| Bryophytes were widely used in the world as one kind of indicative plant sensitive to environmental pollution. Developed countries had done many researches in this field, had reached delightful achievements, and established some practical techniques and measures. In China, the research in this field was weak relatively. There were just some researchs in environgmental monitoring used bryophytes as indicators in recent 10 years, but most were concentrated on qualitative reseach by ecological ingdicating means, which could be influenced easily by the subjective factors of researchers in certain extent. The quantitative research was less, and the monitored objects were mainly gaseous pollutions such as SO2, etc. but less in heavy metals, the reseach scope was confined. So, by combinating quatative chemistry analysis and qualitative ecological indicating, as well as studying the bryophytes' adsorption characters to heavy metal, we could know the bryophytes' adsorption rules to heavy metals in atmosphere, which is significant in monitoring atmaspheric pollution.As this, we firstly investigated the bryophytes species, growth status and distributing characters, primarily disclosed relativity between the bryophytes' ecological charateras and the atmospheric pollution. Secondly, through comparing the heavy metal content in different bryophytes by quantitative analysis, and studying the bryophytes' adsorption characters to heavy metals, we selected out the bryophyte species which have high accumulative ability to heavy metals. Which could be the base of atmospheric environmental monitoring. Thirdly, we adopted moss-bag technology, one simple method, to identify territorial atmosphere heavy metal pollutants qualitatively and quantitatively, to monitor the atmosphere quality in Nanan district, Jiulongpo district, Jiangbei district in Chongqing, and Tiansheng Road in Beibei, disclosed furtherly the dry and wet deposition of atmospheric contaminants and their spatial-temporal variation in monitored regions. The results showed:The bryophytes' species, existence frequency and quantity differed heavily in investigated spots. Among them, the bryophytes was enrich and grown well in Golden Buddha Mountain, Tiansheng Road, Longjushi, North Hotspring, the Second Mountain Cliff, but few and grown worse in Laifeng. The most pervasive bryophyte species in investigated districts were Entodon, Brachythecium, Claopodium, Taxiphyllum, Hypnum, Taxiphyllum, etc.Pollutant contents varied as Qingmuguan>Tiansheng Road>North Hotspring>Longjushi> Laifeng>the Second Mountain Cliff. Thereout, according to relative pollution extent, the investigated spots could be sorted into three grades, in them, Tiansheng Road, North Hotspring, Qingmuguan was polluted region, Laifeng was light polluted region, and the Second Mountain Cliffwas clean region. Through clustering analysis, we sorted the six spots into four types, the first type was clean area, it was the Second Mountain Cliff, the second type was Hg polluted area, included North Hotspring and Longjushi, the third type was Cu, Ni polluted area, included Qingmuguan and Tiansheng Road, the fourth type was Zn polluted area, included Laifeng.By comparing accumulative indexes of the bryophytes in same spots, we found the bryophytes which had strong accumulative ability to Hg are Hypum cupressiforme, Brachythecium, Entodon, Claopodium, Racoplium, etc. Which had strong accumulative ability to Cu were Brachythecium, Claopodium, Racoplium, Bryohaplocladium microphyllum, etc. Which had strong accumulative ability to Cd were Brachythecium, Entodon, Weisia planifolia Dix, etc. Which had strong accumulative ability to Pb were Brachythecium, Entodon, Barbula, Weisia planifolia Dix, Racoplium, etc. Which had strong accumulative ability to Zn were Brachythecium, Entodon, Barbula, Weisia planifolia Dix, Racoplium, Leskea, etc. Which had strong accumulative ability to Ni were Brachythecium, Entodon, Taxiphyttum, etc. In them, Weisia planifolia Dix., Taxiphyllum, Bryohaplocladium microphyllum (Hedw.) Broth, Pseudoleskeopsis zippelii (Dozy et Molk.)Broth., Brachythecium, Racoplium, Claopodium, etc. had higher accumulative ability to heavy metals, the common bryophytes' accumulative ability to heavy metals varied as:Racoplium > Entodon > Claopodium>Taxiphyllum>Brachythecium. And this was the base of selecting bryophyte materials in atmospheric environmental monitor.Correlation analysis showed that the bryophyte species in this study