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1.
Pistón M Silva J Pérez-Zambra R Dol I Knochen M 《Environmental geochemistry and health》2012,34(2):273-278
A multicommutated flow system was designed and evaluated for the determination of total arsenic and selenium by Hydride Generation
Atomic Absorption Spectrometry (HG-AAS). It was applied to the determination of arsenic and selenium in samples of natural
and drinking water. Detection limits were 0.46 and 0.08 μg l−1 for arsenic and selenium, respectively; sampling frequency was 120 samples h−1 for arsenic and 160 samples h−1 for selenium. Linear ranges found were 1.54–10 μg l−1 (R = 0.999) for arsenic and 0.27–27 μg l−1 (R = 0.999) for selenium. Accuracy was evaluated by spiking various water samples and using a reference material. Recoveries
were in the range 95–116%. Analytical precision (s
r
(%), n = 10) was 6% for both elements. Compared with the Standard Methods, APHA, 3114B manual method, the system consumes at least
10 times less sample per determination, and the quantities of acid and reducing agent used are significantly lower with a
reduction in the generation of pollutants and waste. As an additional advantage, the system is very fast, efficient and environmentally
friendly for monitoring total arsenic and selenium levels in waters. 相似文献
2.
A simple, sensitive, accurate, and selective method for determination of ultratrace levels of Co is modified. The method is
based on preconcentration of Co on the PAR-loaded Amberlite XAD-7 at pH 2.0 ± 0.2 for contact time as low as 45 min. The adsorbed
cobalt was eluted with concentrated nitric acid and measured by flame atomic absorption spectrometry. Recoveries up to 90%
were achieved. The optimized preconcentration method was applied to cobalt determination in natural mineral waters. The detection
limit was found to be 0.1 ng mL−1. The relative standard deviation was found to be 13% for 600 mL of 2.0 ng mL−1, for 10 replicate preconcentration procedures. Cobalt concentrations in the studied water samples were found to be in the
ranges of 0.5–3.5 ng mL−1. 相似文献
3.
Bacterial abundance, production, and extracellular enzyme activity were determined in the shallow water column, in the epiphytic
community of Thalassia
testudinum, and at the sediment surface along with total carbon, nitrogen, and phosphorus in Florida Bay, a subtropical seagrass estuary.
Data were statistically reduced by principle components analysis (PCA) and multidimensional scaling and related to T. testudinum leaf total phosphorus content and phytoplankton biomass. Each zone (i.e., pelagic, epiphytic, and surface sediment community)
was significantly dissimilar to each other (Global R = 0.65). Pelagic aminopeptidase and sum of carbon hydrolytic enzyme (esterase, peptidase, and α- and β-glucosidase) activities
ranged from 8 to 284 mg N m−2 day−1 and 113–1,671 mg C m−2 day−1, respectively, and were 1–3 orders of magnitude higher than epiphytic and sediment surface activities. Due to the phosphorus-limited
nature of Florida Bay, alkaline phosphatase activity was similar between pelagic (51–710 mg P m−2 day−1) and sediment (77–224 mg P m−2 day−1) zones but lower in the epiphytes (1.1–5.2 mg P m−2 day−1). Total (and/or organic) C (111–311 g C m−2), N (9.4–27.2 g N m−2), and P (212–1,623 mg P m−2) content were the highest in the sediment surface and typically the lowest in the seagrass epiphytes, ranging from 0.6 to
8.7 g C m−2, 0.02–0.99 g N m−2, and 0.5–43.5 mg P m−2. Unlike nutrient content and enzyme activities, bacterial production was highest in the epiphytes (8.0–235.1 mg C m−2 day−1) and sediment surface (11.5–233.2 mg C m−2 day−1) and low in the water column (1.6–85.6 mg C m−2 day−1). At an assumed 50% bacterial growth efficiency, for example, extracellular enzyme hydrolysis could supply 1.8 and 69% of
epiphytic and sediment bacteria carbon demand, respectively, while pelagic bacteria could fulfill their carbon demand completely
by enzyme-hydrolyzable organic matter. Similarly, previously measured T. testudinum extracellular photosynthetic carbon exudation rates could not satisfy epiphytic and sediment surface bacterial carbon demand,
suggesting that epiphytic algae and microphytobenthos might provide usable substrates to support high benthic bacterial production
rates. PCA revealed that T. testudinum nutrient content was related positively to epiphytic nutrient content and carbon hydrolase activity in the sediment, but
unrelated to pelagic variables. Phytoplankton biomass correlated positively with all pelagic components and sediment aminopeptidase
activity but negatively with epiphytic alkaline phosphatase activity. In conclusion, seagrass production and nutrient content
was unrelated to pelagic bacteria activity, but did influence extracellular enzyme hydrolysis at the sediment surface and
in the epiphytes. This study suggests that seagrass-derived organic matter is of secondary importance in Florida Bay and that
bacteria rely primarily on algal/cyanobacteria production. Pelagic bacteria seem coupled to phytoplankton, while the benthic
community appears supported by epiphytic and/or microphytobenthos production. 相似文献
4.
