Pesticide occurrence in groundwater and the physical characteristics in association with these detections in Ireland

This study explores the associations of pesticide occurrence in groundwater to geological characteristics of the monitoring points (MPs) contributing area. Pesticide analyses were undertaken during a 2-year groundwater monitoring campaign which generated 845 samples. MCPA and mecoprop were the most frequently detected pesticides in groundwater. Each MP (n?=?158) had a specifically delineated zone of contribution (ZOC) and the dominant physical characteristics present from nine national datasets were recorded for each ZOC. Associations between detections in groundwater and the dominant physical characteristic in each MPs ZOC tested were then statistically analyzed using Fisher’s exact test, logistic regression, and multiple logistic regression. The original physical characteristic datasets used that were associated with detections in groundwater were the type of MP, aquifer type, and Quaternary deposit type. Logistic regression revealed that springs, regionally important aquifer types, aquifers with a karstic flow regime, and alkaline Quaternary deposits in existence above karst aquifers in a MP’s ZOC were more likely to have a pesticide detection in groundwater. Multiple regression from this exploratory work showed some mutual dependency between soil association, aquifer type, and the Geological Survey of Ireland groundwater vulnerability map. The combination of national monitoring data and physical attribute datasets can be used to explore key areas where groundwater is more vulnerable to pesticide contamination.     

空气污染对儿童肺功能指标影响的初步分析

报告中国 4城市 8所小学儿童肺功能指标受室外空气污染影响的结果。以 FVC/预测值 (85% )、FEV1 /预测值(85% )、FEV1 / FVC(实测值之比 ) (80 % )作为判断肺功能指标异常的参考标准 ,并将 8所小学按污染程度分为污染严重和污染较轻两类三组。污染严重组儿童肺功能指标的异常率均比污染较轻组要高。空气的严重污染 ,可使儿童肺功能FVC、FEV1 、FEV1 / FVC异常率的危险程度分别增高 3 0 %～ 78%、52 %～ 86%和 1 0 2 %～ 1 2 7%。异常组儿童的 FVC、FEV1 的平均值约下降 3 3 0～ 4 60 ml,FEV1 / FVC平均值约下降 1 3 %～ 1 5%。说明空气的严重污染对儿童肺功能生长发育可能有不利影响     

Mercury, methylmercury, and selenium in blood of bird species from Doñana National Park (Southwestern Spain) after a mining accident

Total mercury (Hg), monomethylmercury (MeHg), and selenium (Se) were determined in blood of 11 bird species living in Doñana National Park (DNP, Southwestern Spain) and the surrounding area in 1999 and 2000 after a mine spill accident. The total Hg contents found varied from 1.00 to 587 ng/mL, with an MeHg percentage higher than 80 %, except in mallard species. In all the cases, the concentrations found were below the threshold of high risk for the bird populations. The parameters which most affected the accumulation of Hg and MeHg in the birds studied were, first, species, or trophic position, and second sampling area. Age does not seem to have a great influence on the content of Hg in the blood of these birds. The levels of Se found ranged from 108 to 873 ng/mL, and they were not affected by species, trophic level, age, or sampling area. The blood Hg concentrations of birds living in the area directly affected by the toxic mud, outside the park, were higher than those found in the other birds, and this could be explained by the mine spill accident happened in 1998.     

Cadmium and lead bioavailability and their effects on polycyclic aromatic hydrocarbons biodegradation by spent mushroom substrate

Bioremediation of mixed metal–organic soil pollution constitutes a difficult task in different ecosystems all around the world. The aims of this work are to determine the capacity of two spent mushroom substrates (Agaricus bisporus and Pleurotus ostreatus) to immobilize Cd and Pb, to assess the effect of these metals on laccase activity, and to determine the potential of spent A. bisporus substrate to biodegrade four polycyclic aromatic hydrocarbons (PAH): fluorene, phenanthrene, anthracene, and pyrene, when those toxic heavy metals Cd and Pb are present. According to adsorption isotherms, spent P. ostreatus and A. bisporus substrates showed a high Pb and Cd adsorption capacity. Pb and Cd interactions with crude laccase enzyme extracts from spent P. ostreatus and A. bisporus substrates showed Cd and Pb enzyme inhibition; however, laccase activity of A. bisporus presented lower inhibition. Spent A. bisporus substrate polluted with PAH and Cd or Pb was able to biodegrade PAH, although both metals decrease the biodegradation rate. Spent A. bisporus substrate contained a microbiological consortium able to oxidize PAH with high ionization potential. Cd and Pb were immobilized during the bioremediation process by spent A. bisporus substrate. Consequently, spent A. bisporus substrate was adequate as a multi-polluted soil bioremediator.     

The Use of Indoor Air Measurements To Evaluate Intrusion of Subsurface VOC Vapors into Buildings

ABSTRACT

The implementation of a risk-based corrective action approach often requires consideration of soil vapor migration into buildings and potential inhalation exposure and risk to human health. Due to the uncertainty associated with models for this pathway, there may be a desire to analyze indoor air samples to validate model predictions, and this approach is followed on a somewhat frequent basis at sites where risks are considered potentially significant. Indoor air testing can be problematic for a number of reasons. Soil vapor intrusion into buildings is complex, highly dependent on site-specific conditions, and may vary over time, complicating the interpretation of indoor air measurements when the goal is to deduce the subsurface-derived component. An extensive survey of indoor air quality data sets highlights the variability in indoor volatile organic compound (VOC) concentrations and numerous sources that can lead to elevated VOC levels. The contribution from soil vapor is likely to be small relative to VOCs from other sources for most sites. In light of these challenges, we discuss how studies that use indoor air testing to assess subsurface risks could be improved. To provide added perspective, we conclude by comparing indoor air concentrations and risks arising from subsurface VOCs, predicted using standard model equations for soil vapor fate and intrusion into buildings, to those associated with indoor sources.     

