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561.
Geochemical mapping is a technique rooted in mineral exploration but has now found worldwide application in studies of the
urban environment. Such studies, involving multidisciplinary teams including geochemists, have to present their results in
a way that nongeochemists can comprehend. A legislatively driven demand for urban geochemical data in connection with the
need to identify contaminated land and subsequent health risk assessments has given rise to a greater worldwide interest in
the urban geochemical environment. Herein, the aims and objectives of some urban studies are reviewed and commonly used terms
such as baseline and background are defined. Geochemists need to better consider what is meant by the term urban. Whilst the
unique make up of every city precludes a single recommended approach to a geochemical mapping strategy, more should be done
to standardise the sampling and analytical methods. How (from a strategic and presentational point of view) and why we do
geochemical mapping studies is discussed.
相似文献
Christopher C. JohnsonEmail: |
562.
Davies BE 《Environmental geochemistry and health》2008,30(6):639-646
In 2002, The (UK) Department for Environment, Food and Rural Affairs (DEFRA) together with the Environment Agency published
document SGV10 “Contaminants in soil: collation of toxicological data and intake values for humans. Lead”. This publication
sets out the derivation of Soil Guideline Values for lead contamination. Values for soil lead that are protective of the health
of children and also for adults are derived using the model recommended by an international task force working under the auspices
of the Society for Environmental Geochemistry and Health (SEGH) (Wixson and Davies 1993, 1994). Detailed examination of the DEFRA publication shows it uses unrealistic values for two variables in the SEGH model. The
consequence is both actual and has potential adverse societal impacts. These impacts could be avoided if the appropriate scientific
community were regarded as stakeholders in the legislative outcome and not simply the providers of the research data. 相似文献
563.
Posada-Baquero R Niqui-Arroyo JL Bueno-Montes M Gutiérrez-Dabán A Ortega-Calvo JJ 《Environmental geochemistry and health》2008,30(2):159-163
The aim of this work was to develop a method to assess the microbial accessibility of native phenanthrene present in soils
and sediments. We developed an accelerated biodegradation assay, characterized by (a) inoculation with a sufficient number
of phenanthrene-degrading microorganisms, (b) monitoring of the biodegradation activity through 14C-mineralization measurements, and (c) single-step chemical analysis of the native compound in the residue. The use of 14C-labeling allowed the determination of the time period needed for biodegradation of the bioaccessible fraction of the native
chemical. The method was tested with environmental samples having a wide range of phenanthrene concentrations, i.e., from
background levels (μg kg-1) originating in soil from atmospheric deposition, to acute concentrations (g kg-1) corresponding to industrial pollution of soils and sediments. The results showed a wide range of bioaccessibility (15–95%
of the initial amount). The method can be used for the assessment of bioaccessibility involved in the management of polycyclic
aromatic hydrocarbon (PAH) pollution. 相似文献
564.
Johnson DL 《Environmental geochemistry and health》2008,30(6):589-596
This work introduces a spatially resolved quantitative model, based on conservation of mass and first order transfer kinetics,
for following the transport and redistribution of outdoor soil to, and within, the indoor environment by track-in on footwear.
Implementations of the DIRT model examined the influence of room size, rug area and location, shoe size, and mass transfer
coefficients for smooth and carpeted floor surfaces using the ratio of mass loading on carpeted to smooth floor surfaces as
a performance metric. Results showed that in the limit for large numbers of random steps the dual aspects of deposition to
and track-off from the carpets govern this ratio. Using recently obtained experimental measurements, historic transport and
distribution parameters, cleaning efficiencies for the different floor surfaces, and indoor dust deposition rates to provide
model boundary conditions, DIRT predicts realistic floor surface loadings. The spatio-temporal variability in model predictions
agrees with field observations and suggests that floor surface dust loadings are constantly in flux; steady state distributions
are hardly, if ever, achieved.
A contribution from ESF Center for the Urban Environment. 相似文献
565.
Previous soil lead studies in New Orleans focused on the geochemical footprint and its health impacts. This study examines
the human geography of race, income, and age in pre-Katrina metropolitan New Orleans within the context of lead accumulation
in soils. Sample points of soil lead data (n = 5,467) collected in 1998–2000 were mapped in a geographic information system (GIS), binned into 9 ranges, and queried by
(1) 2000 Census racial demographic data, (2) 1999 median household income, and (3) 2000 age data. The absolute population
generally declines as lead levels increase except at lead levels from 200–400 to 400–1,000 mg/kg when population increases;
the African–American population comprises a disproportionate share of this cohort. The high-lead areas occur in the inner
city, home to the largest populations of African-Americans in New Orleans. The mean household income curve indicates that
lower economic groups are at risk to higher levels of lead. A total of 44,701 children under the age of 5 years, plus 123,579
children aged 5–17, lived in census block groups containing at least one sample point with over 100 mg/kg lead, and these
include 23,124 and 64,064 young people, respectively, who live near at least one point over 400 mg/kg. Lead exposure affects
a panoply of outcomes that influence the health and welfare of the community. Unless corrected, children are likely to return
to the same or, because of lack of lead-safe practices during renovation, even higher exposure risks than before the flooding
of New Orleans. 相似文献
566.
