Water and sediment were studied to assess the impact of wastes from an area used for a disposal area of treated petrochemical effluents in Rio Grande do Sul, Brazil. The study was performed using the Daphnia magna (Straus 1820) for chronical evaluations, mutagenesis in Salmonella/microsome assays, and micronuclei induction in cultures of V79 cell to assess genotoxicity. Six sites were defined for chronic and genotoxic tests by micronuclei induction with liquid and sediment samples. Long-term tests were planned in semi-static flow, with microcrustaceans 2 to 26 h old in the beginning of assays. The minimum level of reproduction required to maintain the species was not reached. There are delays for the beginning of the reproductive process. Survival was also affected in some samples. The reproductive responses were more sensitive on identifying environmental quality than the survival rate. The study of mutagenicity by Salmonella/microsome assay made it possible to define the seasonality of the components showing greater frequency in winter. The predominant event was the frameshift mutation in assays with the presence of metabolism. However, the cytotoxic activity, although present in all seasons, was less frequent in winter. The genotoxicity analysis in V79 cells exposed to liquid samples from the area also showed that cytotoxicity was the most frequent event. This may have interfered in the detection of a potential micronuclei induction. The results showed that, even after treatment, effluents disposed on the soil continue with active pollutants interfering in cladoceran's quality of life, cellular physiology, and DNA integrity.

The concentrations of As and Zn in 100 georeferenced soils uniformly distributed throughout the area affected by the spill from the Aznalcóllar mine (April 1998) were analysed at three depths (0-10, 10-30, and 30-50 cm) and on four dates (autumn-winter 1998, 1999, 2001, and 2004). For an estimate of the geochemical background, 30 unaffected soils near the edge of the spill were also analysed at the same depths. The soils were contaminated before the spill and, the accident seriously increased the concentration of As and Zn in the first 10 cm of almost all the affected soils. After the enormous efforts of cleaning up the tailings, around 45% of the soils had a concentration higher than 100 mg As kg⁻¹ dry soil, and some 35% had a concentration higher than 1,000 mg Zn kg⁻¹ dry soil. Both As and Zn penetrated between 10 and 30 cm in 25% and 45% of the soils, respectively, but reached 30 cm in only 12% of the soils. The remediation actions, especially the tilling and homogenisation of the uppermost 25 cm of the all soils, caused the As and Zn concentrations to decline in the soils, but this change was not very effective from the standpoint of pollution. Thus, 6 years after the spill, the uppermost 10 cm of 30% of the soils continued to have an As concentration higher than 100 mg As kg⁻¹, while the Zn concentration diminished considerably on the surface due to its greater mobility, accumulating between 10 and 30 cm in depth, where 20% of the soils continued to register more than 1,000 mg Zn kg⁻¹ dry soil.

An experimental study to investigate the potential soil accumulation of the triazole fungicide difenoconazole in soil was carried out in northwestern Italy. The fungicide was applied to sugar beet for 4 years with three applications per year at a rate of 75 g ha⁻¹ each, according to formulated product recommended use. Soil cores were collected each year before the first application, after each application and at harvest of the crop. The soil samples were then split into 0-10 and 10-40 cm depth layers, extracted and quantitatively analysed by gas chromatography for difenoconazole residues. The study evidenced that difenoconazole residues could be detected in the upper soil layer only, in quantities detectable after several applications (0.14 to 0.32 mg kg⁻¹ after the third application) which then become undetectable the following year. It can be concluded, therefore, that difenoconazole does not accumulate in soil.

The Litavka River (length 56 km, watershed area 630 km², average flow at the outlet to the Berounka River 2.57 m³ s⁻¹) drains the historical mining, ore processing, and smelting region of Příbram. This Ag-Pb-Zn±Sb ore district (production from the thirteenth century to 1978, locally to 1980) is known for extensive heavy metal contamination. Recent contamination of the Litavka River system is mostly related to the erosion of contaminated soils and fluvial floodplains sediments, especially from a low-gradient river section located immediately below the ore district, where the fine-grained floodplain sediments are from 1.0 to 1.7 m thick. Radiocarbon accelerator mass spectrometry dating of charcoal fragments separated from one floodplain profile showed calibrated ¹⁴C age in the range AD 1220-1284 at a depth of 1.2 m below the surface, while depths of 0.4 and 0.8 m yielded ages in the range AD 1680-1939. Formation of this floodplain was related to disturbance of the river equilibrium resulting from deforestation and the influx of fine-grained material from ore processing, including historical failures of settling ponds. Fluxes of heavy metals during flood events in the Litavka River were studied 35 km downstream below the ore district. Metals are transported here mostly (more than 99% for Pb) in the form of suspended particulate matter (SPM), which at the outlet of the Litavka River contains 2,016 mg kg⁻¹ Zn, 918 mg kg⁻¹ Pb, and 25.5 mg kg⁻¹ Cd on average. During a snowmelt-related minor flood event between March 25 and 29, 2006 (peak flow 36.6 m³ s⁻¹), the river transported 2,400 tonnes of SPM during 4 days, containing 74 kg of Cd, 2,954 kg of Pb, and 5,811 kg of Zn. During larger floods (water flows above 55 m³ s⁻¹ have occurred here 27 times during the last 77 years), the contamination is more diluted by material eroded in the floodplain along the middle and lower river course.

