Effects of long-term alachlor exposure on hepatic antioxidant defense and detoxifying enzyme activities in crucian carp (Carassius auratus)

Fitness assessment of Mytilus galloprovincialis Lamarck, 1819 after exposure to herbicide metabolite propachlor ESA

The lack of data on the chronic effects of chloroacetanilide herbicide metabolites on non-target aquatic organisms creates a gap in knowledge about the comprehensive impacts of excessive and repeated pesticide use. Therefore, this study evaluates the long-term effects of propachlor ethanolic sulfonic acid (PROP-ESA) after 10 (T1) and 20 (T2) days at the environmental level of 3.5 μg.L^-1 (E1) and its 10x fold multiply 35 μg.L^-1 (E2) on a model organism Mytilus galloprovincialis. To this end, the effects of PROP-ESA usually showed a time- and dose-dependent trend, especially in its amount in soft mussel tissue. The bioconcentration factor increased from T1 to T2 in both exposure groups - from 2.12 to 5.30 in E1 and 2.32 to 5.48 in E2. Biochemical haemolymph profile and haemocyte viability were not affected by PROP-ESA exposure. In addition, the viability of digestive gland (DG) cells decreased only in E2 compared to control and E1 after T1. Moreover, malondialdehyde levels increased in E2 after T1 in gills, and DG, superoxidase dismutase activity and oxidatively modified proteins were not affected by PROP-ESA. Histopathological observation showed several damages to gills (e.g., increased vacuolation, over-production of mucus, loss of cilia) and DG (e.g., growing haemocyte trend infiltrations, alterations of tubules). This study revealed a potential risk of chloroacetanilide herbicide, propachlor, via its primary metabolite in the Bivalve bioindicator species M. galloprovincialis. Furthermore, considering the possibility of the biomagnification effect, the most prominent threat poses the ability of PROP-ESA to be accumulated in edible mussel tissues. Therefore, future research about the toxicity of pesticide metabolites alone or their mixtures is needed to gain comprehensive results about their impacts on living non-target organisms.

Sub-chronic ammonia exposure induces hepatopancreatic damage, oxidative stress, and immune dysfunction in red swamp crayfish (Procambarus clarkii)

Ammonia, as one of the primary water pollutants in aquaculture, has been shown to induce a wide range of ecotoxicological effects on aquatic animals. In order to investigate the antioxidant and innate immune responses in crustaceans disrupted by ammonia, red swamp crayfish (Procambarus clarkii) were exposed to 0, 15, 30, and 50 mg/L total ammonia nitrogen for 30 d, the alterations of antioxidant responses as well as innate immunity were studied. The results showed that the severity of hepatopancreatic injury were aggravated by the increasing ammonia levels, which were mainly characterized by tubule lumen dilatation and vacuolization. The swollen mitochondria and disappeared mitochondria ridges suggested that oxidative stress induced by ammonia targets the mitochondria. Concurrently, enhanced MDA levels, and decreased GSH levels as well as the decreased transcription and activity of antioxidant enzymes, including SOD, CAT, and GPx were noticed, which suggested that high concentrations of ammonia exposure induce oxidative stress in P. clarkii. Furthermore, a significant decrease of the hemolymph ACP, AKP, and PO along with the significant downregulation of immune-related genes (ppo, hsp70, hsp90, alf1, ctl) jointly indicated that ammonia stress inhibited the innate immune function. Our findings demonstrated that sub-chronic ammonia stress induced hepatopancreatic injury and exert suppressive effects on the antioxidant capacity as well as innate immunity of P. clarkii. Our results provide a fundamental basis for the deleterious effects of ammonia stress on aquatic crustaceans.

Cyhalofop-butyl and pyribenzoxim-induced oxidative stress and transcriptome changes in the muscle of crayfish (Procambarus clarkii)

Cyhalofop-butyl and pyribenzoxim are commonly used herbicides in rice-crayfish co-culture fields. In actual production, weed control in paddy fields is inseparable from cyhalofop-butyl and pyribenzoxim, while its risk to P. clarkii is still unclear. The present study investigated the risk of acute and subchronic toxicity of cyhalofop-butyl and pyribenzoxim to P. clarkii. The results showed that cyhalofop-butyl and pyribenzoxim exposure for 28 days could accumulate in P. clarkii muscle and inhibit P. clarkii growth. Further research found that the malondialdehyde (MDA) level and glutathione-S-transferase (GST) activity in muscle of P. clarkii were significantly increased after exposure to cyhalofop-butyl and pyribenzoxim (4 days and 28 days), and the superoxide dismutase (SOD) and catalase (CAT) activities were significantly altered. Histological results also confirmed cyhalofop-butyl and pyribenzoxim-induced muscle damage in P. clarkii. Additionally, after 28 days exposure to 1.02 mg/L cyhalofop-butyl and 10.4 mg/L pyribenzoxim, transcriptome analysis identified 2029 and 4246 differentially expressed genes (DEGs), respectively. Exposure to 1.02 mg/L cyhalofop-butyl significantly altered metabolism-related pathways, such as drug metabolism-other enzymes, glutathione metabolism, drug metabolism-cytochrome P450, fatty acid biosynthesis and fatty acid degradation. While the pathways related to antioxidant system and nutrient substances synthesis and metabolic were significantly enriched after exposure to 10.4 mg/L pyribenzoxim. This research has significant implications for scientific and rational use of herbicides under rice-crayfish co-culture and will contribute to the development of the highly productive agricultural model.

Oxidative stress, DNA damage, and gene expression induced by flufiprole enantiomers in the earthworms (Eisenia fetida)

To evaluate flufiprole enantiomers ecotoxicology and early warning to earthworms in the soil, the effect of flufiprole enantiomers on the activity of antioxidative enzymes (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD), malondialdehyde (MDA) content, DNA damage and expression level of target genes (SOD, TCTP, l-rRNA, and HSP90) have been investigated. Compared to the controls, the activities of SOD, CAT, POD, and MDA content were first inhibited and then stimulated by all concentrations of flufiprole enantiomers in 28 days. The olive tail moment (OTM) value was maximum on the 14th day, then decreased gradually, and the higher the concentration, the slower the decrease. The expression level of the SOD and TCTP genes increased first and then decreased. In conclusion, the toxicity of flufiprole enantiomers to earthworms is: R-(+)- flufiprole >Rac-(±)- flufiprole >S-(-)- flufiprole. The SOD could be the key biomarker for monitoring the risk of flufiprole enantiomers.

