Land use in east China tends to change from paddy rice to vegetables or other high-value cash crops, resulting in high input rates of organic manures and increased risk of contamination with both heavy metals (HMs) and antibiotics. This investigation was conducted to determine the accumulation, distribution and risks of HMs and tetracyclines (TCs) in surface soils and profiles receiving different amounts of farmyard manure. Soil samples collected from suburbs of Hangzhou city, Zhejiang province were introduced to represent three types of land use change from paddy rice to asparagus production, vineyards and field mustard cultivation, and divided into two portions, one of which was air-dried and sieved through 2-, 0.3- and 0.149-mm nylon mesh for determination of pH and heavy metals. The other portion was frozen at -20 °C, freeze-dried and sieved through a 0.3-mm nylon mesh for tetracyline determination. HM and TC concentrations in surface soils of 14-year-old mustard fields were the highest with total Cu, Zn, Cd and ∑TCs of 50.5, 196, 1.03 mg kg(-1) and 22.9 μg kg(-1), respectively, on average. The total Cu sequence was field mustard > vineyards > asparagus when duration of land use change was considered; oxytetracycline (OTC) and doxycycline were dominant in soils used for asparagus production; OTC was dominant in vineyards and chlortetracycline (CTC) was dominant in mustard soils. There were positive pollution relationships among Cu, Zn and ∑TCs, especially between Cu and Zn or Cu and ∑TCs. Repeated and excessive application of manures from intensive farming systems may produce combined contamination with HMs and TCs which were found in the top 20 cm of the arable soil profiles and also extended to 20-40 cm depth. Increasing manure application rate and cultivation time led to continuing increases in residue concentrations and movement down the soil profile.

This study assessed the effect of ambient air pollution on leaf characteristics of white willow, northern red oak, and Scots pine. Willow, oak, and pine saplings were planted at sixteen locations in Belgium, where nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO 2), and particulate matter (PM10) concentrations were continuously measured. The trees were exposed to ambient air during 6 months (April-September 2010), and, thereafter, specific leaf area (SLA), stomatal resistance (R s), leaf fluctuating asymmetry (FA), drop contact angle (CA), relative chlorophyll content, and chlorophyll fluorescence (F v/F m) were measured. Leaf characteristics of willow, oak, and pine were differently related to the ambient air pollution, indicating a species-dependent response. Willow and pine had a higher SLA at measuring stations with higher NO2 and lower O3 concentrations. Willow had a higher R s and pine had a higher F v/F m at measuring stations with a higher NO2 and lower O 3 concentrations, while oak had a higher F v/F m and a lower FA at measuring stations with a higher NO2 and lower O3 concentrations. FA and R s of willow, oak, and pine, SLA of oak, and CA of willow were rather an indicator for local adaptation to the micro-environment than an indicator for the ambient air pollution. © 2013 Springer Science+Business Media Dordrecht.

The fate and behaviour of tributyltin (TBT) at two wastewater treatment works was examined. Both sites had two inlet streams, and each utilised high rate biological filters (biofilters) on one the streams, before treatment of the combined flows on trickling filters, with one having additional tertiary processes, installed to remove ammonia and solids. The study was designed to determine if these processes enhanced the removal of TBT. Degradation of TBT was observed in one of the biofilters, possibly as a result of temperature and hydraulic loading. At the treatment works with tertiary processes, the mass flux showed the overall removal of TBT was 68 %, predominantly due to removal with solids in the primary settlement processes. However, overall removal of 95 % was observed in the conventional trickling filter works with 94 % of this due to biodegradation in the trickling filter. The two works both removed TBT, but at different treatment stages and by different processes. Differences in the form (solubility) of TBT in the influent may have attributed to this, although further understanding of factors controlling degradation would allow for a more complete assessment of the potential of biological processes to remove hazardous compounds from wastewaters.

