Evaluation of the effect of different sampling time periods and ambient air pollutant concentrations on the performance of the Radiello diffusive sampler for the analysis of VOCs by TD-GC/MS

The effect of different sampling exposure times and ambient air pollutant concentrations on the performance of Radiello? samplers for analysis of volatile organic compounds (VOCs) is evaluated. Quadruplicate samples of Radiello? passive tubes were taken for 3, 4, 7 and 14 days. Samples were taken indoors during February and March 2010 and outdoors during July 2010 in La Canonja (Tarragona, Spain). The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detection (MS). The results show significant differences (t-test, p < 0.05) between the amounts of VOCs obtained from the sum of two short sampling periods and a single equivalent longer sampling period for 65% of all the data. 17% of the results show significantly larger amounts of pollutant in the sum of two short sampling periods. Back diffusion due to changes in concentrations together with saturation and competitive effects between the compounds during longer sampling periods could be responsible for these differences. The other 48% of the results that are different show significantly larger amounts in the single equivalent longer sampling period. The remaining 35% of the results do not show significant differences. Although significant differences are observed in the amount of several VOCs collected over two shorter sampling intervals compared to the amount collected during a single equivalent longer sampling period, the ratios obtained are very close to unity (between 0.7 and 1.2 in 75% of cases). We conclude that Radiello? passive samplers are useful tools if their limitations are taken into account and the manufacturer's recommendations are followed.     

Amplified ribosomal DNA restriction analysis as a routine tool to assess toxicant driven changes in hindgut bacterial populations of Porcellio dilatatus (Crustacea: Isopoda)

Changes in saprophytic organism's gut microbial communities may present a threat to organic matter breakdown which can ultimately lead to soil function impairment. In this study, Amplified Ribosomal DNA Restriction Analysis (ARDRA) was evaluated as a potential simple molecular tool to assess shifts in bacterial community structure in hindgut populations of Porcellio dilatatus exposed to contaminated food. This prospective tool can also be used for a variety of purposes and samples prior to the use of more specific and sophisticated methods.     

Use of feathers of feral pigeons (Columba livia) as a technique for metal quantification and environmental monitoring

This study quantifies metal concentrations in washed and unwashed feathers of feral pigeons (Columba livia). The material was collected in two different sites: Goiania (capital of Goiás State), with high anthropic activities, and Jataí (a city in Goiás), with low anthropic activities. Results revealed that metals such as Pb, Cr, and Cd were deposited in the feathers originating from air and soil (exogenous process). Other metals such as Cu, Fe, Mn, and Zn, which are part of the tissue constitution of a living being, were absorbed through the pigeons' diet (endogenous process). There was a statistically significant difference between mean values of Cd, Pb, and Cr in the three collection sites. The order of metal concentrations were Civic Square > Zoo > Jataí, which shows highest levels of metal contamination in anthropic environments. Significant differences between Cd, Pb, and Cr in washed and unwashed feathers suggest that metal concentrations are directly related to exposure time due to exogenous sources. We concluded that it is possible to quantify and monitor metal levels in the environment by analyzing the feathers of urban feral pigeons. Furthermore, unwashed feathers were especially efficient to investigate endogenous and exogenous absorption of the metals in our study.     

Monitoring of pharmaceutically active compounds on the Guadalquivir River basin (Spain): occurrence and risk assessment

Guadalquivir River (South of Spain) is among the major freshwater sources of the European Atlantic basin. Until now scientific efforts have been focused on contamination by heavy metals and some priority pollutants in Guadalquivir River. However, the presence of "emerging contaminants", such as pharmaceutically active compounds, has not yet been studied. In this work the occurrence and risk assessment of sixteen pharmaceutically active compounds, belonging to different therapeutic groups, in Guadalquivir River during its course through Seville city are reported. Wastewater effluents from four wastewater treatment plants discharging into Guadalquivir River and river water samples were analyzed. All studied pharmaceutically active compounds, except sulfamethoxazole, trimethoprim, estrone and clofibric acid, were detected in effluent wastewaters at concentration levels up to 28.9 μg L(-1). Among the pharmaceutically active compounds found in effluent wastewater, seven were present in Guadalquivir River samples at concentration levels up to 0.75 μg L(-1), which indicated an important dilution from effluent discharge. Environmental risk assessment reveals that potential ecotoxicological risk cannot be expected on Guadalquivir River at measured concentration levels. Only, the lipid regulator gemfibrozil showed a medium risk for the environment. The risk for acute toxic effects in the environment with the current use of active pharmaceutical ingredients is unlikely. However, the results do not rule out the potential for chronic environmental effects.     