Accumulation of commonly used agricultural herbicides in coral reef organisms from iSimangaliso Wetland Park, South Africa

Coral reefs are amongst the most biodiverse ecosystems on earth, but are significantly impacted by agricultural runoff. Despite herbicides being commonly detected in coastal waters, the possibility of herbicide accumulation in coral reef species has largely been overlooked. We investigate the accumulation of several herbicides in five species of coral reef invertebrates collected from ten sites along the Maputaland coast, South Africa. Multiple herbicide residues were detected in 95% of the samples, with total average concentrations across sites ranging between 25.2 ng g^-1 to 51.3 ng g^-1 dw. Acetochlor, alachlor and hexazinone were the predominant herbicides detected at all sites, with atrazine and simazine detected less frequently. Significant interactive effects were detected between sites nested in reef complex crossed with species, based on multiple and total herbicide concentrations. In general, multivariate herbicide concentrations varied significantly between species within and across most sites. Contrastingly, the concentrations of the different herbicides and that of total herbicide did not differ between conspecifics at most sites nested in their respective reef complexes. On average, highest total herbicide concentrations were measured in soft coral (Sarcophyton glaucum; 90.4 ± 60 ng g^-1 and Sinularia gravis; 42.7 ± 25 ng g^-1) and sponge (Theonela swinhoei; 39.0 ± 40 ng g^-1) species, while significantly lower concentrations were detected in hard corals (Echinopora hirsutissima; 10.5 ± 5.9 ng g^-1 and Acropora austera; 5.20 ± 4.5 ng g^-1) at most sites. Agricultural runoff entering the ocean via the uMfolozi-St Lucia Estuary and Maputo Bay are likely sources of herbicide contamination to coral reefs in the region. There is an urgent need to assess the long-term effects of herbicide exposure on coral reef communities.

Induced Hepatic Glutathione and Metabolomic Alterations Following Mixed Pesticide and Fertilizer Exposures in Juvenile Leopard Frogs (Lithobates sphenocephala)

The increasing use of agrochemicals, alone and in combination, has been implicated as a potential causative factor in the decline of amphibians worldwide. Fertilizers and pesticides are frequently combined into single-use tank mixtures for agricultural applications to decrease costs while meeting the food demands of a growing human population. Limited data are available on the effects of increased nitrogen levels in nontarget species, such as amphibians, and therefore investigating alterations in the nitrogen cycle and its impacts on amphibians needs to be considered in best management practices going forward. The objective of the present study was to elucidate the impact of fertilizer (urea) and herbicide (atrazine and/or alachlor) tank mixtures on the hepatic metabolome of juvenile leopard frogs as well as to investigate alterations in oxidative stress by relating these changes to glutathione (GSH) levels. Herbicide exposure only moderately increased this parameter in amphibians, however, urea alone and in combination with either atrazine or alachlor statistically elevated GSH levels. Interestingly, urea also inhibited pesticide uptake: calculated bioconcentration factors were greatly decreased for atrazine and alachlor when urea was present in the exposure mixture. Metabolomic profiling identified fluxes in hepatic metabolites that are involved in GSH and carbohydrate metabolic processes as well as altered intermediates in the urea cycle. Ultimately, understanding the biological impacts of nitrogenous fertilizers alone and in combination with pesticide exposure will inform best management practices to conserve declining amphibian populations worldwide. Environ Toxicol Chem 2022;41:122-133. © 2021 SETAC.

Improving pollutants environmental risk assessment using a multi model toxicity determination with in vitro, bacterial, animal and plant model systems: The case of the herbicide alachlor

Several environmental pollutants, including pesticides, herbicides and persistent organic pollutants play an important role in the development of chronic diseases. However, most studies have examined environmental pollutants toxicity in target organisms or using a specific toxicological test, losing the real effect throughout the ecosystem. In this sense an integrative environmental risk of pollutants assessment, using different model organisms is necessary to predict the real impact in the ecosystem and implications for target and non-target organisms. The objective of this study was to use alachlor, a chloroacetanilide herbicide responsible for chronic toxicity, to understand its impact in target and non-target organisms and at different levels of biological organization by using several model organisms, including membranes of dipalmitoylphosphatidylcholine (DPPC), rat liver mitochondria, bacterial (Bacillus stearothermophilus), plant (Lemna gibba) and mammalian cell lines (HeLa and neuro2a). Our results demonstrated that alachlor strongly interacted with membranes of DPPC and interfered with mitochondrial bioenergetics by reducing the respiratory control ratio and the transmembrane potential. Moreover, alachlor also decreased the growth of B. stearothermophilus and its respiratory activity, as well as decreased the viability of both mammalian cell lines. The values of TC₅₀ increased in the following order: Lemna gibba < neuro2a < HeLa cells < Bacillus stearothermophilus. Together, the results suggest that biological membranes constitute a putative target for the toxic action of this lipophilic herbicide and point out the risks of its dissemination on environment, compromising ecosystem equilibrium and human health.

Spatiotemporal pattern models for bioaccumulation of pesticides in common herbaceous and woody plants

Pesticides are widely used in agriculture, but they can bioaccumulate in plants, entering the food chain and potentially threaten human health. Thus, this study explored the spatiotemporal patterns of pesticide bioaccumulation in plants from soil using a spatiotemporal model. Air temperature (T_Air) and relative humidity (RH_Air) were selected as the principal spatiotemporal indicators to characterize the seasonal and geographical variation of the pesticide bioaccumulation factors (BAFs; i.e., the pesticide concentration ratio of plant to soil) of the leaves of common plants. The simulation results indicate that hot and dry climates typically increase the pesticide BAFs by enhancing the transpiration rate of plants. For example, the annual average BAF of alachlor was 5.75 in Arizona, while the BAFs in states with cold and humid weather, such as Maine, were below 2.00. Additionally, the monthly average BAF of alachlor during hot seasons can be double that of other seasons in the same region. For some pesticides, the simulated BAF intervals were consistent with those reported in the literature, whereas for others, the results were inconsistent. The major reasons for these inconsistencies include differences in the pesticide application scenarios, the distribution of pesticides in different compartments, and insufficient field data for some pesticides. We also applied the simulated BAFs of pesticide in plant leaves to address the seasonal and geographical health risks of herbivores, which could help regulate pesticide standards in ecological soils.

The herbicide alachlor severely affects photosystem function and photosynthetic gene expression in the marine dinoflagellate Prorocentrum minimum

Alachlor is one of the most widely used herbicides and can remain in agricultural soils and wastewater. The toxicity of alachlor to marine life has been rarely studied; therefore, we evaluated the physiological and transcriptional responses in the marine dinoflagellate Prorocentrum minimum. The herbicide led to considerable decreases in P. minimum cell numbers and pigment contents. The EC₅₀ was determined to be 0.373 mg/L. Photosynthesis efficiency and chlorophyll autofluorescence dramatically decreased with increasing alachlor dose and exposure time. Real-time PCR analysis showed that the photosynthesis-related genes PmpsbA, PmatpB, and PmrbcL were induced the most by alachlor; the transcriptional level of each gene varied with time. PmrbcL expression increased after 30 min of alachlor treatment, whereas PmatpB and PmpsbA increased after 24 h. The PmpsbA expression level was highest (5.0 times compared to control) after 6 h of alachlor treatment. There was no significant change in PmpsaA expression with varying treatment time or concentration. Additionally, there was no notable change in the expression of antioxidant genes PmGST and PmKatG, or in ROS accumulation. These suggest that alachlor may affect microalgal photosystem function, with little oxidative stress, causing severe physiological damage to the cells, and even cell death.

