Search

We compared the effects of lambda‐cyhalothrin as the pure active ingredient and as a formulated product (Zero®), on the larval stage of the autochthonous species Boana pulchella. We evaluated ecotoxicological endpoints, behavioral and developmental alterations, and the biochemical detoxifying, neurotoxic, and oxidative stress responses, covering a wide concentration range from environmental to high application levels. Both pyrethroid preparations displayed similar ecotoxicity (median lethal concentration of ~0.5 mg/L), with the lethal effect of Zero® being more pronounced than that of the active ingredient. Sublethal behavioral alterations in natatory activity were observed at 1000 times lower concentrations, indicating the ecological hazard of tadpole exposure to this pyrethroid at environmentally relevant concentrations. Biochemical endpoints in B. pulchella larvae showed significant responses to lambda‐cyhalothrin in the ng/L range; these responses were different for the pure or the formulated product, and they were variable at higher concentrations. Principal components analysis confirmed the prevalence of biochemical responses as early endpoints at the lowest lambda‐cyhalothrin concentrations; the Integrated Biomarker Response Index proportionally increased with pyrethroid concentration in a similar way for the pure and the formulated products. We conclude that lambda‐cyhalothrin is of concern from an environmental perspective, with particular emphasis on autochthonous anuran development. The battery of biochemical biomarkers included in our study showed a consistent integrated biomarker response, indicating that this is a potent tool for monitoring impacts on amphibians. Environ Toxicol Chem 2024;43:2134–2144. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Copyright of Harran Journal of Agricultural & Food Science is the property of Harran University, Faculty of Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the state of Paraná, Brazil, calcined sewage sludge (biosolid) without remediation is used as a fertilizer in different crops, such as soybeans and corn. Evaluated the chemical composition, pathogenic potential, and toxic potential to plants and E. fetida of biosolid produced in the state. The analysis of metals and pathogens, based on the Brazilian Resolution 498/2020 of the National Council for the Environment (CONAMA), classified the residue as suitable for incorporation into crop soils in Brazil. However, all concentrations of the biosolid (6.25, 25, 50, and 100%) caused phytotoxicity to Lactuca sativa, Allium cepa, Cucumis sativus, and Triticum aestivum. A. cepa meristematic cells exposed to the residue revealed division disruption, including clastogenic damage to chromosomes, and death. All concentrations promoted swelling in onion roots, drastic inhibition of ascorbate peroxidase and superoxide dismutase, activation of guaiacol peroxidase, and lipid peroxidation in their meristems. Studies with Eisenia fetida showed biosolid has strong repellent effects and higher concentrations caused 100% mortality. In surviving animals, catalase and guaiacol peroxidase showed higher tissue levels of activity, suggesting a response to increased environmental free radicals, including reactive oxygen species. Therefore, in Paraná, the current and recurring incorporation of biosolids, without adequate remediation, into cropping soils has the potential to trigger extensive oxidative stress in plants and animals, representing an environmental risk. Furthermore, this study brings important elements that advance the understanding of how biosolids trigger phytotoxicity and cellular toxicity in different organisms. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper introduces the lethal, sublethal, and ecotoxic effects of peppermint and palmarosa essential oils (EOs) and their polymeric nanoparticles (PNs). The physicochemical analyses indicated that peppermint PNs were polydisperse (PDI > 0.4) with sizes of 381 nm and loading efficiency (LE) of 70.3%, whereas palmarosa PNs were monodisperse (PDI < 0.25) with sizes of 191 nm and LE of 89.7%. EOs and their PNs were evaluated on the adults of rice weevil (Sitophilus oryzae L.) and cigarette beetle (Lasioderma serricorne F.) and the larvae of Culex pipiens pipiens Say. On S. oryzae and L. serricorne, PNs increased EOs' lethal activity, extended repellent effects for 84 h, and also modified behavioral variables during 24 h. Moreover, EOs and PNs generated toxic effects against C. pipiens pipiens. On the other hand, peppermint and palmarosa EOs and their PNs were not toxic to terrestrial non-target organisms, larvae of mealworm (Tenebrio molitor L.), and nymphs of orange-spotted cockroach (Blaptica dubia S.). In addition, PNs were slightly toxic to aquatic non-target organisms, such as brine shrimp (Artemia salina L.). Therefore, these results show that PNs are a novel and eco-friendly formulation to control insect pests. [ABSTRACT FROM AUTHOR]

Pollution is the biggest concern nowadays in which aquatic pollution is on top. Many xenobiotic components are responsible for causing the pollution in aquatic ecosystem due to their high toxicity and endurance in the environment. In the present study pernicious effects of synthetic pyretheroid pesticides (Cypermethrin and Lambda-cyhalothrin) on the marine fish (Oreochromis mossambicus) was studied. Toxicity of the pesticide on marine organism was estimated by determination of the 24 h LC50. The toxicity tests were performed separately for each pesticide. Data generated from the acute toxicity tests were evaluated using the probit analysis statistical method. After the exposure of fish to the pesticides the LC50 values were estimated which were showing that both the chemicals have lethal effect on the fish. Concentration of pesticide is directly proportional to the mortality rate of the fish. The investigation shows that the pyrethroid pesticides have lethal effects. [ABSTRACT FROM AUTHOR]

Ecdysone receptor (EcR) plays important roles in molting, metamorphosis, and reproduction of insects. EcR ortholog and its function in melon aphid Aphis gossypii have not been documented yet. RNA interference (RNAi) is a reverse-genetic approach used to study functional genomics, but recently, it has also shown promise as a novel tool that could be used to control insect pests. In this study, reverse transcription-PCR (RT-PCR), quantitative real-time PCR (qPCR), RNAi, and bioassays were employed to isolate EcR gene and investigate its knock-down effects on aphids. The lethal and sublethal effects were also studied after silencing the EcR gene. The results showed that EcR gene is highly expressed (P < 0.006) in 2nd nymphal stage of A. gossypii while expression was statistically lower in all other developmental stages. Knock-down of EcR gene caused up to 43 and 68% mortality in 2nd instar nymphs after feeding dsEcR for 48 and 72 h, respectively, compared to the control. Moreover, RNAi-induced silencing of EcR gene caused sublethal effects on surviving aphids. Significantly lower longevity (about 42%) and fecundity (about 44.22%) were observed in insects fed with dsEcR solution at their nymphal stage. Analysis of gene expression showed that the mortality rates and the lowered longevity and fecundity were attributable to the down-regulation of EcR gene by RNA interference technology. Taken together, our results demonstrate that EcR is an essential gene for aphid growth and development and could be a potential target gene for the development of an RNAi-based bio-aphicide. [ABSTRACT FROM AUTHOR]