Longitudinal variability in streamwater chemistry and carbon and nitrogen fluxes in restored and degraded urban stream networks

Stream restoration has increasingly been used as a best management practice for improving water quality in urbanizing watersheds, yet few data exist to assess restoration effectiveness. This study examined the longitudinal patterns in carbon and nitrogen concentrations and mass balance in two restored (Minebank Run and Spring Branch) and two unrestored (Powder Mill Run and Dead Run) stream networks in Baltimore, Maryland, USA. Longitudinal synoptic sampling showed that there was considerable reach-scale variability in biogeochemistry (e.g., total dissolved nitrogen (TDN), dissolved organic carbon (DOC), cations, pH, oxidation/reduction potential, dissolved oxygen, and temperature). TDN concentrations were typically higher than DOC in restored streams, but the opposite pattern was observed in unrestored streams. Mass balances in restored stream networks showed net uptake of TDN across subreaches (mean ± standard error net uptake rate of TDN across sampling dates for Minebank Run and Spring Branch was 420.3 ± 312.2 and 821.8 ± 570.3 mg m(-2) d(-1), respectively). There was net release of DOC in the restored streams (1344 ± 1063 and 1017 ± 944.5 mg m(-2) d(-1) for Minebank Run and Spring Branch, respectively). Conversely, degraded streams, Powder Mill Run and Dead Run showed mean net release of TDN across sampling dates (629.2 ± 167.5 and 327.1 ± 134.5 mg m(-2) d(-1), respectively) and net uptake of DOC (1642 ± 505.0 and 233.7 ± 125.1 mg m(-2) d(-1), respectively). There can be substantial C and N transformations in stream networks with hydrologically connected floodplain and pond features. Assessment of restoration effectiveness depends strongly on where monitoring is conducted along the stream network. Monitoring beyond the stream-reach scale is recommended for a complete perspective of evaluation of biogeochemical function in restored and degraded urban streams.     

Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment

Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10?cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.     

Use of pharmaceuticals and pesticides to constrain nutrient sources in coastal groundwater of northwestern Long Island, New York, USA

In developed, non-agricultural, unsewered areas, septic systems and fertilizer application to lawns and gardens represent two major sources of nitrogen to coastal groundwater, in addition to atmospheric input. This study was designed to distinguish between these two possible nitrogen sources by analyzing groundwater samples for pharmaceutical residuals, because fertilizers do not contain any of these pharmaceuticals, but domestic wastewater commonly does. In addition, several herbicides and insecticides used in lawn treatment were analyzed as indicators of nitrogen delivery to groundwater from fertilizers. Groundwater samples were taken through piezometres at shoreline sites in unsewered areas surrounding Northport Harbor and in sewered areas adjacent to Manhasset Bay (hereafter referred to as "Northport" and "Manhasset", respectively), both in northwestern Long Island, USA. Excessive nitrogen loading has led to reduced dissolved oxygen concentrations in Long Island Sound, and the groundwater contribution to the nitrogen budget is poorly constrained. The frequent detection of the anticonvulsant compound carbamazepine in groundwater samples of the Northport Harbor area (unsewered), together with the fact that few pesticides associated with lawn applications were detected, suggests that wastewater input and atmospheric input are the likely sources of nitrogen in the Northport groundwater. High concentrations of nitrogen were also detected in the Manhasset (sewered) groundwater. The low detection frequency and concentration of carbamazepine, however, suggest that the sewer system effectively intercepts nitrogen from wastewater there. The likely sources of nitrogen in the Manhasset groundwater are atmospheric deposition and lawn fertilizers, as this area is densely populated.     

