Twelve Mediterranean hydrophyte species collected inLebanon were evaluated for their potential asbioindicator species for heavy metal pollution innutrient cultures enriched with 1 ppm Cr, Ni and Cd.These were: Nasturtium officinale R.Br, Apium nodiflorum L., Veronica beccabunga L., Veronica anagallis aquatica L., Veronicalysimachioides L., Veronica anagalloides L., Mentha longifolia L., Mentha aquatica L., Mentha pulegium L., Potentilla reptansL., Mentha sylvestris L., and Cardamine uliginosa L.. Large variability in responseto exposure to the heavy metals was observed. Growthrates remained high during the experimental period,indicating that the plants were little affected by thepresence of the metal at the experimentalconcentration. Metal accumulation and bioconcentrationvaried within at least one order of magnitude, andranged from less than 10 to over 200. Cr waspreferentially accumulated in the roots. All speciesbut M. pulegium, P. reptans and V. anagallisaquatica accumulated and bioconcentrated sufficientCr to qualify as bioindicator species. Five of thespecies that accumulated Cr also accumulated Ni, withthe same partitioning into the root. These were: N. officinale, C. uliginosa sp., M. longifolia, M. aquatica and M. sylvestris, all of which mayalso be used as bioindicators of Ni pollution. Onlyone species, M. aquatica, accumulated Cdsignificantly, and may, therefore, be used as abioindicator for all three metals.

Sludge from a wastewater treatment plant can be applied to soil to make use of its fertilizing properties, neverthelessit is necessary to study all the effects of this deposition to ascertain any possible hazardous properties. Interactions among the soil, the water, and a lime-stabilized waste watersludge were studied, both in batch experiments, and in columnpercolation experiments. Firstly a physico-chemical characterization of the soil and the sludge used for the experiments was carried out. This analysis included pH, organic matter, cation exchange capacity, metals and cations.The kinetics and equilibrium of the sludge-water and leachate-soil systems were studied in batch experiments; thekinetics were fitted to a first order differential equation and distribution coefficients were found for the equilibrium.Experiments in columns (10 cm diameter × 50 cm height) were carried out with a bed of sludge over a bed of soil usingdifferent sludge/soil ratios and then 6 L of water (rainfall)was poured over the beds. Results showed good adsorption of Ca and a complete leaching of the aqueous phase of this ion afterpassing a volume of water equivalent to three volumes of the column. The concentration of heavy metals (Zn, Ni, Hg, Cd, Pb and Cr) in the leachates did not reach the admissible legal limits (Spanish and European regulations) in any case.

To compare the soil remediation effectiveness of saltsof weak organic acids with strongchelating agents, three soils of different textures,all polluted by heavy metals, were washed in a column,at optimum pH, with salts of weak organic acids,namely, citrate, tartarate or oxalate + citrate orchelating agents (EDTA or DTPA). For the clay loam,Cr, Mn, Hg and Pb were removed by citrate andtartarate at levels of 43 to 45, 37 to 41, 91 to 92and 75%, respectively. EDTA and DTPA effectivelyleached only Pb after 20 pore volumes. For the loam,citrate leached 98 and 89% of Cd and Pb after 20 porevolumes, respectively, while tartarate leached out 91and 87% of Cd and Pb. EDTA and DTPA removed 93 to97% of these metals after 20 pore volumes. For thesandy clay loam, 84 to 91, 73 to 84, 56 to 70 and 72to 81% of Cd, Cu, Pb and Zn were removedrespectively, by citrate and tartarate. EDTA and DTPAremoved 93 to 97% of these metals after 20 porevolumes. An in situ soil remediation simulation wasalso tested using the sandy clay loam in a tub. After12 hr of retention, the citrate solution washed 81, 82,73 and 90%, of Cd, Cu, Pb and Zn, respectively, aftersix pore volumes. EDTA and DTPA effectively removedall heavy metals, except for Hg, but also extractedlarge quantities of soil nutrients and pollute thesoil by being adsorbed on the soil particles. Thesalts of citrate and tartarate effectively removed theheavy metals from the three polluted soils whileleaching little macro-nutrients and improving soilstructure. Each soil reached C and B levels ofsoil-clean-up criteria after 10 to 20 pore volumes andwithin 10 to 15 hr of flushing.

Polycyclic aromatic hydrocarbon and heavymetal (Pb, Cd, Cu, Zn, Hg, Fe, Co, Cr, Mo) contentswere established in soil and plant samples collectedin different areas of the railway junction IławaGłówna, Poland. Soil and plant samples werecollected in four functional parts of the junction, i.e. the loading ramp, platform area, rolling stockcleaning bay and the railway siding. It was found thatthe PAH contamination of soil and plants was thehighest in the platform area and near the railwaysiding and lowest in the loading ramp and cleaning bayareas. The contamination exceeded control levels up toalmost twenty fold. The heavy metal contaminationpattern was different. The soil and plants were veryhighly contaminated in the cleaning bay and side trackareas while the loading ramp and platform areas wereless contaminated. A particularly high pollution levelwas observed for mercury in the cleaning bay area.Also lead, zinc and copper pollution levels wererelatively high in the cleaning bay and side trackareas. No significant increase in molybdenum contentwas observed in comparison with the control area.

The objectives of this investigation in the HolyCross Mountain region of Poland were (1) to determineconcentration ranges and (2) mobility of elements within fivedetailed soil profiles and their apparent impact on thechemistry of some plant bioindicators, i.e. lichen thalli ofthe species Hypogymnia physodes (L.) Nyl. and Scotspine (Pinus sylvestris L.) bark. The results ofelemental determinations performed on soils and vegetationfrom the Holy Cross Mts show that some concentrations ofelements are elevated primarily due to air pollution.However, since 1994 a steady decrease in the content of S andsome heavy metals has been recorded in all the mediaexamined. Concentrations of many elements in H.physodes thalli and P. sylvestris needles of the Holy Cross Mountains are generally similarto those in other areas of Europe.

Seven sediment cores were collected along a transect about20 km off from the mouth of the Po River, in the northernAdriatic Sea (Italy). Cores were characterised by differentdepositional sequences associated with late Pleistocene-Holocene lowstand (LST), transgressive (TST) and highstand (HST) system tracts. Sediment samples were analysed for mercury, copper, nickel, chromium, manganese and iron, aswell as for total organic matter. Metal distributiongenerally showed vertical and spatial variability ascribed tograin size effects with no significant anthropogenicperturbation. Conversely, mercury showed vertical profilescharacterised by surface enrichment, with concentrations inthe upper layer (50–230 ng g⁻¹) exceeding 3–11 times the background value of 20 ng g⁻¹ determined in bottomcores. Surface maxima were attributed to anthropogenic mercurydelivered mainly by the Po River.