Assessment of oxidative stress and phospholipids alterations in chloroacetanilides-degrading Trichoderma spp

To investigate the induction of oxidative stress and antioxidant response in the chloroacetanilides-degrading Trichoderma spp. under alachlor and metolachlor exposure, a comparative analysis using popular biomarkers was employed. An increased intracellular level of reactive oxygen species (ROS; especially superoxide anion [O₂^-]) as well as products of lipid and protein oxidation after 24 h incubation with the herbicides confirmed chloroacetanilide-induced oxidative stress in tested Trichoderma strains. However, the considerable decline in the ROS levels and the carbonyl group content (biomarkers of protein peroxidation) in a time-dependent manner and changes in the antioxidant enzyme activities indicated an active response against chloroacetanilide-induced oxidative stress and the mechanism of tolerance in tested fungi. Moreover, the tested herbicides clearly modified the phospholipids (PLs) content in Trichoderma spp. in the stationary phase of growth, which was manifested through the difference in phosphatidic acid (PA), phosphatidylethanolamine (PE) and phosphatidylcholines (PC) levels. Despite enhanced lipid peroxidation and changes in PLs in most tested fungi, only a slight modification in membrane integrity of Trichoderma spp. under chloroacetanilides exposure was noted. The obtained results suggest that the alterations in the antioxidant system and the PLs profile of Trichoderma spp. might be useful biomarkers of chloroacetanilide-induced oxidative stress.

Biochemical and morphological responses in Ucides cordatus (Crustacea, Decapoda) as indicators of contamination status in mangroves and port areas from northern Brazil

The aims of this study were to analyze biochemical and morphological responses (glutathione S-transferase activity and branchial lesions) in Ucides cordatus (crabs) and to verify how the species is responding to environmental contamination in a port (potentially contaminated area) and mangrove (reference area; Amazon Coast, Maranhão, Brazil). Adult males were captured bimonthly for a period of 1 year. Higher GST activity (1.03 ± 0.07 μmol min^-1 mg protein^-1) was observed in crabs in the port when compared with those in the reference area (p < 0.05). The greatest number of branchial lesions (serious alterations) was recorded in crabs only in the port area. The GST activity increased until serious lesions appeared; after this limit, GST activity decreased dramatically to very low levels, thus resulting in irreversible lesions (lamella collapse). The mathematical model based on the two parameters evaluated in U. cordatus showed that the port area experienced substantial contamination impact, while the mangroves (reference area) presented moderate environmental quality.

Endocrine and physiological effects of linuron and S-metolachlor in zebrafish developing embryos

Evaluation of the effects of linuron and S-metolachlor on apical, biochemical and transcriptional endpoints in zebrafish (Danio rerio) early life stages was the main purpose of this work. Embryos were exposed for 96h to a range of concentrations of each herbicide to determine lethal and sub-lethal effects on apical (e.g. malformations, hatching) and biochemical parameters (cholinesterase, ChE; catalase, CAT; glutathione S-transferase, GST; lipid peroxidation, LPO and lactate dehydrogenase, LDH). To evaluate endocrine disruption effects, embryos were exposed during 96h to 0.88mg/L linuron and 9.66mg/L S-metolachlor, isolated or in binary mixture. Expression of a suite of genes involved in HPT, HPG and HPA-axis was then assessed. Highest concentration of linuron (5.0mg/L) decreased hatching rate to 5% and 70.0mg/L S-metolachlor completely inhibited hatching, about 100%. Both herbicides impaired development by inducing several malformations (100% in 5.0mg/L linuron and 70.0mg/L S-metolachlor). Linuron only affected GST and CAT at concentrations of 0.25 and 0.0025mg/L, respectively. S-metolachlor induced GST (to 256%), inhibited ChE (to 61%) and LDH (to 60%) and reduced LPO levels (to 63%). Linuron isolated treatment seems to have an estrogenic mode of action due to the observed induction of vtg1. Exposure to S-metolachlor seems to interfere with steroidogenesis and with HPT and HPA-axis, since it has inhibited cyp19a2, TSHβ and CRH gene expression. In addition to vtg1 induction and CRH inhibition, herbicide combination also induced sox9b that has a role in regulation of sexual development in zebrafish. This study pointed out adverse effects of linuron and S-metolachlor, namely impairment of neurotransmission and energy production, induction of steroidogenesis, and interference with HPT and HPA-axis. These results contributed to elucidate modes of action of linuron and S-metolachlor in zebrafish embryo model. Furthermore, gene expression patterns obtained are indicative of endocrine disruption action of these herbicides.

Allelopathic effects of volatile organic compounds from Eucalyptus grandis rhizosphere soil on Eisenia fetida assessed using avoidance bioassays, enzyme activity, and comet assays

Allelopathy has been identified as an underlying mechanism of detrimental environmental impacts within commercial plantations. Eucalyptus spp. are known to generate huge amounts of volatile organic compounds (VOCs) that can function as phytotoxins and thus inhibit other plants. In the present study, biochemical markers, including activities of acetylcholinesterase (AChE) and oxidative stress enzymes, such as superoxide dismutase (SOD) and glutathione S-transferase (GST), were assayed to assess changes in Eisenia fetida at the physiological level induced by different doses of VOCs as part of an acute toxicity test over 7 and 14-day exposures. In addition, the toxicities of VOCs were investigated using a soil avoidance test and comet assay. The results revealed that E. fetida exhibited significant avoidance behavior towards the highest concentrations of undecane, decane, 2,4-dimethyl heptane, and 2,2,4,6,6-pentametyl heptane. The tail DNA percentages were significantly increased for all experimental treatments relative to control. However, under the treatments of VOCs, Olive tail moment content and comet tail length also display an obvious increase compared to control, except for that of octane, undecane and decane treatments. As VOC concentrations and durations increased in the soil, activities of AChE, SOD, and GST were either stimulated or inhibited. Among the VOCs, decane, 2,4-dimethyl heptane, 2,2,4,6,6-pentamethyl heptane, and 2,4-di tert buyl phenol exerted stronger effects on enzymatic activities. In summary, VOCs in rhizosphere soils of E. grandis might exert a toxic impact on E. fetida, among which 2,4-dimethyl heptane, 2,2,4,6,6-pentamethyl heptane, and 2,4-di tert buyl phenol have the strongest effects.