H. D. Revanasiddappa B. P. Dayananda T. N. K. Kumar 《Environmental Chemistry Letters》2007,5(3):151-155
We developed a cost-effective and sensitive spectrophotometric method for the determination of arsenic at trace level using
a new reagent, leuco malachite green. Here we show that, arsenic reacts with potassium iodate in acidic conditions to liberate
iodine, and the liberated iodine selectively oxidizes leuco malachite green to malachite green dye. We studied the Beer’s
law at 617 nm, which showed linearity over the concentration range 0.09–0.9 μg ml−1 of arsenic. We show that the molar absorptivity, Sandell’s sensitivity and detection limit of the method are 6.1 × 104 l mol−1 cm−1, 0.0012 μg cm−2 and 0.025 μg ml−1, respectively. We applied the developed method for the determination of arsenic in environmental samples. 相似文献
5.
Residues of fluoroquinolones in marine aquaculture environment of the Pearl River Delta, South China 总被引:4,自引:0,他引:4
He X Wang Z Nie X Yang Y Pan D Leung AO Cheng Z Yang Y Li K Chen K 《Environmental geochemistry and health》2012,34(3):323-335
Concentrations and distributions of selected fluoroquinolones (norfloxacin, ciprofloxacin and enrofloxacin) in water, sediments
and nine kinds of fish species collected from 6 sites in two marine aquaculture regions of the Pearl River Delta, China, were
analyzed by using high-performance liquid chromatography with fluorescence detector (HPLC). The results showed that the concentrations
of ciprofloxacin and enrofloxacin were below the limits of quantification (LOQ) in all water samples except for norfloxacin.
Norfloxacin and ciprofloxacin concentrations ranged from 1.88 to 11.20 ng g−1 dry wt, 0.76–2.42 ng g−1 dry wt in sediments collected from the Dapeng’ao region (sites 1–3) and ranged from 2.31 to 4.75 ng g−1 dry wt, 1.26–1.76 ng g−1 dry wt in sediments collected from the Hailing Island region (sites 4–6), respectively. However, no enrofloxacin was found
in all sediment samples. The three fluoroquinolones (FQs) were detected in all fish samples, and the concentrations were higher
in liver tissues than those in muscle tissues. The levels of norfloxacin were higher than ciprofloxacin and enrofloxacin in
both liver and muscle tissues. Among the nine marine fish species, Siganus fuscescens from Hailing Island had a significantly high level of norfloxacin in liver tissue (254.58 ng g−1 wet wt), followed by Sparus macrocephalus (133.15 ng g−1 wet wt) from Dapeng’ao, and the lowest value was Lutianus argentimaculatus (5.18 ng g−1 wet wt) from Hailing Island. The obtained results of FQs in present study do not represent a risk to the human health in
Guangdong coastal area, based on the maximum residue limits (MRLs) established by Chinese Government and the acceptable daily
intake (ADI) recommended by the Food and Agriculture Organization and World Health Organization (FAO/WHO). 相似文献
6.
Miriam Schutter Sander Kranenbarg René H. Wijffels Johan Verreth Ronald Osinga 《Marine Biology》2011,158(4):769-777
In this study, we tested the hypothesis that the importance of water flow for skeletal growth (rate) becomes higher with increasing
irradiance levels (i.e. a synergistic effect) and that such effect is mediated by a water flow modulated effect on net photosynthesis.