Anticoagulant rodenticides have been detected in many species of wildlife worldwide; yet the origins, exposure pathways, and effects of this exposure are not well understood. Furthermore, to accurately characterize the risks from rodenticide use, information is needed on what proportion of populations are being exposed, what proportion of the exposed individuals are affected, and in what ways. The relationship between anticoagulant rodenticide concentrations found in wildlife and the rate of mortality or illness is the subject of much current research. Residue levels observed in liver and whole body analyses vary, and overlap extensively among apparently healthy asymptomatic individuals and sublethal and lethal cases. Results from laboratory studies also show there can be wide variability in lethal and sublethal effects among and within taxonomic groups. Correlating the sublethal and reproductive effects observed in laboratory studies with realistic exposure scenarios and effects in the wild is needed to improve risk assessments. For species with limited numbers/declining populations, a critical question is whether the rodenticide exposure documented in individual animals inhibit population growth or contribute to population declines by lowering survival and reproductive success. This information is essential to the regulatory agencies that must weigh the risks and benefits of rodenticide uses and identify restrictions that are effective in reducing risks to wildlife. A primary objective of this symposium was to facilitate communication between regulators and researchers. Current research on many of these topics was presented, and was followed by discussions on how to improve our understanding of what factors lead to wildlife exposure and improve our ability to assess the effects of exposure on individuals and populations. A collaborative approach will be developed to design studies that provide regulatory and wildlife management agencies with additional science on which to base their decisions.

The present research was performed to evaluate the bioactivity of Citrullus colocynthis (L.) and Melia azedarach L. extracts against three major stored grain insect pests including Tribolium castaneum (Herbst), Trogoderma granarium Everts, and Sitophilus granaries (L.). Toxicity and enzyme inhibition activity of acetylcholinesterase (AChE), α-carboxylesterase (α-CE), β-carboxylesterase (β-CE), acid phosphatases (ACP) and alkaline phosphatases (ALP) in three insect species induced by both plant extracts were evaluated at four different dose rates viz., 5, 10, 15 and 20%. Results showed maximum mortality (34.29%) in S. granarius with M. azedarach at maximum interaction of time and dilution level. In T. castaneum and T. granarium maximum recorded values for mortality were 30.87% and 18.95%, respectively, with extract of M. azedarach. Plant extract of C. colocynthis reported a maximum mortality of 21.92%, 19.18% and 16.89% in T. castaneum, S. granarius and T. granarium, respectively. Findings proved that both plant extracts had decent lethal impacts on tested insect species. Exposure of studied insects to plants extracts also resulted in significant inhibition of AChE, α-CE, β-CE, ACP and ALP. All tested enzymes in three insects were maximally inhibited by plant extract of M. azedarach except α-CE which was slightly more inhibited in S. granarius and ACP which was highly inhibited in T. granarium and S. granarius, by plant extract of C. colocynthis. Outcomes exhibit that plant based extract of M. azedarach is more pronounced in stored grain insect pests and propose the capability of using these plant extracts for safety of stored commodities as a safe substitute for insecticides.

Abstract Passive integrated transponder (PIT) tags allow a range of individual‐level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (

As several reports of impacts arise due to the use of synthetic insecticides, the investigation for safer alternative insecticides should be continued. Using plant material that has several bioactivities is a promising way out to control insect pest. The objective of this study was to evaluate the effect of leaf and seed extract of Castanopsis megacarpa on mortality, longevity development and feeding preference of Crocidolomia pavonana larvae. Extraction conducted by infusion method. The bioassay assesment was carried out using the residual method. The concentration-mortality relationship was analyzed by probit. The antifeedant test was tested using choice and no-choice methods. Both extracts showed the same strong insecticidal activity, LC50 of 0.18% (leaf) and 0.12% (seed). Leaf and seed extracts at concentrations equivalent to LC50 and LC75 in both methods used showed consistent antifeedant properties. The antifeedant activity of extracts in the no-choice method at both concentrations showed a range of activities of 40.1%-53.7% (leaf) and 74.4%-82.7% (seed) extracts. The leaf and seed extracts of C. megacarpa did not significantly extend the larval development period. Plant material that has more than one bioactivity will be better for suppress the insect pest populations in the field.

Currently, interests in the cultivation of aromatic and medicinal plants gained a rapid momentum worldwide. These find great application in various industries such as; cosmetic, pharmaceutical, perfumery and other industrial sectors. Therefore, product safety issues are of paramount importance for the betterment of the consumer. Presently, heavy metal (HMs) pollution is one of the serious issues for the environment and agriculture as it has a direct impact on the production yield. This situation has worsened in the present era due to the population pressure, industrialization and various anthropogenic activities which in turn lead to oxidative stress in plants and thus disturbs the redox homeostasis and ultimate affects the quality and production yield. However, plants possess a different regulatory system that work in a synergetic manner to combat stress and thus adapts themselves in such contaminated soils. These act as sinks to neutralize the toxic effects of these heavy metals either by chelation, sequestration, intensification of enzyme system. Here we discuss the impact of heavy metals on aromatic and medicinal plants and how they play an essential role as a sustainable phytoremediation crops.

Trichogrammabrassicae Bezdenkois an important egg parasitoid of several lepidopteran insect pests. The parasitism potencial of this parasitoid is affected by insecticides applications. In this study, lethal and sublethal effects of propargite, benomyl, haloxyfop etotyl, imidacloprid and chlorpyrifos were evaluated on different life stages and biological parameters of the insect. Bioassays were carried out by residual contact method on adult stage of the parasitoid at 26±1 , 70±5% RH and a photoperiod of 16: 8 (L: D) h. The LC50 values of propargite, benomyl, haloxyfop etotyl, imidacloprid and chlorpyrifos were 753, 1190, 1731.6, 5.85 and 1.96 mg a.i./L on adult T. brassicae, respectively. The results of bioassays on adult stage showed that chlorpyrifos had the highest toxicity compared to the other tested pesticides. Field recommended rate of the pesticides excluding chlorpyrifos showed lower adverse effects on immature stages of the parasitoid. According to IOBC standards, propargite, benomyl, haloxyfop etotyl and imidacloprid were classified as harmless and chlorpyrifos as slightly harmful at immature stages. The sublethal effect studies revealed that LC30 of chlorpyrifos and propargite negatively affected the fecundity and fertility of the females; but the other pesticides did not. Intrinsic rate of increase (rm) values for propargite, benomyl, haloxyfop etotyl, imidacloprid and chlorpyrifos were 0.344, 0.322, 0.338, 0.337, 0.334 and 0.318 (female offspring/female/day), respectively. Results showed that almost all pesticides excluding chlorpyrifos had less adverse effects on the parasitoid. Therefore, propargite, benomyl, haloxyfop etotyl and imidacloprid can be choose for further evaluation including semifield and field studies. Whether getting suitable results in field studies they would be used in combination with T. brassicae as biological control agent in integrated pest management (IPM) programs.

