Combined Effects Of Pesticides Research Articles

Combined toxicity of abamectin and carbendazim on enzymatic and transcriptional levels in the soil-earthworm microcosm.

To reveal the toxicological mechanisms of pesticide mixtures on soil organisms, this study concentrated on evaluating enzymatic activity and gene expression changes in the earthworm Eisenia fetida (Savigny 1826). Despite being frequently exposed to multiple pesticides, including the common combination of abamectin (ABA) and carbendazim (CAR), environmental organisms have primarily been studied for the effects of individual pesticides. Acute toxicity results exhibited that the combination of ABA and CAR caused a synergistic impact on E. fetida. The levels of MDA, ROS, T-SOD, and caspase3 demonstrated a significant increase across most individual and combined groups, indicating the induction of oxidative stress and cell death. Additionally, the expression of three genes (hsp70, gst, and crt) exhibited a significant decrease following exposure to individual pesticides and their combinations, pointing toward cellular damage and impaired detoxification function. In contrast, a noteworthy increase in ann expression was observed after exposure to both individual pesticides and their mixtures, suggesting the stimulation of reproductive capacity in E. fetida. The present findings contributed to a more comprehensive understanding of the potential toxicity mechanisms of the ABA and CAR mixture, specifically on oxidative stress, cell death, detoxification dysfunction, and reproductive capacity in earthworms. Collectively, these data offered valuable toxicological insights into the combined effects of pesticides on soil organisms, enhancing our understanding of the underlying risks associated with the coexistence of different pesticides in natural soil environments.

Combined effects of three insecticides with different modes of action on biochemical responses of the solitary bee Osmia bicornis

Bees are simultaneously exposed to a variety of pesticides, which are often applied in mixtures and can cause lethal and sublethal effects. The combined effects of pesticides, however, are not measured in the current risk assessment schemes. Additionally, the sublethal effects of pesticides on a variety of physiological processes are poorly recognized in bees, especially in non-Apis solitary bees. In this study, we used a full-factorial design to examine the main and interactive effects of three insecticide formulations with different modes of action (Mospilan 20 SP, Sherpa 100 EC, and Dursban 480 EC) on bee biochemical processes. We measured acetylcholinesterase (AChE), glutathione S-transferase (GST) and esterase (EST) activities, as well as a nonenzymatic biomarker associated with energy metabolism, i.e., ATP level. All studied endpoints were affected by Sherpa 100 EC, and the activities of AChE and EST as well as ATP levels were affected by Dursban 480 EC. Moreover, complex interactions between all three insecticides affected ATP levels, showing outcomes that cannot be predicted when testing each insecticide separately. The results indicate that even if interactive effects are sometimes difficult to interpret, there is a need to study such interactions if laboratory-generated toxicity data are to be extrapolated to field conditions.

Individual and Combined Effects of Pesticides with Active Ingredients of Mancozeb and Methomyl on the DNA Damage of Daphnia magna (Straus, 1820; Cladocera, Daphniidae)

Mancozeb and methomyl are active ingredients commonly contained in pesticides applied in shallot farming. Surface runoff can carry pesticide residues that enter water bodies and affect non-target organisms, such as Daphnia magna. This study evaluated the genotoxicity effects of individual and combined mancozeb and methomyl on the DNA damage of D. magna. Organisms at 24 h old and 48 h old were exposed to individual and combined concentrations of mancozeb and methomyl for 24 h to obtain the LC50-24 h values. These values were used to evaluate DNA damage by calculating the tail intensity (TI) (%), tail moment (TM), and tail factor (TF). Results showed that based on the LC50-24 h values, methomyl has the highest toxicity level, followed by the mancozeb:methomyl combination, and then mancozeb. The combination index of mancozeb:methomyl for both D. magna ages (24 h and 48 h) indicated that the two pesticides antagonistically interact (CI>1). However, based on TI%, TM, and TF values, the level of damage was almost the same between the individual and combined pesticide concentrations, and the DNA damage was more massive with increased pesticide concentration. The DNA damage of 24 h old and 48 h old D. magna did not significantly differ. Increased DNA damage in D. magna indicated that this parameter was sensitive to the presence of pesticides. In application, DNA damage can be used as a biomarker for biomonitoring pesticide pollution in the aquatic ecosystem.