Effects of oxidative stress reaction for the Eisenia fetida with exposure in Cd2

Earthworms are widely used in all kinds of pollutants as sensitive bio-indicator organisms because of their immediately oxidative stress response under the stress of heavy metal. However, there are a large number of indexes associated with the oxidative stress response. Finding out the key monitoring indexes in the stress process becomes a practical demand of the pollution monitoring and warning process. We studied two groups, the short-term test and the long-term test. The former one is for 10 days, taking out an earthworm every day. The latter test lasted 30 days, taking out an earthworm every 10 days. The Cd²⁺ concentration was set at 50, 100, 125, 250, and 500 mg kg^-1. Post-clitellum segments of earthworms were chosen to determine superoxide enzyme (SOD), peroxidase (POD), glutathione peroxidase (GSH-Px), glutathione-S transferase (GST), catalase (CAT), vitamin E (VE), malondialdehyde (MDA), and acetylcholinesterase (AChE). The results showed that the main bio-indicators associating with oxidative stress reaction in short-term group were CAT, SOD, and POD. MDA could be used as a bio-indicator in the early and mid-term. VE was only the bio-indicator in the mid-term stress. While with the long-term test, the main bio-indicators associated with oxidative stress reaction were GSH-Px and MDA. The AChE activity was only suitable for oxidative stress response caused by heavy metal stress more than 30 days.

Study on the influential factors of Cd(2+) on the earthworm Eisenia fetida in oxidative stress based on factor analysis approach

When earthworms are exposed to pollutants, their antioxidant system will have responses immediately. Consequently earthworms are widely used to monitor various pollutants as a sensitive bio-indicator. However, there are a large number of indices associated with the oxidative stress response. Finding out the key monitoring indices in the stress process becomes a practical demand of the pollution monitoring and warning process. Factor analysis approach is a statistical method that uses a few factors to replace many original factors. This paper is aimed at analyzing and sorting factors related to Cd(2+) on the earthworm Eisenia fetida in oxidative stress. We studied two groups, the short-term test and the long-term test. The former test lasted for ten days, removing an earthworm every day for analysis; The latter test lasted for 30 days, taking out an earthworm every ten days. The Cd(2+) concentration was set at 0, 50, 100, 125, 250 and 500 mg kg(-1), post-clitellum segments of earthworms were chosen to determine SOD, POD, GPX, GST, CAT, VE, MDA and AChE. The results showed that in the short-term group, the main bioindicator associated with oxidative stress reaction was CAT at the exposure time of 1-3 days, at 4-5 days MDA, 6-7 days POD, and GST and GPX at 8th day, CAT at 9-10 days. While with the long-term test, the main bioindicator associated with oxidative stress reaction was GPX.

Multibiomarker toxicity characterization of uranium mine drainages to the fish Carassius auratus

The release of acidic effluents, naturally enriched in metals and radionuclides, is the main legacy of uranium mines. Generally, metals dissolved by these acidic effluents can cause significant alterations in exposed organisms, with distinct toxicological outcomes. In this study, 72 individuals of the freshwater fish species Carassius auratus were exposed in situ for different periods (8, 16, 24, and 48 h) to water from a pond (treatment pond (TP)) with a chemically treated effluent and a reference pond (PRP), in the vicinity of the Cunha Baixa uranium mine (Portugal). Comparing the water of the two ponds, the PRP pond was characterized by higher pH and oxygen values and lower conductivity and hardness values. Regarding total metal concentrations, among others, magnesium (56,000 μg/L), sodium (17,400 μg/L), zinc (86 μg/L), manganese (6340 μg/L), and uranium (1380 μg/L) concentrations in the TP pond were above the values obtained for the PRP pond. The values of manganese and uranium exceeded the values of quality criteria established for surface waters for cyprinids and for irrigation purposes. After exposure to pond water, significant differences were recorded for several biomarkers: (i) between ponds for acetylcholinesterase (AChE) with higher activities for animals from the PRP and glutathione-S-transferase (GST) activities that were particularly enhanced in animals from the TP pond; (ii) between ponds and exposure periods for lactate dehydrogenase (LDH) activity, since organisms from PRP pond presented always higher values than those from the TP pond, and among these, organisms exposed for the longer period presented a further depression in LDH activity; and (iii) between exposure periods for erythrocyte micronucleus. GSTs and LDH were the most sensitive biomarkers within the timeframe of the in situ assay performed. Despite the alleged efficacy of the chemical treatment (evidenced by a significantly lower pH), some metals persisted in the treated effluent (TP pond), potentially contributing to the induction of oxidative stress or increased conjugation metabolic activity in fish.

Cu/Zn-superoxide dismutase and glutathione are involved in response to oxidative stress induced by protein denaturing effect of alachlor in Saccharomyces cerevisiae

Alachlor is a widely used pre-emergent chloroacetanilide herbicide which has been shown to have many harmful ecological and environmental effects. However, the mechanism of alachlor-induced oxidative stress is poorly understood. We found that, in Saccharomyces cerevisiae, the intracellular levels of reactive oxygen species (ROS) including superoxide anions were increased only after long-term exposure to alachlor, suggesting that alachlor is not a pro-oxidant. It is likely that alachlor-induced oxidative stress may result from protein denaturation because alachlor rapidly induced an increased protein aggregation, leading to upregulation of SSA4 and HSP82 genes encoding heat shock proteins (Hsp) of Hsp70 and Hsp90 family, respectively. Although only SOD1 encoding Cu/Zn-superoxide dismutase (SOD), but not SOD2 encoding Mn-SOD, is essential for alachlor tolerance, both SODs play a crucial role in reducing alachlor-induced ROS. We found that, after alachlor exposure, glutathione production was inhibited while its utilization was increased, suggesting the role of glutathione in protecting cells against alachlor, which becomes more important when lacking Cu/Zn-SOD. Based on our results, it seems that alachlor primarily causes damages to cellular macromolecules such as proteins, leading to an induction of endogenous oxidative stress, of which intracellular antioxidant defense systems are required for elimination.

Toxicological effects of soil contaminated with spirotetramat to the earthworm Eisenia fetida

The aim of this study was to evaluate the potential toxicity of spirotetramat to the earthworm Eisenia fetida in a natural soil environment. Many biochemical markers, viz., superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione S-transferase (GST), cellulase, and malondialdehyde (MDA) contents were measured after exposure to 0.25, 1.25, and 2.5mgkg(-1) for 2, 7, 14, 21, and 28days. In addition, the comet assay was performed on earthworm coelomocytes to assess the level of genetic damage. The results demonstrate that the SOD activity and MDA content were significantly stimulated by the highest dose (2.5mgkg(-1)) of spirotetramat for the entire period of exposure. The activities of CAT and POD increased significantly by 2d and 21d, respectively, but the activities of both were significantly inhibited after prolonged exposure (28d). After an initial increase on the 2nd day, the cellulase activity in the high-dose treatment group was significantly inhibited for the entire remaining exposure period. The comet assay results demonstrate that spirotetramat (⩽2.5mgkg(-1)) can induce low and intermediate degrees of DNA damage in earthworm coelomocytes. The results indicate that spirotetramat may pose potential biochemical and genetic toxicity to earthworms (E. fetida), and this information is helpful for understanding the ecological toxicity of spirotetramat on soil invertebrate organisms.