Passive integrated transponder (PIT) tags allow a range of individual-level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black-capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio-frequency identification (RFID) redetections of leg band PIT tags to evaluate sex-specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine. [ABSTRACT FROM AUTHOR]

Passive integrated transponder (PIT) tags allow a range of individual-level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black-capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio-frequency identification (RFID) redetections of leg band PIT tags to evaluate sex-specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine. [ABSTRACT FROM AUTHOR]

The use of pesticides for greenbug, Schizaphis graminum in wheat not only can manage the pest population but also can influence its predator, Coccinella septempunctata. Acute and chronic effects of imidacloprid, clothianidin and sulfoxaflor on S. graminum and its predator, C. septempunctata were investigated. The results showed that LC50 of imidacloprid, clothianidin and sulfoxaflor to S. graminum at 48 h was 9.80, 34.29 and 4.40 ml a.i. L−1, respectively, while LC50 of imidacloprid, clothianidin and sulfoxaflor to C. septempunctata at 48 h was 107.80, 49.52 and 379.26 ml a.i. L−1. Sulfoxaflor and clothianidin were found the most toxic to S. graminum and C. septempunctata, respectively. Tested sublethal doses (LC10 and LC30) of all insecticides had significant effects on percent repellency of both S. graminum and C. septempunctata. Sulfoxaflor and clothianidin proved the most repellent to S. graminum (67.00 ± 2.03% at LC10 and 86.20 ± 1.62% at LC30) and C. septempunctata (50.60 ± 2.81% at LC10 and 60.00 ± 3.26% at LC30), respectively. Sublethal doses also demonstrated significant and the lowest percentage reduction in feeding by C. septempunctata on S. graminum in sulfoxaflor treatment (LC10: 4.13 ± 0.61%; LC30: 5.26 ± 0.69%). Additionally, sublethal doses reduced body-weight of C. septempunctata adults emerged from its treated grubs. These results revealed that sublethal doses of sulfoxaflor, imidacloprid and clothianidin negatively affected the biological activities of S. graminum and C. septempunctata as compared to control. Hence it can be concluded that more attention should be paid towards strategic application of these chemicals as a part of an integrated pest management program for an agro-ecosystem exhibiting maximum activity of coccinelid-predators. Overall, sulfoxaflor proved more appropriate for use against S. graminum in C. septempunctata manipulated agro-ecosystem. However, C. septempunctata compatible integration-strategy for field-application of sulfoxaflor should be devised to enhance its effectiveness against S. graminum and selectivity against C. septempunctata. [ABSTRACT FROM AUTHOR]

Invasive predators might serve as ecological filters for prey communities, either through non-consumptive or consumptive effects. The Western Mosquitofish (Gambusia affinis [Baird and Girard, 1853]) is an invasive non-native fish that affects native aquatic communities, potentially because of effects on oviposition or initial colonization of habitats (non-consumptive effects), post-colonization effects (i.e., consumptive effects), or a combination of both non-consumptive and consumptive effects. We conducted a mesocosm experiment to examine non-consumptive and consumptive effects of G. affinis on colonization of experimental ponds by native macroinvertebrates. We predicted that, if G. affinis affects macroinvertebrates through non-consumptive effects, there would be lower abundances in both the non-lethal (caged G. affinis) and lethal (free-ranging G. affinis) treatments compared to the control (no G. affinis), whereas, if the effect of G. affinis is primarily due to consumptive effects, there would be lower abundances of macroinvertebrates in the lethal treatment compared to the non-lethal and control treatments. Most macroinvertebrate taxa (dytiscid beetles, baetid Ephemeroptera, corixid and gerrid hemipterans, libellulid odonates) were less abundant, or even absent, in the presence of G. affinis in the lethal treatment compared to their abundance in the non-lethal G. affinis treatment; however, notonectids were not affected by treatment. The invasive fish predator, G. affinis , therefore, can act as an ecological filter for macroinvertebrates in invaded aquatic habitats, primarily through lethal consumptive effects. [ABSTRACT FROM AUTHOR]

Top‐predators can suppress mesopredator behaviour through risk effects. However, there is limited understanding of whether such behavioural suppression can dampen the lethal and sub‐lethal effects of mesopredators on bottom level prey. Here, we document a field experiment that examines whether the presence of top‐predator cues (visual and chemical stimuli from a coral trout) can cascade to indirectly influence the behaviour and survival of juvenile fish prey of different species (Pomacentrus amboinensis and P. chrysurus) and size (small = 1.18 cm SL versus large = 1.32 cm SL). Results showed that habitat patches exposed to top‐predator cues received fewer visits and foraging attacks from mesopredators, leading to higher space use (~ 46%), feeding rate (~ 95%) and survival (~ 67%) from juvenile fish prey. Survival was always higher for individuals of P. amboinensis and of large‐size, independent of the presence or absence of top‐predator cues. Our data indicate that predation risk from the top‐predator indirectly favoured the persistence and behaviour of juvenile fishes by promoting risk‐averse behavioural responses in mesopredators. This study underscores the behavioural mechanisms by which risk effects can cascade through the food web and highlights the consequences that harvesting top‐predators may have on the replenishment of bottom prey populations. [ABSTRACT FROM AUTHOR]

Salinization in freshwaters is gradually increasing as a result of human activities and climatic changes. Higher salt content causes stress for freshwater organisms. Sodium chloride (NaCl) is among the most frequently occurring salts in freshwater ecosystems. The objective of the present study was to investigate the lethal and sublethal effects of NaCl on freshwater ecosystems, using as test organism the dipteran Chironomus xanthus and the planarian Girardia tigrina. Acute tests showed that C. xanthus was more sensitive (48-h LC50 (median lethal concentration) of 2.97 g NaCl L−1) than G. tigrina (48-h LC50 of 7.77 g NaCl L−1). C. xanthus larvae growth rate (larvae length and head capsule width) was significantly reduced under exposure to concentrations as low as 0.19 g L−1 NaCl and higher. A delay in the emergence time (EmT50) was also demonstrated for the same concentration. Sublethal NaCl effects in G. tigrina included feeding inhibition (LOEC (lowest observed effect concentration) of 0.4 g L−1), reduced locomotion (LOEC = 0.2 g L−1), and 24–48-h blastema regeneration (LOEC = 0.2 g L−1 and 0.1 g L−1, respectively). The results demonstrated the toxicity of NaCl to C. xanthus and G. tigrina including sublethal effects that can result in negative consequences for populations in natural freshwaters under salinization. [ABSTRACT FROM AUTHOR]

