Adult rare minnow (Gobiocypris rarus) were exposed to 0, 1, 5, and 25 ng/l (nominal concentrations) of 17a-ethynylestradiol (EE 2 ) and 3, 10, and 30 lg/l (nominal concentrations) of 4-nonylphenol (NP) under flow-through conditions for a period of 28 d. Low mortality was observed at 5 and 25 ng/l EE 2 and the growth of fish reduced significantly at 25 ng/l EE 2 compared to controls. However, the gonadosomatic indices (GSI) of male fish were significantly higher in 1 ng/l EE 2 treatments and in 10 and 30 lg/l NP treatments (p < 0.05). Renal somatic indices (RSI) of male fish in EE 2 treatments were significantly higher than those in controls (p < 0.05). In contrast, significantly decreased GSI and RSI of female fish could only be observed in 5 and 25 ng/l EE 2 treatments (p < 0.05). Hepatosomatic indices (HSI) of male fish were significantly higher in 25 ng/l EE 2 treatments. However, significantly increased of HSI of female fish could only be observed in 1 ng/l EE 2 treatments. Plasma vitellogenin (VTG) induction could be observed in males after exposed to different concentrations of EE 2 and NP, and plasma VTG concentrations in females exposed to 5 and 25 ng/l EE 2 were also significantly higher than in controls (p < 0.05). At level higher than 5 ng/l EE 2 or 30 lg/l NP, hepatic tissue and renal tissue impairment of males could be observed. The pathological male liver was associated with a hypertrophy of hepatocytes and damages to cellar structure and accumulated eosinophilic material. Renal tissue showed different pathological effects which was reflected by accumulated eosinophilic material, hemorrhages within the kidney tubules and hypertrophy of the tubular epithelia. Also at these levels of exposure, feminization of male fish could be noticed and parts of males manifested the testis-ova phenomenon. Ovaries of female rare minnow in 25 ng/l EE 2 treatment group were degenerated. Therefore when exposed to EE 2 and NP even at environmental observed concentrations, adverse effects could occur in the reproductive system of adult fishes. The observed hepatic tissue and renal tissue impairment should be due to the induction and accumulation of VTG in organs, especially in males.

No abstract

In this paper, the movement behavior of Daphnia magna was studied as a bio-indicator of organophosphorous pesticide (OP) contamination, using an on-line bio-monitoring method, the Multispecies Freshwater Biomonitor®. A static test of acute toxicity test revealed the 24-h and 48-h LC 50 values (95% confidence limit) for Daphnia magna to be respectively 0.45 μg/l and 0.21 μg/l for dipterex 3.80 μg/l and 0.90 μg/l for malathion, and 1.25 μg/l and 0.38 μg/l for parathion. The behavior strength of Daphnia magna was a sensitive indicator of sublethal OP stress and resulted in significant concentrationresponse relationships for the three OPs. Increasing OP concentration will result in more intensive behavioral responses of Daphnia magna and shorter response time, which could be described by the Stepwise Stress Model (SSM). Therefore movement behavior can be effectively applied in early warning of environment quality by on-line bio-monitoring. The intensive changes in behavior strength of Daphnia magna over a short time follow the SSM concept and can be used as an indicator of early stress response to OP accidental contamination.

No abstract

Organophosphate flame retardants (PFRs) can be rapidly metabolized in the body, and recent studies have shown that the di-alkyl phosphates (DAPs) are important metabolites. The accumulation and distribution of 8 PFRs and their 4 DAPs metabolites were first investigated in whole-body samples and various tissues of three freshwater fish species (topmouth gudgeon, crucian carp and loach) with different feeding habits from locations around Beijing, China. Concentrations of ΣPFRs in whole-body samples across all sampling locations ranged from 264.7 to 1973 ng g lipid weight (lw), while all the paired DAP metabolites were detected in the total range from 35.3 to 510 ng g lw. The calculated log bioconcentration factors (BCFs) of PFRs in whole fish were correlated with their log K (P < 0.05). The metabolite/parent ratios (MPRs) of ΣDAPs were calculated and ranged from 0.10 to 1.12 in whole-fish of all species. The MPRs of BBOEP/TBOEP were the highest. With respect to their distribution in different tissues, both the parent PFRs and metabolites were found at relatively higher levels in the liver than in other tissues (muscle, intestine, kidney and ovary), which was markedly different from those observed in avian species in previous studies. The accumulation of PFRs and DAPs in various tissues was not significantly correlated with the lipid content. The highest PFRs level in the liver may be related to the active hepatic accumulation processes. Meanwhile, the MPRs for all 4 pairs were the highest in the kidney relative to the other tissues. To the best of our knowledge, this is first study of DAPs in wild animals, and our study may improve the understanding of the accumulation and metabolism of PFRs in the body.

