Multivariate statistical techniques are efficient ways to display complex relationships among many objects. An attempt was made to study the data of trace elements in groundwater using multivariate statistical techniques such as principal component analysis (PCA), Q-mode factor analysis and cluster analysis. The original matrix consisted of 17 trace elements estimated from 55 groundwater samples colleted in 27 wells located in a coastal area in Shenzhen, China. PCA results show that trace elements of V, Cr, As, Mo, W, and U with greatest positive loadings typically occur as soluble oxyanions in oxidizing waters, while Mn and Co with greatest negative loadings are generally more soluble within oxygen depleted groundwater. Cluster analyses demonstrate that most groundwater samples collected from the same well in the study area during summer and winter still fall into the same group. This study also demonstrates the usefulness of multivariate statistical analysis in hydrochemical studies. Multivariate statistical analysis was used to investigate relationships among trace elements and factors controlling trace element distribution in groundwater.

The efficiency of several lab scale treatments (aerobic, anaerobic and ozone or combination of these) was evaluated using two packaging board mill whitewaters. The effect of the different treatments on the elimination of the organic load, the chemical oxygen demand (COD) and the toxicity was tested as well as the relationship between these parameters. Biocides, phenolic compounds, surfactants, plasticiziers and wood extractives were identified in untreated and treated whitewaters by liquid chromatography coupled with mass spectrometry (LC-MS) or gas chromatography coupled with mass spectrometry (GC-MS). A strong dependency on the water type and treatment efficiency was observed, being the combination of anaerobic and aerobic treatments the best option to reduce the organic contaminants in these waters, although in some cases, the toxicity did not decrease. However, ozone as post-treatment permitted a further reduction of organic compounds, toxicity and COD. Aerobic and anaerobic treatments remove organic compounds in paper mill effluents but toxicity remains.

Aquatic macrophytes were found to be the potential scavengers of heavy metals from aquatic environment. In this study, several physiological responses of Alternanthera philoxeroides (Mart.) Griseb leaves to elevated concentrations of cadmium (up to 10 mM) were investigated. It was found that A. philoxeroides was able to accumulate cadmium in its leaves. The pigment contents decreased with the increase of the Cd concentrations. The Cd could induce rise of the activity of peroxidase (POD) at lower concentration (<5 mM), however, when the concentration of Cd rose up to 10 mM, the POD activity declined. The changes of superoxide dismutase (SOD) and Catalase (CAT) activities were exactly opposite to that of POD. In the leaves of Cd-treated fronds, the amounts of three polypeptides with apparent molecular weights 80, 39 and 28 kDa, respectively, were became visible in SDS-PAGE. The nature of these polypeptides remains to be determined. Cd modified a number of physiological processes and particularly chlorophyll degradation.

The representativeness of soil pore water extracted by suction lysimeters in ground-water monitoring studies is a problem that often confounds interpretation of measured data. Current soil water sampling techniques cannot delineate from which soil volume a pore water sample is extracted, neither macroscopic, microscopic, or preferential flowpath. This research was undertaken to compare δ¹⁸O and Br- values of extracted suction lysimeters samples from intact soil cores with samples obtained by the direct extraction methods of centrifugation and azeotropic distillation. Also, the study was concerned with determining what portion of soil pore water is sampled by each method and explaining differences in concentrations of the extracted water from each method to allow a determination of the accuracy and viability of the three methods of extraction. Intact soil cores (30 cm diameter by 40 cm height) were extracted from two different sites. Site 1 was rapid infiltration basin number 50, near Altamonte Springs in Seminole County, Florida. Site 2 was the Missouri Management System Evaluation Area (MSEA) near Centralia in Boone County, Missouri. Isotopically (¹⁸Oδ) labeled water and bromide concentrations within water samples taken by suction lysimeters was compared with samples obtained by methods of centrifugation and azeotropic distillation. The ¹⁸Oδ water was analyzed by mass spectrometry while bromide concentration, applied in the form of KBr was measured using standard IC procedures. Water collected by centrifugation and azeotropic distillation data were about 0.25[per thousand] more negative than that collected by suction lysimeter values from a sandy soil and about 2-7[per thousand] more negative from a well structured soil. Results indicate that the majority of soil water in well-structured soil is strongly bound to soil grain surfaces and is not easily sampled by suction lysimeters. In cases where a sufficient volume of water has passed through the soil profile and displaced previous pore water, suction lysimeters will collect a representative sample of soil pore water from the sampled depth interval. It is suggested that for stable isotope studies monitoring precipitation and soil water, suction lysimeter be installed at shallow depths (10 cm). Samples should also be coordinated with precipitation events. The data also suggest that each extraction method samples a separate component of soil-pore water. Centrifugation can be used with success, particularly for efficient sampling of large areas. Azeotropic distillation is more appropriate when strict qualitative and quantitative data on sorption desorption, and various types of kinetic studies may be needed.