Reef sharks may be ecologically redundant, such that other mesopredatory fishes compensate for their functions when they decline in number, preventing trophic cascades. Oral jaw gape, hereafter referred to as gape, determines maximum prey size in many piscivores and therefore affects the size structure of prey assemblages. Here, we examine whether gape and maximum prey size differ between five species of reef shark and 21 species of teleost (n = 754) using data collected from 38 reefs in the Indo-Pacific. Sharks displayed relatively small gape dimensions compared to most teleost species and, at smaller sizes, the giant trevally Caranx ignobilis and other teleosts may be able to consume larger prey than similar-sized sharks. However, ecological redundancy between reef sharks and teleosts appears to decline at larger sizes, such that the grey reef shark Carcharhinus amblyrhynchos, for example, may be capable of consuming larger prey than any other reef predator at its largest sizes, regardless of prey body shape. Moreover, sharks may be able to consume proportionally larger prey as they grow, in contrast to reef teleosts, which may largely be limited by their gapes to ever-smaller prey as a proportion of their body size. Our results also suggest that reef sharks may be unable to swallow whole prey that are > 36% of their length, consistent with gut-content studies. Conservation of reef ecological function may therefore depend not only on the protection of sharks but also particular size classes and key components of the mesopredatory guild. [ABSTRACT FROM AUTHOR]

Duckweeds, such as Lemna minor Linnaeus (Alismatales: Lemnaceae), are common in aquatic habitats and have been suggested to reduce larval mosquito survivorship via mechanical and chemical effects. Furthermore, pond dyes are used increasingly in aquatic habitats to enhance their aesthetics, although they have been shown to attract mosquito oviposition. The present study examined the coupled effects of L. minor and black pond dye on the oviposition selectivity of Culex pipiens Linnaeus (Diptera: Culicidae) mosquitoes in a series of laboratory choice tests. Subsequently, using outdoor mesocosms, the combined influence of duckweed and pond dye on mosquito abundances in aquatic habitats was quantified. Mosquitoes were strongly attracted to duckweed, and oviposited significantly greater numbers of egg rafts in duckweed‐treated water compared with untreated controls, even when the duckweed was ground. The presence of pond dye interacted with the duckweed and further enhanced positive selectivity towards duckweed‐treated water. The presence of duckweed caused significant and sustained reductions in larval mosquito numbers, whereas the relative effects of dye were not evident. The use of floating aquatic plants such as duckweed, combined with dye, may help reduce mosquito populations via the establishment of population sinks, characterized by high rates of oviposition coupled with high levels of larval mortality. [ABSTRACT FROM AUTHOR]

Anticoagulant rodenticides have been detected in many species of wildlife worldwide. However, the origins, exposure pathways, and effects of this exposure are not well understood. To accurately characterize the risks to wildlife from rodenticide use, better information is needed regarding the proportion of populations being exposed, what proportion of individuals in populations are affected, and in what ways. The relationship between anticoagulant rodenticide concentrations found in wildlife and the rate of mortality or illness have been the subjects of much research. Residue levels observed in liver and whole-body analyses vary and overlap extensively among apparently healthy asymptomatic individuals and sublethal and lethal cases. Results from laboratory studies also show there can be wide variability in lethal and sublethal effects among and within taxonomic groups. Correlating the sublethal and reproductive effects observed in laboratory studies with realistic exposure scenarios and effects in the wild is needed to improve risk assessments. For species with limited numbers or declining populations, a critical question yet to be answered is if the rodenticide exposure documented in individual animals inhibits population growth or contributes to population declines by lowering survival and reproductive success. This information is essential to the regulatory agencies that must weigh the risks and benefits of rodenticide uses and identify restrictions that are effective in reducing risks to wildlife.

The wheat aphid Rhopalosiphum padi (Linnaeus) (Hemiptera: Aphididae) is a devastating pest of wheat crops worldwide. Dinotefuran, a novel neonicotinoid insecticide, has been used to prevent piercing-sucking agricultural insects, such as R. padi. This research showed that the dinotefuran not only caused direct mortality but also affected the physiology of R. padi via sublethal effects. In this study, residual film bioassay results indicated that there were no significant differences in the toxicity of dinotefuran between field in 2017 and laboratory strains. However, the longevity, fecundity and female preoviposition of the F0 generation were significantly decreased by exposure to different sublethal doses (L10, L20 and L30) of dinotefuran. In contrast, the fecundity and female preoviposition of the F1 generation were significantly increased by the sublethal treatment L20, although this dose reduced net reproductive rate, intrinsic rate of increase and finite rate of increase. These findings are the first laboratory evidence of hormesis attributable to low dinotefuran doses. Developmental duration of nymphs was significantly increased by the sublethal doses L20 and L30 but not L10. Sublethal exposure to dinotefuran can increase the transgenerational population growth of R. padi and affected demographic parameters of the target insect. This study provides useful data for developing management strategies for R. padi involving the use of dinotefuran. [ABSTRACT FROM AUTHOR]

Anticoagulant rodenticides have been detected in many species of wildlife worldwide. However, the origins, exposure pathways, and effects of this exposure are not well understood. To accurately characterize the risks to wildlife from rodenticide use, better information is needed regarding the proportion of populations being exposed, what proportion of individuals in populations are affected, and in what ways. The relationship between anticoagulant rodenticide concentrations found in wildlife and the rate of mortality or illness have been the subjects of much research. Residue levels observed in liver and whole-body analyses vary and overlap extensively among apparently healthy asymptomatic individuals and sublethal and lethal cases. Results from laboratory studies also show there can be wide variability in lethal and sublethal effects among and within taxonomic groups. Correlating the sublethal and reproductive effects observed in laboratory studies with realistic exposure scenarios and effects in the wild is needed to improve risk assessments. For species with limited numbers or declining populations, a critical question yet to be answered is if the rodenticide exposure documented in individual animals inhibits population growth or contributes to population declines by lowering survival and reproductive success. This information is essential to the regulatory agencies that must weigh the risks and benefits of rodenticide uses and identify restrictions that are effective in reducing risks to wildlife. [ABSTRACT FROM AUTHOR]

As several reports of impacts arise due to the use of synthetic insecticides, the investigation for safer alternative insecticides should be continued. Using plant material that has several bioactivities is a promising way out to control insect pest. The objective of this study was to evaluate the effect of leaf and seed extract of Castanopsis megacarpa on mortality, longevity development and feeding preference of Crocidolomia pavonana larvae. Extraction conducted by infusion method. The bioassay assesment was carried out using the residual method. The concentration-mortality relationship was analyzed by probit. The antifeedant test was tested using choice and no-choice methods. Both extracts showed the same strong insecticidal activity, LC50 of 0.18% (leaf) and 0.12% (seed). Leaf and seed extracts at concentrations equivalent to LC50 and LC75 in both methods used showed consistent antifeedant properties. The antifeedant activity of extracts in the no-choice method at both concentrations showed a range of activities of 40.1%-53.7% (leaf) and 74.4%-82.7% (seed). The leaf and seed extracts of C. megacarpa did not significantly extend the larval development period. Plant material that has more than one bioactivity will be better for suppress the insect pest populations in the field. [ABSTRACT FROM AUTHOR]