Four series of nine nubbins of G. fascicularis were grown at either high (600 μE m−2 s−1) or intermediate (300 μE m−2 s−1) irradiance in combination with either high (15–25 cm s−1) or low (5–10 cm s−1) flow. Growth was measured as buoyant weight and surface area. Photosynthetic rates were measured at each coral’s specific
experimental irradiance and flow speed. Additionally, the instantaneous effect of water flow on net photosynthetic rate was
determined in short-term incubations in a respirometric flowcell. A significant interaction was found between irradiance and
water flow for the increase in buoyant weight, the increase in surface area, and specific skeletal growth rate, indicating
that flow velocity becomes more important for coral growth with increasing irradiance levels. Enhancement of coral growth
with increasing water flow can be explained by increased net photosynthetic rates. Additionally, the need for costly photo-protective
mechanisms at low flow regimes could explain the differences in growth with flow. 相似文献
7.
The Salí River Basin in north-west Argentina (7,000 km2) is composed of a sequence of Tertiary and Quaternary loess deposits, which have been substantially reworked by fluvial and
aeolian processes. As with other areas of the Chaco-Pampean Plain, groundwater in the basin suffers a range of chemical quality
problems, including arsenic (concentrations in the range of 12.2–1,660 μg L−1), fluoride (50–8,740 μg L−1), boron (34.0–9,550 μg L−1), vanadium (30.7–300 μg L−1) and uranium (0.03–125 μg L−1). Shallow groundwater (depths up to 15 m) has particularly high concentrations of these elements. Exceedances above WHO (2011) guideline values are 100% for As, 35% for B, 21% for U and 17% for F. Concentrations in deep (>200 m) and artesian groundwater
in the basin are also often high, though less extreme than at shallow depths. The waters are oxidizing, with often high bicarbonate
concentrations (50.0–1,260 mg L−1) and pH (6.28–9.24). The ultimate sources of these trace elements are the volcanic components of the loess deposits, although
sorption reactions involving secondary Al and Fe oxides also regulate the distribution and mobility of trace elements in the
aquifers. In addition, concentrations of chromium lie in range of 79.4–232 μg L−1 in shallow groundwater, 129–250 μg L−1 in deep groundwater and 110–218 μg L−1 in artesian groundwater. All exceed the WHO guideline value of 50 μg L−1. Their origin is likely to be predominantly geogenic, present as chromate in the ambient oxic and alkaline aquifer conditions. 相似文献
8.
Although mysids play important roles in marine food chains, studies on their production are scarce, especially for warm-water
species. We investigated life history and production of Orientomysis robusta in a shallow warm-temperate habitat of the Sea of Japan. Its spawning and recruitment occurred throughout the year; 19 overlapping
cohorts were recognizable over an annual cycle. The summer cohorts recruited in July–September exhibited rapid growth, early
maturity, small brood size, and small body size. A converse set of life history traits characterized the autumn–winter cohorts
recruited in October–March. The spring cohorts recruited in April–June had intermediate characteristics of both cohorts. Life
spans were 19–33, 21–48, and 69–138 days for summer, spring, and autumn–winter cohorts, respectively, and mortality rates
were high for spring and summer cohorts, especially during June–August but were low for autumn–winter cohorts. Production
calculated from the summation of growth increments was 488.8 mg DW m−2 year−1 with an annual P/B ratio of 21.26. The short life span seems to be responsible for such an extremely high P/B ratio. A method not requiring recognition and tracking cohorts gave similar values (534.0 mg DW m−2 year−1 and 20.49). The close agreement in production values between the two methods indicates our estimates are valid. 相似文献
9.
