Oil derivatives are commonly used and they play a key role in the economy. They are used in many industries. Such big amounts of oil derivatives products generate vast quantity of pollution. Those pollutants can get into the ground and water beyond any control during catastrophes or due to inadequately managed waste and storage. The aim of the paper was to determine the level of oil derivatives pollution in the groundwater on the area of a former airbase, where between 1950 and 1990 the Soviet Army stationed. Analysis was carried out on groundwater samples from three piezometers placed on the area of the former airbase. In the samples some parameters were determined, i.e. temperature, reaction, electrolytic conductivity, the depth of groundwater surface, the content of aliphatic hydrocarbons, monoaromatic and polycyclic aromatic hydrocarbons. Determined amount of dissolved hydrocarbons was large what proves unsatisfactory effectiveness of previous rehabilitation processes.

The Henaya Irrigated Perimeter (HIP) is an agricultural area irrigated by treated wastewater (TWW) of Ain El Hout treatment plant. Various analyses have shown that i) this water has low concentration of heavy metals and toxic elements, ii) the average values of the physicochemical parameters for 136 samples are satisfactory (29.2 mg O2∙dm–3 for chemical oxygen demands – COD, 13.14 mg O2∙dm–3 for biological oxygen demands – BOD, 14.2 mg∙dm–3 of suspended matter – SM, 1.82 mg∙dm–3 of N-NO3, 7.7 for pH and 927.74 μS∙cm–1 for electric conductivity – EC). Thirdly, it contains a high number of bacteria and nematodes (7200 CFU∙(100 dm3)–1 for faecal coliforms and 30 eggs∙dm–3 for intestinal Nematodes) which makes it dangerous for groundwater contamination. The objective in this work is to characterize the TWW and evaluate the impact of it use for irrigation on the quality of Hennaya groundwater. Before this, one has to prove that there is an amount of TWW that feeds the water table to show that there is a risk of pollution. We then estimated the aquifer minimum recharge value by TWW using the Thormthwaite meth-od. The estimation has given 92 mm which is an important quantity. The results of the groundwater microbiological anal-yses reveal no sign of contamination. The cause is the efficiency of the degradation of pollutants of the Vadose zone. The soil purifying power Md of the HIP was evaluated by the Rehse method and gave values ranging from 2.1 to 12.7 which indicated a complete purification.

The study of groundwaters was carried out in two different forest ecosystems of Słowiński National

Park: Vaccinio uliginosi-Betuletum pubescentis and Empetro nigri-Pinetum in the period of 2002-2005. Differences were found in the position of the groundwater table and in the concentrations of nitrogen and phosphorus

compounds in the investigated forest associations. In the Vaccinio uliginosi-Betuletum pubescentis association

the groundwater table was found on average at a depth of -73.3 cm, while in Empetro nigri-Pinetum at -90.2

cm. No statistically significant effect of precipitation on the position of the groundwater table was found in

this study. Statistical calculations (U Mann-Whitney test) for groundwaters in the analyzed forest associations

showed statistically significant differences in the dynamics of concentrations of total nitrogen (T-N), organic

nitrogen (Norg.), nitrate nitrogen (N-NO3

), total phosphorus (T-P), organic phosphorus (Porg.) and the level of

groundwaters.

The aim of the study was to compare the physical-chemical quality parameters of shallow groundwater quality in peat bogs of the Łęczna-Włodawa Lake District in the context of the occurrence of selected boreal species of plant relics: dwarfbirch (Betula humilis Schrank), downy willow (Salix lapponum L. ) and swamp willow (Salix myrtylloides L. ). Analyzes of shallow groundwater quality parameters included physical-chemical parameters: reaction (pH), electrolytic conductivity(EC), dissolved organic carbon (DOC), total nitrogen (TN), ammonium nitrogen (NH4), nitrite nitrogen (NO2), nitrate nitrogen (NO3), total phosphorus (TP), phosphate (PO4), sulfate (SO2), sodium (Na), potassium (K), calcium (Ca) and mag-nesium (Mg) by certified laboratory tests.