Studies on invertebrates and small vertebrates demonstrated the underappreciated importance of the non-consumptive effects (NCE) of predators on their prey. Recently, there has been a growing interest for such effects in large vertebrates. Here, we review the empirical literature on large carnivore-ungulate systems to map our knowledge of predation NCE (from trait modification to the consequences on prey populations), and identify the gaps in our approaches that need to be fulfilled to reach a comprehensive understanding of these NCE. This review reveals (i) biases in the studies towards North American (and to a lesser extent African) ecosystems, protected areas, and investigation of NCE by wolf Canis lupus (and to a lesser extent African lion Panthera leo); (ii) a diversification of the systems studied in the past decade, which led to contrasted conclusions about the existence of NCE; (iii) that most existing work studied the effects caused by one predator only, even in ecosystems characterized by a rich carnivore community; and (iv) that the majority of the literature on NCE focused on the anti-predator behavioural responses of prey, whereas this is only the tip of the iceberg of NCE. Indeed, little is known on the other NCE components (energetic costs, stress, reproduction, survival, and population dynamics) and the links between the different components. Linking anti-predator behavioural responses to demography is thus the key challenge ahead of us to fully understand the NCE of predators on their prey in large mammals. • Review of empirical works on non-consumptive effects of predation in large mammals • A diversification of the systems studied has started and needs to continue • Most existing work took into account one predator species only • Most studies focused on the anti-predator behavioural responses of prey • Linking these responses to prey demography is the key challenge ahead of us [ABSTRACT FROM AUTHOR]

• Toxicity of three γ-Al 2 O 3 nanoceramics (SPC, PC, NC) was evaluated on amphibian development. • Toxicity of PC and NC increased with exposure time and very low sensitivity to SPC. • NCs exposed larvae showed severe morphological and behavioral alterations. • Pharyngeal and intestinal epithelia of NCs exposed larvae exhibited alterations. • Results indicate the vulnerability of R. arenarum embryo-larval development to these NCs. Alumina nanoparticles (NP-Al 2 O 3) are widely used but their environmental effects are unknown, so they can become potentially dangerous. The aim of this study was to evaluate the toxicity of a nanoceramic catalyst Ni/γ-Al 2 O 3 (NC) and NPs involved in their synthesis, γ-Al 2 O 3 support (SPC) and NiO/γ-Al 2 O 3 precursor (PC) on Rhinella arenarum embryo-larval development. The NPs toxicity significantly increased over time obtaining a similar sensitivity to PC and NC (336 h-LC50 = 4.03 and 5.11 mg/L respectively) and very low sensitivity to SPC (336 h-LC50 = 90.83 mg/L). Embryos exposed to SPC and PC exhibited general underdevelopment, axial flexures and behavioral alterations. Pharyngeal and intestinal epithelia alterations at the level of cell surface as dissociation, apoptosis and numerous lysosomes were observed at light and transmission electronic microscopy. Images of scanning electron microscope with backscattered electron detector revealed the presence of nickel in the intestinal epithelium. The increased toxicity of PC could be due to the presence of Ni as oxide which could interfere with vital functions such as breathing and feeding. Taking into account the exponential production and use of these NPs it is expected that their pollution levels will considerably increase and amphibians will be more exposed and at higher risk. [ABSTRACT FROM AUTHOR]

The effects of co-occurring harmful algal blooms (HABs) on marine organisms is largely unknown. We assessed the individual and combined impacts of the toxin producing HABs, Alexandrium catenella and Dinophysis acuminata , and a non-toxin-producing HAB (Gymnodinium instriatum) on early life stages of two estuarine fish species (Menidia beryllina and Cyprinodon variegatus). Lethal (i.e. time to death) and sublethal (i.e. growth, grazing rate, and swimming activity) effects of cultured HABs were investigated for eleutheroembryo and larval life stages. Mixed algal treatments (i.e. A. catenella and D. acuminata mixtures) were often equally toxic as A. catenella monoculture treatments alone, although responses depended on the fish species and life stage. Fish exposed to toxin producing HABs died significantly sooner (i.e. <1–3 days) than controls. Significant differences in sublethal effects were also found between fed controls and toxic HAB treatments, although responses were often similar to G. instriatum or starved controls. Collectively, the results demonstrate that HABs may reduce fish productivity and fitness. [ABSTRACT FROM AUTHOR]

Abstract The final fate of many drugs is release into the natural aquatic environment. It is necessary to assess the toxicity caused by this situation and the associated concerns for human beings. Zebrafish (Danio rerio) is a common biomodel used to assess toxicity in aquatic environments. The zebrafish embryo toxicity test was selected to evaluate the acute toxicity of several drugs (diphenhydramine, gentamicin, tobramycin, enalapril and lidocaine) due to the lack of such information. Lethal and sublethal effects were detected, and the LC 50 values of the drugs ranged from 11.0 mg/L to 422·102 mg/L. For all of the drugs tested, these values were higher than the concentrations found in the natural environment. Therefore, there was a low environmental toxicological risk. Nevertheless, teratogenic effects were also recorded when embryos of zebrafish were exposed to caffeine (control drug), diphenhydramine and lidocaine at lower concentrations than the respective LC 50 values. Quantitative structure–activity relationship analysis was also performed to analyse these drugs and other chemicals with pharmaceutical uses as well as previous toxicological data in this vertebrate after 48 h of exposure. It is estimated that the partition coefficient, log P, is the main physicochemical property related to the ecotoxicological data and can be used for the development of a mathematical model. Highlights • The FET was selected to evaluate the acute toxicity of several drugs. • Results indicate a low environmental risk (LC 50 > environmental concentration). • The QSAR revealed that Log P is the property that best fits the data. • QSAR analysis improves the correlation when lethal activity is using for classifying. • For Cramer classification, class I chemical group showed the best correlation. [ABSTRACT FROM AUTHOR]

