RESUMO
Non-target species from agricultural areas might be exposed to sublethal pesticide concentrations favoring survival and reproduction of the resistance individuals. The objective of this study was to evaluate chlorpyrifos toxicity and detoxification enzymatic activities on three species (Hyalella curvispina, Heleobia parchappii and Girardia tigrina) from a drain channel with history of insecticide contamination (EF) and the Neuquén river (NR) in Argentina. Chlorpyrifos toxicity on amphipods (H. curvispina) and planarians (G. tigrina) from NR was about six- and two-fold higher than that of their counterparts from EF. Mean carboxylesterases (CarE) activities determined in the three species from NR were significantly different from EF, whereas mean glutathione-S-transferase (GST) activities were no significantly different. Finally, planarians from EF showed significantly higher mean 7-ethoxycoumarine O-deethylase (ECOD) activity than those from NR. Amphipods from both sites displayed similar ECOD activities. The present results suggest that chlorpyrifos resistance in amphipods from EF is not conferred by increased detoxification.
Assuntos
Anfípodes , Clorpirifos , Inseticidas , Praguicidas , Poluentes Químicos da Água , Humanos , Animais , Clorpirifos/toxicidade , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Inseticidas/toxicidade , AgriculturaRESUMO
Insecticides are widely used for pest control and frequently reach aquatic systems, imposing a risk to the biota. In this work, the effect of environmental concentrations of bifenthrin on the grazing capacity of Simocephalus vetulus (Cladocera) and Argyrodiaptomus falcifer (Copepoda) on phytoplankton was evaluated. Fifteen microcrustacean individuals and a natural phytoplankton assemblage dominated by Cyanobacteria were exposed during 46 h to three concentrations of bifenthrin (C0 0 µg L-1, C1 0.02 µg L-1, and C2 0.05 µg L-1). A significant decrease in both microcrustaceans grazing rates on total phytoplankton was observed in C2 compared to C0 and C1. The filtration rate (ml ind-1 h-1) of S. vetulus decreased significantly for the cyanobacteria Anabaenopsis arnoldii, Dolichospermum circinale, and Glaucospira sp. in C2 compared to C0 and C1. The ingestion rate (org ind-1 h-1) of A. falcifer decreased significantly in C1 and C2 compared to C0 only for A. arnoldii. Regarding phytoplankton morphological groups, the filtration rate of S. vetulus decreased in C1 and C2 compared to C0 for Colonies and Coenobiums in C2 concerning C0 and C1 for Filaments and in C2 compared to C0 for Silicified. For A. falcifer, the ingestion rate was reduced in C2 compared to C0 for Silicified, Flagellated, and Sessile. The results showed that bifenthrin affected both microcrustaceans grazing capacity on phytoplankton, especially at the highest insecticide concentration.
Assuntos
Cladocera , Copépodes , Cianobactérias , Inseticidas , Piretrinas , Humanos , Animais , Fitoplâncton , Zooplâncton , Inseticidas/farmacologiaRESUMO
Daphnia spinulata Birabén, 1917 is an endemic cladoceran species, frequent in the zooplankton communities of the shallow lakes of the Pampean region of Argentina. These lakes have varying salinity levels and, being located in agricultural areas, are frequently subject to pesticide pollution. This study aimed to determine the effects of the herbicide glyphosate (Panzer Gold®) in combination with different salinity levels on the biological parameters of D. spinulata and its recovery ability after a short exposure. Three types of assays were performed: an acute toxicity test, a chronic assessment to determine survival, growth and reproduction, and recovery assays under optimal salinity conditions (1 g L-1). The LC50-48 h of glyphosate was 7.5 mg L-1 (CL 3.15 to 11.72). Longevity and the number of offspring and clutches were significantly reduced due to the combined exposure of glyphosate and increased salinity. The timing of the first offspring did not recover after glyphosate exposure. Our results reveal that D. spinulata is sensitive to the herbicide Panzer Gold® at concentrations well below those indicated in the safety data sheet of this commercial formulation, which causes stronger negative effects in conditions of higher salinity. Further research is needed to shed light on the sensitivity of this cladoceran to glyphosate and its variability under other interactive stress factors.