Comparative toxicological and hygienic assessment and combined action of modern fungicides based on azoxystrobin, pydiflumetofen, propiconazole

Annotation. The creation of combined pesticide formulations for the purpose of more effective protection of agricultural crops is a significant factor in the importance of assessing their synergistic effects. Substances that produce a similar pesticidal effect, in combination with each other, can enhance the toxic effect and, therefore, show dose additivity. The aim is toxicological and hygienic evaluation and determination of the type of combined action of pydiflumetofen, azoxystrobin and propiconazole – the active substances of the mixed formulations “Miravis Ace 275 SE” and “Miravis Neo 300 SE” according to toxicity indicators. Analytical review of scientific publications was carried out using data from EFSA, FAO, ECHA, PPDB, Internet sites. According to the literature, a comparative toxicological-hygienic evaluation of fungicidal preparations and their active substances was carried out. The general mechanism of fungicidal action was evaluated according to the classification developed by the Fungicide Resistance Action Committee (FRAC). The hazard class according to the toxic metric parameters of the substances under study was determined in accordance with the Hygienic classification of pesticides according to the degree of hazard (DSanPiN 8.8.1.002-98). The nature and type of combined action was carried out according to the Finney method with evaluation according to the criteria of acute toxicity. Systematization of data, their structuring for the purpose of further toxicological assessment of substances at the level of their inactive and threshold doses was carried out in the table editor Microsoft Excel 2019 (Microsoft Office 2019, Microsoft). As a result of the conducted research, the most toxic mixed fungicide “Miravis Neo 300 SE” based on three active substances was determined (the average lethal dose (LD50) is 550 mg/kg). It has been established that in cases of combinations of active substances to obtain a lethal effect, a dose of substances that does not exceed 100% in total is required, which indicates the strengthening (potentiation) of toxicity. It was pointed out that the share of propiconazole in the potentiation of the toxic effect in both mixed preparations is the highest compared to other active substances and is 0.87 for “Miravis Neo 300 SE” and 0.88 for “Miravis Ace 275 SE”. It was observed that the adverse effects of simultaneous exposure to several pesticides may change during the transition from acute to chronic exposure. Therefore, it is important to continue the research of the active substances of pesticides with the determination of limiting criteria for harmfulness, taking into account the remote effects of exposure. Thus, the toxicological and hygienic assessment made it possible to establish that the combined fungicides “Miravis Neo 300 SE” and “Miravis Ace 275 SE” are more toxic in the mode of single oral exposure in comparison with the single-component fungicide “Miravis 200 SC”. Increased toxicity (potentiation) can be considered as a consequence of the simultaneous exposure of several active substances. The active substance propiconazole poses the main danger of adverse effects on the body at the level of lethal doses. The obtained values of the potentiation coefficients will be taken into account in further studies of the risk assessment of complex and combined effects of pesticides on workers and their potential danger when entering the human body with food products.

Temperature affects the toxicity of pesticides to cercariae of the trematode Echinostoma trivolvis.

Global climate change is predicted to have significant impacts on ecological interactions such as host-parasite relationships. Increased temperatures may also interact with other anthropogenic stressors, such as chemical contaminants, to exacerbate or reduce parasite transmission. However, studies on the effects of pesticides on non-target species are typically conducted at one standard temperature, despite the toxicity of many agrochemicals being temperature-dependent. Furthermore, most studies assessing the effects of temperature on pesticide toxicity have been conducted on host organisms, limiting our understanding of how temperature affects the toxicity of pesticides to free-living parasite stages as they move through the environment in search of a host. Using the free-swimming cercariae stage of the trematode Echinostoma trivolvis, we examined how the toxicities of three different pesticides (a carbamate insecticide, strobilurin fungicide, and triazine herbicide) vary by temperature by monitoring cercarial swimming activity over time. Our three main findings were: 1) a strong main effect of temperature across all pesticide trials - higher temperatures caused cercariae to cease swimming activity earlier, likely due to an increased rate of energy expenditure, 2) atrazine, azoxystrobin, and carbaryl were directly toxic to cercariae to some degree, but not in a predictable dose-dependent manner, and 3) the temperature at which pesticide exposure occurs could affect its toxicity to cercariae. The interaction between pesticide and temperature was most evident in the azoxystrobin exposure; azoxystrobin caused cercariae to cease swimming activity earlier at 30°C but caused cercariae to maintain swimming activity longer at 18°C relative to their respective pesticide-free control treatments. These findings highlight the importance of conducting toxicity assays at multiple temperatures and suggest that the combined effects of pesticides and temperature on host-parasite interactions may be difficult to generalize.

Oxidative stress is involved in the activation of NF-κB signal pathway and immune inflammatory response in grass carp gill induced by cypermethrin and/or sulfamethoxazole.

