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Bromophenols (BRPs) have been widely detected in human tissues, however, relative proportions from natural products and/or anthropogenic flame retardants are not clear. 21 polybrominated diphenyl ethers (PBDEs), 15 MeO/OH-PBDEs, and 10 BRPs were simultaneously quantified in adipose collected from people from New York City, USA. An in vitro assay utilizing human liver microsomes was performed for detected predominant organobromine. High concentrations of 2,4,6-triBRP and PBDEs were observed, and extremely low concentrations of naturally occurring MeO/OH-PBDEs were detected. Similar biotransformatioin rates of BRPs and MeO/OH-PBDEs indicated that the relative high concentration of 2,4,6-triBRP in humans was not of natural origin. Significant correlation observed between concentrations of 2,4,6-triBRP and BDE-209 suggested that the two chemicals may share a common source. Both 2,4,6-triBRP and BDE-209 were detected in commercial ABS resins, suggesting that plastic products made from ABS resins could be potential sources of co-exposure of the two compounds for humans. [ABSTRACT FROM AUTHOR]

Abstract: Methoxylated brominated diphenyl ethers (MeO-BDEs) in aquatic environments have been found to be primarily of natural origin in the marine environment and not from biotransformation of synthetic PBDEs. Two of the eight MeO-PBDEs (2′-MeO-BDE-68 and 6-MeO-BDE-47) that were detected in anchovy from the Yangtze River Delta, were natural products from marine organisms. So 2′-MeO-BDE-68 and 6-MeO-BDE-47 were chosen to study the potential to modulate androgen, estrogen, or thyroid hormone receptor- (AR, ER, ThR) mediated responses by use of reporter gene assays. 2′-MeO-BDE-68 was antiandrogenic at 50μM, estrogenic at 10μM and antiestrogenic at 10 and 50μM (IC50 =4.88μM). 2′-MeO-BDE-68 enhanced luciferase expression by 5nM T3 at 50μM. 6-MeO-BDE-47 exhibited potent antiandrogenicity at 1μM and greater (IC50 =41.8μM) and possessed estrogenic activity at 10μM and antiestrogenic activity at 10 and 50μM (IC50 =6.02μM). [Copyright &y& Elsevier]

Abstract: Polybrominated diphenyl ethers (PBDEs) are now found ubiquitously in the aquatic environment and biota, and there is a growing concern that PBDEs may disrupt endocrine systems, leading to reproductive impairments of aquatic animals. In our study, zebrafish (Danio rerio) were exposed to the 5ng/L, 1μg/L and 50μg/L of DE-71 for the duration of the whole life cycle (120days, from eggs to adults). The expression of selected genes along the brain–pituitary–gonadal (BPG) axis and liver, and the levels of plasma sex hormones were examined. In male fish, up-regulation of GnRH in brain, FSHβ and LHβ in pituitary, FSH-receptor, LH-receptor, and CYP19a in testis was clearly evident, while down-regulation of CYP11a and 3β-HSD was found in testis. In female fish, a 2.4-fold up-regulation of 3β-HSD was found in ovary upon exposure to 50μg/L of DE-71. GnRH in brain, FSHβ and LHβ in pituitary were also up-regulated, while ERβ, TH and TPH in brain and GnRH-receptor in pituitary were significantly down-regulated. Hepatic ERα, AR and VTG in males were all down-regulated, while hepatic ERα and AR in female were up-regulated. Serum estradiol (E2) was reduced in both male and female upon exposure to DE-71, while significant increases in serum testosterone (T) and 11-keto-testosterone (11-KT) were only found in male but not female fish. The ratio of T/E2 as well as the ratio of 11-KT/E2 in male fish increased in a dose-dependent manner upon exposure to DE-71. Our overall results showed that whole life exposure of DE-71 altered the expression of regulatory genes and receptors at all three levels of the BPG axis in zebrafish, and the responses are sex dependent. The observed disruption of GnRH and GtHs can be further related to the subsequent disruption in both levels and balance sex steroid hormones. [Copyright &y& Elsevier]