It was found that the natural hydrochemical specification of peat bogs is characterized by fluctuations associated with the dynamics of internal metabolism of peat ecosystems without the visible impact of anthropopressure. This is confirmed by the concentration of nutrients: TNat the study sites were within a broad range of mean values: 16.92–45.31 mg·dm–3; NH4 (0.55–0.76 mg·dm–3); NO2 (0.06–4.33 mg·dm–3); and NO3 did not exceed 0.2 mg·dm–3, and concentration of TP adopted mean values in a range of 0.22–0.42 mg·dm–3.

The studied physical-chemical factors of shallow groundwater were within the habitat preferences of the studied species, but in differentiated qualitative and quantitative ways determined optimal conditions for building the population of the studied species. Particularly values of TP lower than other obtained values in a range of: 0.08–0.32 mg·dm–3; PO4 = 0.1 mg·dm–3; TN = 2.2–21.2 mg·dm–3; NH4 = 0.1–0.46 mg·dm–3; DOC = 24.6–55.9 mg·dm–3, as well as higher than average pH values in a range of: 5.34–5.95 and concentration of Ca = 5.67–28.1 mg·dm–3 and Mg = 0.56–2.41 mg·dm–3, as well as EC = 72.1–142.3 μS·cm–1 can be treated as a condition favouring proper development of the population of dwarf birch. For Salix lapponum: a reduced level of values of nitrogen fractions (TN = 3.01–18.84 mg·dm–3; NH4 = 0.1–0.41 mg·dm–3), a reduced level of values of phosphorus fractions (TP = 0.09–0.44 mg·dm–3; PO4 = 0.1–0.44 mg·dm–3), part of ions (Ca = 4.39–19.63 mg·dm–3; Mg = 0.77–3.37 mg·dm–3), pH = 5.9–6.4, EC = 124–266 μS·cm–1 and DOC = 24.1–57.5 mg·dm–3. For the equally studied Salix myrtylloides, such conditions were met by: TP = 0.1–0.41 mg·dm–3; PO4 = 0.1–0.18 mg·dm–3, DOC = 27.5–50.9 mg·dm–3, pH = 5.3–5.94 andEC = 62.2–139.3 μS·cm–1.

The article presents research results of the introduction of powdery activated carbon to the existing technological system of the groundwater treatment stations in a laboratory, pilot plant and technical scale. The aim of the research was to reduce the content of organic compounds found in the treated water, which create toxic organic chlorine compounds (THM) after disinfection with chlorine. Nine types of powdery active carbons were tested in laboratory scale. The top two were selected for further study. Pilot plant scale research was carried out for the filter model using CWZ-30 and Norit Sa Super carbon. Reduction of the organic matter in relation to the existing content in the treated water reached about 30%. Research in technical scale using CWZ-30 carbon showed a lesser efficiency with respect to laboratory and pilot-plant scale studies. The organic matter decreased by 15%. Since filtration is the last process before the individual disinfection, an alternative solution is proposed, i.e. the second stage of filtration with a granular activated carbon bed, operating in combined sorption and biodegradation processes. The results of tests carried out in pilot scale were fully satisfactory with the effectiveness of 70–100%.

Wonji Shoa Sugar Estate (WSSE), located in the flood plain of the Awash River (Ethiopia), has been under long-term (>60 years) irrigation, industrial activities and agro-chemical usage. In this study, the hydrochemical properties of ground-water bodies available at WSSE have been characterized for quality compositions. Water samples were collected from groundwater monitoring piezometers distributed in the sugarcane plantation and then analysed for physico-chemical quality parameters (pH, EC,major cations and anions) following standard procedures. Other chemical indices (e.g., total dissolved solids (TDS),total hardness(TH),magnesium absorption ratio(MAR), base exchange (r1), meteoric genesis(r2)) were de-rived from the measured water quality parameters. The compositional variability and groundwater classification has been presented using the Box and Piper plots. The potential sources of minerals were suggested for each of the considered water sources based on their quality characteristics. Both trilinear Piper plot and meteoric genesis index revealed that groundwaterof the area is shallow meteoric water percolation type with a changing of hydrochemical facies and mixing trend. Ground-water of the area, is group 1 (Ca-Mg-HCO3) type, with no dominant cations and HCO3 are the dominant anions. Overall, the study result elucidates that the chemical composition of GW of the area showed spatial variability depending upon the variations in hydrochemical inputs from natural processes and/or anthropogenic activities within the region. The local an-thropogenic processes could be discharges from sugar factory, domestic sewage and agricultural activities.

