Biological effects of ammonia released from a composting plant assessed with lichens

Abstract

In this study, we investigated whether ammonia emissions from industrial composting of organic waste may influence the surrounding environment, using lichens as bioindicators. To this purpose, samples of N-tolerant and N-sensitive lichens, namely Xanthoria parietina and Evernia prunastri, were transplanted for 1-3 months along transects at increasing distance (0-400 m) from a composting facility in Tuscany, Italy. Atmospheric concentrations of ammonia were measured using passive samplers. The physiological response of lichen transplants was investigated by means of the photosynthetic efficiency (measured as chlorophyll a fluorescence emission), the integrity of cell membranes (measured as electrolyte leakage), and sample viability (measured as enzymatic activity of dehydrogenase). Epiphytic lichen communities were investigated using biodiversity indices. The results showed decreasing concentrations of ammonia, from 48.7 μg/m(3) at the composting facility to 2.7 μg/m(3) at 400 m. The N-tolerant X. parietina was not affected and some physiological parameters even showed a higher performance, while the N-sensitive E. prunastri showed a reduced performance with increasing atmospheric concentrations approaching the source. A shift from lichen communities composed by meso-acidophilous species (actual condition) to more nitrophilous communities in the near future, approaching the composting facility is suggested. It is concluded that lichens can provide useful data for decision-makers to establish correct science-based environmentally sustainable waste management policies.

Spatial variation of eco-physiological parameters in the lichen Pseudevernia furfuracea transplanted in an area surrounding a cement plant (S Italy)

“…The gases NO x and SO 2 are known to negatively affect both the physiological status of lichens (Egger et al 1994;Das et al 2011) and the species composition of communities (Davies et al 2007;Hawksworth and Rose 1970). Ammonia can cause changes in epiphytic communities (Wolseley et al 2006) since it is detrimental to some eco-physiological parameters (Paoli et al 2014). Dusts emitted from kilns are highly noxious due to their alkaline nature and the associated metals.…”

Effects of acute NH3 air pollution on N-sensitive and N-tolerant lichen species

“…Paoli et al (2010a) During the aerobic composting of biowaste, concentrations of NH 3 in the waste gas up to 227 mg/m 3 were reported (Smet et al, 1999), while during animal housing and transportation, values up to 22.5 mg/m 3 have been documented (Costa et al, 2003), corresponding to levels potentially harmful for the animals (Gustin et al, 1994). Paoli et al (2014a) assessed the biological effects of NH 3 released during three months of activity from a composting plant of organic wastes using lichen transplants. Respect to unexposed samples, NH 3 around the facility (peak of 48.7 7 18.9 μg/m 3 ) affected the overall vitality (in particular the photosynthetic performance) of non-nitrophilous lichens (E. prunastri), but did not affect negatively that of nitrophilous species (X. parietina).…”

“…Based on previous field studies (Paoli et al, 2014a), each experimental chamber simulated a different situation of impact according to a gradient of NH 3 pollution: no impact (control), intermediate impact, high impact. In order to work with a similar lichen biomass, each experimental chamber contained about 50 thalli of F. caperata and about 100 thalli of X. parietina (whose thalli are generally more little than those of F. caperata).…”

“…In a previous work we investigated whether NH 3 emissions released during composting of organic waste influenced during short-term exposures the lichens in the surrounding environment (Paoli et al, 2014a). It was shown that exposing lichens around a composting plant allowed detecting early physiological indications of potential biological changes before these consequences were apparent at the community level.…”

“…In particular, N-tolerant species were not affected by the proximity to the facility and some parameters even suggested a better performance, while N-sensitive species showed reduced performances approaching the source. In addition, it was hypothesised that the concentrations of NH 3 were highly fluctuating, with peaks during outdoor handling and maturation of the compost, suggesting that acute episodes of pollution could be the reason for the observed effects (Paoli et al, 2014a). It was concluded that lichens can provide useful data for decision-makers to establish correct science-based environmentally sustainable waste management policies.…”