In this paper, Taguchi method was applied to determine the optimum condition for Pb (II) removal from aqueous solution by spent Agaricus bisporus. An orthogonal array experiment design (L₉(3⁴) which is of four control factors (pH, t (contact time), m (sorbent mass), and C ₀ (initial Pb (II) concentration)) having three levels was employed. Biosorption capacity (mg metal/g biosorbent) and percent removal (%) were investigated as the quality characteristics to be optimized. In order to determine the optimum levels of the control factors precisely, range analysis and analysis of variance were performed. The optimum condition for biosorption capacity was found to be pH = 5.00, t = 5.0 h, m = 0.010 g, and C ₀ = 50 mg/L. And for percent removal, the optimum condition was found to be pH = 4.00, t = 4.0 h, m = 0.100 g, and C ₀ = 50 mg/L. Under these optimum conditions, biosorption capacity and percent removal can reach 60.76 mg/g and 80.50%, respectively.

The effect of waterborne zinc on survival, growth, and feed intake of Indian major carp, Cirrhinus mrigala (Hamilton), advanced fry was studied under laboratory condition. Survival rates of C. mrigala advanced fry (2.71 ± 0.49 g) after 30 days exposure to control (0.01), 0.03, 0.06, 0.10, and 0.15 mg/L zinc using the static renewal method in freshwater at pH 7.3 ± 0.2, temperature 26 ± 2°C, and total hardness 114 ± 16 mg/L as CaCO₃ were 100%. Growth of the fish exposed to 0.10 and 0.15 mg/L of zinc was significantly lower (P < 0.05) than in control (0.01), 0.03, and 0.06 mg/L of zinc after 30 days of exposure. However, there were no significant differences (P > 0.05) in fish growth between 0.03 and 0.06 mg/L zinc concentrations. Feed intake rates were significantly (P < 0.05) reduced in the fish exposed to 0.10 mg/L and higher levels of zinc. The zinc accumulation in the whole body of the fish increased with increasing concentrations of the metal.

Activities of ²¹⁰Pb carrier aerosols in an age-graded Sitka spruce conifer, three deciduous (oak, lime and sycamore) foliage and in rain and throughfall samples have been measured during the period of 2001-2002. The ²¹⁰Pb concentrations in the age-graded Sitka leaf needles have shown to accumulate until a steady state between accretion and loss of particulate matter is maintained with time. Similarly, the concentrations of ²¹⁰Pb on deciduous tree leaves increased with time until the leaves began to senesce. The ²¹⁰Pb inventory in bulk precipitation was significantly (r ² = 0.99; P < 0.001) large compared with that in throughfall samples, as indicated by a ratio of 1 to 0.1 of ²¹⁰Pb deposition in bulk precipitation to throughfall. This suggests that ²¹⁰Pb is retained in the Sitka spruce foliage during deposition until transfer to the ground mainly through litterfall. These findings suggest that the presence of woodland is responsible for enhanced ²¹⁰Pb deposition fluxes beneath wooded areas relative to open grassland soils.

Two studies were conducted to determine a feasible and practical phytoremediation strategy for Zn-contaminated soils. The aim of the first study was to identify promising plant species capable of Zn remediation for the soils and climatic conditions of British Columbia. The purpose of the second study was to assess the effects of soil amendments in modifying the soil properties and providing the right conditions for the plants to immobilise Zn. Promising plants for phytostabilisation in the first study (Lolium perenne, Festuca rubra and Poa pratensis) were tested in the presence of soil amendments (lime, phosphate and compost, both individually and in combination) in the second study. The efficiency of treatments to stabilise Zn was based on Zn fractionation in the soil and on absorption and partitioning of Zn in plants. Maximum Zn immobilisation was achieved in the soil by a combination of lime, phosphate and compost, in conjunction with growth of P. pratensis.

In the greenhouse and container nursery production industry there is potential for runoff of nitrogen (N) and phosphorus (P), which may contaminate surface and groundwater. Since the 1950s constructed wetlands (CWs), as a simple, low-technology method, have been shown to effectively treat agricultural, industrial, and municipal wastewater. We investigated the N and P attenuating potential of three floating hydrophytes planted in a laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period plants were supplied with N and P (0.39 to 36.81 mg·L⁻¹ N and 0.07 to 6.77 mg·L⁻¹ P) that spanned the rates detected in nursery runoff between the discharge and inflow locations of a commercial nursery currently employing CWs. Whole plant dry weight was positively correlated with N and P supplied. Highest N recovery rates were exhibited by water hyacinth (Eichhornia crassipes [Mart.] Solms.) and water lettuce (Pistia stratiotes L.). P recovery rates were similar for water hyacinth, water lettuce, and dwarf redstemmed parrotfeather (Myriophyllum aquaticum [Vell.] Verdc.). These floating hydrophytes can be cultivated in a SSF CW to remediate runoff losses of N and P. The possibility exists for integrating them into a polycultural remediation system that includes emergent aquatic macrophytes for processing and polishing nursery/greenhouse wastewater.

The distribution and geochemical behavior of nonylphenol (NP) in suspended and settling particles were studied in Lake Biwa, Japan. The vertical distribution of the particulate nonylphenol (PNP)/particulate organic carbon (POC) ratio showed a characteristic and hitherto unreported profile. The ratio was low at the surface, increased with depth to the middle layer before reaching a maximum at a depth of 45 or 65 m, and decreased toward the bottom. This profile is thought to have been due to the particulate organic matter (POM) in the lake being either freshly produced or aged POM and because the aged POM has a relatively higher affinity for NP compared to freshly produced POM. This idea was supported by the statistical analysis of physicochemical data (PNP, POC and chlorophyll a) and because the average PNP/POC ratio in the aged POM (2.24 x 10⁻⁵ g/g) was approximately four times higher than that of the freshly produced POM (0.63 x 10⁻⁵ g/g). The settling flux was estimated to be 2.2-6.4 μg/m²/day.