Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant that was recently detected in the environment in China.TBC is semi-volatile and can accumulate in the lipid of some species,but little is known about its effect on aquatic organisms.We exposed adult zebrafish to 0,0.25,1 and 4mg/L TBC for 28 d and measured the effect on survival,growth,histopathology,hormone levels,enzyme activity,and gene expression.TBC exposure had no effect on survival or growth.We observed significant damage to the liver and gill,including hepatocellular swelling and fatty degeneration in the liver as well as proliferation and edema of epithelial cells in the gills.In addition,exposure to 4mg/L TBC induced proliferation of goblet cells in the intestine of both sexes,acellular areas in the testis,and thinly scattered vitellogenic granules in vitellogenic oocytes.TBC exposure had no effect on the levels of thyroid hormones,testosterone,estradiol,liver superoxide dismutase activity,malondialdehyde content,and brain cholinesterase activity.By contrast,hepatic vitellogenin and cytochrome P4501A gene expression was significantly down-regulated in both male and female zebrafish in response to TBC exposure.Our results suggest that exposure to TBC causes a variety of potential reproductive and endocrine toxic effects.
Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate. Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 lag Sn L 1. The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar. Vinegar samples with relatively high butyltin concentration (〉1.5 μg Sn L-1) were those stored in plastic bags, indicating that the plastic bag was one of the possible sources of butyltin contamination. This was further confirmed by the leaching experiments of three selected plastic bags, and monobutyltin was detected in the leaching solvents. According to the estimation, the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w., much lower than the Tolerable Daily Intake (TDI) of 100 ng Sn/kg b.w. set by the European Food Safety Authority (EFSA).
CUI ZongYanZHANG KeGangZHOU QunFangLIU JiYanJIANG GuiBin
Decabromodiphenyl ether(BDE209) is poorly absorbed by mammals,and little information is available on the toxicokinetics of BDE209 and its metabolites in fish.In the present study,rainbow trout(Oncorhynchus mykiss) were administered to 100 ng/g and 500 ng/g body wet weight of BDE209 via a single intraperitoneal injection and parent BDE209 and its metabolites were sequentially monitored for 28 days.The results showed that toxicokinetic profiles of BDE209 could be described by the one-compartment model.In the higher dose group(500 ng/g wet weight),the calculated half-life(t1/2) and elimination rate(ke) were 17.7 d and 0.039/d in the liver,and 100.3 d and 0.007/d in the muscle,respectively.Three major methoxylated brominated diphenyl ethers(MeO-BDEs) were detected with 2,2',4,4'-tetrabromo-5-methoxydiphenyl ether(5-MeO-BDE47) being detected in all tissue samples.There was no significant temporal change of 5-MeO-BDE47 concentration in the muscle,whereas an exponential increase was observed in the liver.Therefore,the metabolism rate of BDE209 depended on the administered dose.BDE209 was hardly accumulated in the muscle of rainbow trout,while the liver was a primary metabolic organ.MeO-BDEs were formed via metabolism of BDE209,which probably played a significant role in fish toxicology as a potential indicator.
FENG ChengLian,XU YiPing,ZHA JinMiao,LUO Qian,SHAN XiaoQuan & WANG ZiJian State Key Laboratory of Environmental Aquatic Chemistry
Polychlorinated naphthalenes (PCNs) are dioxin-like environmental contaminants. There is growing concern over the endocrine-disrupting effects of PCNs, but very few studies have investigated the effect of PCNs on the thyroid system. This study used a yeast two-hybrid assay, which included the recombinant human thyroid receptor(TR)-β and reporter genes, to characterize the TRβ-disrupting effects of five individual PCN congeners, five PCN Halowax mixtures, and naphthalene. Their agonist and antagonist effects were studied in the absence and presence of 5×10-7 mol/L 3,3′,5-triiodo-L-thyronine, which induced submaximal β-galactosidase activity. Naphthalene, 1,2,3,4,5,6,7,8-octachloronaphthalene and all of the Halowax mixtures (Halowax 1000, 1001, 1013, 1014 and 1099) showed no agonist or antagonist activity on TRβ at the concentrations tested (up to 10-2 g/L). The lighter PCN congeners, namely 1-chloronaphthalene, 2-chloronaphthalene, 1,4-dichloronaphthalene and 1,2,3,4-tetrachloronaphthalene showed no agonist activity but showed significant antagonist activity on TRβ. The 20% relative inhibitory concentrations of these PCNs were less than 9.13 × 10-3 g/L. Thus, bioaccumulation of these lighter PCN congeners may disrupt the thyroid hormone system and inhibit TR-mediated cellular responses. Studies in the future should investigate the possible associations between the presence PCNs and adverse health outcomes.
LI NaMA MeiWANG ZiJianSENTHIL KUMARAN Satyanarayanan
The arsenic contamination accident in Yangzonghai Lake,Yunnan has been of wide concern.In order to investigate the arsenic distribution and concentration trends after the accident,samples including lake water,sediments,soil,aquatic organisms and crops were collected in November 2008,as well as in February,May and September 2009.The average arsenic concentrations (arithmetic average) in lake water in the four sampling events were 176.9,147.3,159.3,and 161.1 μg/L,while those in the sediments were 32.87,62.41,62.99,and 46.96 μg/g,respectively.The highest content of total arsenic in soil in the vicinity of Yangzonghai was 23.33 μg/g,which was below the limits of the relevant national standard.The total arsenic levels in most aquatic plants were in the range of 100-200 μg/g,with Vallisneria natans (Lour.) Hara having the highest concentration of ～300 μg/g.The arsenic levels of fish and shrimps were in the range of 1.52-11.4 μg/g (dry weight).
WANG ZhenHua1,HE Bin1,PAN XueJun2,ZHANG KeGang1,WANG Chang1,SUN Jing1,YUN ZhaoJun1 & JIANG GuiBin11State Key Laboratory of Environmental Chemistry and Ecotoxicology
