Trophic transfer of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems is an important criterion for assessing their ecological risk. This study analyzed 18 PAHs in phytoplankton/seston, zooplankton, five invertebrate species, five fish species, and one seabird species collected from Bohai Bay, and trophic transfer of the PAHs was determined in the food web, of which the length was approximately 4 on the basis of stable nitrogen isotope values. The concentrations of PAHs (2-64.5 ng/g wet weight) in the marine ecosystem were moderate compared with other marine organisms worldwide, and the PAH compositions exhibited species-specific profiles that were related to trophic levels in some organisms. Significant negative relationships were also found between trophic levels and lipid-normalized concentrations for 10 PAH compounds (acenaphthylene, anthracene, fluoranthene, pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene + benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, and perylene), and their trophic magnification factors (TMFs) ranged from 0.11 for fluoranthene to 0.45 for acenaphthylene. These results confirm that PAHs undergo trophic dilution in the marine food web, which is likely to be the combined results of low assimilation efficiencies and efficient metabolic transformation at higher trophic levels.

Grippers are widely used for the gripping, manipulation, and assembly of objects with a wide range of scales, shapes, and quantities in research, industry, and our daily lives. A simple yet universal solution is very challenging. Here, we manage to address this challenge utilizing a simple shape memory polymer (SMP) block. The embedding of objects into the SMP enables the gripping while the shape recovery upon stimulation facilitates the releasing. Systematic studies show that friction, suction, and interlocking effects dominate the grip force individually or collectively. This universal SMP gripper design provides a versatile solution to grip and manipulate multiscaled (from centimeter scale down to 10-μm scale) 3D objects with arbitrary shapes, in individual, deterministic, or massive, selective ways. These extraordinary capabilities are demonstrated by the gripping and manipulation of macroscaled objects, mesoscaled steel sphere arrays and microparticles, and the selective and patterned transfer printing of micro light-emitting diodes.

Many investigations have highlighted the bioaccumulation of dioxins in animals, but little is known about the trophodynamics of dioxins in the food web. In this study, the trophic transfer of nine dibenzo-p-dioxin (PCDD) congeners, eleven dibenzofuran (PCDF) congeners, and twelve non-, mono-ortho polychlorinated biphenyl (non-and mono-ortho PCBs) congeners in a marine food web were determined. The concentrations of PCDDs, PCDFs, non-and mono-ortho PCBs were analyzed in phytoplankton/ seston, zooplankton, three invertebrate species, six fish species, and one seabirds species collected from Bohai Bay, representing approximately 4 trophic levels based on stable nitrogen isotope values. Positive relationships were found between trophic levels and lipid equivalent concentrations of non-and mono-ortho PCBs except for PCB-77, PCB-81, PCB-126, PCB-156, and PCB-167, indicating bioaccumulation of these compounds in this food web. But lipid equivalent concentrations of low chlorinated 2,3,7,8-substituted-PCDD/Fs did not exhibit statistically significant trends with trophic levels. And lipid equivalent concentrations of high chlorinated 2,3,7,8-substituted-PCDD/Fs and three non-2,3,7,8-substituted-PCDD/Fs declined significantly with increasing trophic levels providing that these isomers undergo trophic dilution. The similarity in log K ow values for non-, mono-ortho PCBs, non-2,3,7,8-substituted-PCDD/Fs, and some 2,3,7,8-substituted-PCDD/Fs suggests that the difference of trophic transfer is mainly due to their different metabolic transformation rates.

