Species Invasions in Freshwater Ecosystems
Kezia Barker, Robert A. Francis in Routledge Handbook of Biosecurity and Invasive Species, 2021
Chemical control is the application of herbicides and pesticides to kill or reduce competitive or reproductive fitness of organisms. The use of chemicals is a common form of control, and, when utilised correctly, such chemicals can be both cost-effective and have fewer collateral impacts than physical control methods (Hussner et al., 2017). They nevertheless do carry some risk of non-target impact, as in many cases they do not affect individual species alone. For plants, herbicides are usually applied where there are large monocultural stands of non-natives to maximise effectiveness. Common herbicides include 2,4-D, diquat, paraquat, glyphosate, fluridone and triclopyr (Coetzee and Hill, 2009; Hussner et al., 2017), but these have restricted availability in some regions (e.g. some European countries) due to their wider impacts (Hussner et al., 2017). For freshwater animals, common pesticides include various forms of piscicides (esp. rotenone, antimycin and saponins; Ling, 2009), insecticides (often organophosphates, carbamates and pyrethroids) and molluscicides (usually niclosamide/clonitralid).
Herbicides
Frank A. Barile in Barile’s Clinical Toxicology, 2019
Paraquat (PQ) and diquat are nonselective bipyridyl herbicides used widely in agricultural and commercial residential applications (lawn maintenance) to eradicate broad-leaf plants and shrubs. The chemicals inhibit plant photosynthesis by interfering with NADPH/NADP+ redox cycling. Their usefulness as contact herbicides resides in their ability to promote the reseeding of lawns and gardens within 24 hours after application. The two structurally similar compounds are often combined in commercial products. The acute toxicity of diquat, however, is lower than that of than PQ in humans (Figure 29.2). Structures of the bipyridal herbicides—paraquat and diquat.
Miscellaneous pesticides*
Bev-Lorraine True, Robert H. Dreisbach in Dreisbach’s HANDBOOK of POISONING, 2001
Paraquat or methyl viologen (1,1′-dimethyl-4,4′-dipyridylium dichloride), diquat, chlormequat (Cycocel), mepiquat (Pix), morfamquat, and difenzoquat (Avenge) are water-soluble quaternary ammonium herbicides supplied in concentrations of 20–50%. They are inactivated by contact with soil, presumably as a result of combination with clay particles in the soil, and are also subject to rapid photodecomposition.
Evidence for the efficacy of the emetic PP796 in paraquat SL20 formulations – a narrative review of published and unpublished evidence
Published in Clinical Toxicology, 2022
The Gramoxone® Inteon formulation was introduced into agricultural practice in Sri Lanka in October 2004 as part of a company-funded observational study to assess its effect on mortality at three months after ingestion in collaboration with the South Asian Clinical Toxicology Research Collaboration (SACTRC) [31]. The study was conducted in nine large hospitals from before its introduction in 2003 until 2006; patients were recruited into the study if they reported ingesting products containing paraquat or, if the pesticide ingested was unknown, had clinical signs typical of paraquat poisoning. Packaging was similar to the standard products, but the product included a tracer compound (500 ppm diquat dibromide) that could be detected in blood/urine following oral ingestions. Data on product and volume ingested, and the timing of vomit, were collected prospectively by trained researchers soon after presentation to hospital, a median of 3–4 h post-ingestion. Plasma and/or urine samples were analysed for paraquat concentration and the presence of diquat to classify the case as standard formulation or Inteon.
Acute diquat poisoning resulting in toxic encephalopathy: a report of three cases
Published in Clinical Toxicology, 2022
Guangcai Yu, Tianzi Jian, Siqi Cui, Longke Shi, Baotian Kan, Xiangdong Jian
Diquat is a nonselective contact bipyridyl herbicide and a preharvest desiccant. As paraquat is banned in China, the use of diquat has gradually increased because of its effective herbicidal activity [1], resulting in an increase in the incidence of diquat poisoning. Diquat mainly affects cell membranes through lipid peroxidation via the production of oxygen free-radicals, leading to cell death and multiple-organ failure [2]. The target organs include the kidneys, liver, lungs, gastrointestinal tract, cardiovascular system, and central nervous system [3,4]. Acute kidney injury is common, leading to renal tubule damage. In severe cases, neurological disorders are a common clinical feature, often accompanied by a poor prognosis [5]. Herein, we report three cases of acute diquat poisoning resulting in acute renal failure, neurological disorders, and respiratory failure. This report highlights the imaging features and hypothesis mechanisms of diquat-related toxic encephalopathy.
Identification of differentially expressed genes and pathways in diquat and paraquat poisoning using bioinformatics analysis
Published in Toxicology Mechanisms and Methods, 2022
Diquat (DQ) (Magalhães et al. 2018) and paraquat (PQ) (Mitra et al. 2011) are nonselective and widely used herbicides. DQ (1,1′-ethylene-2,2′-bipyridinium ion) (Magalhães et al. 2018; Jones and Vale 2000) is an analog of PQ (1,1′-Dimethyl-4,4′-bipyridinium dichloride) (Mitra et al. 2011). The 50% of lethal dose (LD50) of PQ in humans is 20–40 mg ion/kg of body weight (Vale et al. 1987); In rats, the LD50 of oral PQ is 150 mg/kg (World Health and International Programme on Chemical 2004), whereas, that of oral DQ is 215-235 mg/kg (Magalhães et al. 2018). Therefore, DQ is considered less toxic than PQ (Fortenberry et al. 2016). PQ and DQ poisoning remain fairly common in developing countries (Xing et al. 2020; Lu et al. 2021).
Related Knowledge Centers
- Bromide
- Chloride
- Counterion
- Defoliant
- Desiccation
- Pyridine
- Trivial Name
- Salt
- Herbicide
- 2,2′-Bipyridine