Abstract: The potential of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) and its related hydroxylated analogs (2′-HO-BDE28, 6-HO-BDE47, 4′-HO-BDE17, and 4′-HO-BDE49) to modulate estrogen/thyroid/androgen receptor-(ER, TR, AR), mediated responses were investigated by use of reporter gene assays. Exposure to 1 or 10μM, 4′-HO-BDE17 significantly up-regulated expression of Luc, whereas other four chemicals did not induce Luc expression under control of the ER. Anti-estrogenic potency was observed for 4′-HO-BDE17 (IC50=1.14μM)>6-HO-BDE47 (IC50=2.65μM)>2′-HO-BDE28 (IC50=9.49μM)>BDE47 (IC50=21.11μM). No anti-estrogenic effect of 4′-HO-BDE49 was observed. Both 4′-HO-BDE17, 4′-HO-BDE49 resulted in greater responses of Luc expression induced by T3. BDE47, 2′-HO-BDE28, 6-HO-BDE47 did not show any effect on the expression of Luc induced by 5nM T3. 6-HO-BDE47 (IC50=0.34μM)>4′-HO-BDE17 (IC50=1.41μM)>BDE47 (IC50=3.83μM)>2′-HO-BDE28 (IC50=29.22μM) exhibited anti-androgenic potency, while 4′-HO-BDE49 did not show androgenic transcriptional activity. [Copyright &y& Elsevier]

Abstract: Since 1990s, various booster biocides have been increasingly used as substitutes of organotins. However, knowledge about their toxicities on tropical/sub-tropical marine species is significantly lacking. This study comprehensively investigated the acute toxicities of copper, tributyltin (TBT), and five commonly used booster biocides including Irgarol, diuron, zinc pyrithione (ZnPT), copper pyrithione (CuPT) and chlorothalonil on the growth or survival of 12 marine species in which eight of them are native species of subtropical Hong Kong. We found that Irgarol was more toxic than TBT on the growth of autotrophic species. The toxicity of CuPT was comparable to that of TBT on almost all test species, while it showed higher toxicity than TBT on medaka fish larvae. As the usage of these biocides is expected to further increase worldwide, accurate assessments of their ecological risks are required for better informed decision on their management. This study provided useful datasets for such purposes. [Copyright &y& Elsevier]

Irgarol 1051 (2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine) is an algaecide commonly used in antifouling paints. It undergoes photodegradation which yields M1 (2-methylthio-4-tert-butylamino-6-amino-s-triazine) as its major and most stable degradant. Elevated levels of both Irgarol and M1 have been detected in coastal waters worldwide; however, ecotoxicity effects of M1 to various marine autotrophs such as cyanobacteria are still largely unknown. This study firstly examined and compared the 96h toxicities of Irgarol and M1 to the cyanobacterium Chroococcus minor and two marine diatom species, Skeletonema costatum and Thalassiosira pseudonana. Our results suggested that Irgarol was consistently more toxic to all of the three species than M1 (96h EC50 values: C. minor, 7.71μgL−1 Irgarol vs. >200μg L−1 M1; S. costatum, 0.29μgL−1 Irgarol vs. 11.32μgL−1 M1; and T. pseudonana, 0.41μgL−1 Irgarol vs. 16.50μgL−1 M1). Secondly, we conducted a meta-analysis of currently available data on toxicities of Irgarol and M1 to both freshwater and marine primary producers based on species sensitivity distributions (SSDs). Interestingly, freshwater autotrophs are more sensitive to Irgarol than their marine counterparts. For marine autotrophs, microalgae are generally more sensitive to Irgarol than macroalgae and cyanobacteria. With very limited available data on M1 (i.e. five species), M1 might be less toxic than Irgarol; nonetheless this finding warrants further confirmation with additional data on other autotrophic species. [Copyright &y& Elsevier]

Abstract: Concentrations of 22 trace elements were determined in green turtle (Chelonia mydas) eggs collected from Hong Kong. Concentrations of selenium, lead and nickel in these eggs were generally higher than those reported in other studies. The predicted no effect concentrations (PNEC; ng/g wet weight) of Pb (1000), Se (340 and 6000 for the worst-case and best-case scenarios, respectively) and Ni (17) in the green turtle eggs were estimated. Hazard quotients (HQs) estimate that Se (HQs: 0.2–24.5) and Ni (HQs: 4.0–26.4) may pose some risks to the turtles. Our study also found that concentrations of Ag, Se, Zn, Hg and Pb in the shell of the turtle eggs were significantly correlated with levels in the whole egg contents (yolk+albumen). Once the precise relationships of specific elements are established, egg-shell concentrations may be used as a non-lethal, non-invasive, surrogate for predicting whole egg burden of certain contaminants in marine turtles. [Copyright &y& Elsevier]

Abstract: Green-lipped mussels (Perna viridis) were collected from seven fish culture zones (FCZs) in Hong Kong and analyzed for okadaic acid (OA). A conventional HPLC method was modified by incorporating a proteinase K digestion step. Results suggest that a higher recovery (2.5 times higher) of OA was obtained from spiked samples after the addition of 1.08mg proteinase K in comparison with samples incubated without the proteolytic enzyme. For the hepatopancreas (HP) of individual field-collected mussels, the additional digestion step can enhance OA extraction by 3.1 times. Spatial and temporal variations in OA concentrations in the mussels from various FCZs were investigated. The highest concentration of OA in mussel HP samples was 1164.9ng/g HP wet wt. With respect to OA concentrations in whole mussel tissues from seven sites and four seasonal samplings, the concentrations were between 70.0 and 131.0ng/g wet wt., which did not exceed the generally recognized international regulatory criteria (>200ng/g) for OA. [Copyright &y& Elsevier]

