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Use of siliceous algae as biological monitors of heavy metal pollution in three lakes in a mining city, southeast China

Chen X., Mao X., Cao Y., Yang X.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

233--242

EN

In order to assess the ecological status of three lakes in a historical mining city (SE China), water metal concentrations and surface sedimentary diatoms and chrysophyte cysts were analyzed in 20 sampling sites. The significant correlations between the algal indices and the cumulative criterion unit (CCU) scores confirmed the importance of heavy metals in shaping algae communities. In the metal-polluted sites, diatom assemblages were dominated by metal-tolerant species, such as Nitzschia palea and Nitzschia perminuta. In the unpolluted samples, diatom assemblages were characterized by Cyclostephanos dubius, Discostella pseudostelligera and Aulacoseira species (mainly A. alpigena, A. granulata and A. ambigua). These dominant taxa in the unpolluted samples might be sensitive to metal contamination but tolerant of eutrophication. In addition, nonspherical cysts were much more abundant in the polluted sites, indicating that their presence should be indicative of metal contamination in this region. This study provides some clues for future metal pollution assessment through the use of siliceous algae in metal polluted lakes.

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Experimental study of acoustic resonance technology for nonmetallic mines detection

Mao X., Li G.-Q., Wang C., Ding W.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

162-165

EN

An outdoor experimental system was designed to investigate the acoustic resonance method for non-metallic landmines detection. Firstly, the principle of acoustic-to-seismic coupling and its application in mines detection were overviewed. Then, the design process and experimental design of the system were discussed in details. Finally, experiments were performed with an antitank plastic coach mine. The results show that the buried mine can resonate at frequencies from 300 to 430Hz.

PL

Przedstawiono możliwości wykorzystania metody rezonansu akustycznego do wykrywania min niemetalicznych. Przedstawiono projekt systemu oraz dane eksperymentalne.

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Study of organohalogens in foodstuffs and environmental samples by neutron activation analysis and related techniques

Xu D., Chai Z., Zhang H., Mao X., Ouyang H., Sun H.

Nukleonika

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2004

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Vol. 49, nr 3

101-106

EN

Pine needles and foodstuffs collected from Beijing, China, were analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction for total halogens, extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX). The INAA detection limits are 50 ng, 8 ng and 3.5 ng for Cl, Br and I, respectively. The contents and distribution patterns of organohalogens in these samples are reported. EOCl accounted for 0.013 0.016% and 1.6 2.7% of the total chlorine in yogurt and apples, respectively, which suggested that chlorine in foodstuffs mainly existed as inorganic species and non-extractable organochlorines. EOCl contents in pine needles and foodstuffs were noticeably higher than those of EOBr and EOI. For pine needles, yogurt and apples, 1.6 34%, 23 58% and 29 35% of EOCl remained as extractable persistent organochlorine (EPOCl), respectively. Pine needle containing higher EOCl contents in chemical industrial and traffic hub areas indicated that chemical industries and exhaust emission from vehicle were the main sources of organochlorines in the Beijing's air. The relative proportions of the known organochlorines (such as HCHs, DDTs, chlordanes, heptachlor, HCB and PCBs) to the total EOCl and EPOCl were 0.04 1.6% and 0.7 21.5%, respectively, which implied that the identity of species of a major portion of the EOCl and EPOCl measured in pine needles was unknown.