Despite many studies of the N₂O emission, there is a lack of knowledge on the role of subsoil for N₂O emission, particularly in sandy soils. To obtain insight into the entrapment, diffusion, convection and ebullition of N₂O in the soil, the N₂O concentration in the soil atmosphere was measured over a period of 1 year in 4 lysimeters (agricultural soil monoliths of 1 m2 x 2 m) at 30, 50, 80, 155, and 190 cm depth with altogether 86 gas probes. Additionally the N₂O emission into the atmosphere was measured in 20 closed chambers at the soil surface. Concurrently the soil temperature and soil water content were recorded in order to quantify their effects on the fate of N₂O in the soil. Results of the continuous measurements between January and December 2006 were: N₂O concentrations were highest in the deeper soil; maximum concentration was found at a depth of 80 cm, where the water content was high and the gas transport reduced. The highest N₂O concentration was recorded after 'special events' like snowmelt, heavy rain, fertilization, and grubbing. The combination of fertilization and heavy rain led to an increase of up to 2,700 ppb in the subsoil.

Sandstorms which distribute a great number of particles are a special atmospheric occurrence and are uncommon in northern China. This study was conducted to determine, for the first time, the concentration of organochlorine pesticides (OCPs) in sandstorm depositions. Samples were collected from urban areas of Beijing and a total of eight OCPs were measured. All samples contained OCP residues. The total hexachlorocyclohexane (HCHs) concentration ranged from 20.6 to 59.8ng g⁻¹ and the total dichlorodiphenyltrichloroethane (DDTs) concentration ranged from 12.0 to 14.3ng g⁻¹. Furthermore, increasing HCH contamination was observed from the northwest to the southeast and a uniform distribution of DDT contamination was discovered in Beijing. Analysis of the sources of contamination showed that HCHs in the sandstorm depositions were derived from a relatively old source of lindane, and DDTs mainly originated from an old source of dicofol in Beijing. The preliminary pollution assessment of the samples indicated that HCH levels might be categorized as low pollution and DDT levels might be categorized as no pollution. The present study suggests that sandstorm depositions may not produce the special risk of adverse health effect from OCPs for the residents of Beijing, China.

The biodegradation of different peat types was studied with a manometric respirometric test. Compaction peat and sphagnum peat samples were analysed, and the effect of peat pH on biodegradation behaviour was evaluated. Only minor (BOD/ThOD < 0.4%) biodegradation was observed with compaction peat samples, and the stable state, in which biodegradation stopped, was achieved during a two month period. As expected, sphagnum peat samples with a lower decomposition rate degraded more than compaction peat samples. Alkalinity (pH between ca. 4-9) of the peat was noticed to reduce the degree of biodegradation and accelerate the achievement of the stable state.

Metal (Cu, Mn, Ni, Zn, Fe) concentrations in marine sediment and zooplankton were investigated in Izmir Bay of the Eastern Aegean Sea, Turkey. The study aimed to assess the levels of metal in different environmental compartments of the Izmir Bay. Metal concentrations in the sediment (dry weight) ranged between 4.26-70.8 μg g-¹ for Cu, 233-923 μg g-¹ for Mn, 14.9-127 μg g-¹ for Ni, 25.6-295 μg g-¹ for Zn, 12,404-76,899 μg g-¹ for Fe and 38,226-91,532 μg g-¹ for Al in the Izmir Bay. Maximum metal concentrations in zooplankton were observed during summer season in the inner bay. Significant relationships existed between the concentrations of certain metals (Al, Fe, Mn and Ni) in sediment, suggesting similar sources and/or similar geochemical processes controlling such metals. Higher concentrations of Cu, Zn and percent organic matter contents were found in the middle-inner bays sediments. Based on the correlation matrix obtained for metal data, organic matter was found to be the dominant factor controlling Cu and Zn distributions in the sediment. In general, mean Cu and Zn levels in the bay were above background concentrations in Mediterranean sediments. Zooplankton metal concentrations were similar to sediment distributions.

The removal of ⁶⁵Zn from tidal water by underlaying sediment cores collected in a mangrove forest and a tidal creek that drains this forest in Sepetiba Bay (SE Brazil) was investigated. After 30-h experiments in laboratory microcosms, the ⁶⁵Zn half-removal times from tidal creek and mangrove forest sediments were 8.7 ± 1.8 and 9.2 ± 0.9 h respectively. Depth penetration of ⁶⁵Zn was mainly restricted to the upper 3 cm in mangrove forest cores, while detectable ⁶⁵Zn activities were found in all layers (0-7 cm depth) of tidal creek cores. An unexpected ⁶⁵Zn release back to the overlaying water was observed for one of the tidal creek experiments in the 12-18 h interval (corresponding to a return of 17% of the initial ⁶⁵Zn activity in overlaying water), suggesting a reversibility of the ⁶⁵Zn removal process (e.g., by adsorption) in tidal creek sediments. The results indicate that mangrove-vegetated sediments allowed a lower vertical mobility of Zn than observed in creek sediments and mangrove sediments appear to be less susceptible to a reversion in the process of zinc removal from overlaying water, suggesting a greater capacity to retain this metal near the water-sediment interface. This first radiotracer approach on the mangrove sediments removal of Zn from tidal waters supports earlier experimental studies employing stable Zn, contributing for a better understanding of the metal uptake kinetics by such sediments and suggesting that these sediments act as active sinks for trace metals.

