Lichen metal contents as correlates of air filter measurements

This article was downloaded by: [98.219.159.190] On: 26 March 2014, At: 01:20 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Grana Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/sgra20 Lichen metal contents as correlates of air filter measurements Marian G. Glenn a , Ernest V. Orsi a & Mary Ellen Hemsley a a Biology Department , Seton Hall University , South Orange, NJ, 07079, USA Published online: 01 Sep 2009. To cite this article: Marian G. Glenn , Ernest V. Orsi & Mary Ellen Hemsley (1991) Lichen metal contents as correlates of air filter measurements, Grana, 30:1, 44-47, DOI: 10.1080/00173139109427767 To link to this article: http://dx.doi.org/10.1080/00173139109427767 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms- and-conditions Grana 30: 44-47, 1991 Lichen metal contents as correlates of air filter measurements MARIAN G. GLENN, ERNEST V. ORSI and MARY ELLEN HEMSLEY Glenn, hl. G., Orsi. E. V. & Hemsley, M. E. 1991. Lichen metal contents as correlates of air filter measurements. - Grana 30 44-47. Odense, September 1991. ISSN 0017-3131. Lichens and air-borne particulates were analysed for Pb. Zn and Cu content at sites for which air qualily data and traffic flow were known. Three localities were sampled: SHU, HP and BW, which were 20, 100 and 500 km from New York City. The foliose lichen Partnelia capcrata was found at all three localities, and the fruticose Claditra ratrgiferitta at the two rural localities only. Particulates collected on air filters at each locality contained 1.7~ as much Pb as Cu and 4-20X as much Pb as Zn. Lichens selectively accumulated Zn at all sites, and Pb at roadside sites, but not at forest sites. Filters had ratios of PblZn twice as high as those in I! caperata. and lox higher than C. ratigiferiina. Differences in lichen response to Pb, Cu and Zn suggest that when using lichen metal content to assess ecosystem impacts including effects on human health, adjustments should be made for accumulation rates of metals by the lichens used for biomonitoring. hlarian G. Glenn. Ernest V. Orsi and hlary Ellen IIenuley, Biology Department, Seton Hall Uniwrsity, Soiitlr Orange, NJ, 07079. USA. The diversity and abundance of lichen species is a well-accepted bioindicator of air .quality (Nash & Wirth 1988, Ammann et al. 1987). In addition, li- chens accumulate air-borne particulates within the intercellular spaces of the lichen thallus (Nieboer et al. 1978, reviewed by Kershaw 1985). For example, lichcns accumulated radioactive Cs, Fe and Pb fol- lowing nuclear tests (reviewed by James 1973), and also Pb arising from gasoline (Lawrey & Hale 1981), sulphur from acid rain (Lawrey & Hale 1988), and toxic effluents containing Cd, Cu, Zn, etc. from smelters and other industrial processes (reviewed by Nieboer et al. 1978). The trapped particulates ap- pear to be solubilized by the lichen and metal ions rclcased by this process may have several fates. Some arc adsorbed onto the fungal cell walls of the lichens by an ion-exchange mechanism (e.g., Sr, Fe, Pb, Cu, Ni, Zn. Co) others are taken up intra- cellularly (c.g., K, Hg, Ag). Zinc ions and Cu2+ appear to be taken up intracellularly in part (re- viewed by Kershaw 1985). The different metabolic fates of the various metals suggest that lichens are not passivc air filtcrs, but rathcr that they may selec- tively accumulate those elements that remain extra- cellular, whereas those elements which gain entry into the cell may be metabolized and eliminated or may lead to death of the lichen. 4111 hit. Cotif. A r r o b i o l . l S ~ ~ k h o l m l l ~ : Session I The study reported here compares the metal con- tent of two lichen species to that of nitrocellulose air filters. Particulates were collected onto the filters by an air pump. Also, lichen metal content was com- pared in samples collected in different microsites in each locality, to determine how accurately the li- chens would reflect small differences in levels of air particulates. METHODS Choice of sampling sites Lichens and air were sampled at three Iocalities: 1. on the campus of Seton Hall University (SHU) in urban New Jersey, 2. at High Point State Park (HP) in rural, northwest New Jersey, and 3. at Beaver-Wil laboratory in the Adiron- dack hlountains of New York State. These localities are, ‘respectively, 20, 100 and 500 km from New York City. Intensity of vehicular traffic was recorded at two sampling sites within each of these localities, due to the importance of vehicular exhaust as a source of air-borne particulates. Data on air-borne particulates at sampling sites within each locality were used to establish gradients of pollution within the site. These gradients were supported by the nature of the sampling site