Abstract: Sediments and green-lipped mussels, Perna viridis, were used to investigate concentrations of polybrominated diphenyl ethers (PBDEs) in Hong Kong’s marine environment. PBDEs have been used extensively over the past two decades as flame retardants in polymer additives for a variety of plastics, computers, furniture, building materials, and fabrics. Many measurements of PBDEs in various environmental matrices have been reported from Belgium, Holland, Japan, Europe and North America, but few measurements are available for the southeast Asian region and Hong Kong. PBDE congeners (n =15) were measured in 13 sediments and nine mussel samples, taken from Hong Kong marine waters. The in sediments ranged between 1.7 and 53.6ngg−1 dry wt, with the highest concentrations located around the most heavily populated areas of Victoria Harbour and Sai Kung, while the lowest concentrations of were found at more remote locations of Sha Tau Kok, Wong Chuk Bay, Castle Peak Bay, and Gold Coast. ranged from 27.0 to 83.7ngg−1 dry wt of mussel tissues. Although not identical, most of the congeners in sediments were found in mussel tissues, with BDE-47, BDE-99, BDE-153 and BDE-183 being the most prominent in both matrices. On the basis of a literature survey, the concentrations of PBDEs reported in Hong Kong sediments and mussel tissues are amongst the highest in the world. [Copyright &y& Elsevier]

Abstract: Concentrations of 17 trace elements (As, Se, Rb, Sr, Ag, Sb, Cs, Tl, Pb, V, Cr, Mn, Co, Cu, Zn, Cd, and Hg) were determined in eggs of little egrets (Egretta garzetta), black-crowned night herons (Nycticorax nycticorax) and bridled terns (Sterna anaethetus) from northwestern and northeastern coastal areas of Hong Kong. Results indicated significant differences among the three species. Eggs of little egrets and black-crowned night herons appeared to be good bioindicators for monitoring selected elements (As, Pb, Zn Cr, Cu, and V) due to consistent correlations between metal concentrations in eggs and those in coastal marine sediments. Based on limited toxicological information, the predicted no effect concentrations (PNECs) of Hg and Se in the bird eggs were estimated as 0.5 to 1.8 and 0.90 to 1.45 μg g-1, dry wt., respectively. Hazard quotients (HQs) indicated that Hg and Se might pose some risk to certain waterbirds in Hong Kong. [Copyright &y& Elsevier]

Irgarol 1051 is highly toxic to marine autotrophs and has been widely used as an antifouling booster biocide. This study tested the toxicities of two s -triazine derivatives of Irgarol, namely M2 (3-[4- tert -butylamino-6-methylthiol- s -triazin-2-ylamino]propionaldehyde) and M3 (2-methylthio-4,6-bis- tert -butylamino- s -triazine) to two marine diatom species, Skeletonema costatum and Thalassiosira pseudonana through standard acute (96h) and chronic (7d) growth inhibition tests. Results showed that both of the two chemicals significantly inhibited the growth of S. costatum (M2: 96h-EC50 = 6789.7 μg L−1, 7d-EC50 = 3503.7 μg L−1; M3: 96h-EC50 = 45193.9 μg L−1, 7d-EC50 = 5330.0 μg L−1) and T. pseudonana (M2: 96h-EC50 = 366.2 μg L−1, 7d-EC50 = 312.5 μg L−1; M3: 96h-EC50 = 2633.4 μg L−1, 7d-EC50 = 710.5 μg L−1), while their toxicity effects were much milder than Irgarol and its major degradation product M1. By comparing with previous findings, the susceptibilities of these s -triazine compounds to two tested species were ranked as: Irgarol > M1 ≫ M2 > M3. This study promotes future research efforts on better understanding of the ecotoxicities of M2 and M3, and incorporating such information to improve the current monitoring, risk assessment and regulation of the use of Irgarol. Image 1 • Toxicities of two Irgarol derivatives M2 and M3 to two marine diatoms were tested. • Both M2 and M3 significantly inhibited the growth of two diatom species. • Thalassiosira pseudonana appeared to be more sensitive than Skeletonema costatum. • Toxicity order of Irgarol and its derivatives was: Irgarol > M1 ≫ M2 > M3. [ABSTRACT FROM AUTHOR]