Both groundwater flow and mercury concentrations in pore water and seawater were quantified in the groundwater seeping site of the Bay of Puck, southern Baltic Sea. Total dissolved mercury (HgTD) in pore water ranged from 0.51 to 4.90 ng l⁻¹. Seawater samples were characterized by elevated HgTD concentrations, ranging from 4.41 to 6.37 ng l⁻¹, while HgTD concentrations in groundwater samples ranged from 0.51 to 1.15 ng l⁻¹. High HgTD concentrations in pore water of the uppermost sediment layers were attributed to seawater intrusion into the sediment. The relationship between HgTD concentrations and salinity of pore water was non-conservative, indicating removal of dissolved mercury upon mixing seawater with groundwater. The mechanism of dissolved mercury removal was further elucidated by examining its relationships with both dissolved organic matter, dissolved manganese (Mn II), and redox potential. The flux of HgTD to the Bay of Puck was estimated to be 18.9 ± 6.3 g year⁻¹. The submarine groundwater discharge-derived mercury load is substantially smaller than atmospheric deposition and riverine discharge to the Bay of Puck. Thus, groundwater is a factor that dilutes the mercury concentrations in pore water and, as a result, dilutes the mercury concentrations in the water column.

Soils polluted by metals and organic compounds are a major challenge in soil remediation and environmental recovery; however, the technology to efficiently decontaminate soils polluted by both metal and organic pollutants does not yet exist. Most of these soils are disposed of in landfills. This study first evaluates chemical reagents (hydrochloric, nitric, sulfuric and lactic acids and ethanol) for leaching metals from soil. Assays were then conducted to evaluate non-ionic, ionic and amphoteric surfactants for pentachlorophenol (PCP) removal by flotation. Finally, a laboratory-scale leaching/flotation process was applied to treat four soil samples polluted with both organic ([PCP]ᵢ = 2.5–30 mg kg⁻¹) and metals ([As]ᵢ = 50–250 mg kg⁻¹, [Cr]ᵢ = 35–220 mg kg⁻¹, [Cu]ᵢ = 80–350 mg kg⁻¹) compounds. The organic compounds and metals are concentrated in the froth and liquid fractions, respectively. Removal yields of 82–93 %, 30–80 %, 79–90 % and 36–78 % were obtained from As, Cr, Cu and PCP, respectively, under optimized process conditions (H₂SO₄ = 1 N, [cocamidopropyl betaine]ᵢ = 1 % (w w⁻¹), t = 60 min, T = 60 °C, PD = 10 % (w v⁻¹)). The treatment of the produced leachate was also tested by chemical precipitation using different reagents.

Organoclays possess unique adsorption behaviour towards hydrophobic organic contaminants. They can also remediate ionic contaminants such as heavy metals and metalloids. The objective of the present study was to prepare organoclay and organoclay mixtures efficient to adsorb both cationic and anionic contaminants. The adsorbents were characterised by X-ray diffraction and infrared spectroscopy. Trivalent (Cr3+) and hexavalent (Cr2O 7 2-) chromium were selected as the model contaminants representing cationic and anionic properties. Bentonite modified with cationic surfactant hexadecyl trimethylammonium bromide at double the cation exchange capacity of the clay remarkably improved Cr2O7 2- adsorption capacity (as high as 0.49 mmol g-1). Similarly, its modification with anionic surfactant sodium dodecyl sulphate at the same dosage improved Cr3+ adsorption (as high as 0.36 mmol g -1). When these two organoclays were physically mixed in equal proportions (1:1), the resultant organoclay mixture efficiently adsorbed both Cr3+ (as high as 0.21 mmol g-1) and Cr2O 7 2- (as high as 0.32 mmol g-1) implying that the mixture could remediate both anionic and cationic contaminants simultaneously. The adsorption of Cr3+ by the organoclay and organoclay mixture fitted well to the Langmuir isothermal model whereas the adsorption of Cr2O7 2- fitted well to the Freundlich model. © 2013 Springer Science+Business Media Dordrecht.

