An experiment of Randomized Block Design was conducted during 2005 in a greenhouse of the University of Ioannina, Department of Environmental Management and Natural Resources, in order to study the effect of the Treated Municipal Wastewater (TMWW) on the interrelationships of macro, micronutrients, heavy metals and physical and chemical properties of a soil cultivated with Brassica oleracea var. italica (broccoli). The experimental design included the following treatments: (a) TMWW, (b) Fresh irrigation water or “control”, in six replications, with a total number of 2 x 6 = 12 plots of 2.5 x 1.8 = 4.5 m² size. The following were found. Numerous interactions are taking place in the soil under the effect of TMWW, between: (a) macro-, micronutrients, and heavy metals, i.e. (N, P, K, Ca, Mg, Zn, Mn, Fe, B, Cu)x(Ni (Co, Pb, Cd) and (b) between all the above metals and the soil properties i.e. (nutrients and heavy metals)x(pH,CaCO₃, O.M) These interactions could have an important impact on plant growth and the environment, as they can either supply the plants with nutrients, due to their synergistic effects or they can contribute to the decrease or inactivation (fixation) of some undesirable soil heavy metals, owing to their antagonism. Examples of these interactions are studied, and their significance in plants and the environment, is examined, under the effect of the TMWW reuse.

Acid mine drainage (AMD), a legacy of coal and mineral extraction, contaminates streams with complex mixtures of acid and heavy metals that are usually partitioned between the water column and substrate. Understanding the conditions under which sediments retain toxicity after the water column is cleared is important for predicting the long term success of remediation efforts. We conducted laboratory and field experiments to evaluate the relative contribution of acidity versus metals to the toxicity of AMD contaminated sediment towards aquatic macroinvertebrates. Laboratory bioassays showed that precipitate-coated substrate from AMD-impacted sites were toxic to Ctenodaphnia magna and reduced growth of mayflies (Ephemeroptera: Heptageniidae). Toxicity correlated more with acidity released from the sediment than with metals. After transplantation to a clean stream, the same Al- and Fe-contaminated substrate were not toxic to daphnia and was readily colonized by benthic macroinvertebrates within 5 weeks.

Salvinia minima has been reported as a cadmium and lead hyperaccumulator being the adsorption and intracellular accumulation the main uptake mechanisms. However, its physicochemical properties, the effect of metal concentration and the presence of organic and inorganic compounds on its hyperaccumulating capacity are still unknown. Furthermore, the specific adsorption and accumulation mechanisms occurring in the plant are not clear yet. Thus, based on a compartmentalization analysis, a bioadsorption (BAF) and an intracellular accumulation factor (IAF) were calculated in order to differentiate and quantify these two mechanisms. The use of kinetic models allowed predicting the specific type of uptake mechanisms involved. Healthy plants were exposed to five lead concentrations ranging from 0.80 ± 0.0 to 28.40 ± 0.22 mg Pb²⁺l⁻¹ in batch systems. A synthetic wastewater, amended with propionic acid and magnesium sulfate, and deionized water were used as media. The BAF and IAF contributed to gain an in-depth insight into the hyperaccumulating lead capacity of S. minima. It is clear that such capacity is mainly due to adsorption (BAF 780–1980) most likely due to its exceptional physico-chemical characteristics such as a very high surface area (264 m² g⁻¹) and a high content of carboxylic groups (0.95 mmol H⁺g⁻¹ dw). Chemisorption was predicted as the responsible mechanism according to the pseudo-second order adsorption model. Surprisingly, the ability of S. minima to accumulate the metal into the cells (IAF 57–1007) was not inhibited at concentrations as high as 28.40±0.22 mg Pb²⁺l⁻¹.

Anaerobic benzene biodegradation was performed in batch experiments using Rhine River sediment as inoculum and amorphous Mn(IV) or Fe(III) as independent final electron acceptors. Benzene (4.5 μmol) was degraded in 80 and 710 days in batch experiments under Mn(IV) and Fe(III) reducing conditions, respectively. Highest benzene degradation rate, 0.07 μmol/day, was obtained under Mn (IV) reducing conditions, with soluble Mn(II) and CO₂ recoveries of 71.5% and 93% regarding to the stoichiometric values, respectively. Likewise, benzene biodegradation was performed in a continuous column coupled to the reduction of Mn(IV). Efficiency of benzene biodegradation was up to 97% under steady state operation in a sediment column operated continuously for more than 160 days. The carbon dioxide and Mn(II) recoveries were 88% and 77%, respectively, of the theoretical ratio according to the stoichiometry for benzene biodegradation.

