Regis de Campos Oliveira, Lucas Kortz Vilas Boas, and Ciro Cesar Zanini Branco, “Assessment of the potential toxicity of glyphosate-based herbicides on the photosynthesis of Nitella microcarpa var. wrightii (Charophyceae),” Phycologia, 2016, 55:5,  577-584, DOI:  10.2216/16-12.1.

ABSTRACT:

Although macroalgae are considered one of the most important primary producers in streams, to our knowledge there has been no research on the effects of herbicides on these organisms. Such studies are crucial for improving our understanding of the impact of these substances on stream ecology. In this study, we assess the effects of technical-grade glyphosate, Roundup and aminomethylphosphonic acid (AMPA; the main degradation product of glyphosate) on the photosynthetic rate, dark respiration rate and chlorophyll a content of Nitella microcarpa var. wrightii, a green algae found worldwide. Three concentrations of technical-grade glyphosate and Roundup were tested (0.28, 3.5 and 6 mg l1), while for AMPA only one concentration was evaluated (0.03 mg l1). Our results indicate that glyphosate has a stronger inhibitory effect on photosynthetic rate when applied in association with a surfactant (Roundup). These effects are related both to the concentration of the active ingredient and to exposure time. On the other hand, treatment with AMPA had a stimulatory effect on the photosynthetic rate, which may be associated with an increased supply of phosphorus available to the algae from the AMPA degradation process. From an ecological perspective, our results show that the ecological distribution of N. microcarpa var. wrightii, in terms of both spatial and temporal scales, can be affected by glyphosate-based herbicides in streams.  FULL TEXT

M. Cuhra, T. Traavik, and T. Bohn, “Life cycle fitness differences in Daphnia magna fed Roundup-Ready soybean or convetional soybean or organic soybean,” Aquaculture Nutrition, 2014, DOI: 10.1111/ani.12199.

ABSTRACT:

A lifelong feeding study with soybean from different production systems was carried out in the crustacean Daphnia magna (water flea), an acknowledged model organism for ecotoxicological studies. Experimental diets were prepared with soybean meal from different agriculture production systems: (i) genetically modified Roundup-Ready soy (Glyphosate-Tolerant), (ii) conventional soy and (iii) soy from organic agriculture (agriculture with neither synthetic pesticides nor synthetic fertilizers). Overall, feed produced from organic soybeans resulted in the highest fitness (higher survival, better growth and fecundity) in the model organism. Animals fed Roundup-Ready soybean consistently performed less well compared to animals fed either conventional or organic soybeans. We conclude that accumulation of herbicide residues in Roundup-Ready soy and related nutritional differences between the soy types may have caused the observed fitness differences. The results accentuate the need for further research clarifying qualitative aspects, including potential large-scale consequences for food and feed quality, of this dominant crop.  FULL TEXT

Rick A. Relyea, “Amphibians Are Not Ready for Roundup®,” in Wildlife Ecotoxicology: Forensic Approaches, J.E. Elliott et al. (eds.), 2011, DOI 10.1007/978-0-387-89432-4_9.

ABSTRACT:

The herbicide glyphosate, sold under a variety of commercial names including Roundup® and Vision® , has long been viewed as an environmentally friendly  herbicide. In the 1990s, however, after nearly 20 years of use, the first tests were conducted on the herbicide’s effects on amphibians in Australia. The researchers found that the herbicide was moderately toxic to Australian amphibians. The leading manufacturer of glyphosate-based herbicides, Monsanto, declared that the researchers were wrong. Nearly 10 years later, my research group began examining the effects of the herbicides on North American amphibians. Based on an extensive series of experiments, we demonstrated that glyphosate-based herbicides can be highly toxic to larval amphibians. Monsanto declared that we were also wrong. These experiments have formed the basis of a spirited debate between independent, academic researchers, and scientists that either work as consultants for Monsanto or have a vested interest in promoting the application of the herbicide to control undesirable plants in forests and agriculture. The debate also moved into unexpected arenas, including the use of glyphosate-based herbicides in the Colombian drug war in South America where a version of Roundup is being used to kill illegal coca plantations. In 2008, the US EPA completed a risk assessment for the effects of glyphosate-based herbicides on the endangered California red-legged frog (Rana aurora draytonii) and concluded that it could adversely affect the long-termpersistence of the species. More recent data from Colombia have confirmed that the herbicides not only pose a risk to tadpoles in shallow wetlands, but that typical applications rates also can kill up to 30% of adult frogs. As one reflects over the past decade, it becomes clear that our understanding of the possible effects of glyphosatebased herbicides on amphibians has moved from a position of knowing very little and assuming no harm to a position of more precise understanding of which concentrations and conditions pose a serious risk. FULL TEXT

Laís de Brito Rodrigues, Rhaul de Oliveira , Flávia Renata Abe, Lara Barroso Brito, Diego Sousa Moura, Marize Campos Valadares, Cesar Koppe Grisolia, Danielle Palma de Oliveria, and Gisele Augusto Rodrigues de Oliveira, “Ecotoxicological Assessment of Glyphosate-Based Herbicides,” Environmental Toxicology and Chemistry, 2017, 36:7, DOI: 10.1002/etc.3580.

ABSTRACT:

Glyphosate-based herbicides are the most commonly used worldwide because they are effective and relatively nontoxic to nontarget species. Unlimited and uncontrolled use of such pesticides can have serious consequences for human health and ecological balance. The present study evaluated the acute toxicity and genotoxicity of 2 glyphosate-based formulations, Roundup Original (Roundup) and Glyphosate AKB 480 (AKB), on different organisms: cucumber (Cucumis sativus), lettuce (Lactuca sativa), and tomato (Lycopersicon esculentum) seeds, and microcrustacean Artemia salina and zebrafish (Danio rerio) early life stages. For the germination endpoint, only L. esculentum presented significant sensitivity to AKB and L. sativa to Roundup, whereas both formulations significantly inhibited the root growth of all species tested. Both AKB and Roundup induced significant toxicity to A. salina; both are classified as category 3, which indicates a hazard for the aquatic environment, according to criteria of the Globally Harmonized Classification System. However, Roundup was more toxic than AKB, with 48-h median lethal concentration (LC50) values of 14.19 mg/L and 37.53 mg/L, respectively. For the embryo–larval toxicity test, Roundup proved more toxic than AKB for the mortality endpoint (96-h LC50 values of 10.17 mg/L and 27.13 mg/L, respectively), whereas for the hatching parameter, AKB was more toxic than Roundup. No significant genotoxicity to zebrafish larvae was found. We concluded that AKB and Roundup glyphosate-based formulations are phytotoxic and induce toxic effects in nontarget organisms such as A. salina and zebrafish early life stages.  FULL TEXT