Controlling the fate of roxarsone and inorganic arsenic in poultry litter

A growing body of literature reports 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) degradation in poultry litter (PL) to the more toxic inorganic arsenic (As). Aluminum-based drinking-water treatment residuals (WTR) present a low-cost amendment technology to reduce As availability in PL, similar to the use of alum to reduce phosphorus availability. Batch experiments investigated the effectiveness of WTR in removing roxarsone and inorganic As species from PL aqueous suspensions. Incubation experiments with WTR-amended PL evaluated the effects of WTR application rates (2.5-15% by weight) and incubation time (up to 32 d) at two incubation temperatures (23 and 35 degrees C) on As availability in PL. Batch PL aqueous experiments showed the high affinity of As(V), As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), and roxarsone for the WTR. The 10% WTR amendment rate decreased As availability in PL by half of that of the unamended (no WTR) PL-incubated samples. The reduction in dissolved As concentrations during incubation of WTR-amended PL samples was kinetically limited, being complete within 13 d. Parallel reductions in roxarsone, As(V), and DMA concentrations were observed with liquid chromatography-inductively coupled plasma mass spectrometry, whereas As(III) and MMA concentrations were always <5% of dissolved As. Incubation temperature did not significantly (p > 0.05) influence dissolved As concentrations in the WTR-amended PL. Potential formation of a copper-containing roxarsone metabolite was considered in PL aqueous suspensions with the aid of electrospray mass spectrometry. Further experiments in the field are necessary to ensure that sorbed As is stable in WTR-amended PL.     

Nitrous oxide supersaturation at the liquid/air interface of animal waste

Concentrated animal feeding operations around the globe generate large amounts of nitrous oxide (N₂O) in the surrounding atmosphere. Liquid animal waste systems have received little attention with respect to N₂O emissions. We hypothesized that the solution chemistry of animal waste aqueous suspensions would promote conditions that lead to N₂O supersaturation at the liquid/air interface. The concentration of dissolved N₂O in poultry litter (PL) aqueous suspensions at 25 °C was 0.36 μg N₂O mL⁻¹, at least an order of magnitude greater than that measured in water in equilibrium with ambient air, suggesting N₂O supersaturation. There was a nonlinear increase in the N₂O Henry constants of PL from 2810 atm/mole fraction at 35 °C to 17 300 atm/mole fraction at 41 °C. The extremely high N₂O Henry constants were partially ascribed to N₂O complexation with aromatic moieties. Complexed N₂O structures were unstable at temperatures > 35 °C, supplying the headspace with additional free N₂O concentrations.     

Assessing PM10 source reduction in urban agglomerations for air quality compliance

The objective of this work was to study PM(10) and PM(2.5) concentration data available from monitoring stations in two large urban agglomerations in Greece and to estimate the emissions reduction required for compliance with the EU Air Quality Standards (AQS) for particulate matter. The cities studied are namely the Athens and Thessaloniki Metropolitan Areas (AMA and TMA, respectively). PM(10) concentrations during the period 2001-2010 have been evaluated for 15 air quality monitoring stations in the two urban areas. It was found that the concentrations of PM(10) during the period studied constantly exceeded the threshold values at the traffic and industrial stations in TMA and most of the traffic sites in AMA. Most of the occurrences of non-attainment to the daily AQSs were observed during the winter period at all stations (more pronounced for TMA stations). The reduction in current emission source strength to meet the air quality goal was calculated by the rollback equation using PM(10) day-averaged concentrations over the selected period at each station. Among the lognormal and Weibull distributions, the lognormal distribution was found to best fit the frequency distributions of PM(10) concentrations at the selected stations. The results showed that the minimum reduction required in order to meet the AQS in the AMA ranges from approximately 20 to 38% and up to 11% for traffic and background stations, respectively. Reductions in the range of 31% for traffic and 44% for industrial areas in TMA are also required. The same methodology was applied to PM(2.5) concentrations in the AMA and showed that emission reductions up to 31% are necessary in order to meet the 2020 EU AQS. Finally, continuous concentration data of organic (OC) and elementary carbon (EC) in PM(2.5) were used to study the possibility of achieving specific emission attenuation objectives in AMA.     

Changes of the bacterial assemblages throughout an urban drinking water distribution system

We analyzed the bacterial 16S rRNA gene diversity throughout the major components of the drinking water distribution system of a ca. 52,000-inhabitants city (Trikala City, Greece) in order to describe the changes of the bacterial assemblages and to detect possible bacterial pathogens which are not included in the standard monitoring process. Bacterial DAPI counts and DNA extraction was performed in the water pumping wells, the water treatment tank and tap water from households. Approximately 920 bp of the bacterial 16S rDNA were PCR-amplified, cloned, and sequenced for a total of 191 clones, which belonged to 112 unique phylotypes. The water of the pumping wells harbored a typical subsurface bacterial assemblage, with no human pathogens, dominated by β-Proteobacteria. Cell abundance in the water treatment tank decreased significantly, close to detection limit, but bacterial diversity remained high. However, the dominance of β-Proteobacteria decreased considerably, indicating the sensitivity of this group to drinking water disinfection treatment. Tap water from the households hosted a much less diverse, low-cell bacterial assemblage, dominated by Mycobacterium-like phylotypes, related to biofilm bacterial communities.     

Geochemical characterisation of the thermo-mineral waters of Greece

Environmental Geochemistry and Health - Geothermal areas of Greece are located in regions affected by recent volcanism and in continental basins characterised by elevated heat flow. Many of them...     

Aluminum-based drinking-water treatment residuals: a novel sorbent for perchlorate removal

Perchlorate contamination of aquifers and drinking-water supplies has led to stringent regulations in several states to reduce perchlorate concentrations in water at acceptable levels for human consumption. Several perchlorate treatment technologies exist, but there is significant cost associated with their use, and the majority of them are unable to degrade perchlorate to innocuous chloride. We propose the use of a novel sorbent for perchlorate, i.e. an aluminum-based drinking-water treatment residual (Al-WTR), which is a by-product of the drinking-water treatment process. Perchlorate sorption isotherms (23+/-1 degrees C) showed that the greatest amount (65%) of perchlorate removed by the Al-WTR was observed with the lowest initial perchlorate load (10 mg L(-1)) after only 2 h of contact time. Increasing the contact time to 24 h, perchlorate removal increased from 65 to 76%. A significant correlation was observed between the amounts of perchlorate removed with evolved chloride in solution, suggesting degradation of perchlorate to chloride.     

Continental scale passive air sampling of persistent organic pollutants using rapidly equilibrating thin films (POGs)

A novel design of rapidly equilibrating passive air sampler was deployed at 38 sites across 19 European countries to investigate short-term spatial variability of persistent organic pollutants (POPs). Devices were sealed in airtight containers to eliminate the possibility of contamination during transit and couriered to recipients with deployment instructions. Exposure times of 7days permitted the use of back trajectory analysis to further understand the factors responsible for influencing the large-scale spatial distribution of PCBs, PBDEs, PCNs, PAHs, lindane and HCB. Following sampler harvest, devices were sealed and returned for analysis. Comparison of sequestered levels showed that PAHs exhibited the greatest spatial variability (by a factor of 30) with higher levels often associated with greater population density. In contrast, HCB values were much more uniform, reflecting its well mixed distribution in the atmosphere. Spatial variation was strongly influenced by air mass origin, with lower levels being observed at most sites impacted by maritime air masses.