At present, the concentration of environmental pollutants, such as pesticides and antibiotics exposed in environment, especially in aquatic environment is increasing. Research on environmental pollutants has exploded in the last few years. However, studies on the combined effects of pesticides and antibiotics on fish are rare, especially the toxic damage to gill tissue is vague. In this paper, cypermethrin (CMN) and sulfamethoxazole (SMZ) were analyzed and found that there was a strong correlation between the pathways affected by the first 30 genes regulated by CMN and SMZ, respectively. Therefore, the toxic effects of CMN (0.651μgL-1) and/or SMZ (0.3μgL-1) on grass carp gill were studied in this paper. Histopathology, quantitative real-time PCR, and other methods were used to detect the tissue morphology, oxidative stress level, inflammation, and apoptosis-related indicators of the fish gills after exposure of 42days. It was found that compared with the single exposure (CMN/SMZ) group, the combined exposure (MIX) group had a more pronounced oxidative stress index imbalance. At the same time, nuclear factor-κB (NF-κB) signal pathway was activated and immuno-inflammatory reaction appeared in MIX group. The expression of tumor necrosis factor (TNF-α) in the rising range is 2.94 times that of the C group, while the expression of interleukin 8 (IL-8) is as high as 32.67 times. This study reveals the harm of CMN and SMZ to fish, and provides a reference and basis for the rational use of pesticides and antibiotics.

Parasites and pesticides act antagonistically on honey bee health

Abstract Pesticides and parasites have each been linked to increased mortality in western honey bees (Apis mellifera). Currently, it is uncertain if one makes the other worse; several studies have tested for potential synergistic stressor effects, but results have been mixed. Here, we use a hierarchical meta‐analysis of 63 experiments from 26 studies to gain a clearer view of the combined effects of parasites and pesticides on honey bee health. We found that combined pesticide–parasite treatments do tend to be deadlier than uncombined treatments but are significantly less deadly than predicted additive or multiplicative effects. In other words, combined treatment effects are not synergistic, but antagonistic. Much of the previous uncertainty about the combined effects of pesticides and parasites on honey bee health can be attributed to a bias in the previous research against stressor antagonism; many researchers have excluded the possibility of antagonism a priori. Synthesis and applications. Meta‐analysis shows that when honey bees are stressed by a combination of pesticides and parasites, the combined stress effect is antagonistic, that is, less than the sum of its parts. A better understanding of the mechanisms underlying this antagonism could prove critical for effective management of honey bee health.

Pesticides and land cover heterogeneity affect functional group and taxonomic diversity of arthropods in rice agroecosystems

Biodiversity can be characterised across several dimensions, which are crucial for the evaluation of ecosystem services. Functional diversity, a key aspect of biodiversity, provides a more realistic characterisation of the functioning of ecological communities than only studying their taxonomic diversity. The relevance of functional ecology studies has steadily increased in agroecosystems. However, the combined effects of pesticides and land cover heterogeneity on the taxonomic and functional diversity of arthropod communities have been studied less frequently. We sampled arthropods during the dry season in 19 rice fields located in two different regions of Northern Vietnam. We assorted the arthropods into functional groups corresponding to different feeding habits and calculated the taxonomic and functional group diversities. Finally, we analysed the impacts of pesticide applications and land cover heterogeneity on both diversity measures. Taxonomic and functional group diversity measures were highly correlated. In turn, both diversity measures responded similarly to land cover heterogeneity and pesticides. Land cover heterogeneity had positive effects on taxonomic and functional group diversity, mainly at the early stage of rice crops. Conversely, the impact of pesticide application on both diversity measures was strongly negative. Our results suggest that rice agroecosystems can be more sustainable by increasing landscape heterogeneity and a reduced pesticide use. Such schemes may help to maintain higher levels of biodiversity that ensure ecosystem functioning, which will be therefore likely beneficial to provide ecosystem services in agroecosystems.