Protocatechuic Acid Promoted Alachlor Degradation in Fe(III)/H2O2 Fenton System

In this study, we demonstrate that protocatechuic acid (PCA) can significantly promote the alachlor degradation in the Fe(III)/H2O2 Fenton oxidation system. It was found that the addition of protocatechuic acid could increase the alachlor degradation rate by 10 000 times in this Fenton oxidation system at pH = 3.6. This dramatic enhancement of alachlor degradation was attributed to the complexing and reduction abilities of protocatechuic ligand, which could form stable complexes with ferric ions to prevent their precipitation and also accelerate the Fe(III)/Fe(II) cycle to enhance the ·OH generation. Meanwhile, the Fe(III)/PCA/H2O2 system could also work well at near natural pH even in the case of PCA concentration as low as 0.1 mmol/L. More importantly, both alachlor and PCA could be effectively mineralized in this Fenton system, suggesting the environmental benignity of PCA/Fe(III)/H2O2 Fenton system. We employed gas chromatography-mass spectrometry to identify the degradation intermediates of alachlor and then proposed a possible alachlor degradation mechanism in this novel Fenton oxidation system. This study provides an efficient way to remove chloroacetanilide herbicides, and also shed new insight into the possible roles of widely existed phenolic acids in the conversion and the mineralization of organic contaminants in natural aquatic environment.

Modulated expression and enzymatic activity of the monogonont rotifer Brachionus koreanus Cu/Zn- and Mn-superoxide dismutase (SOD) in response to environmental biocides

Superoxide dismutases (SODs) are important antioxidant enzymes whose expression levels are often used as biomarkers for oxidative stress. To investigate the biomarker potential of the monogonont rotifer Brachionus koreanus SOD genes, the full-length Cu/Zn-SOD (Bk-Cu/Zn-SOD) and Mn-SOD (Bk-Mn-SOD) genes were cloned from genomic DNA and characterized. All amino acid residues involved in the formation of tertiary structure and metal binding in Bk-Cu/Zn-SOD and Bk-Mn-SOD were highly conserved across species. Phylogenetic analysis revealed that Bk-Mn-SOD, in particular, was closely clustered with mitochondrial Mn-SOD. Transcript analysis after exposure to six different biocides (alachlor, chlorpyrifos, dimethoate, endosulfan, lindane, and molinate) revealed that the transcriptional level of Bk-Cu/Zn-SOD was significantly increased in a dose-dependent manner. In contrast, the level of Bk-Mn-SOD transcript was significantly increased compared with control cells in response to chlorpyrifos, endosulfan, and molinate at their no observed effect concentrations (NOECs). However, exposure to alachlor, chlorpyrifos, and molinate significantly reduced the enzymatic activity of total SOD protein, while a decreased pattern was observed in all biocide treatments. Taken together, these results indicate that exposure to waterborne environmental biocides induces the transcription of Bk-Cu/Zn-SOD and Bk-Mn-SOD, but inhibits the enzymatic activity of Bk-SODs. These results contribute to our understanding of the modes of action of oxidative stress-mediating biocides on rotifer.

Effect of soil HHCB on cadmium accumulation and phytotoxicity in wheat seedlings

The accumulation of cadmium (Cd) in wheat seedlings under single and joint stress of galaxolide (HHCB) and Cd was investigated, and their phytotoxicity and oxidation stress including chlorophyll (CHL), malondialdehyde (MDA), superoxide dismutase, and perosidase were assessed. The results showed that the accumulation of Cd in wheat seedlings increased with an increase in the concentration of Cd in soil. The low concentration of HHCB inhibited the accumulation of Cd, while the high concentration of HHCB induced the accumulation of Cd. The content of CHL increased significantly in treatments with 1-50 mg kg(-1) Cd. However, the content of CHL under joint stress of Cd and HHCB was significantly lower than that in the control. Besides, the content of MDA in wheat leaves and roots was also significantly affected by HHCB and Cd, particularly by their joint stress. Co-contamination of HHCB significantly affected the activity of antioxidant enzymes in wheat seedlings stressed by Cd. In a word, HHCB could aggravate the phytotoxicity of Cd to wheat seedlings.

The Mancozeb-containing carbamate fungicide tattoo induces mild oxidative stress in goldfish brain, liver, and kidney

Tattoo belongs to the group of carbamate fungicides and contains Mancozeb (ethylene(bis)dithiocarbamate) as its main constituent. The toxicity of Mancozeb to living organisms, particularly fish, is not resolved. This work investigated the effects of 96 h of exposure to 3, 5, or 10 mg L(-1) of Tattoo (corresponding to 0.9, 1.5, or 3 mg L(-1) of Mancozeb) on the levels of oxidative stress markers and the antioxidant enzyme system of brain, liver, and kidney of goldfish, Carassius auratus). In liver, Tattoo exposure resulted in increased activities of superoxide dismutase (SOD) by 70%-79%, catalase by 23%-52% and glutathione peroxidase (GPx) by 49%. The content of protein carbonyls (CP) in liver was also enhanced by 92%-125% indicating extensive damage to proteins. Similar increases in CP levels (by 98%-111%) accompanied by reduced glucose-6-phosphate dehydrogenase activity (by 13%-15%) was observed in kidney of fish exposed to Tattoo; however, SOD activity increased by 37% in this tissue after treatment with 10 mg L(-1) Tattoo. In brain, a rise in lipid peroxide level (by 29%) took place after exposure to 10 mg L(-1) Tattoo and was accompanied by elevation of high-molecular mass thiols (by 14%). Tattoo exposure also resulted in a concentration-dependent decrease in glutathione reductase activity (by 26%-37%) in brain. The data collectively show that exposure of goldfish to 3-10 mg L(-1) of the carbamate fungicide Tattoo resulted in the development of mild oxidative stress and activation of antioxidant defense systems in goldfish tissues.

The bioaccumulation and biotransformation of synthetic estrogen quinestrol in crucian carp

The occurrence and fate of endocrine disrupting chemicals (EDCs) in aquatic species have attracted close attention during the last decades. In this study, the bioaccumulation and biotransformation of synthetic estrogen quinestrol, one of the typical EDCs, in the plasma and liver of crucian carp, were investigated by a newly developed and validated reversed-phase high performance liquid chromatography with fluorescent detection method. Crucian carp were exposed to quinestrol in concentration of 2, 10, 50, 100 μg/L (5.49, 27.43, 137.17, 274.34 nmol/L) for 60 days. After 60 days' exposure, the concentrations of quinestrol found in liver and plasma were in the range of 0.25-0.69 mg/kg and 0.19-0.30 mg/L respectively, positively correlated with the exposure concentrations ranged 2-100 μg/L (5.49-274.34 nmol/L). There was a negative correlation between the bio-accumulation ratios and the exposure concentrations of quinestrol. 17α-Ethinylestradiol was also found in liver and plasma, and the concentrations were 0.02-0.19 mg/kg and 0.37-0.96 mg/L, respectively. The results indicated that quinestrol can be accumulated and transformed to 17α-ethinylestradiol in crucian carp. Moreover, exposure to quinestrol caused oxidative damages to crucian carp and the content of malondialdehyde increased in all treatment concentrations.

