An Asian quandary: where have all of the PBDEs gone?   总被引：10，自引：0，他引：10  

Martin M  Lam PK  Richardson BJ 《Marine pollution bulletin》2004,49(5-6):375-382

Polybrominated diphenyl ethers (PBDEs) are widely used fire retardant compounds which, like polychlorinated biphenyls (PCBs), have become ubiquitous in environmental media. Time trend analyses of PBDE levels in sediments and biota generally show an increasing trend. The lower (tetra- and penta-) PBDEs accumulate and predominate in biota, whilst the higher congeners (deca-) are prevalent in aquatic environments and sediments. PBDEs also biomagnify, with highest concentrations of the lower brominated congeners being seen in top predators including birds, marine mammals and humans. Toxicological studies of PBDEs have been limited, although effects mediated via the thyroid gland may be extremely important. Disturbingly, PBDEs may be sequestering in certain Asian environments to a higher degree than in other parts of the world, due to the unregulated disposal of computers and electronic equipment. However, this potential problem remains poorly investigated, to date.  相似文献   

Predicting effects of toxic chemicals in the marine environment     

Lam PK  Gray JS 《Marine pollution bulletin》2001,42(3):169-173

Ecological risks are typically characterized in risk assessment procedures by considering the ratio between exposure concentrations and critical effect concentrations. In OECD countries, critical effect concentrations are typically derived from laboratory-based ecotoxicity tests using well-defined protocols on a limited number of species. More and more countries in the tropics are adopting this approach in environmental assessment, protection, and management. In this article we consider a number of issues associated with such an approach, and in particular potential problems with extrapolating effects on individuals observed in laboratory-based ecotoxicological investigations to effects on ecosystems. It is hoped that by making explicit some of the assumptions made in the potential limitations of these tests, we can better target our limited resources to protect valuable and vulnerable systems.  相似文献   

Performance of ethylene-vinyl acetate foam as cushioning material for rigid debris-resisting barriers     

Carlos Lam  Julian S. H. Kwan  Y. Su  Clarence E. Choi  Charles W. W. Ng 《Landslides》2018,15(9):1779-1786

This paper reports an investigation on the performance of ethylene-vinyl acetate (EVA) foam when used as a cushion layer for rigid barriers used to resist debris flow. Large-scale pendulum impact tests were conducted to study the effects of layer thickness on cushion performance under six successive impacts. Results show that for the first impact at 70 kJ, the peak contact force with the EVA foam thickness of 500 mm is about twice larger compared to that of 1000 mm. Results also reveal that the cushion mechanism of elastic collapse of cell walls in the EVA foam results in peak contact forces and maximum transmitted loads that are up to 30 and 50% lower compared to gabions for the first impact at 70 kJ, respectively. The elastic behavior of EVA foam provides consistent cushioning efficiency. Furthermore, EVA foam is found to be susceptible to degradation by ultraviolet light so that a suitable coating layer is required for outdoor use. Polyurea was identified as a suitable coating material and a small-scale coating trial was performed to confirm this. Findings presented in this paper will have direct implications on the future design of cushion layers for rigid barriers used to intercept debris flows.  相似文献   

Morphology and distribution of the three epiphytic dinoflagellate species Coolia monotis,C. tropicalis,and C. canariensis (Ostreopsidaceae,Gonyaulacales, Dinophyceae) from Vietnamese coastal waters     

The V. Ho  Lam N. Nguyen 《Ocean Science Journal》2014,49(3):211-221

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Energy Transfer Mechanism and Probability Analysis of Submarine Pipe Laterally Impacted by Dropped Objects     

梁静  余建星  余杨  W. Lam  赵羿羽  段晶辉 《海洋工程》2016,(3):319-328

Energy transfer ratio is the basic-factor affecting the level of pipe damage during the impact between dropped object and submarine pipe. For the purpose of studying energy transfer and damage mechanism of submarine pipe impacted by dropped objects, series of experiments are designed and carried out. The effective yield strength is deduced to make the quasi-static analysis more reliable, and the normal distribution of energy transfer ratio caused by lateral impact on pipes is presented by statistic analysis of experimental results based on the effective yield strength, which provides experimental and theoretical basis for the risk analysis of submarine pipe system impacted by dropped objects. Failure strains of pipe material are confirmed by comparing experimental results with finite element simulation. In addition, impact contact area and impact time are proved to be the major influence factors of energy transfer by sensitivity analysis of the finite element simulation.  相似文献   

A review of precision fertilization research   总被引：3，自引：0，他引：3  

Can Chen  Jianjun Pan  Shu Kee Lam 《Environmental Earth Sciences》2014,71(9):4073-4080

Precision agriculture plays an important role in sustainable development. Precision fertilization is the core of this field. Three methods of precision fertilization are introduced in this paper. They are: testing soil for formulated fertilization technology, decision support system and expert decision support system. Their development situations are also examined. Some suggestions in the agriculture sustainable development are also provided. The review summarized that 3S technology will become the main data source in the decision support system and in development process of expert decision support system. The MIII technology can raise the soil testing efficiency. The development of precision fertilization has great utility in sustainable development of agriculture.  相似文献   

Nitrogenase activity and estimates of nitrogen fixation by freshwater benthic blue‐green algae     

Catherine W. Y. Lam  Warwick F. Vincent  Warwick B. Silvester 《新西兰海洋与淡水研究杂志》2013,47(1):187-192

The sandy substrate of Lake Taharoa (west coast, North Island, New Zealand ‐ 35°50'S, 173°41'E) is covered by communities of filamentous algae that extend from the exposed beach down to 21 m depth. The algae bind the sand to form crusts and mats which may break off as discrete plates. The dominant species are the blue‐greens Microcoleus, Nostoc, Phormidium, Lyngbya, Oscillatoria, Scytonema, Stigonema, Shizothrix, Calothrix, Dichothrix, Tolypothrix, and Anabaena, with occasional high concentrations of the desmid Cylindrocystis. Nitrogenase activity, measured by acetylene reduction, showed a wide range of rates (4–150 μmol C₂H₄ m^‐2h^‐1). Estimates of annual rates of nitrogen fixation by the Taharoa communities are comparable with those for periphytic blue‐green algae‐dominated systems reported elsewhere.  相似文献   

Biokinetics of paralytic shellfish toxins in the green-lipped mussel, Perna viridis     

Yu KN  Kwong RW  Wang WX  Lam PK 《Marine pollution bulletin》2007,54(7):1068-1071

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