Hg transfer from contaminated soils to plants and animals 总被引:1,自引:0,他引:1
S. M. Rodrigues B. Henriques A. T. Reis A. C. Duarte E. Pereira P. F. A. M. R?mkens 《Environmental Chemistry Letters》2012,10(1):61-67
Understanding the transfer of mercury (Hg) from soil to crops is crucial due to Hg toxicity and Hg occurrence in terrestrial
systems. Previous research has shown that available Hg in soils contributes to plant Hg levels. Plant Hg concentrations are
related to soil conditions and plant characteristics. Mechanistic models describing such soil–plant interactions are however
difficult to quantify. Here we performed a field study in agricultural, mining and industrial areas in Portugal to evaluate
potential food chain risks. The uptake of Hg by Italian ryegrass, ryegrass, orchard grass, collard greens and rye was measured
to calculate daily intakes (DI) of Hg for cows and sheep grazing. A total of 136 soil samples and 129 plant samples were analysed.
Results show that total Hg concentrations ranged from 0.01 to 98 mg kg−1 in soils; 0.01–5.4 mg kg−1 in shoots and 0.01–42 mg kg−1 in roots. Calculated DI ranged from 0.18 to 132 mg d−1 for cows, and from 0.028 to 23 mg d−1 for sheep. In 27 grassland sites, daily intakes exceeded the acceptable daily intake of both cows and sheep in view of food
safety considering Hg in animal kidneys evidencing potential risks to human health. The transfer of Hg from soil to crops
was described using empirical Freundlich-type functions. For ryegrass, orchard grass and collard greens, the soil-to-root
or soil-to-shoot transfer of Hg appeared to be controlled by the total soil Hg concentration and levels of Alox and Feox. Empirical functions allowed us to obtain realistic estimates of Hg levels in crops and can be used as an alternative to
mechanistic models when evaluating food chain risks of Hg contamination in agricultural soils. 相似文献
10.
M. J. Watts J. O’Reilly A. L. Marcilla R. A. Shaw N. I. Ward 《Environmental geochemistry and health》2010,32(6):479-490
A field method is reported for the speciation of arsenic in water samples that is simple, rapid, safe to use beyond laboratory
environments, and cost effective. The method utilises solid-phase extraction cartridges (SPE) in series for selective retention
of arsenic species, followed by elution and measurement of eluted fractions by inductively coupled plasma mass spectrometry
(ICP-MS) for “total” arsenic. The method is suitable for on-site separation and preservation of arsenic species from water.
Mean percentage accuracies (n = 25) for synthetic solutions of arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MA), and dimethylarsinic acid (DMA) containing 10 μg l−1 As, were 98, 101, 94, and 105%, respectively. Data are presented to demonstrate the effect of pH and competing anions on
the retention of the arsenic species. The cartridges were tested in the UK and Argentina at sites where arsenic was known
to be present in surface and groundwaters, respectively, at elevated concentrations and under challenging matrix conditions.
In Argentinean groundwater, 4–20% of speciated arsenic was present as MA and 20–73% as AsIII. In UK surface waters, speciated arsenic was measured as 7–49% MA and 12–42% DMA. Comparative data from the field method
using SPE cartridges and the laboratory method using liquid chromatography coupled to ICP-MS for all water samples provided
a correlation of greater than 0.999 for AsIII and DMA, 0.991 for MA, and 0.982 for AsV (P < 0.01). 相似文献
11.
A. Cornils S. B. Schnack-Schiel M. Böer M. Graeve U. Struck T. Al-Najjar C. Richter 《Marine Biology》2007,151(4):1261-1274
A total of 12 feeding experiments were conducted in the northern Gulf of Aqaba during spring (March/April) and autumn (September/October)
2002 at the Marine Science Station (MSS) in Aqaba. Females of three species of clausocalanids were selected: Clausocalanus
farrani, C. furcatus and Ctenocalanus vanus. Natural occurring particle (NOP) larger than 5 μm were investigated as food source. The ambient chlorophyll a concentration at sampling depth (∼70 m) ranged between 0.15 and 1.00 μg chl a l−1 and NOP concentrations ranged between 1.78 and 14.0 × 103 cells l−1 during the sampling periods. The division of particles into five size classes (5–10, 10–20, 20–50, 50–100 and >100 μm) revealed
that most of the particles were found in the size classes below 50 μm (81–98%), while most of the natural occurring carbon
(NOC) was concentrated in the size classes larger than 20 μm (70–95%). Ingestion rates were food density dependent rather
than size dependent ranging between 0.02 and 1.65 × 103 NOP ind−1 day−1 and 0.01 and 0.41 μg NOC ind−1 day−1, respectively, equivalent to a body carbon (BC) uptake between 0.4 and 51.8% BC day−1. The share of the size classes to the total ingestion resembled in most cases the size class composition of the natural particle
community. 相似文献
12.