Six firing range soils were analyzed, representing different environments, firing conditions, and maintenance practices. The
particle size distribution and lead (Pb) concentration in each soil fraction were determined for samples obtained from the
backstop berms. The main factors that were found to influence Pb fragment size were the type of soil used to construct the
berms and the type of weapon fired. The firing of high velocity weapons, i.e., rifles, onto highly angular soils induced significant
fragmentation of the bullets and/or pulverization of the soil itself. This resulted in the accumulation of Pb in the finer
soil fractions and the spread of Pb contamination beyond the vicinity of the backstop berm. Conversely, the use of clay as
backstop and the use of low velocity pistols proved to be favorable for soil clean-up and range maintenance, since Pb was
mainly present as large metallic fragments that can be recovered by a simple screening process. Other factors that played
important roles in Pb particle size distribution were soil chemistry, firing distance, and maintenance practices, such as
the use of water spray for dust suppression and deflectors prior to impact. Overall, coarse Pb particles provide much easier
and more cost-effective maintenance, soil clean-up, and remediation via physical separation. Fine Pb particles release Pb
more easily, pose an airborne Pb hazard, and require the application of stabilization/solidification treatment methods. Thus,
to ensure sustainable firing range operations by means of cost-effective design, maintenance, and clean-up, especially when
high velocity weapons are used, the above mentioned factors should be carefully considered. 相似文献
567.
Mobilization of heavy metals from contaminated paddy soil by EDDS,EDTA, and elemental sulfur 总被引:1,自引:0,他引:1
Wang G Koopmans GF Song J Temminghoff EJ Luo Y Zhao Q Japenga J 《Environmental geochemistry and health》2007,29(3):221-235
For enhanced phytoextraction, mobilization of heavy metals (HMs) from the soil solid phase to soil pore water is an important
process. A pot incubation experiment mimicking field conditions was conducted to investigate the performance of three soil
additives in mobilizing HMs from contaminated paddy soil (Gleyi-Stagnic Anthrosol): the [S, S]-isomer of ethylenediamine disuccinate
(EDDS) with application rates of 2.3, 4.3, and 11.8 mmol kg−1 of soil, ethylenediamine tetraacetate (EDTA; 1.4, 3.8, and 7.5 mmol kg−1), and elemental sulfur (100, 200, and 400 mmol kg−1). Temporal changes in soil pore water HM and dissolved organic carbon concentrations and pH were monitored for a period of
119 days. EDDS was the most effective additive in mobilizing soil Cu. However, EDDS was only effective during the first 24
to 52 days, and was readily biodegraded with a half-life of 4.1 to 8.7 days. The effectiveness of EDDS decreased at the highest
application rate, most probably as a result of depletion of the readily desorbable Cu pool in soil. EDTA increased the concentrations
of Cu, Pb, Zn, and Cd in the soil pore water, and remained effective during the whole incubation period due to its persistence.
The highest rate of sulfur application led to a decrease in pH to around 4. This increased the pore water HM concentrations,
especially those of Zn and Cd. Concentrations of HMs in the soil pore water can be regulated to a large extent by choosing
the proper application rate of EDDS, EDTA, or sulfur. Hence, a preliminary work such as our pot experiment in combination
with further plant experiments (not included in this study) will provide a good tool to evaluate the applicability of different
soil additives for enhanced phytoextraction of a specific soil. 相似文献
568.
Bioleaching from soil artificially contaminated with analogues of radionuclides, Co and Sr, was carried out using a Fe-oxidizing
bacterium, Acidithiobacillus ferrooxidans. Due to bacterial metabolism, the pH and dissolved Fe3+ concentration in a biotic slurry decreased and increased respectively, over time, but the concentrations of Co and Sr extracted
from the soil showed no significant enhancement compared with those under abiotic control. In both cases, Co and Sr were leached
from the soil during the initial period of the experiment, due to the initially low solution pH of 2.0, and the dissolved
concentrations remained almost constant for the duration of the experiment (300 h). Since oxidation of Fe2+ by A. ferrooxidans led to the production of Fe precipitates and colloidal suspensions, the Co and Sr extracted into solution were most likely
re-adsorbed onto the Fe solids. Also, A. ferrooxidans, without an external supply of Fe2+, extracted almost equal or greater amounts of Co and Sr from the soil than when Fe2+ was supplied. Under the same leaching conditions, the extent of Sr removal was much lower than that of Co. On the contrary
to the high efficiency of microbial metal leaching in biohydrometallurgy for low-graded sulfide ores, which has been widely
documented, conventional bioleaching techniques with A. ferrooxidans supplied with enough Fe2+ showed low efficiency for the removal of radionuclides loosely bound onto soil particle surfaces. 相似文献
569.
土地利用变更的土壤及地下水污染调查方法及实例 总被引:8,自引:0,他引:8
以南京大厂区某地块的土壤及地下水污染调查为实例,提出了资料收集、源项分析、监测因子筛选、监测布点.场地地质水文勘探和土壤及地下水采样分析的土壤及地下水污染调查方法,探讨了评价标准和确定土壤及地下水污染范围的方法。 相似文献
570.
Gilles Carbonnier 《Disasters》2015,39(2):189-207
The humanitarian sector has grown enormously over the past two decades. Some fear that professionalisation comes at the expense of altruistic volunteering. This may be a valid concern if altruism is the product of organisational culture and individual experiences rather than an innate trait. This paper examines advances in evolutionary biology and neurology that provide evidence in support of both the nature and nurture arguments, echoing earlier insights from social sciences. It then questions to what extent humanitarian principles build on altruistic impulses or instead seek to constrain them, and reviews recruitment profiles of selected humanitarian organisations and applicants' letters accordingly. This initial investigation warrants further research to identify how altruism as a personal trait and an organisational principle has influenced diverse humanitarian actors and traditions. This paper outlines how training curricula and organisational reward systems can build on—rather than stifle—natural altruism to nurture critical, reflexive practitioners. 相似文献