was correlative evidently, and could substitute for each other in environmental monitoring, but must be revised before use.Different bryophytes' adsorption isotherms were common, that was, the adsorption contents to Hg and Cd increased with the concentration of the balanced solution, and all could be simulated by Liner equation, Freundlich equation and Langmuir equation. In them, the Langmuir equation was the best in simulating the bryophytes' adsorption character to Hg, and the Langmuir equation was the best in simulating the bryophytes' adsorption character to Cd (r=0.9617-0.9996). But the bryophytes' saturation adsorption contents were different with each other, the maximum adsorption content to Hg was 23.702-456.20lmg/g, the maximum adsorption content to Cd was 31.118-259.917mg/g. The Bryophytes' adsorption ability varied as Isothecium alopecuroides (Dubois)Isov.>Bryhnia trichomitria Dix. et Ther.>Hypnum plumaeforme Wils.>Gollania robusta Broth.>Bazzania yoshinagana (Steph.) Steph. ex Yasuda>Brotherella (Duby)Fleisch>Dicranum nipponense Besch. and Thuidium cymbifolium (Dozy et Molk.) Dozy et Molk>Dicranum sp., In all, the adsorption content of Bazzania yoshinagana (Steph.) Steph. ex Yasuda, Dicranum nipponense Besch., and Dicranum sp. were lower than other species, but within this experimental concentration ranges, all didn't reach their maximum adsorption content.The bryophytes' adsorption dynamics to heavy metals could be carved into two stages, that was, the rapid reaction phase and the slow reaction phase. Bryophytes' adsorption content increased rapidly in the beginning 30 minutes, and almost reach maximum until 2 hours, after that, it increased very slow and almost without change. This illuminated the process of the bryophytes' adsorption to heavy metal was initiative and rapid. The adsorption contents of Bazzania yoshinagana (Steph.) Steph. ex Yasuda, Dicranum nipponense Besch., and Dicranum sp. to Hg ion were lower than other species, this showed their accumulative abilities were weaker than other species and maybe related to their grown forms.The bryophytes adsorption dynamics to Hg could be generally imitated by exponential (double constent) equation and Elovich equation. But exponential equation imitated Brotherella (Duby)Fleisch, Bryhnia trichomitria Dix. et Ther., Eurhynchium eustegium (Broth.) Dix.'s adsorption dynamics better(r=0.9250~0.9353).Similar to the adsorption process, the bryophytes' desorption dynamics character to Hg solution could be carved into two stages, that was, the rapid reaction phase and the slow reaction phase. Samely, the rapid reaction phase finished rapidly in the first 2 hours, almost reached it's maximum. In the slow reaction phase, the dis-adsorption content increase very slow and almost without increase. But under same condition, Bazzania yoshinagana (Steph.) Steph. ex Yasuda, Dicranum nipponense Besch., and Dicranum sp. had larger desorption content. The desorption content of Bazzania yoshinagana (Steph.) Steph. ex Yasuda was 1/4 of it's adsorption content, The proportions of the desorption contents to their adsorption contents of Dicranum nipponense Besch., and Dicranum sp. were larger than other species. This illuminated the heavy metal ions could be released easier from them and further confirmed their ability of holding Hg ions were lower than other species.In this study, we selected out seven species as the best adsorptive species to heavy metal. They were Thuidium cymbifolium (Dozy et Molk.) Dozy et Molk, Brotherella (Duby) Fleisch, Hypnum plumaeforme Wils., etc. but in reality reseach, we must select bryophytes material referring to the bryophytes' growth status and distributions.Heavy metal contents in moss-bags hung in all monitored spots were higher than Jinyun Mountain spot, which indicated these spots had been polluted in different content. But in the five monitored spots, the content of Hg Cu Cd, Pb Zn Ni in Jiulongpo district is higher than other spots obviously. Jiangbei and Nanan districts and Tiansheng Road were polluted in certain extent. Atmospheric heavy metal content in monitored spots varied little in monitorred span.The wet and dry deposition of atmospheric pollutants was: in controlled spots, the average deposition speed of Hg was 8.50ug.m~-2.mon~-1, dry deposition accounted for 62%. In Tiansheng Road, the deposition speed of Hg was 12.50 g.m~-2.mon~-1, dry deposition accounted for 59%. In Nanan,... |
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