Assuntos
Daphnia , Glicina , Glifosato , Herbicidas , Salinidade , Animais , Glicina/análogos & derivados , Glicina/toxicidade , Daphnia/efeitos dos fármacos , Herbicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Argentina , Reprodução/efeitos dos fármacosRESUMO
Glyphosate [N-(phosphonomethyl) glycine] is currently the most widely used herbicide worldwide. Its application in agricultural and urban areas can lead to the dispersion and arrival to aquatic systems causing environmental deterioration with detrimental effects on the inhabiting biota. This is triggered not only by the herbicide per se but also its metabolite aminomethyl-phosphonic acid (AMPA), which can be highly toxic to many aquatic organisms. Water fleas are some of the key components in aquatic food webs, being one of the most sensitive groups to pollutants. Although being often used in standardized toxicity tests, they are comparatively less studied in relation to glyphosate exposition. Here we examine the current scientific literature regarding the acute and sublethal toxicity of glyphosate in the Cladocera taxonomic group, with special comparisons between the active ingredient (A.I) and formulations. Our results document a high variation in the lethal concentrations reported for different cladoceran species, due to the high diversity of products used in the toxicity tests. Most articles accounting for sublethal effects were performed on the standard Daphnia magna species. Reproduction, including decreased fecundity and delayed age of first reproduction, is usually one of the most severely affected individual traits. Although still scarce, studies documenting metabolic and genetic alterations might provide accurate information on the mechanisms of action of the herbicide.
Assuntos
Cladocera , Herbicidas , Poluentes Químicos da Água , Animais , Glicina/análogos & derivados , Herbicidas/toxicidade , Poluentes Químicos da Água/toxicidade , GlifosatoRESUMO
Chemical and toxicological crude oil analysis was performed on water-accommodated fraction of oil (WAF). This study characterized the chemical composition of WAF and its dissipation over a period of 192â¯h. Acute (96â¯h) and chronic (14â¯d) toxicity of WAF were evaluated on Hyalella curvispina from both reference (Los Barreales lake, LB) and hydrocarbon-contaminated (Durán stream, DS) sites. The total hydrocarbon (TPHs) concentration in WAF was 2.18â¯mgâ¯L-1. The dissipation rates of hydrocarbons in WAF showed a first-order kinetics, with half-lives ranging between 65â¯h-200â¯h. Amphipods from LB showed acute and chronic LC50 values of 0.33 and 0.018â¯mgâ¯L-1, respectively. Amphipods from DS exposed to pure WAF showed no mortality in either acute or chronic assays. Further biochemical and molecular research is required to determine the mechanisms underlying the resistance to WAF exposure on DS amphipods.
Assuntos
Anfípodes/efeitos dos fármacos , Hidrocarbonetos/análise , Petróleo/análise , Poluentes Químicos da Água/análise , Animais , Monitoramento Ambiental/métodos , Petróleo/toxicidade , Poluição por Petróleo , América do SulRESUMO
Agriculture represents the second most important economic activity in the North Patagonian Region of Argentina and non-selective insecticides are still being used with significant implications to the quality of the environment. The range of concentrations (µg/L) determined for azinphosmethyl, chlorpyrifos, and carbaryl in drainage channels were from non-detected to 1.02, 1.45, and 11.21, respectively. Macroinvertebrate abundance and taxon richness in drainage channels were significantly lower in November compared to the other sampling months (October, February). The decrease in taxon richness observed in November was associated with chlorpyrifos and azinphosmethyl peak concentrations. The most remarkable changes were the decrease in sensitive taxa such as Baetidae and the increase in some tolerant taxa such as Chironomidae and Gastropoda.For all three pesticides, the acute hazard quotient exceeded the risk criteria for invertebrates. The effects of the three pesticides on aquatic organisms, characterized by joint probability curves, showed that the LC50 of 10% of the species were exceeded five and three times by the concentrations of azinphosmethyl and chlorpyrifos during the study period, respectively. However, the correlation between the pesticide concentrations and both taxon richness and abundance of macroinvertebrates at each site (irrigation and drainage channels) was indicative that only chlorpyrifos was negatively correlated with both parameters (Spearman r2 - 0.61, p = 0.0051 and Spearman r2 - 0.59, p = 0.0068 for taxon richness and abundance correlation, respectively). We conclude that macroinvertebrate assemblages in drainage channels were highly affected by chlorpyrifos levels.