Predation is a fundamental force exerting strong selective pressure on prey populations. Predators not only kill prey, triggering lethal effects, but also hunt prey which can induce risk effects. Foundational research has documented the importance of risk effects in predator-prey systems of arthropods, fish, birds, and rodents, among others. Risk effects research in carnivore-ungulate systems has expanded in the last 20 years. Presently, the degree to which this research mirrors the complexity of carnivore-ungulate trophic systems has been questioned. We synthesized this literature to quantify the tendency of risk effects research in carnivore-ungulate systems to be multispecies in design. Among the 170 studies that we reviewed, we found that on average just 1.26 (range = 1 to 5) carnivore species and 1.60 (range = 1 to 11) ungulate species were considered per study. Furthermore, 63% (n = 107 of 170) of the studies featured single predator - single prey research designs. These results contrast with the fact that all but one of the 82 carnivore-ungulate systems used this literature had multiple species of carnivores and/or ungulates. Thus, we detected a tendency to simplify complex systems. We relate these observations to the role of simplicity as: i) an underlying value of science (i.e., Occam's razor), ii) a cornerstone of predator-prey theory (e.g., Lotka-Volterra equations), and iii) part of the origins of risk effects research (i.e., experimental systems). Finally, we ground our discussion in the implications of this research for the conservation of carnivores and ungulates in the dynamic 21st century. • Predators not only kill prey, triggering lethal effects, but also hunt prey which can induce risk effects • The degree to which this research mirrors the complexity of carnivore-ungulate trophic systems has been questioned • We quantified the tendency of risk effects research in carnivore-ungulate systems to be multispecies in design • We found that on average just 1.26 carnivore species and 1.60 ungulate species were considered per study • Thus, we detected a tendency to simplify complex systems in carnivore-ungulate risk effects research [ABSTRACT FROM AUTHOR]

Effects of the water-soluble extracts (dry leaf powder of Azadirachta indica, Datura stramonium and Acanthus ilicifolius) were studied on the behavioral pattern and mortality of Artemia species. The extracts of all the plants brought significant change in the behavioral pattern of Artemia. The Artemia become agitated just offer exposure to the extract and started to move upwards and downwards vigorously. The Artemia exposed to the various concentration of water-soluble plant extracts were unable to maintain dorsoventral position and dropped to the bottom finally. The mortality rates recorded after 24 h exposure to the extract Azadirachta indica were 30% at 1500 mg/L and 70% at 3000 mg/L. Similarly, after 24 h exposure to the extracts of Datura stremonium, the mortality rates were 40% at 2000 mg/L and 75% at 3500 mg/L. Again, after 24 h has exposure to the extracts of Acanthus ilicifolius, the mortality rates were 35% at 2500 mg/L and rose to 80% at 4000 mg/L. The 24 h LC50 values of the water-soluble extracts of Neem, Datura and Acanthus were 2331.930, 2357.948 and 2922.957. Artemia was more sensitive to the watersoluble extract of Neem than Datura and Acanthus. [ABSTRACT FROM AUTHOR]

Assessment of the susceptibility of natural enemies of pests to selective pesticides is relevant for a sustainable agriculture with low impact on the environment. The aim of this study was to assess the toxicity of two biorational insecticides, azadirachtin and pyriproxyfen in comparison to a neonicotinoid insecticide, acetamiprid, on pupae and adults of a Neotropical strain of Eretmocerus mundus . Adult emergence and survival were evaluated as lethal effects whereas the sublethal effects were assessed through the reproductive capacity, sex ratio, and longevity of the surviving first progeny. Adult emergence from treated pupae was reduced by all three insecticides, but azadirachtin at its maximum field recommended concentration (MFRC) proved the most toxic insecticide. The survival probability of emerged adults was reduced by the three insecticides below than 50% from 2 to 5 days after the adult emergence. Malformations in nonemerged adults from treated pupal hosts were observed at the MFRC of all three insecticides. Sublethal effects on survivors from pupal treatment could be evaluated at only the lowest azadirachtin concentration. At that concentration, though azadirachtin did not affect the reproductive capacity of females, the sex ratio and the longevity of the first progeny were disrupted. The survival of parasitoid adults after adult exposure was reduced by all three insecticides, pyriproxyfen at the MFRC being the most toxic. All insecticides at their half of MFRCs induced sublethal effects in the survivors’ adults, with pyriproxyfen being the most harmful to the reproductive capacity of females. In conclusion, both biorational insecticides were toxic to E. mundus . [ABSTRACT FROM AUTHOR]

We analyzed the acute toxicity of the 48% glyphosate (GLY)-based Credit ® , the 57.71% dicamba (DIC)-based Kamba ® , and the 83.5% 2,4-dichlorophenoxyacetic acid (2,4-D)-based Weedar ® Full, alone and as mixtures on the fish Cnesterodon decemmaculatus . Mortality revealed the LC 50 96h values of 91.73 mg L −1 (range: 86.80–98.00 mg L −1 ), 1401.57 mg L −1 (range: 1243.78–1527.35) and 678.04 mg L −1 (range: 639.35–718.04 mg L −1 ) for GLY, DIC and 2,4-D, respectively. Mean values for the toxic unit (TU) that induced 50% mortality (TU 50 96h ) of fish exposed to equitoxic mixtures were 1.67 (range: 1.65–1.69) for Credit ® and Kamba ® and 1.28 (range: 1.20–1.36) for Credit ® and Weedar ® Full suggesting that both mixtures are antagonic. Non-equitoxic combinations demonstrated an antagonistic interaction of herbicides Credit ® and Kamba ® , whereas a synergistic effect was observed for Credit ® and Weedar ® Full formulations. GLY and DIC as a mixture demonstrated lower toxicity on non-target species compared to GLY and 2,4-D in combination, at least for C. decemmaculatus , leading to the conclusion that the former combination could be strongly recommended in further agricultural practices. [ABSTRACT FROM AUTHOR]