a b s t r a c tThyroid hormones (THs) play an important role in the development and metabolism of fish through their influences on genetic transcription and are targets for endocrine disruptive agents in the aquatic environment. Amitrole is a pesticide potentially interfering with thyroid hormone regulation. In this study, the rare minnow (Gobiocypris rarus) was exposed to different levels of 3-amino-1,2,4-triazole (amitrole) and allowed to recover in clean water. Plasma TH levels and the expression of TH-related genes, including transthyretin (ttr), deiodinases (d1 and d2), and the thyroid hormone receptor (tr˛) from the livers and brains were evaluated. After exposure, the plasma TH levels did not change. Histopathological observations showed that livers were degenerated at 10,000 ng/l and these damages could be recovered by the withdrawal of amitrole. However, the ttr, d1, and d2 mRNA levels in the livers of males were significantly up-regulated in all exposure groups (p < 0.05). The ttr and d2 mRNA levels were significantly up-regulated at 10,000 ng/l and 10, 100, and 1000 ng/l in the livers of females, respectively (p < 0.05). In the brains of males, a twofold increase of d2 mRNA levels at ≥100 ng/l and a fivefold decrease of tr˛mRNA levels at ≥10 ng/l were observed (p < 0.05), whereas no significant differences were observed in the expression of d2 and tr˛in the brains of females. After a recovery period, the ttr, d1, and d2 mRNA levels in the livers of males returned to control levels, but the tr˛mRNA levels were irreversibly decreased at all treatments (p < 0.05). In addition, the d2 mRNA levels in the livers of females were significantly induced at ≥100 ng/l. Moreover, the d2 mRNA levels in the brains of males and females were up-regulated at 10,000 ng/l. These results indicated that amitrole exposure could result in alternations of ttr, d1, d2, and tr˛gene expression in different tissues of the rare minnow. The expression of these TH-related genes in males was more sensitive to amitrole than those of females. Recovery in clean water was associated with the selective regulation of TH-related gene transcription in the rare minnow. Therefore, these TH-related genes can serve as biomarkers to screen the effects of thyroid disruption chemicals in rare minnow.

No abstract

Abstract-Perfluorooctanoic acid (PFOA) is an important perfluorinated compound (PFC) with various applications and has been widely disseminated in the environment, wildlife, and humans. The present study investigated the effects of waterborne PFOA on the expression of hepatic estrogen-responsive genes, vitellogenin (VTG), and estrogen receptor ␤ (ER␤) and on the gonadal development in a freshwater rare minnow (Gobiocypris rarus). The mRNA levels of VTG and ER␤ were determined using reverse transcription polymerase chain reaction (RT-PCR) techniques, and VTG protein levels were identified using enzyme-linked immunosorbent assay. A significant increase of VTG expression in the livers of both mature males and females was observed after 14 and 28 d of exposure to 3, 10, and 30 mg/L PFOA, indicating that PFOA could induce VTG synthesis. The expression of ER␤ increased significantly in livers of both mature males and females after a 14-d exposure, although no difference was observed after a 28-d exposure. The development of oocytes in testes exposed to PFOA also provided evidence of estrogenic activity in males. The ovaries of PFOA-exposed females underwent degeneration, as reported in other fish species exposed to environmental estrogens. This preliminary study indicates that PFOA can disturb the activity of estrogen in mature male rare minnows by inducing hepatic estrogen-responsive genes, VTG and ER␤, and barrier female reproduction.