In situ polar organic chemical integrative sampling (POCIS) of steroidal estrogens in sewage treatment works discharge and river water

A passive sampler (the polar organic chemical integrative sampler; POCIS) was assessed for its ability to sample natural estrogens (17β-estradiol, E2; estrone, E1 and estriol, E3) and the synthetic estrogen (17α-ethynylestradiol, EE2) in the outlet of a sewage treatment works over several weeks. The performance of the POCIS was investigated and optimised in the laboratory before field deployment with high recoveries (66-99%) were achieved for all estrogens. Moreover, it was shown that POCIS does not exhibit any preferential selectivity towards any of the target compounds. The sampling rates of E1, E2 and E3 were 0.018 ± 0.009, 0.025 ± 0.014 and 0.033 ± 0.019 L d(-1), respectively. Following field deployments of 28 days in the discharge of a sewage works, POCIS was shown to enhance the sensitivity of estrogen detection, especially for E3, and provide time-weighted average (TWA) concentrations of E1, E2 and E3, ranging from undetectable to 12 ng L(-1) upstream of the outflow of a sewage treatment works, 13 to 91 ng L(-1) at the outflow and 8 to 39 ng L(-1) downstream of the outflow. This revealed that E1, E2 and E3 are not completely removed during sewage treatment, with concentrations most likely being maintained by contributions from conjugated estrogen analogues. Grab water samples showed considerable variation in the concentrations of estrogens over a longer period (6 months). The results confirm that POCIS is an effective and non-discriminatory method for the detection of low concentrations of estrogens in the aquatic environment.     

Long-term changes of heavy metal and sulphur concentrations in ecosystems of the Taymyr Peninsula (Russian Federation) North of the Norilsk Industrial Complex

The Norilsk industrial ore smelting complex (Taymyr Peninsula, Russian Federation) has significantly impacted many components of local terrestrial and aquatic environments. Whether it has had a major impact on the wider Russian Arctic remains controversial as studies are scarce. From 1986 to 2004, data on heavy metal (Cu, Ni, Zn, Hg, Cd and Hg) concentrations in fish (burbot), moss, lichens, periphyton, hydric soils and snow in and around Norilsk and the most northern parts of the Taymyr Peninsula were analysed. Very high concentrations of Cu (203 μg L?1 ± 51 μg L?1) and Ni (113 μg L?1 ± 15 μg L?1) were found in the water of the Schuchya River close to Norilsk. Heavy metal concentrations in burbot liver were highest in Lake Pyasino near Norilsk compared to other study regions that were >100 km distant. From 1989-1996, Cu (121 μg L?1 ± 39 μg L?1 SD), Zn (150 μg L?1) ± 70 μg L?1) and Ni (149 μg L?1 ± 72 μg L?1) snow concentrations were greatest in Norilsk, but were low elsewhere. By 2004, these concentrations had dropped significantly, especially for Cu-74 μg L?1 (±18.7 μg L?1 SD), Zn-81.7 μg L?1 (± 31.3 μg L?1 SD) and Ni-80 μg L?1(±18.0 μg L?1 SD). Norilsk and its surroundings are subject to heavy pollution from the Norilsk metallurgical industry but these are absent from the greater Arctic region due to the prevailing winds and the Byrranga Mountains. Pollution abatement measures have been made so further investigations are necessary in order to assess their efficiency.     

Chemical techniques for assessing bioavailability of sediment-associated contaminants: SPME versus Tenax extraction

The traditional approach for predicting the risk of hydrophobic organic contaminants (HOCs) in sediment is to relate organic carbon normalized sediment concentrations to body residues or toxic effects to organisms. However, due to the multiple variables controlling bioavailability, this method has limitations. A matrix independent method of predicting bioavailability needs to be used in order to be universally applicable. Both chemical activity (freely dissolved chemical concentrations) measured by solid-phase microextraction (SPME) and bioaccessibility (rapidly desorbing fraction) estimated by Tenax extraction have been developed to predict bioavailability of sediment-associated HOCs. The objectives of this review are to summarize a number of studies using matrix-SPME or Tenax extraction to estimate bioavailability and/or toxicity of different classes of HOCs and evaluate the strengths and weakness of these two techniques. Although the two chemical techniques assess different components of the matrix, estimates obtained from both techniques have been correlated to organism body residues. The advantages of SPME fibers are their applicability for use in situ and their potential usage for a wide array of contaminants by selection of appropriate coatings. Single time-point Tenax extraction, however, is more time- and labor-effective. Tenax extraction also has lower detection limits, making it more applicable for highly toxic contaminants. This review also calls for additional research to evaluate the role of sequestrated contaminants and ingestion of sediment particles by organisms on HOC bioavailability. The use of performance reference compounds to reduce SPME sampling time and linking chemical based bioavailability estimates to toxicological endpoints are essential to expand the applications of these methods.