Effects of mercury on oxidative stress and gene expression of potential biomarkers in larvae of the Chinese rare minnow Gobiocypris rarus

Mercury levels have increased in aquatic food webs throughout the world and can be found at toxic levels in some biota. However, the molecular mechanisms and effects of mercuric chloride (Hg(2+)) remain poorly understood. In the present study, antioxidant parameters (superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde)-as well as a series of gene expressions, including cortisol receptor (cr), Na(+)/K(+)-ATPase (aptase), and prolactin (prl) genes involved in ion-regulatory process, insulin-like growth factor I (igf1) and growth hormone (gh) related to growth rate, as well as heat shock protein70 (hsp70) and metallothionein (mt) used as physiological stress identification-were measured in whole body of Chinese rare minnow larvae (Gobiocypris rarus) after exposure to Hg(2+) (0, 0.1, and 0.3 mg/L) for 4 days. Results show that oxidative stress was generated in fish exposed to Hg(2+) and that the transcription levels of cr, atpase, gh, hsp70, and mt genes increased in a dose-dependent manner, but expression levels of prl and igf1 genes were showed to be decreased in the treated groups. Based on principal component analysis, the correlation between gh and igf1 genes and cr and prl genes was negative. In conclusion, exposure to Hg(2+) could alter multiple physiological and molecular indices in fish; however, before those parameters are used as special biomarkers for monitoring Hg(2+) in aquatic environment, more detailed experiments in laboratory must be performed in the future.

The protective role of antioxidants in the defence against ROS/RNS-mediated environmental pollution

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, β-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants.

Acute toxicity of multi-walled carbon nanotubes, sodium pentachlorophenate, and their complex on earthworm Eisenia fetida

Laboratory experiments were undertaken to relate biomarker responses to the toxicities of multi-walled carbon nanotubes (MWCNTs) and sodium pentachlorophenate (PCP-Na), both individually and combined. The acute toxicities of MWCNTs and PCP-Na on earthworm Eisenia fetida were studied through different exposure methods (filter paper contact test, immersion contact test, and artificial soil contact test). Enzyme activity and malondialdehyde (MDA) content in the earthworm E. fetida exposed to MWCNTs and PCP-Na in filter paper contact test, both individually and under combined exposure, were determined. After exposure, PCP-Na induced observable acute toxicity while the MWCNTs induced slight toxicity. Interestingly the earthworms exposed to the mixture of MWCNTs and PCP-Na demonstrated different expression of enzymatic biomarkers from those exposed to MWCNTs or PCP-Na alone. Our results indicated that the toxicity of PCP-Na on E. fetida may be alleviated by the appearance of MWCNTs for all exposure methods except for immersion contact test.

Hepatic antioxidant enzymes SOD and CAT of Nile tilapia (Oreochromis niloticus) in response to pesticide methomyl and recovery pattern

Hepatic antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) of Nile tilapia in response to pesticide methomyl and recovery pattern were researched by exposing tilapia to sub-lethal methomyl concentrations of 0, 0.2, 2, 20 and 200 μg/L for 30 days, and then transferred to methomyl-free water for 18 days. Hepatic SOD and CAT were measured at 10 min (day 0), 6, 12, 18, 24 and 30 days after starting the experiment and at 18 days after transferring to methomyl-free water. The results showed hepatic SOD and CAT activities in 2, 20 and 200 μg/L groups were affected significantly, however, that in 0.2 μg/L group didn't change significantly compared to control during 30-day exposure period. Thus it would appear the 0.2 μg/L methomyl might be considered the no observed adverse effect level. Recovery data showed that, for SOD, the effects produced by lower concentration of methomyl 2 μg/L were reversible but not at concentrations higher than 20 μg/L, however, for CAT, the effects produced by all the concentrations were reversible.

Effects of four commonly used UV filters on the growth, cell viability and oxidative stress responses of the Tetrahymena thermophila

UV filters are increasingly used in sunscreens and other personal care products. Although their residues have been widely identified in aquatic environment, little is known about the influences of UV filters to protozoan. The growth inhibition effects, cell viability and oxidative stress responses of four commonly used UV filters, 2-ethylhexyl 4-methoxycinnamate (EHMC), benzophenone-3 (BP-3), 4-methyl-benzylidene camphor (4-MBC) and octocrylene (OC), to protozoan Tetrahymena thermophila were investigated in this study. The 24-h EC50 values with 95% confidence intervals for BP-3 and 4-MBC were 7.544 (6.561-8.675) mg L(-1) and 5.125 (4.874-5.388) mg L(-1), respectively. EHMC and OC did not inhibit the growth of T. thermophila after 24h exposure at the tested concentrations. The results of cell viability assays with propidium iodide (PI) staining were consistent with that of the growth inhibition tests. As for BP-3 and 4-MBC, the relatively higher concentrations, i.e. of 10.0 and 15.0 mg L(-1), could lead to the cell membranes impairment after 4h exposure. With the increase of the exposure time to 6h, their adverse effects on cell viability of T. thermophila were observed at the relatively lower concentration groups (1.0 mg L(-1) and 5.0 mg L(-1)). In addition, it is noticeable that at environmentally relevant concentration (1.0 μg L(-1)), BP-3 and 4-MBC could lead to the significant increase of catalase (CAT) activities of the T. thermophila cells. Especially for the BP-3, the oxidative injuries were further confirmed by the reduction of glutathione (GSH) content. It is imperative to further investigate the additive action of UV filters and seek other sensitive endpoint, especially at environmentally relevant concentration.

Effects of deltamethrin on biometric parameters and liver biomarkers in common carp (Cyprinus carpio L.)

The present study is aimed to evaluate the effect of sublethal exposure to the pyrethroid pesticide deltamethrin, according to biometric parameters and important liver biomarkers in the common carp (Cyprinus carpio). Fish were exposed for 4, 15 and 30 days to deltamethrin mixed to the aquaria water at the concentrations of 0.08, 0.4 and 0.8μg/L. The exposure did not affect fish biometric parameters. Glutathione-S-transferase (GST) activity in liver (hepatopancreas) increased in fish exposed to the high concentration of pesticide only after 30 days when compared to controls. A significant increase of malondialdehyde (MDA) content (79.4% and 90.2% of control) was remarked after 15 and 30 days of exposure to the highest concentration of pesticide. Catalase activities (CAT) went up after 4 days of was to the concentration of 0.4μg/L and 0.8μg/L and at 15 days of exposure to 0.4μg/L. The most significant change of glutathione reductase (GR) activity was recorded at the fourth day, when GR activity was significantly increased after exposure to the concentrations of 0.4μg/L and 0.8μg/L of deltamethrin.

