Reducing overall herbicide use may reduce risks to humans but increase toxic loads to honeybees, earthworms and birds

Abstract

Background Pesticide use has been associated with risks for human health and an overall decline in biodiversity. Although herbicides are the most commonly used pesticides worldwide, they have received less attention in this debate. We investigated the extent to which long-term trends in herbicide use in Austria influence potential toxic exposures to non-target organisms and potential risks to humans. We analyzed official sales data of 101 herbicide active ingredients (AIs) approved in Austria between 2010 and 2019 regarding their ecotoxicological properties based on lethal doses (LD50 and LC50) weighed by their persistence in the environment (DT50) for honeybees (Apis mellifera), earthworms (Eisenia fetida), and birds (Serinus serinus). Human health risks were qualitatively assessed based on official hazard statements for the AIs used. Results In Austria, herbicide amounts sold decreased significantly by 24% from 1480 to 1123 tonnes between 2010 and 2019. This also led to a considerable decrease in the amounts of AIs classified by H-statements of the EU Pesticides Database: − 71% acute inhalation toxicity, − 58% reproductive toxicity,− 47% specific target organ toxicity. Yet, 36% of herbicides used were still classified as highly hazardous pesticides according to the Pesticide Action Network. Surprisingly, over the same period, toxic loads to honeybees increased by 487% (oral exposure), while lethal toxic loads to earthworms increased by 498%, and to birds by 580%. This can be attributed to a shift toward the use of more acutely toxic and especially more persistent AIs. The most problematic AI for honeybees, earthworms, birds and humans was the highly persistent diquat. The further ranking of the most toxic herbicides varied considerably depending on the organism. It is important to note that this toxic load assessment, like official environmental risk assessments, evaluates the potential risk but not the actual fatalities or real-world exposure. Conclusions Our results show a trade-off between herbicide amounts and toxicological hazards to humans and other non-target organisms. These interdependencies need to be considered when implementing pesticide reduction targets to protect public health and biodiversity, such as the EU´s “farm-to-fork” strategy, which aims to reduce the amounts and risks of synthetic pesticides.

Effects of Piper betle L. Extract and Allelochemical Eugenol on Rice and Associated Weeds Germination and Seedling Growth

“…A number of chemicals are commonly used for weed management in agriculture, because of their speed and efficiency. Unfortunately, the synthetic herbicides are poisonous to human health and biodiversity [ 1 , 2 ]. They are directly toxic to farmers and indirectly accumulated in agricultural products [ 3 ].…”

Pesticide Use and Associated Greenhouse Gas Emissions in Sugar Beet, Apples, and Viticulture in Austria from 2000 to 2019

“…Energy consumption per ha of herbicide production exceeded that for all other pesticide types in sugar beet production [17]. Reducing pesticide use would have the positive side effect of reducing toxic exposure not only in the field, but also in ambient air and non-agricultural areas [44][45][46][47][48][49]. We assume that the pesticide-related GHG emissions we reported for sugar beet are higher for wheat but lower for maize, because the corresponding mean pesticide treatment frequency indices are higher for wheat (5.3 vs. 4.0 for wheat vs. sugar beet, respectively) and lower for maize (1.9 vs. 4.0 for maize vs. sugar beet, respectively; mean values 2011-2020 for Germany [27]).…”

Trends of Total Applied Pesticide Toxicity in German Agriculture

“…It thereby avoids the shortcomings of solely mass-based evaluations and has been shown indicative of potential biodiversity effects on aquatic organisms . Similar approaches had already been applied to specific pesticide or species groups; ,− however, so far, TAT provides the most comprehensive large-scale approach for the identification of long-term temporal trends of potential pesticide risks for different nontarget species groups. Calculation of TAT is straightforward but depends on the availability of two data sets: high-quality ecotoxicity data (endpoints) for a large range of pesticides and species, and use data for these pesticides over a sufficiently long time period.…”

“…Here, we calculate TAT trends for three aquatic (invertebrates, fish, and plants) and five terrestrial (arthropods, pollinators, vertebrates, soil organisms, and plants) species groups. This study extends the species groups of the US study by calculating TAT for soil organisms, which, on the one hand, are particularly important for ecosystem services (e.g., nutrient cycling or carbon storage), soil health, and agricultural sustainability, and, on the other hand, are exposed to risks from pesticide use. , Compared to aquatic and terrestrial off-field ecosystems, in-field soil ecosystems are more directly exposed to applied pesticides. , We also present maps of the spatial TAT distribution for the eight species groups in Germany based on the available use data, the information on the use of individual pesticides in different crops, and a high-resolution crop map for Germany …”

“…This study extends the species groups of the US study 14 (e.g., nutrient cycling or carbon storage), soil health, and agricultural sustainability, 23 and, on the other hand, are exposed to risks from pesticide use. 19,24 Compared to aquatic and terrestrial off-field ecosystems, in-field soil ecosystems are more directly exposed to applied pesticides. 25,26 We also present maps of the spatial TAT distribution for the eight species groups in Germany based on the available use data, the information on the use of individual pesticides in different crops, 27 and a high-resolution crop map for Germany.…”