Growth and reproduction of vascular plants in polluted environments: a synthesis of existing knowledge

Identification of factors explaining diversity in plant responses to industrial pollution is crucial for predicting fates of polluted ecosystems. Meta-analysis based on 203 publications demonstrated that plants growing near point polluters showed similar decreases in characters reflecting growth (–13.1%) and reproduction processes (–8.5%). In herbaceous plants, root growth was reduced, while aboveground biomass did not change, because the decrease in leaf size was compensated by an increase in leaf number. In contrast, woody plants demonstrated no changes in allometry and their growth was reduced to a greater extent than growth of herbaceous plants. Raunkiaer’s classification of life forms appeared the best predictor of species’ responses to pollution. Within woody plants, trees and shrubs, but not dwarf shrubs, showed strong decreases in growth and reproduction. Within herbaceous plants, significant growth reduction was observed only in annuals. Longevity of foliage or plant phylogeny did not explain variation in species’ responses. Adverse effects of pollution were stronger in regions with higher temperature and precipitation, hinting that existing pollution loads may become more harmful for plants as climate changes. Relatively minor explanatory value of the characteristics of individual polluters removes one of the principal obstacles to accounting for the effects of pollution in vegetation models and allows extrapolation of the effects observed near point polluters to both regional and global scales. We conclude that losses in productivity of plant communities due to aerial pollution can be approximately estimated on the basis of the life form spectra and climate.

INVESTIGATIONS OF MUNICIPAL SOLID WASLE LANDFILLS LEACHALE TREATMENT

Municipal solid waste landfills are one of the most dangerous environment “point" polluters. The main polluter in landfills is leachate, which arise mainly of waste moisture and precipitations. Leachate is very contaminated wastewater and all landfills operators have problems in leachate treatment sector, because composition of leachate contaminants and concentrations very changed in time. It is very problematic task for selection of leachate treatment method or methods. Normally, in leachate treatment practice combination of different treatment methods are used. In this paper composition of leachate in two biggest Latvia landfills are described. Leachate treatment investigations were achieved with coagulation and sorbtion methods. In researches leachate with coagulants Al2(SOf3 and FeCl3 and peat as sorbent are treated. Researches showed that peat is very effective sorbent for heavy metals removing from leachate.