differences (e.g. forest vs. roadside for HP and BW, and main avenue vs. side road for StIU). Air-borne particulates were measured using a portable small-particle detector (Gardner Associates, Schenectady. NY) set for condensation nuclei having a diameter of less than 0.001 pm. D ow nl oa de d by [9 8.2 19 .15 9.1 90 ] a t 0 1:2 0 2 6 M arc h 2 01 4 Metal contetit of lichens and air filters 45 which grows on the bark of trees, and Cludina rangiferinu, a fruticose lichen which grows on soil, were chosen for analysis. P. cuperato was found at all three localities, and C. rungiferinu at HP and BW only. In the lab, lichens were carefully removed from adherent substrate, dried to con- stant weight in an enclosed oven, and ground with a mortar and pestle. Powdered samples underwent wet-digestion with nitric acid followed by 60% perchloric acid. Samples were filtered and analysed by flame atomic absorption spectroscopy (Viera & Glenn 1990). Fig. 1. Air sampling apparatus. Air from the outside (A) is pulled by a brushless pump (B) (Brailsford Co.. Rye, NY) through a set of four double filters (C) arranged in series. The pump is operated intermittently by the interval timer (D). Determination of the metal content of the air Particulate air samples were collected on two nitrocellulose filters, pore sizes 0.45 pm and 0.2 pm, arranged in series (Fig. 1). Air was pulled through the filters using a brushless pump operated intermittently for two weeks to one month. Filters were dissolved in nitric acid (Ultrex I1 Ultrapure reagent. J. T. Baker Inc., Phillipsburg, NJ) and the levels of Pb, Zn and Cu were analysed by flame atomic absorp- tion spectroscopy. Sampling of the lichens Purmeliu cuperura, a distinctive lime-green foliose lichen Fig. 2. Filters exposed at Beaver-Wil lab (BW), Seton Hall University (SHU), compared to an unexposed filter (K). RESULTS AND DISCUSSION Lichen species distribution and abundance At the most rural site, BW, lichens (predominately C. rangiferina) were the dominant vegetation on the soil in open areas of the forest and were also found along sandy patches beside the road. Tree trunks and branches both in the forest and along the roadside were covered by a great variety of lichens, including prominent colonies of P. caperata with diameters of 10-30 cm. At HP, lichen cover was less noticeable, occurring mostly on rocks, trees trunks and dead branches. Many live trees had dead or partly dead colonies. C. rnngifPrtia was found on forest soil, 20 m from the roadside, and P. caperata was found on tree trunks at the roadside. At SHU minute (all less than 2 cm diameter) colonies of P. cnperntn were found near the base of the oak trees along a sideroad. No lichens of any species were found on trees along the main road running perpendicular to this side road. Metal content of lichens and filters Air filters exposed for one month at SHU and BW are shown in Fig. 2. The filter from BW is not much darker than the'control (K). Table I shows the lichen metal content, the vehicular traffic and the average particle counts at each sampling site. In general, the foliose 'lichen, P. cnperatn accumulated the three metals to levels higher than the fruticose lichen, C. rarigiferitia. This was true even when both species were collected from the same site. This result is in line with results found by Wetmore (1987) for these species collected in the Delaware Water Gap Na- tional Recreation Area, adjacent to HP. In contrast to the differences in absolute levels of metal accumulation, the patterns of metal accumu- lation relative to site were similar for both lichens. Three similarities were apparent for the BW and HP 4' 41h Inl. Con/. Aerobiol.lS~ockholmll!2%l: Session 1 D ow nl oa de d by [9 8.2 19 .15 9.1 90 ] a t 0 1:2 0 2 6 M arc h 2 01 4 46 Alnrinti G. Gletiti et nl. Table I. Mctnl cotitettts of liclietis (CN - ~ n i - ~ = condensation nuclei . cm-’) Lichen Site (# samples) Pb c u Zn Ve h i c k CN - cm-’ species (Pglg) per hour air Pnrriielia cnperntn SHU (1) 70 10 7 400 40,000 (minute colonies) HP (12) 176 38 70 300 8000 BW - roadside (2) 96 30 29 1 3soo B W - forest (4) 41 12 24 0 2800 Clnrliria rarigiferiiia HP - forest (3) 12 2 10 8 8000 BW - roadside (3) 7 6 16 1 3s00 B W - forest (3) 4 2 7 0 2soo samples of both lichen species: copper was present in small amounts, lead levels corresponded to the amount of vehicular traffic, and roadside samples contained higher levels of mctals than forest sam- The metal content of the P. cnpernta colonies col- lected at SHU was surprisingly low, considering the urban setting and the heavy traffic. These colonies were minute, less than 2 cm diameter, compared to colonies from the other sites which were all at least 8 cm diameter. This suggests that colonies of P. caper- atn growing at SHU may