Antioxidant enzyme activities and lipid peroxidation in earthworm Eisenia fetida exposed to 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-γ-2-benzopyran

Polycyclic musks have been indicated to cause lethal and sublethal effects on exposed biota. However, knowledge about the effect of polycyclic musks on the antioxidant defense system in earthworms is vague. In this work, the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) exposed to 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-γ-2-benzopyran (HHCB) were systematically investigated. The investigation shows that their activities are closely related to the exposed dose and time of HHCB. For SOD and CAT, the activities increased monotonically with increased exposed dose of HHCB, which indicates a dose-dependent change pattern. POD exhibited its peak activity in 0.0157 μg cm(-2) HHCB treatment and decreased at higher concentrations. These two changing patterns were complementary, which reveals the cooperation of enzymes in response to oxidative stress. MDA content in earthworms was basically unaffected with a 1-day exposure and significantly increased after 2-day and 3-day exposures, correlating with changes in the activities of SOD and CAT when the concentration of HHCB was high. It was also found that the sensitivity of Eisenia fetida to HHCB increased over time. These results may support the theoretical hypothesis that oxidative stress is an important component for the response of earthworms to the toxicity of HHCB in environment. Among the studied enzymes, SOD and CAT appeared to be the most responsive biomarkers of oxidative stress caused by HHCB. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

The use of a lacertid lizard as a model for reptile ecotoxicology studies: part 2--biomarkers of exposure and toxicity among pesticide exposed lizards

As part of a wider study examining the impacts of corn pesticides on lacertid lizards in north-western Portugal, we examined various physiological, biochemical, and histological biomarkers of exposure and effect among field populations of Podarcis bocagei. Biomarkers included body condition index, standard metabolic rate, locomotor performance, parasitization, glutathione oxidative pathways and related enzyme activity, lipid peroxidation and liver and testis histology. Few of the various biomarkers investigated provided statistically significant evidence of toxic effect. However, using a weight of evidence approach, we conclude that pesticides are affecting lizards living in the vicinity of pesticide exposed corn agriculture sites. Lizards from these locations present a profile of animals under metabolic stress with reduced condition indices, increased standard metabolic rate, lower incidence of hepatocyte vacuolation, altered iron metabolism, increased activation of GSH oxidation pathways, and even increased prevalence of hemoparasites.

Sublethal effects of waterborne herbicides in tropical freshwater fish

The study evaluated the sublethal effects of the herbicides glyphosate (Roundup) and diuron (Hexaron) and the mixture of them, used extremely in agriculture, through biomarkers in fish. The glutathione S-transferase activity increased (74%) and catalase activity decreased (37%) at the higher exposure concentration of Hexaron in comparison to the control group, suggesting an activation of this metabolism route. Membrane damage was observed at the higher exposure of Roundup and in the mixture group compared to the control group, which can be related to the nuclear alterations observed in these exposed groups. The cholinesterase activity was also inhibited (37%) in mixture group compared to the control group and no gill morphology damage was found. The results suggested a potential synergic effect in some analysed parameters.

Genotoxicity and oxidative stress biomarkers in Carassius gibelio as endpoints for toxicity testing of Ukrainian polluted river waters

This study aimed to assess oxidative stress and genotoxicity biomarkers in Prussian carp Carassius gibelio laboratory-exposed to water from polluted Ukrainian rivers in order to evaluate their usefulness as endpoints in a short-term bioassay for toxicity testing of freshwaters. The micronucleus (MN) test and the frequency of cells with double nuclei (DN) in erythrocytes and gill cells were used as indicators of chromosome aberrations and abnormalities in cell divisions, respectively. Cellular antioxidant defenses i.e. antioxidant enzyme activities (catalase, Se-dependent glutathione peroxidase, total glutathione peroxidase and glutathione-S-transferase) and oxidative damage, i.e. lipid peroxidation (measured as thiobarbituric acid reactive substances) in the fish liver were used as biomarkers of oxidative stress. Exposure to the polluted river water samples for 96 h resulted in significantly increased MN and DN frequencies, limited increases in antioxidant enzyme activities and no changes in lipid peroxidation. Results suggest that MN and DN frequencies in C gibelio are useful endpoints in a short-term bioassay for genotoxicity testing of environmental water samples in contrast to the oxidative stress biomarkers applied that showed low potential for assessing sublethal effects after a 96 h exposure.

Transcriptional profiling in Saccharomyces cerevisiae relevant for predicting alachlor mechanisms of toxicity

Alachlor has been a commonly applied herbicide and is a substance of ecotoxicological concern. The present study aims to identify molecular biomarkers in the eukaryotic model Saccharomyces cerevisiae that can be used to predict potential cytotoxic effects of alachlor, while providing new mechanistic clues with possible relevance for experimentally less accessible eukaryotes. It focuses on genome-wide expression profiling in a yeast population in response to two exposure scenarios exerting effects from slight to moderate magnitude at phenotypic level. In particular, 100 and 264 genes, respectively, were found as differentially expressed on a 2-h exposure of yeast cells to the lowest observed effect concentration (110 mg/L) and the 20% inhibitory concentration (200 mg/L) of alachlor, in comparison with cells not exposed to the herbicide. The datasets of alachlor-responsive genes showed functional enrichment in diverse metabolic, transmembrane transport, cell defense, and detoxification categories. In general, the modifications in transcript levels of selected candidate biomarkers, assessed by quantitative reverse transcriptase polymerase chain reaction, confirmed the microarray data and varied consistently with the growth inhibitory effects of alachlor. Approximately 16% of the proteins encoded by alachlor-differentially expressed genes were found to share significant homology with proteins from ecologically relevant eukaryotic species. The biological relevance of these results is discussed in relation to new insights into the potential adverse effects of alachlor in health of organisms from ecosystems, particularly in worst-case situations such as accidental spills or careless storage, usage, and disposal.

DNA damage and effects on glutathione-S-transferase activity induced by atrazine exposure in zebrafish (Danio rerio)

This study was undertaken to investigate the protective effect of atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-S-triazine) on the activity of glutathione-S-transferase (GST) and DNA damage in males and females of adult zebrafish (Danio rerio). Zebrafish were exposed to control and three treatments (0.01, 0.1, and 1 mg/L) of atrazine for 5, 10, 15, 20, and 25 days. The results indicated that, for males, the GST activity at lower atrazine concentrations (0.01 and 0.1 mg/L) was markedly higher than that of the controls throughout the duration of the experiment while there was a significant inhibition of the GST activity at 1 mg/L atrazine at days 5 and 20. For females, a significant increase was detected at 0.1 mg/L on the days 5 and 15 and at 0.01 mg/L on day 20. The DNA damage in zebrafish was evaluated using the comet assay; the olive tail moments obtained for hepatopancreas were enhanced after treatment with different concentrations of atrazine on days 5, 10, 15, 20, and 25. The DNA damage increased with increasing atrazine concentrations, indicating that genotoxicity of atrazine and significant differences was found compared to the controls. In conclusion, these findings provide further evidence of the effects of atrazine on aquatic ecosystems.