Agricultural fungicide application in Argentina has increased twice since 2008, with Maxim® XL (2.5% fludioxonil +1% metalaxyl-M) as one of the most used fungicide formulation. The toxicity of this pesticide on Rhinella arenarum was assessed by means of continuous (from embryo and larval development) and 24-h pulse exposure standardized bioassays. Lethality was concentration- and exposure time-dependent. Maxim® XL caused a progressive lethal effect along the bioassays with higher toxicity on embryos than larvae, obtaining 50% lethal concentrations at 96, 336, and 504 h of 10.85, 2.89, and 1.71 mg/L for embryos, and 43.94, 11.79, and 5.76 mg/L for larvae respectively. Lethal 504-h no observed effect concentration values for embryos and larvae were 1 and 2.5 mg/L respectively. A stage-dependent toxicity of Maxim® XL was also demonstrated within the embryo development, with early stages more sensitive than the later ones, and blastula as the most sensitive developmental stage. The risk quotients obtained for chronic risk assessment determined a potential threat for the survival and continuity of R. arenarum populations under these conditions. The results indicate that the levels of the fungicide reaching amphibian habitats could be risky for the early development of this amphibian species. This study also emphasizes the necessity to evaluate the chronic effects of fungicides in pesticide risk assessment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Southern Agriculture is the property of Journal of Southern Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two of the most applied auxinic herbicides worldwide, both individually and as part of a mixture. However, the toxicity and interactions achieved when applied as a mixture have not yet been characterised. The equitoxic and non-equitoxic acute toxicity exerted by binary mixtures of Banvel ® (57.71% DIC) and DMA ® (58.4% 2,4-D) on the Neotropical fish Cnesterodon decemmaculatus were evaluated. Results revealed mean values of 1.02 (range, 0.96–1.08) for the toxic unit (TU) that induced 50% mortality (TU 50 96 h ) to the fish exposed to binary equitoxic mixtures of the commercial formulations Banvel ® –DMA ® . These results suggest that the mixture is nearly concentration additive. Furthermore, results demonstrated the occurrence of synergistic interaction when non-equitoxic combinations of Banvel ® -or DMA ® -formulated herbicides were assayed. In this context and regardless of their concentrations, either Banvel ® - or DMA ® -induced toxicity were synergised by the presence of the counterpart within mixtures. The present study represents the first evidence of the lethality exerted by mixtures of two auxinic herbicides—namely, DIC and 2,4-D—reported to date for fish and other biotic matrices. When C. decemmaculatus is used as the target organism, a synergistic pattern is observed following exposure to a mixture of both herbicides. [ABSTRACT FROM AUTHOR]

Prolonged exposure to a disturbance such as a toxicant has the potential to result in rapid evolution to toxicant resistance in many short-lived species such as daphniids. This evolution may allow a population to persist at higher levels of the toxicant than is possible without evolution. Here we apply evolutionary game theory to a Leslie matrix model for a daphniid population to obtain a Darwinian model that couples population dynamics with the dynamics of an evolving trait. We use the Darwinian model to consider how the evolution of resistance to the lethal or sublethal effects of a disturbance may change the population dynamics. In particular, we determine the conditions under which a daphniid population can persist by evolving toxicant resistance. We then consider the implications of this evolution in terms of the use of daphniids as surrogate species. We show for three species of daphniids that evolution of toxicant resistance means that one species may persist while another does not. These results suggest that toxicant studies that do not consider the potential of a species (or its surrogate) to develop toxicant resistance may not accurately predict the long term persistence of the species. [ABSTRACT FROM AUTHOR]

Mucus secretions play a number of functions related to polychaete physiology and ecology. Under stress conditions, the polychaete Halla parthenopeia (Oenonidae) produces a purple mucus after mechanical stimulation, whose function is still unknown. Here, we assessed the toxicity of this purple mucus by means of both acute toxicity bioassays on the polychaete Dinophilus gyrociliatus and commercial ecotoxicological kits (Microtox®, Rotoxkit® and Artoxkit®). Palatability was also tested with the fish Oryzias melastigma. After emitting purple mucus, H. parthenopeia quickly moves away and starts releasing transparent mucus. Acute toxicity bioassays showed that the mucus was harmless (transparent), or lethal even when diluted about 1000 times (purple). Purple mucus was toxic at different concentrations, the LC50 ranging from 0.7-0.3 g l–1 for D. gyrociliatus to 76 g l–1 for Artemia franciscana (Artoxkit®). Freeze-dried brine shrimp coated with transparent or purple muci were both consumed by O. melastigma. We hypothesized that the purple mucus is involved in the chemical defence of H. parthenopeia against competitors and parasites, and that its colour and toxicity are due to hallachrome, a 1,2-anthraquinone found in the skin of H. parthenopeia.

The negative impact of conventional pesticides on the environment is already extensively discussed worldwide. Although the use of chemical agents for controlling agricultural pests remains as first-line strategy for pest control, novel biorational active insecticides, such as spirotetramat, have appeared in the pesticide market during recent years in Argentina. The aim of this study was to assess the toxicity of spirotetramat on two developmental stages of a Neotropical strain of Eretmocerus mundus, with the conventional insecticide cypermethrin as a positive control, and to determine spirotetramat's side effects on parasitoid demographic parameters. Lethal effects of both insecticides on pupae and adults were evaluated by adult emergency and survival, respectively; whereas sublethal effects on both development stages were assessed by adult longevity, reproduction capacity, sex ratio, and longevity of the first progeny. Spirotetramat proved less harmful than cypermethrin at both developmental stages studied, corroborating once more the high toxicity of this pyrethroid to natural enemies. Although spirotetramat did not affect the emergence and reproductive capacity of adults surviving pupal exposure, the longevity of the first progeny was reduced as was adult survival and longevity after exposure to residues. Spirotetramat also reduced all demographic parameters in the population evaluation. This work is the first report of spirotetramat toxicity at the population level and demonstrates the need to assess the total effect of pesticides on natural enemies. [ABSTRACT FROM AUTHOR]

Research was carried out for the appraisal of toxic and anti-enzymetic action of acetone extracts of Datura inoxia and Azadirachta indica against Tribolium castaneum, Trogoderma granarium and Sitophilus granarius in the grain research training and storage management cell of department of entomology and in protein molecular biology laboratory (PMBL) department of biochemistry (UAF) during the year 2014. Various dilution levels viz., 5.0, 10.0, 15.0 and 20.0% of both plants extracts were assessed against test insects. Toxic effect of plant extracts in T. castaneum, T. granarium and S. granarius was observed after an exposure period of 2, 4, 6, 8 and 10 days while inhibition of different enzymes acetylcholinesterase (AChE), α-carboxylesterase (α-CE), β-carboxylesterase (β-CE), acid phosphatases (ACP) and alkaline phosphatases (ALP) were calculated spectrophotometrically in the survivors of toxicity assay. The results evidenced that both plant extracts had lethal effects against three stored grain insect species. Comparison of means of mortality in T. castaneum, T. granarium and S. granarius proved that A. indica extract was more effective, causing maximum 38.41, 24.35 and 28.56% mortality, respectively. D. inoxia resulted in 15.12, 13.52 and 14.07% maximum mortality in T. castaneum, T. granarium and S. granarius, respectively. The results also revealed significant inhibition of AChE, α-CE, β-CE, ACP and ALP upon exposure to various concentrations of tested plants. Plant extract of A. indica proved more efficient for the inhibition of all test enzymes in three stored grain insect pests. The results suggest the ability of using these plants extracts for wheat flour and grains protection as a safe alternative to insecticides. [ABSTRACT FROM AUTHOR]