Combined effects of pesticides on weedines and seed yield of soybean crops

Goal. of my study was to investigate the combined effect of pesticides, including seed dressers, post-emergence herbicides, fungicides, biologicals, and plant growth regulators on weediness and soybean yield in the Eastern Forest-Steppe of Ukraine.
 Methods. Field, analytical and statistical.
 Results. The weeds in the soybean crops were represented by 15 species. Cockspur (Echinochloa crusgalli (L.) Roem et Schult.), yellow foxtail (Setaria glaua (L.) Beauv.), lamb’s quarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.) dominated in the soybean crops. In the controls, the dominant position in the soybean crops (in terms of the wet weight of weeds) was occupied by biennial and annual dicotyledonous weeds (56—57% of the total wet weight of weeds). Annual gramineous weeds (37—42%) and perennial dicotyledonous weeds (2—6%) ranked the second and third most spread species. Pre-sowing treatment of seeds increased the competitiveness of soybean plants against weeds. Herbicide composition Tabezon (2.0 l/ ha) + Formula (6 g/ ha) + surfactant Trend 90 (0.2 l/ ha) (primordial leaves) + Lemur (1.5 l/ ha) (biternate/ triternate leaves) significantly reduced the total number of weeds in the soybean crops by 89% and their wet weight by 97%. There was no evidence of significant effects of post-emergence combinations of herbicides with chemical or biological pesticides on the effectiveness of weed control in the soybean crops. Analyzing the soybean seed yield, I revealed that application of herbicides alone in the crops was the most justified.
 Conclusions. Increased competitiveness of soybean plants against weeds on pre-sowing seed treatment has been demonstrated. There was no evidence of significant effects of post-emergence combinations of herbicides with chemical and biological pesticides on the weed control effectiveness. Monoapplication of herbicides was the most justified.

Bee pollination outperforms pesticides for oilseed crop production and profitability.

Nature-based agriculture that reduces dependency on chemical inputs requires using ecological principles for sustainable agro-ecosystems, aiming to balance ecology, economics and social justice. There is growing evidence that pollinator-dependent crops with high insect, particularly bee, pollination service can give higher yields. However, the interacting effects between insect pollination and agricultural inputs on crop yields and farm economics remain to be established to reconcile food production with biodiversity conservation. We quantified individual and combined effects of pesticides, insect pollination and soil quality on oilseed rape (Brassica napus L.) yield and gross margin, using a total of 294 farmers' fields surveyed between 2013 and 2016. We show that yield and gross margins are greater (15-40%) in fields with higher pollinator abundance than in fields with reduced pollinator abundance. This effect is, however, strongly reduced by pesticide use. Greater yields may be achieved by either increasing agrochemicals or increasing bee abundance, but crop economic returns were only increased by the latter, because pesticides did not increase yields while their costs reduced gross margins.

Environmental Stress Increases Synergistic Effects of Pesticide Mixtures on Daphnia magna.

Some widely used pesticide mixtures produce more than additive effects according to conventional combined effect models. However, synergistic effects have been so far generally observed at unrealistically high pesticide concentrations. Here, we used Daphnia magna as a test organism and investigated how food limitation-a common ecological stressor-affects the mixture toxicity of a pyrethroid insecticide and azole fungicide. We also compared three models regarding the prediction of mixture effects, including concentration addition (CA), effect addition (EA), and stress addition model (SAM). We revealed that especially under low food, the strength of synergism between esfenvalerate and prochloraz increased with an increasing concentration of prochloraz independent of the null model. Under high food conditions and at concentrations of prochloraz ≥32 μg/L, we observed a marginal synergistic effect with a model deviation ratio (MDR) = 2.1 at 32 μg/L prochloraz and 2.2 at 100 μg/L prochloraz when using CA as the null model. In contrast, the combination of both pesticides and food stress caused synergistic effects shown by an MDR = 10.9 even at 1 μg/L of prochloraz that is frequently detected in the environment. The combined effects of pesticides and food stress could be predicted best with the SAM that showed the lowest mean deviation between effect observation and prediction (mean deviation SAM = 16 [SD = 28], EA = 1072 [2105], CA = 1345 [2644]). We conclude that common environmental stressors can strongly increase the synergistic effects of toxicants. This knowledge is especially relevant considering current efforts to include the additional risk of pesticide mixtures and environmental stressors into the environmental risk assessment of pesticides.

Antagonistic effects in zebrafish (Danio rerio) behavior and oxidative stress induced by toxic metals and deltamethrin acute exposure