No abstract

Chinese sturgeon (Acipenser sinensis) was listed as a Grade I protected animal in China in 1989, and the observed intersexual phenomenon and sex ratio deviation have suggested that chemicals have posed a risk as environment pollutants. This study analyzed seven musk fragrances in liver, muscle, heart, gonad, stomach, intestines, adipose, gill, pancreas, kidney, gallbladder, and roe from 13 female Chinese sturgeons, and the toxicokinetic behavior of musks were studied and compared with some organochlorines. Of the seven musks, HHCB, AHTN, and musk xylene were detected, and the highest concentrations were observed in adipose tissue: from 33.7 to 62.1 ng/g wet weight (ww), from 1.0 to 5.4 ng/g ww, and from 1.1 to 13 ng/g ww, respectively. Similar to the tissue distribution of DDTs and HCB, musks were detected frequently in high lipid content tissues such as roe, adipose, and liver, suggesting that tissue distribution of musks is controlled by the affinity to lipids. The concentration ratios based on lipid weight between roe and adipose were estimated to be 0.47 for HHCB, 0.58 for AHTN, and 0.51 for musk xylene, and those for the total DDTs and HCB were 0.27 and 0.61, which were relatively low compared with mammals. Relatively high concentrations of p,p'-DDE (68.4-449 ng/g ww) were detected in 10 of total 11 samples, which would cause the feminization of Chinese sturgeons during embryonic development. It was found that lipid-corrected concentrations of HHCB, AHTN, p,p'-DDE, and p,p'-DDD increased with age in female sturgeon, of which the trends were similar to those in fishes and different from those in mammals.

Concentrations of hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), pentachlorobenzene (penta-CB), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (coPCBs), 1,1,1-trichloro-2,2-bis( p-chlorophenyl)ethane (DDTs, including p,pV -DDT; o,pV -DDT; p,pV -DDD; o,pV -DDD; p,pV -DDE; o,pV -DDE; p,pV -DDMU), nonylphenol (NP), and nonylphenol polyethoxylates (NPEOs) were measured in sedimentary cores from Bohai Bay (one core) and its adjacent river, the Nanpaiwu River (two cores), North China. While a-, h-, and g-HCHs were detected in similar abundance in the two cores from the Nanpaiwu River, only a-HCH was detected in the Bohai Bay core, suggesting that a-HCH might be more resistant to degradation than h-or g-HCHs. The concentrations of HCHs and HCB in the core from Bohai Bay were in the range of 0.8-140 and 9.1-1300 ng/g dry wt, respectively, whereas in the cores from the Nanpaiwu River, the maximum concentrations of HCHs and HCB reached 84,200 and 141,400 ng/g dry wt, respectively. There was a similarity of sedimentary profiles between HCHs and HCB in the three cores. The concentration of PCDDs/DFs in Bohai Bay was 0.5-3.5 ng/g dry wt [1.6-6.4 toxic equivalents (TEQ) world health organization (WHO) pg/g], far lower than the concentrations in the core samples taken from the Nanpaiwu River (the maximum concentration: 9200 ng/g dry wt; 22,000 TEQ WHO pg/g). The congener profiles of PCDD/DFs and co-PCB in the cores were similar to those in PCP, and the concentration of co-PCBs was related to that of PCDDs/DFs. In addition, the concentrations of HCH, HCB, PCDD/Fs, and co-PCB all decreased linearly relative to total organic carbon content (TOC) in surface sediment from the river to Bohai Bay. The concentration of DDTs ranged from 1.6 to 12.3 ng/g dry wt in Bohai Bay, significantly different from the profiles from the Napaiwu River (29.3 ng/g dry wt). An abundance of the compounds o,pV -DDE and o,pV -DDD were detected in the cores. The sedimentary profiles of NP and NPEOs were similar, and two peak concentrations of NP/NPEOs were found at the subsurface and subbottom in the core from Bohai Bay, respectively. The concentration of NP and NPEOs in the cores from the Nanpaiwu

The coagulation behavior of aluminum salts in a eutrophic source water was investigated from the viewpoint of Al(III) hydrolysis species transformation. Particular emphasis was paid to the coagulation effect of Al13 species on removing particles and organic matter. The coagulation behavior of Al coagulants with different basicities was examined through jar tests and hydrolyzed Al(III) speciation distribution characterization in the coagulation process. The results showed that the coagulation efficiency of Al coagulants positively correlated with the content of Al13 in the coagulation process ratherthan in the initial coagulants. Aluminum chloride (AICl3) was more effective than polyaluminum chloride (PACI) in removing turbidity and dissolved organic matter in eutrophic water because AlCl3 could not only generate Al13 species but also function as a pH control agent in the coagulation process. The solidstate 27Al NMR spectra revealed that the precipitates formed from AlCl3 and PACl were significantly different and proved that the preformed Al13 polymer was more stable than the in situ formed one during the coagulation process. Through regulating Al speciation, pH control could improve the coagulation process especially in DOC removal, and AlCl3 benefited most from pH control.

No abstract