 0.017). A large number of samples are required to detect differences in pesticide exposures from living and dead invertebrates with confidence. Vertebrate exposures can be influenced by differential residue concentration for living and dead/moribund food items. 

Pesticides, and especially OCPs (DDT and its metabolytes, HCH isomers, aldrine, dieldrin, heptachlor, etc.), are seen everywhere in mammals. Table 4.7 gives data on the death of higher vertebrates from causes linked to agricultural production in the USSR. About 40% of the accidental deaths of animals, and about 80% of birds, are due to pesticides. It is difficult to evaluate how many mammals in the environment die from pesticide contamination, since sick and weakened individuals fall prey to predators [6]. 

Palmateer, S.D. 1990. Registration status of vertebrate pesticides with emphasis on 1080 and strychnine. Pages 113-115 in L.R. Davis and R.E. Marsh (eds.). Proceedings 14th Vertebrate Pest Conference. Univ. California, Davis, CA. 

Wafford KA, Sattelle DB, Gant DB, et al. 1989. Noncompetitive inhibition of GABA receptors in insect and vertebrate CNS by endrin and lindane. Pesticide Biochem Physiol 33 213-219. 

Until twenty-five or thirty years ago, few laboratories around the world were seriously interested in these insect-eating nematodes and their bacteria, but agricultural and industrial scientists are now studying them enthusiastically. Mounting pressures to limit the use of synthetic chemical pesticides have had their effect, and the nematode-bacteria complex may offer a natural environmentally safe biopesticide. Both creatures are harmless to vertebrates, but the bacterial toxins are fatal to a wide spectrum of agricultural pests. An added advantage is that the nematodes actively seek out their hosts, something other pesticides cannot do. 

EPA (2010) Atrazine disrupts reproductive development and function across vertebrate classes. http //www.savethefrogs.eom/actions/pesticides/images/publlcatlons/Hayes-EPA-2010-Submission.pdf. Accessed 2011... 

As reviewed by Ujvary some of the earliest natural product-based pesticides were those for the elimination of vertebrate pests. For example, strychnine (Fig. 19), obtained from seeds of Strychnos nux-vomica, is a rodenticide that is an antagonist to the neurotransmitter glycine and is used against a few mammal species, as well as pest birds and fish. The first generation of anticoagulant rodenticides were based on dicoumarin. 

Animal sequestration of alkaloids is connected not only with taste but also with the toxicity of these compounds. It has been stated that the toxicity of alkaloids is very selective. Aniszewski has published data with some LDjq coefficients for some alkaloids and some pesticides and compared their toxicity from a selectivity point of view. There was clear evidence that alkaloids (sparteine and lupanine) are much more toxic for vertebrates than are some pesticides (e.g. malafione, phenitrothione, etc.). For invertebrates, pesticides were clearly more toxic than alkaloids. Selective toxicity coefficients (STC) were counted by dividing the LDjg for vertebrates by the LDjg for invertebrates. When the STC is 1.0 there is no selectivity when STC is >1 there is invertebrate selectivity and when <1 there is vertebrate selectivity. Selectivity simply means there exists more ability to toxify the organism. 

Strychnine was once used liberally as a pesticide, especially to control vertebrates. It is used as a salt in granular bait formulations. In the United States its use has been... 

---