Acute toxicity of Pb to the water flea; (Daphnia sp) and Copepod, (Cyclop sp) both important component of zooplankton diet of fish was determined by static assay. A positive relationship between percentage mortality and exposure concentration was found in all tests. Mean 24-h LC50, 48-h LC50 and 96-h LC50 values were 2.51 ± 0.0.04 mg l⁻¹, 1.88 ± 0.06 mg l⁻¹ and 1.65 ± 0.19 mg l⁻¹ for Daphnia spp and 3.11 ± 0.03 mg l⁻¹, 2.97 ± 0.05 mg l⁻¹ and 2.61 ± 0.09 mg l⁻¹ for Cyclop spp, respectively. For all tested species did the LC50 values decrease with time; the decrease was more marked for Daphnia spp. Observed symptoms include spiral movement followed by change of body colour to white and rapid disintegration of the skin. The Daphnia spp. appear to be more sensitive to Pb poison than Cyclop spp. The results showed that concentrations of Lead (Pb) in excess of 0.19 mg l⁻¹ and 0.30 mg l⁻¹ can be potentially harmful to Daphnia magna and Cyclop spp respectively.

Selection of a phytoextraction plant with high Cd accumulation potential based on compatibility with mechanized cultivation practice and local environmental conditions may provide more benefits than selection based mainly on high Cd tolerance plants. In this hydroponics study, the potential of Cd accumulation by three plant species; arum (Colocasia antiquorum), radish (Raphanus sativus L.) and water spinach (Ipomoea aquatica) were investigated. Arum (Colocasia antiquorum L.) plants were grown for 60 days in a nutrient solution with 0, 10 or 50 μM Cd, while radish and water spinach plants grew only 12 days in 0, 1.5, 2.5, 5 or 10 μM Cd. Growth of radish and water spinach plants decreased under all Cd treatments (1.5 to 10 μM), while arum growth decreased only at 50 μM Cd. At 10 μM Cd treatment, the growth of arum was similar to the control treatment indicating higher tolerance of arum for Cd than radish and water spinach. Cadmium concentrations in different plant parts of all plant species increased significantly with Cd application in the nutrient solution. Arum and water spinach retained greater proportions of Cd in their roots, while in radish, Cd concentration in leaves was higher than in other plant parts. Cadmium concentrations in arum increased from 158 to 1,060 in the dead leaves, 37 to 280 in the normal leaves, 108 to 715 in the stems, 42 to 290 in the bulbs and 1,195 to 3,840 mg kg⁻¹ in the roots, when the Cd level in the solution was raised from 10 μM Cd to 50 μM Cd. Arum accumulated (dry weight x concentration) 25 mg plant⁻¹ at 10 μM, while the corresponding values for radish and water spinach were 0.23 and 0.44 mg plant⁻¹, respectively. With no growth retardation at Cd concentrations as high as 166 mg kg⁻¹ measured in entire plant (including root) of arum at 10 μM Cd in the nutrient solution, arum could be a potential Cd accumulator plant species and could be used for phytoremediation.

The European Union has introduced a new bathing water directive where future classification of recreational waters will be based on the microbial parameters Escherichia coli, and intestinal enterococci. Introduction of enterococci as a new quality parameter may pose a challenge in some areas because relatively less is known about these organisms compared to E. coli. In the present study, the relative abundance of intestinal enterococci, E. coli, and ten fecal sterol and stanol biomarkers were investigated in water and sediment at two estuarine beach sites affected by fecal pollution. In the bathing water, enterococci were relatively more abundant at low E. coli concentrations. In the sediment, enterococci were generally more abundant than E. coli with surface concentrations between 1.0 × 10² and 4.5 × 10³ CFU cm⁻³. Enterococci populations were relatively similar in water and sediment, and were phenotypically different from that of nearby pollution sources. The putative human specific genetic marker esp in Enterococcus faecium was not detected in water or sediment samples despite occasional inputs of human waste from storm water overflows. Sterol and stanol profiles suggested a direct link between water and sediment pollution profiles on days with wind conditions that facilitated resuspension. Sediment resuspension may occur at wind speeds exceeding 6–8 m s⁻¹, and could contribute significantly to enterococci concentrations in the overlying water. The study emphasized that recontamination of the water column due to wind induced resuspension should be considered when evaluating indicator levels and microbial hazards in estuarine recreational waters.