Acute toxicity and bioconcentration of pyrimorph in zebrafish, Brachydanio rerio

BACKGROUND

Pyrimorph is a novel fungicide being developed in China that shows high antifungal activity against diseases caused by Phytophthora infestans, Phytophthora capsici, Rhizoctonia solani, Peronophythora litchi and Pseudoperonospora cubensis. Until now, no information on the toxicity of pyrimorph to untargeted organisms has been reported. To assess the potential environmental impacts of pyrimorph in fish, the acute toxicity and bioconcentration of pyrimorph in zebrafish were studied in this paper.

RESULTS

When tested by the semi-static method, the 48, 72 and 96 h median lethal concentration (LC50 ) values of pyrimorph to zebrafish were 24.33, 22.61 and 19.79 mg L(-1) respectively. To study the bioconcentration of pyrimorph in zebrafish, the fish were exposed to sublethal concentrations of pyrimorph (2.00 and 0.25 mg L(-1) ) for 192 h, a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was applied to extract pyrimorph from samples and the residues of pyrimorph in the water and fish were determined by high-performance liquid chromatography (HPLC). The highest bioconcentration factor (BCF) of pyrimorph in the fish was 1.07 × 10(2) (144 h) and 23.1 (96 h) after exposure to 2.00 and 0.25 mg L(-1) of pyrimorph respectively.

CONCLUSIONS

The novel fungicide pyrimorph has low toxicity to zebrafish; however, it showed medium BCF to zebrafish. Therefore, more attention should be paid to the residue of pyrimorph in fish, as well as to its long-term ecological effects.

Variability of responses in the crucian carp Carassius carassius from two Ukrainian ponds determined by multi-marker approach

The aim of this study was to evaluate the health status of the comparatively tolerant fish Carassius carassius over three seasons in an area characterized by spontaneous human activities. Sites near the springs of a river (site Z) and downstream of a river (site B) in Western Ukraine were selected. According to the centroid grouping analysis, the biochemical and morphological indices allowed the fish to be distinguished according to season more than to site. The level of nuclear abnormalities was low in fish from both sites. However C. carassius inhabiting site B showed a lower metal-binding capacity of MTs in relation to fish from site Z. This was combined with high levels of MT protein (particularly in the liver), and reduced glutathione (GSH) and redox state of GSH (particularly in the gills), which might confer some advantages to fish inhabiting this site. The levels of ethoxyresorufin-O-deethylase, glutathione-S-transferase, cholinesterase and vitellogenin-like proteins indicated significant but intermittent inter-site differences. In summer, oxidative damage due to a high level of lipid peroxidation, and low superoxide dismutase and catalase activities was observed in fish from site B, and in autumn, it was observed in the gills of fish from site Z. The relationship between MT protein levels and antioxidant defense and the lack of a positive relationship between MT levels and their metal-binding capacity was confirmed by principal component analysis.

Biochemical and physiological responses in liver and muscle of rainbow trout after long-term exposure to propiconazole

In this study, the chronic toxic effects of PCZ, a triazole fungicide commonly present in surface and ground water, on morphological indices, ROS generation and RNA/DNA ratio in liver and white muscle of rainbow trout were investigated. Fish were exposed at sublethal concentrations of PCZ (0.2, 50 and 500 microg L(-1)) for 7, 20 and 30d. Compared with the control, there were significant lower CF and HSI in fish exposed at the highest concentration of PCZ. ROS levels in both tissues increased significantly at higher PCZ concentrations (50 and 500 microg L(-1)) after 20 d and above, as well as in muscle of fish exposed at lowest PCZ concentration (0.2 microg L(-1)) after 30 d. The hepatic antioxidant enzymes (SOD and CAT) activities were induced significantly at higher concentrations (50, 500 microg L(-1)) of PCZ after 20 d and at 50 microg L(-1) after 30 d. Additional, hepatic SOD activity was significantly induced at 0.2 microg L(-1) after 30 d. Compared with the hepatic antioxidant enzymes activities in fish exposed to 50 microg L(-1) of PCZ, there was a decreasing trend in those exposed to 500 microg L(-1) after 30 d exposure. However, both the antioxidant enzymes activities were significantly inhibited in muscle of fish exposed to 500 microg L(-1) PCZ after 30 d. Moreover there was significant lower RNA/DNA ratio in both tissues after long-term exposure to higher concentration of PCZ. In short, environmental concentrations of PCZ could not induce obvious impacts on fish, but long-term exposure to higher concentrations of CBZ could affect seriously the health status of fish.

Sublethal cyfluthrin toxicity to carp (Cyprinus carpio L.) fingerlings: biochemical, hematological, histopathological alterations

This study measures a whole series of biological endpoints, and histopathological and behavioral changes of carp (Cyprinus carpio L.) fingerlings in order to investigate the adverse effects of a sublethal concentration of 10 microg/L cyfluthrin for 48h and one week using the semi-static test system. The most significantly altered findings of this study was that total antioxidant status levels decreased in 48h, chloride levels decreased in one week, and sodium and phosphorous levels increased in the 48h-exposed group. Plasma cortisol increased in both the 48h-exposed and the one-week-exposed groups. The unique tissue was the brain that had an increased level of malondialdehyde after one week of exposure. Such biomarkers may be used in assessing adverse/toxic effects of pesticides as environmental stressors. Potential oxidative-stress-inducing effect of synthetic pyrethroid cyfluthrin, as lipid peroxidation, in addition to its sodium channel blocking, is reported for the first time as an additional mechanism of action.

Responses of biochemical markers in carp Cyprinus carpio from two field sites in Western Ukraine

The aim of this study was to compare environmental quality in two sites of the river in Western Ukraine, rural (R) and industrial (I) during three seasons via a set of biochemical markers in carp Cyprinus carpio L. Upon comparing the values of the I-site with those of the R-site, we found that Mn- and Cu, Zn-superoxide dismutase (SOD) activities decreased and O(.) production increased; metallothionein (MT) and glutathione levels increased in most cases, and acetylcholinesterase (AChE) activity decreased in summer. This confirms our hypothesis about continuous environmental press at the I-site. The higher activity of catalase and lipid peroxidation (TBARS), as well as the increased levels of vitellogenin-like proteins at the R-site, compare to the I-site in spring reflects the permitting effect of agricultural discharges. According to the results of PCA, the most sensitive biomarkers of pollution are MT, TBARS, and AChE in liver.

Effects of subchronic exposure to LASSO MTX (alachlor 42% W/V) on hematological indices and histology of the common Carp, Cyprinus carpio L

The aim of the study was to evaluate subchronic toxic effects of the preparation LASSO MTX (alachlor 42% W/V) on hematological indices and histology of the common carp (Cyprinus carpio L.). In carp exposed for 28 days to LASSO MTX in the concentration of 2,400 microg L(-1), significant differences (p < 0.05), were detected in all indices of the erythrocyte profiles tested except hematocrit (PCV) when compared to controls. At a lower exposure (240 microg L(-1)) concentration of blood hemoglobin and mean corpuscular hemoglobin were significantly reduced. In contrast, no influence of the preparation on leucopoiesis was demonstrated, and only slight changes were observed in histopathological indices.