die off before they can accumulate a large burden of air-borne particulates. Table I1 presents a comparison of the metal con- ples. Table 11. Acciitniilntioti of Pb, Cit atid Zti by filters atid by liclietis tent of lichens and air filters, by showing the ratios of Pb to Cu and Pb to Zn for each. Filters at both localities showed Pb and Cu levels considerably greater than for Zn, with Pb almost twice the level of Cu. By contrast, P. cnperntn from urban and road- side sites selectively accumulated Pb relative to Cu, as seen by Pb/Cu ratios ranging from 3.2 to 7, much greater than 1.7 obtained for the filter. P. cnperntn from the forest, not exposed to as.much air-borne Pb, has a Pb/Cu ratio similar to the filters. C. rnrig- iferittn accumulated less Pb than P. c a p t p n (Table I), but the ratios of Pb to Cu are similk to those of I? cnpernta. Zinc is present in quite small amounts in the air at these localities. P. cnperntn selectively accumulated Zn, compared to the filters, as seen by the lower ratios of Pb to Zn. For C. rntigiferitin, the accumu- lation of Zn over Pb was even more pronounced. Sample Locality PblCu PblZn (number of samples measured) Air filters SHU 1.7 (5) 20 (3) B W 1.7 (4) 4.5 (3) Lichens: Pnrriielia cnpernta SHU ( I ) 7.0 10.0 BW - forest (4) 1.8 2.1 BW - roadside (2) 3.2 3.3 HP (3) HP (12) 4.6 2.5 Clarliiia rungiferina 5.6 1.3 0.56 BW - forest (3) 2.2 BW - roadside (3) 1.2 0.43 CONCLUSIONS Lichens do not act like passive air filters. Compared to nitrocellulose filters, lichens accumulated propor- tionately more Pb and Zn, and less Cu. This result suggests that Cu may be more acutely toxic to the lichens than Pb or Zn. This is supported by studies showing that even at micro-molar concentrations, Cu+* disrupts the integrity of the cell membrane, whereas Zn and Pb remain extracellular (Kershaw 1985). Also, studies by Puckett et al. (1973) found that in Cladotiin tiiitis only 20% of the Cu but over 80% of Zn and Pb were extracellular. The foliose lichen P. cnperatn accumulated more 4111 Itit. Cotif. ~lerobiol.lS~ockholrnl1~: Session I D ow nl oa de d by [9 8.2 19 .15 9.1 90 ] a t 0 1:2 0 2 6 M arc h 2 01 4 Metal coriteiit of liclietis arid air filters 47 metals than the fruticose lichen C. rarigijieriria. The generality of this finding is supported by metal anal- ysis of other foliose and fruticose species (Neiboer et al. 1978). The similarity in the patterns and ratios of accumulation of Pb, Zn and Cu in the two lichen species analysed in this study, suggests that both lichens respond similarly to each of the three metals, but that the “storage” capacity of lichens may be a function of morphology. Foliose lichens are con- structed like a sheet, whereas fruticose lichens have a central medulla of fungus surrounded by a layer of algae. Thus, the foliose lichens have a greater ratio of fungal medulla to algal material, and might be expected to accomodate more adsorbed metals for an equivalent mass of lichen. Lichens are extremely sensitive biomonitors of air-borne metals. This is illustrated by the consis- tently lower levels of all three metals in the forest samples of C. rarigijiiriria, compared to the roadside samples, at BW, the rural locality. Thus, a particular species of lichen is well-suited to act as a biomonitor for gradients or pockets of metal-polluted air within a locality. In addition, the large differences in metal content across a wide geographic region are also well-monitored by a species such as P. caperata which is broadly distributed, and easily identified. Metal levels were lower than expected in the min- ute colonies collected at the most urban locality (SHU). Lichens are cspecially sensitive to a number of toxic factors associated with the urban setting. Sulphur dioxide and the oxidant pollutants ozone and peroxyacetyl nitrate (PAN) are especially lethal to lichens (Sigal & Nash 1983). Exposure to such acutely toxic pollutants may prevent urban lichens from growing long enough to accumulate a high level of the less toxic metals deposited as particulates. However, as urban air quality improves, and levels of sulphur dioxide fall below the lethal threshold, some of the more tolerant lichen species are return- ing to the city (Sewall 1989). Monitoring the growth and metal levels of these pioneers may lead to a better understanding of the toxic effects of metal ions, accumulated as particulates. ACKNOWLEDGEMENTS We thank Eva Calcado for photography and thank the Glenbrook Inn and the NJ Correctional facility for accomo- dating our air sampling apparatus. REFERENCES Ammann. K., Herzig. R., Liebendorfer, L. 6: Urech, hf. 1987. hlultivariate correlation of deposition data in a small town in Sivitzcrland. - In: Advances in acro- biology. 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