The transport, bioavailability and fate of aqueous metals in rainfall-runoff are determined, in part, by speciation. In the framework of a monitoring program to investigate the predominant species of zinc, copper, and water chemistry in runoff subject to aviation land use and activities, two rainfall-runoff monitoring stations were installed at the international airport of Genoa (Italy). One catchment was a boarding area (airside) apron and the other a parking area for vehicles (landside). Utilizing water chemistry analyses, ion balances and speciation modelling for a series of five event loadings for each site, results indicated that Zn²⁺ dominated Zn speciation and Cu complexes with carbonate or dissolved organic matter, dominated Cu speciation. With respect to wash-off processes a mass limited behaviour was generally observed for particulate matter (measured as TSS) and TOC; while the mass delivery of aqueous metal species tended to be more proportionate with respect to runoff volume.

A detailed analysis of different types of gravity distribution devices, designed to split on-site wastewater effluent equally between percolation trenches, has been carried out both in the laboratory and also in the field under realistic loading conditions. Four different types of distribution device have been compared: a V-notch distribution box, stilling chamber box and tee-splitters with and without baffles. The trials carried out in the laboratory with clean water showed that flow distribution for all devices was sensitive to both the off-level installation angles and variable flow rates, with the most stable performance achieved using the flow splitter with upstream baffle plates. In parallel to this, the on-site flow regime experienced at two sites was continuously monitored using a tipping bucket and data-logger over twelve month periods, finding that the most common flow rates at the distribution unit were in the range of 0.1–2.5 l min⁻¹. The on-site performance of these devices receiving both septic tank and secondary treated effluent showed that significant solid deposition and biofilm development had severely affected the equal distribution between the trenches, hence highlighting the need for regular maintenance to ensure efficient performance over time after installation.

Urban rainfall-runoff residuals contain metals such as Cr, Zn, Cu, As, Pb and Cd and are thus reasonable candidates for treatment using Portland cement-based solidification-stabilization (S/S). This research is a study of S/S of urban storm water runoff solid residuals in Portland cement with quicklime and sodium bentonite additives. The solidified residuals were analyzed after 28 days of hydration time using X-ray powder diffraction (XRD) and solid-state ²⁹Si nuclear magnetic resonance (NMR) spectroscopy. X-ray diffraction (XRD) results indicate that the main cement hydration products are ettringite, calcium hydroxide and hydrated calcium silicates. Zinc hydroxide and lead and zinc silicates are also present due to the reactions of the waste compounds with the cement and its hydration products. ²⁹Si NMR analysis shows that the coarse fraction of the waste apparently does not interfere with cement hydration, but the fine fraction retards silica polymerization.

The Marais Vernier is the largest freshwater wetland in the Seine Estuary in northern France. It is in a heavily urbanized and industrialized region and could be affected by atmospheric deposition and by fluvial input of contaminants in water diverted from the Seine River. To evaluate contaminant histories in the wetland and the region, sediment cores were collected from two open-water ponds in the Marais Vernier: the Grand-Mare, which was connected to the Seine by a canal from 1950 to 1996, and the Petite Mare, which has a small rural watershed. Diversions from the Seine to the Grand-Mare increased sedimentation rates but mostly resulted in low contaminant concentrations and loading rates, indicating that the sediment from the Seine was predominantly brought upstream by tidal currents from the estuary and was not from the watershed. Atmospheric sources of metals dominate inputs to the Petite Mare; however, runoff of metals from vehicle-related sources in the watershed might contribute to the upward trends in concentrations of Cr, Cu, and Zn. Estimates of atmospheric deposition using the Petite Mare core are consistent with measured deposition in the region and are mixed (similar for Hg and Pb; larger for Cd, Cu, and Zn) compared with deposition estimated from sediment cores in the northeastern United States. A local source of PAHs in the watershed of the Petite Mare is indicated by higher concentrations, higher accumulation rates, and a different, more petrogenic, PAH assemblage than in the Grand-Mare. The study illustrates how diverse sources and transport pathways can affect wetlands in industrial regions and can be evaluated using sediment cores from the wetland ponds.

A study on perchlorate distribution was conducted in male adult prairie voles (Microtus ochrogaster). Excretion via urine was the major pathway for perchlorate fate in the body, with the highest concentrations of perchlorate detected in urine after exposure to perchlorate through drinking water [250 μg/ml Mg(ClO₄)₂], and an average of 34% and 88% of perchlorate intake recovered in urine in the 4- and 8-h exposure groups, respectively. Perchlorate mass in kidney, thyroid, blood, and urine were related to perchlorate intake (254.5-2687.7 μg). Perchlorate excretion and depuration patterns via urine were tested further using male adult deer mice (Peromyscus maniculatus). Animals were exposed to perchlorate through dosed drinking water (0, 17, 165, and 1600 ng/ml). Perchlorate concentrations in urine showed a significant difference among the three dosed groups during a 28-day exposure period. However, no difference was found in urine among the three dosages in terms of mass percentage of perchlorate intake from water at each sampling time over the 28-day exposure period. Both concentrations of perchlorate and mass percentage in urine reached a steady state after 1 day in all treatments. On average 46%, 46%, and 61% of perchlorate intake from water was recovered in urine over the exposure period in high, medium, and low dose groups, respectively. Including perchlorate consumption from rodent chow (1.44 ng/g), less than 46% of perchlorate intake was recovered in urine in the high and medium dose groups, and <61% in the low dose group. Three parameter first-order decay models fit the depuration curve very well, with r > 0.99 in both the low and high dose groups; half-lives of perchlorate in deer mice were estimated as 9.12 and 7.25 h in the low and high dose groups, respectively. Endogenous generation of perchlorate and/or some degree of retention or metabolism of perchlorate may occur in deer mice, based in part on the uncompleted mass balance in the excretion and depuration experiments. The data reported herein should provide additional insight for perchlorate fate determination in animals and humans and valuable information for perchlorate risk assessment in the environment, especially wildlife.