In natural environments, the aquatic organisms are exposed to complex mixtures of chemicals which may originate from natural sources or from anthropogenic activities. In this context, the aim of the study was to assess the potential effects that might occur when aquatic organisms are simultaneously exposed to multiple chemicals. For that, we have studied the acute effects of cadmium (0.2 μg L−1), nickel (10 μg L−1) and deltamethrin (2 μg L−1) as individual toxicants and as mixture on the behavioral responses, oxidative stress (SOD and GPx), body electrolytes and trace metals profiles of zebrafish (Danio rerio). So far the scientific literature did not report about the combined effects of pesticides and toxic metals on zebrafish behavior using a 3D tracking system. Compared with other studies, in the present paper we investigated the acute effects of two heavy metals associated with a pesticide on zebrafish, in the range of environmentally relevant concentrations. Thus, the environmental concentrations of cadmium and nickel in three rivers affected by urban activities and one river with protected areas as background control were measured. The observations that resulted in our study demonstrated that deltamethrin toxicity was significantly decreased in some of the behavioral variables and oxidative stress when combined with CdNi mixture. Consequently, our study supports previous works concerning the combined toxicity of environmental chemicals since their simultaneous presence in the aqueous environment may lead to higher or lower toxicological effects on biota than those reported from a single pollutant. Therefore, the evaluation of toxic effects of a single contaminant does not offer a realistic estimate of its impact against aqueous ecosystems. This study also supports the idea that the interactions between different chemical compounds which do not exceed the maximum permitted limits in environment may have benefits for aquatic life forms or be more toxic.

Effects of Pesticide Mixtures on Zooplankton Assemblages in Aquatic Microcosms Simulating Rice Paddy Fields.

The individual and combined effects of pesticides (chlorpyrifos, triadimefon and butachlor) on the zooplankton assemblages of microcosms were investigated. Laboratory microcosms were constructed with water and sediment to simulate aquatic conditions in China's rice paddy fields. Results from principal response curves analysis showed that butachlor and triadimefon had no significant impact individually on the population level in zooplankton assemblages. The deleterious effects of pesticide mixtures on the zooplankton were mainly caused by chlorpyrifos. In fact, assemblage succession only occurred in the treatments containing chlorpyrifos. There was no synergy effect on the microcosm from combinations of pesticides on the assemblages. The zooplankton assemblages affected by chlorpyrifos did not recover at the termination of the experiment, i.e., after 56 days.

Mutagenic and cytotoxic potential of Endosulfan and Lambda-cyhalothrin — In vitro study describing individual and combined effects of pesticides

Excessive use of pesticides poses increased risks to non target species including humans. In the developing countries, lack of proper awareness about the toxic potential of pesticides makes the farmer more vulnerable to pesticide linked toxicities, which could lead to diverse pathological conditions. The toxic potential of a pesticide could be determined by their ability to induce genetic mutations and cytotoxicity. Hence, determination of genetic mutation and cytotoxicity of each pesticide is unavoidable to legislate health and safety appraisal about pesticides. The objective of current investigation was to determine the genotoxic and cytotoxic potential of Endosulfan (EN) and Lambda-cyhalothrin (LC); individually and in combination. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay was utilized to determine cytotoxicity, while two mutant histidine dependent Salmonella strains (TA98, TA100) were used to determine the mutagenicity of EN and LC. Moreover, mutagenicity assay was conducted with and without S9 to evaluate the effects of metabolic activation on mutagenicity. Even though a dose dependent increase in the number of revertant colonies was detected with EN against both bacterial strains, a highly significant (p<0.05) increase in the mutagenicity was detected in TA98 with S9. In comparison, data obtained from LC revealed less mutagenic potential than EN. Surprisingly, the non-mutagenic individual-concentrations of EN and LC showed dose dependent mutagenicity when combined. Combination of EN and LC synergistically induced mutagenicity both in TA98 and TA100. MTT assay spotlighted comparable dose dependent cytotoxicity effects of both pesticides. Interestingly, the combination of EN and LC produced increased reversion and cytotoxicity at lower doses as compared to each pesticide, concluding that pesticide exposure even at sub-lethal doses can produce cytotoxicity and genetic mutations, which could lead to carcinogenicity.

Study on fish mortality caused by the combined effects of pesticides and changes in environmental conditions

An accident killing many fish occurred in a drainage canal on reclaimed land. More than 10 000 mullet were killed in the accident. Newspapers reported that a decrease in salinity, caused by gate repairs, and a lack of oxygen, caused by rapid increase in the temperature, were the causes of the accident. In addition, our investigation discovered the possibility of pesticide inflow. The effects of these factors were estimated through experiments using mullet. A Shallow Sea Ecological Model (SSEM) was used to simulate the pesticide inflow and salinity change. The SSEM is based on the Object-Oriented Programming concept and it was very easy to extend the SSEM for modelling this accident. The extended SSEM revealed that the combined effects of water quantity, the decrease of salinity and the pesticide inflow caused the accident. The SSEM predicted that by decreasing the amount of pesticide down to one fifth of the actual level, the accident might not have occurred.