Airborne Emissions of Mercury from Municipal Solid Waste. I: New Measurements from Six Operating Landfills in Florida

Abstract

Mercury-bearing material enters municipal landfills from a wide array of sources, including fluorescent lights, batteries, electrical switches, thermometers, and general waste; however, the fate of mercury (Hg) in landfills has not been widely studied. Using automated flux chambers and downwind atmospheric sampling, we quantified the primary pathways of Hg vapor releases to the atmosphere at six municipal landfill operations in Florida. These pathways included landfill gas (LFG) releases from active vent systems, passive emissions from landfill surface covers, and emissions from daily activities at each working face (WF). We spiked the WF at two sites with known Hg sources; these were readily detected downwind, and were used to test our emission modeling approaches. Gaseous elemental mercury (Hg⁰) was released to the atmosphere at readily detectable rates from all sources measured; rates ranged from ～1–10 ng m^?2 hr^?1 over aged landfill cover, from ～8–20 mg/hr from LFG flares (LFG included Hg⁰ at μg/m³ concentrations), and from ～200–400 mg/hr at the WF. These fluxes exceed our earlier published estimates. Attempts to identify specific Hg sources in excavated and sorted waste indicated few readily identifiable sources; because of effective mixing and diffusion of Hg⁰, the entire waste mass acts as a source. We estimate that atmospheric Hg releases from municipal landfill operations in the state of Florida are on the order of 10–50 kg/yr, substantially larger than our original estimates, but still a small fraction of current overall anthropogenic losses.     

The impact of zero-valent iron nanoparticles upon soil microbial communities is context dependent

Nanosized zero-valent iron (nZVI) is an effective land remediation tool, but there remains little information regarding its impact upon and interactions with the soil microbial community. nZVI stabilised with sodium carboxymethyl cellulose was applied to soils of three contrasting textures and organic matter contents to determine impacts on soil microbial biomass, phenotypic (phospholipid fatty acid (PLFA)), and functional (multiple substrate-induced respiration (MSIR)) profiles. The nZVI significantly reduced microbial biomass by 29 % but only where soil was amended with 5 % straw. Effects of nZVI on MSIR profiles were only evident in the clay soils and were independent of organic matter content. PLFA profiling indicated that the soil microbial community structure in sandy soils were apparently the most, and clay soils the least, vulnerable to nZVI suggesting a protective effect imparted by clays. Evidence of nZVI bactericidal effects on Gram-negative bacteria and a potential reduction of arbuscular mycorrhizal fungi are presented. Data imply that the impact of nZVI on soil microbial communities is dependent on organic matter content and soil mineral type. Thereby, evaluations of nZVI toxicity on soil microbial communities should consider context. The reduction of AM fungi following nZVI application may have implications for land remediation.     

What’s the Problem? River Management,Education, and Public Beliefs

This paper invokes the theory of planned behavior (TPB) as a diagnostic tool to explain an existing public education program's limited success at improving river water quality in the City of Perth, Western Australia. A reflective, client-driven research approach was used. A facilitated expert workshop defined an environmental problem (excess nutrients leaving gardens and entering waterways) and a desired behavior (residents purchasing environmentally sensitive fertilizer) to address the problem. A TPB-based belief elicitation survey captured respondents' beliefs regarding the desired behavior. The findings suggest respondents were aware of the links between purchasing environmentally sensitive fertilizer and river water quality. However, this behavior is compromised by the challenges in identifying appropriate products, product quality concerns, and cost. Viewing the content of a public education program through the lens of the TPB reveals insights into how and why the program fell short in achieving one of its key behavioral change goals.     

In situ experiment to determine advective-diffusive controls on solute transport in a clay-rich aquitard

Solute transport in clay-rich aquitards is characterized as molecular diffusion- or advection-dominated based on the Péclet number (P(e)). However, few field-based measurements of the coefficient of molecular diffusion (D(e)) exist, and none with a range of advection- or diffusion-dominated conditions in the same aquitard. In this long-term field experiment, standing water in a recovering well was spiked with deuterium ((2)H), then water-level recovery and δ(2)H values were monitored as the well returned to static conditions over 1054 days. After a second (2)H spike, water levels and δ(2)H values were monitored to day 1644 while under near static conditions. Modeling of the second spike was used to define the D(e) of (2)H as (3-4)× 10(-10)m(2)s(-1) for an accessible porosity of 0.31. Reservoir concentrations from the initial spike were modeled to define the transition from advection- to diffusion-dominated transport. This occurred after 200 days, consistent with a transition in P(e) from <1 to >1 when the length term is taken as the radial extent of the tracer plume (normalized concentration <0.05). This study verifies plume extent as the characteristic length term in the calculation of P(e) and demonstrates the transition from advection- to diffusion-dominated transport as the value of P(e) decreases below unity.