The physicochemical and bacteriological quality of groundwater was assessed to show the impact of the agriculture and human activities in the Triffa Plain located in North-East of Morocco. The current levels of contamination of the groundwater were estimated by analysing electrical conductivity, nitrate, nitrite, ammonia, orthophosphate, and indicators of faecal pollution content.

Water samples from 55 locations were collected during two period of time, the wet and the dry season of the year 2016. Result obtained indicated that most samples are highly contaminated. The electrical conductivity varied from 800 to 9 100 μS∙cm–1. Nitrate levels ranged from 25 to 216 mgꞏdm–3, with 78% of samples exceeding the critical level value set at 50 mgꞏdm–3. Nitrate concentrations are slightly higher during the wet period in 73% of studied cases. Nitrite rarely exceeded the normal rate fixed by World Health Organization and reached 0.90 mgꞏdm–3. Ammonia and orthophosphate contents do not exceed these norms.

The study revealed a wide contamination of groundwater by microbial agents such as, total coliforms, faecal coliforms and faecal streptococci, with content ranged from 0 to 14 000, 0 to 5 000 and 0 to 5 000 CFUꞏ(100 cm3)–1 respectively, con-firming the impact of septic tanks, wastewater discharge into rivers without treatment, and the use of animal waste on the ground water vulnerability.Samplings and measurements were carried out according to the international standard ISO 13395, ISO 11732 and ISO 15681-2 for chemical compounds and ISO 9308-1 and ISO 7899-2 for microbiological numerations.

Water quality is an important criterion for evaluating the suitability of water for drinking and domestic purpose. The main objective of this study was to investigate the physicochemical characterization of groundwater for drinking water con-sumption. Ten captured sources were selected from three aquifers including the Guelma Mio-Plio-Quaternary alluvial ba-sin; the Senonian Heliopolis Neritic limestone aquifer, and the Eocene limestones of Ras El Agba-Sellaoua aquifer. The analyses concerned the periods of high water in May 2017 and low water in August 2017. Twelve parameters were deter-mined for the water samples: pH, T (°C), EC, Ca2+, Mg2+, Na+, K+, Cl–, HCO3–, SO42–, NO3–, TH (hydrotimetric degree), TAT (total alkalinity titration). The interpretation of the various analytical results allowed the determination of the chemical facies and the classification of the groundwater aquifers as follows: (i) in the alluvial layer, the gypsiferous marl substratum and the clays of the three terraces (high, medium and low) have given the water a chlorinated calcium chemical facies in the east part of the study area and travertines feeding partly alluvial layer, and have given a bicarbonated calcium water facies in the west, (ii) in the Senonian of Heliopolis limestone and Eocene carbonate formations of Ras El Agba- -Sellaoua, the chemical facies are calcium bicarbonate. Water isotopes (δ18O and δD) helped to determine the origin of groundwater. Overall, the groundwater in the area is hard and has significant to excessive mineralization. It is progressivelydegraded in the direction of flow, especially in the Guelma alluvial aquifer.

Based on chemical analyses, the quality of ground waters for drinking, agricultural and industrial purposes was deter-mined in Rafsanjan Plain-Iran. Samples for analyses were taken from 22 wells in 2012. Because of high water hardness and total dissolved solids content, water was found to be unsuitable for drinking purposes. Water quality for agriculture was determined with the use of the Wilcox method. Among the analysed water, 10.33% were attributed to C3-S1 class (high electrolytic conductivity and low sodium adsorption ratio), 59.5% to class C4-S1 (very high EC and low SAR) and 30.17% to class C4-S2 (very high EC and medium SAR). 89.67% of studied wells were unsuitable for agriculture. Because of corro-sive water properties all but two wells on Rafsanjan Plain were undesirable for use in the industry. The results of qualitative analyses were presented in GIS and in databases to support making decision and management of groundwater on Rafsanjan Plain.