Nanosized titanium dioxide (nTiO 2 ) is widespread in many commercial products and several authors investigated its ecotoxicity effects focusing mainly on freshwater environments. Data on saltwater species are still lacking or present contradicting results. We compared for the first time the toxicity of TiCl 4 and nTiO 2 considering standard toxicity tests with microalgae Phaeodactylum tricornutum (growth inhibition test, 1.8–90 mg/L) and crustacean Artemia franciscana (mortality test, 0.5–64 mg/L). For A. franciscana , two alternative scenarios were considered beside standard protocol: i) darkness; and ii) starvation. About microalgae, results evidenced that effects of TiCl 4 (EC50 = 63 mg/L) were greater than nTiO 2 (no EC50), but IC10 and IC20 were significantly lower suggesting that nTiO 2 is more harmful than TiCl 4 at lower concentrations. The effects of TiCl 4 to crustaceans larvae in all exposure scenarios were lower compared to nTiO 2 (EC50(96 h) = 15 mg/L - standard protocol). During toxicity testing, the absence of light generally lowered nTiO 2 effects while starvation increased the toxicity of both TiCl 4 and nTiO 2 . [ABSTRACT FROM AUTHOR]

The acute toxicity of two herbicide formulations, namely, the 57.71 % dicamba (DIC)-based Banvel and the 48 % glyphosate (GLY)-based Credit, alone as well as the binary mixture of these herbicides was evaluated on late-stage Rhinella arenarum larvae (stage 36) exposed under laboratory conditions. Mortality was used as an endpoint for determining acute lethal effects, whereas the single-cell gel electrophoresis (SCGE) assay was employed as genotoxic endpoint to study sublethal effects. Lethality studies revealed LC50 values of 358.44 and 78.18 mg L DIC and GLY for Banvel and Credit, respectively. SCGE assay revealed, after exposure for 96 h to either 5 and 10 % of the Banvel LC50 concentration or 5 and 10 % of the Credit LC50 concentration, an equal significant increase of the genetic damage index (GDI) regardless of the concentration of the herbicide assayed. The binary mixtures of 5 % Banvel plus 5 % Credit LC50 concentrations and 10 % Banvel plus 10 % Credit LC50 concentrations induced equivalent significant increases in the GDI in regard to GDI values from late-stage larvae exposed only to Banvel or Credit. This study represents the first experimental evidence of acute lethal and sublethal effects exerted by DIC on the species, as well as the induction of primary DNA breaks by this herbicide in amphibians. Finally, a synergistic effect of the mixture of GLY and DIC on the induction of primary DNA breaks on circulating blood cells of R. arenarum late-stage larvae could be demonstrated. [ABSTRACT FROM AUTHOR]

Pesticides can be toxic to nontarget organisms including the natural enemies of agricultural pests, thus reducing the biodiversity of agroecosystems. The lethal and sublethal effects of four insecticides with different modes of action-pyriproxyfen, teflubenzuron, acetamiprid, and cypermethrin-were evaluated on pupae and adults of Eriopis connexa, an effective predator in horticultural crops. Pupal survival was reduced by pyriproxyfen (26 %) and cypermethrin (41 %). Malformations in adults emerged from treated pupae were observed after acetamiprid (82.7 and 100 % for 100 and 200 mg a.i./l, respectively), pyriproxyfen (48.6 %), and cypermethrin (13.3 %) treatments. A longer mean oviposition time was also observed in adults emerged from pupae treated with cypermethrin. Moreover, the latter insecticide as well as teflubenzuron did not reduce reproductive parameters, whereas females emerged from pyriproxyfen-treated pupae were not be able to lay eggs even when females showed large abdomens. Upon exposure of adults, survival was reduced to approximately 90 % by acetamiprid, but no reduction occurred with pyriproxyfen, teflubenzuron, or cypermethrin though the fecundity at fifth oviposition time of the female survivors was reduced. Pyriproxyfen decreased the hatching at all the oviposition times tested, whereas fertility was reduced in the fourth and fifth ovipositions by teflubenzuron and in the first and third ovipositions by cypermethrin. In conclusion, all four insecticides tested exhibited lethal or sublethal effects, or both, on E. connexa. The neurotoxic insecticides were more harmful than the insect-growth regulators, and pupae were more susceptible than adults. The toxicity of insecticides on the conservation of predators in agroecosystems of the Neotropical Region is discussed. [ABSTRACT FROM AUTHOR]

Production of bisphenol A (BPA) analogues such as bisphenol F (BPF) and bisphenol AF (BPAF) has recently increased, due to clear evidence of adverse effects of BPA on humans and wildlife. Bisphenols (BPs) have already been released into aquatic environment without previous available information about potential adverse effects of BPs and their potential risk to aquatic ecosystems. In this study, lethal and sublethal effects of BPF and BPAF to bacteria, algae, crustacea and fish embryos were investigated and the results were compared to the adverse effects obtained for BPA. We found that BPAF was the most toxic compound to Daphnia magna , Danio rerio and Desmodesmus subspicatus ; the lowest 72 h EC50 (median effective concentration) and 21 d NOEC (no observed effect concentration) values were determined at 2.2 mg/L regarding zebrafish hatching success and 0.23 mg/L of BPAF obtained for growth and reproduction of water fleas, respectively. In most cases, BPA was more toxic to D. magna , D. rerio and D. subspicatus in comparison to BPF, but pigmentation of zebrafish embryos after 48 h of exposure and reproduction of water fleas after 21-day D. magna reproductive test exposure to BPF were much more impaired. Risk quotients (measured environmental concentration/21 d NOEC) showed that BPA, BPF and BPAF are recently not chronically hazardous to the survival, reproduction and growth of water fleas in surface waters. On the other hand, we importantly show that currently present BPAF concentrations in surface waters could cause a potential ecological risk to aquatic organisms. In the near future, higher concentrations of BPF and BPAF in surface waters are anticipated and for this reason further testing using test systems with various aquatic species and endpoints are needed to provide additional information about toxic impacts of BPF and BPAF on aquatic biota. [ABSTRACT FROM AUTHOR]

Ecotoxicological assessment of three different wastewater treatment plant (WWTP) effluents D1, D2 and D3 was performed before and after tertiary treatment using combination of advanced oxidation processes (AOPs). A multibarrier treatment (MBT) consisting of microfiltration (MF), hydrogen peroxide photolysis (H 2 O 2 /UVC) and catalytic wet peroxide oxidation (CWPO) was applied for all effluents. Sparus aurata , Paracentrotus lividus , Isochrysis galbana and Vibrio fischeri, representing different trophic levels, constituted the battery of bioassays. Different acute toxicity effects were observed in each WWTP effluents tested. The percentage of sea urchin larval development and mortality fish larvae were the most sensitive endpoints. Significant reduction (p < 0.05) of effluent's toxicity was observed using a classification pT-method after MBT process. Base on obtained results, tested battery of bioassays in pT-method framework can be recommended for acute toxicity preliminary evaluation of WWTP effluents for the marine environment. [ABSTRACT FROM AUTHOR]