Herbicide Exposure and Toxicity to Aquatic Primary Producers

Abstract

The aim of the present review was to give an overview of the current state of science concerning herbicide exposure and toxicity to aquatic primary producers. To this end we assessed the open literature, revealing the widespread presence of (mixtures of) herbicides, inevitably leading to the exposure of non-target primary producers. Yet, herbicide concentrations show strong temporal and spatial variations. Concerning herbicide toxicity, it was concluded that the most sensitive as well as the least sensitive species differed per herbicide and that the observed effect concentrations for some herbicides were rather independent from the exposure time. More extensive ecotoxicity testing is required, especially considering macrophytes and marine herbicide toxicity. Hence, it was concluded that the largest knowledge gap concerns the effects of sediment-associated herbicides on primary producers in the marine/estuarine environment. Generally, there is no actual risk of waterborne herbicides to aquatic primary producers. Still, median concentrations of atrazine and especially of diuron measured in China, the USA and Europe represented moderate risks for primary producers. Maximum concentrations due to misuse and accidents may even cause the exceedance of almost 60% of the effect concentrations plotted in SSDs. Using bioassays to determine the effect of contaminated water and sediment and to identify the herbicides of concern is a promising addition to chemical analysis, especially for the photosynthesis-inhibiting herbicides using photosynthesis as endpoint in the bioassays. This review concluded that to come to a reliable herbicide hazard and risk assessment, an extensive catch-up must be made concerning macrophytes, the marine environment and especially sediment as overlooked and understudied environmental compartments.

Pesticide responses of Arctic and temperate microalgae differ in relation to ecophysiological characteristics

“…Concentrations of pesticides were evaluated using a QTRAP 5500 mass spectrometer (Sciex, Concord, ON, Canada) according to Chalifour et al (2016) and Takishita et al (2021). The four studied pesticides (atrazine, simazine, trifluralin and chlopyrifos) are known to have relatively long half-lives in water, ranging from months to years (Bai et al 2015, Vonk andKraak 2020), and therefore are stable and do not degrade during our experiments (Du et al 2022, in preparation).…”

“…In that case, ecophysiological properties of Arctic microalgae evolved under the extreme conditions found in the Arctic Ocean and this result in adaptations that may permit these algae to cope with pesticide stress. Although there have been many reports on the impacts of pesticides on the physiology and growth of temperate phytoplankton (Singh et al 2016, Vonk andKraak 2020), very little is known about their potential impacts on microalgae having extreme low temperatures and rapid environmental change due to global warming such as for Arctic phytoplankton. Moreover, the comparison of the tolerance mechanisms and ecophysiological characteristics between the phytoplankton of Arctic with temperate regions is lacking.…”

Cereal species mixtures: an ancient practice with potential for climate resilience. A review

“…Climate change is anticipated to continue to lead to rapid range shifts of weedy species (Peters et al 2014). Meanwhile, input-intensive chemical weed control has contributed to pollution in farmlands and waters (Vonk and Kraak 2020). While weed suppression recorded in varietal mixtures has been limited (Kaut et al 2009;Lazzaro et al 2018), some species mixtures appear to have weed suppression capability compared to pure stands (O'Donovan et al 1985;Kaut et al 2008;Szemplinski and Budzynski 2011;Buczek et al 2012;Kalinina et al 2014;Kholzakov et al 2014.…”

Neurotoxicity in Marine Invertebrates: An Update

“…In the frame of the global environmental changes, rising and worrying data on both the environmental contamination and the related toxicology have been recorded since the mid-twentieth century, when the human activities that are oriented towards industrialization and globalization began to intensify. In particular, marine ecosystems exhibit a wide variety of hazardous anthropogenic pollutants that pervade the entire water column, including sediments, especially along the coasts that exhibit the different levels of human activities releasing industrial, agricultural, hospitals, clinics, and domestic wastes into the sea [ 1 , 2 , 3 ]. Without considering the biodegradable contaminants that arise from organic waste, the main global concerns are related to the release of emerging contaminants (ECs), also called micropollutants, including, among others, heavy metals, microplastics, nanoparticles, pharmaceuticals, and personal care products (PPCPs) (drugs chemicals, etc.…”

“…The environmental risk assessment is currently based on laboratory, mesocosms, and in the field researches, while taking in account that each single chemical introduced in the environment can undergo degradation or interact with other chemicals, or natural factors (biotic/abiotic), leading to synergistic or antagonistic effects [ 3 , 9 , 10 ]. Although growing evidence points to the importance of considering interactions between stressors in the environment, insufficient literature has been produced so far [ 2 , 10 , 11 , 12 ].…”