A special sequential extraction (SE) procedure for mercury (Hg) was conducted to determine biogeochemical fractions of Hg and their controlling factors in four contaminated soil profiles located in two distinct floodplain ecosystems which differ in their industrial histories and thus in their Hg loads. The first study area is located at the Wupper River (Western Germany) and the soil profiles reveal sum of Hg (Hgₛᵤₘ) concentrations up to 48 ppm. The second study area is located at the Saale River (Eastern Germany) and the soil profiles have Hgₛᵤₘ concentrations up to 4.3 ppm. The majority of Hg was found in fraction IV (FIV, Hg⁰) for both study areas, indicating its anthropogenic origin. Moreover, we have detected Hg in fraction V (FV) and in fraction III (FIII). As Hg in FV is mostly associated with Hg sulfides being formed under reducing conditions, it indicates reduction processes which usually occurred during flooding. Mercury in FIII (organo-chelated Hg) exhibits a moderate mobility and a high methylation potential. Between Hg in FIII and hot-water-extractable carbon (CHWE) as a measure of easy degradable, labile soil organic matter, we found a significant correlation. Sum of Hg seem to have a high affinity to organic carbon (Cₒᵣg). The concentrations of Hg in the mobile and exchangeable fractions FI and FII were low. Moreover, the significant positive correlation between iron (Fe) and Hg in FIV indicate an interaction between Hg and Fe. The majority of the Hg in our soils is considered to be relatively immobile. However, since the formation of more mobile Hg species via oxidation or methylation might occur in floodplain soils, the low Hg concentrations in mobile fractions should not be underestimated due to their high mobility and potential plant availability.

Zamioculcas zamiifolia has the potential to reduce the concentration of benzene, toluene, ethylbenzene, and xylene (BTEX) from contaminated indoor air. It can remove all four pollutant gases. Benzene, toluene, ethylbenzene, and xylene uptake per unit area of Z. zamiifolia leaf were about 0.96 ± 0.01, 0.93 ± 0.02, 0.92 ± 0.02, and 0.86 ± 0.07 mmol m -2 at 72 h of exposure, respectively. The physicochemical properties of each BTEX may affect its removal. Benzene, a smaller molecule, is taken up by plants faster than toluene, ethylbenzene, and xylene. The toxicity of BTEX on plant leaves and roots was not found. The chlorophyll fluorescence measurement (F v/F m) showed no significantly difference between controlled and treated plants, indicating that a concentration of 20 ppm of each gas is not high enough to affect the photosynthesis of the plants. The ratio of stomata and cuticles showed that 80 % of benzene, 76 % of toluene, 75 % of ethylbenzene, and 73 % of xylene were removed by stomata pathways, while 20, 23, 25, and 26 % of them were removed by cuticles. The BTEX removal efficiency by well-watered Z. zamiifolia was involved with day stomata opening and night closing, while the BTEX removal efficiency by water-stressed Z. zamiifolia can occur both day and night at a slightly lower rate than well-watered plants. © 2013 Springer Science+Business Media Dordrecht.

While copper is known to be neurotoxic, effects on behavior and especially on group behavior have received much less attention. Yet such behavioral effects can have important ecological consequences. This study determined whether shoaling behavior could be used as an indicator of acute copper toxicity and as an endpoint in studying acclimation in the least killifish (Heterandria formosa). For acute toxicity, least killifish were exposed to 0, 25, 50, or 100 μg/L of Cu for a 2-h duration and then tested for changes in shoaling behavior. The occurrence of copper acclimation was tested by pre-exposing fish to either 0 or 15 μg/L of Cu for a 7-day duration, then exposing them to 25, 50, or 100 μg/L of Cu to assess whether the two pre-exposure groups differed in their behavioral responses to high Cu levels. Behavioral responses were tested in a subdivided aquarium, with one side containing a group of conspecific fish and the other side the focal fish whose behavior was recorded for 3 min. Shoaling was based on the proximity of the focal fish to the divider separating it from the group of conspecific fish. Acute copper exposure resulted in significant decreases in both the time to first shoaling and in the total amount of time spent shoaling. Experiments assessing the occurrence of copper acclimation using shoaling as the toxicity endpoint did not detect a difference between the pre-exposure groups. Overall, this study demonstrated that acute copper exposure can alter shoaling behavior. However, least killifish shoaling behavior appears to be relatively insensitive as an endpoint to assess copper acclimation. © 2013 Springer Science+Business Media Dordrecht.