Tarek G. Ammari Yasin Al-Zu’bi Samih Abu-Baker Basem Dababneh Wafa’ Gnemat Alaeddin Tahboub 《Environmental geochemistry and health》2011,33(5):427-437
Lithium is found in trace amounts in all soils. It is also found in plants and in nearly all the organs of the human body.
Low Li intake can cause behavioral defects. Thus, this study was conducted to investigate the concentration and distribution
of water-soluble Li in soils of the Jordan Valley and its concentration in citrus trees and some important food crops in view
of the significant implications of Li for human health. The concentration of soluble Li was measured in 180 soil samples collected
at two depths (0–20 and 20–40 cm) whereas its content was determined in fully expanded leaves collected from citrus and different
vegetable crops. Concentrations of soluble Li in soils vary from 0.95 to 1.04 mg l−1 in topsoil and from 1.06 to 2.68 mg l−1 in subsoil, while Li concentration in leaves ranged from 2 to 27 mg kg−1 DM. Lithium concentrations in leaves of crops of the same family or different families vary with location in the valley;
i.e., they decreased from north to south. It is concluded that soluble Li in soils and the plant family did not solely affect
Li transfer in the food chain. In addition, soil EC, Ca, Mg, and Cl, which increased from north to south, might adversely
affect plant Li uptake. The current study also showed that consuming 250–300 g FW of spinach day−1 per person is recommended to provide consumers with their daily Li requirement necessary for significant health and societal
benefits. 相似文献
13.
Virginia E. Villafañe Paul J. Janknegt Marco de Graaff Ronald J. W. Visser Willem H. van de Poll Anita G. J. Buma E. Walter Helbling 《Marine Biology》2008,154(6):1021-1029
During austral summer 2006, experiments were carried out to evaluate the effects of ultraviolet radiation (UVR, 280–400 nm)
on carbon fixation of natural phytoplankton assemblages from Patagonia (Argentina). Surface water samples were collected (ca.
100 m offshore) at mid morning using an acid-cleaned (1 N HCl) dark container. The short-term impact of UVR (measured as radiocarbon
incorporation) was immediately assessed by exposing samples to three artificial illumination treatments: PAR (400–700 nm),
PAR + UV-A (320–700 nm), and PAR + UV-A + UV-B (280–700 nm). Pico-nanoplankton characterized the assemblages, and taxon-specific
pigment fingerprinting combined with CHEMTAX and supplemented with microscopic observations showed varied proportions of diatoms,
chlorophytes, and cyanobacteria throughout January–February 2006. Photosynthetic efficiency, as assessed through assimilation
numbers, was high [between 4.4 and 10.4 μg C (μg chl-a)−1 h−1], and it was probably favored by the supply of inorganic nutrients from the Chubut River. UVR-induced photoinhibition appeared
to be related to the taxonomic composition: in general, higher photoinhibition was observed when diatoms dominated, whereas
this was lower when samples were dominated by chlorophytes. Our data suggest that xanthophyll pigments might have provided
only limited protection in these already highlighted acclimated assemblages. 相似文献
14.
Minghong Wu Wenyan Shi Haijiao Zhang Zheng Jiao Jie Chen Side Yao Guoji Ding Jiamo Fu 《Environmental Chemistry Letters》2010,8(1):25-31
A wide range of pharmaceutical compounds have been identified in the environment, and their existence is a topic of growing
concern, both for human and ecological health. The work described here has investigated the photolytic properties of L(+)-α-phenylglycine
(L-α-PG-H) in aqueous solution as it can be degraded by photo-catalysis. In 266 nm laser flash photolysis of aqueous solution
of L-α-PG-H saturated with nitrogen, two transient absorption bands are observed at 280–330 nm and 450–800 nm, respectively,
due to L-α-PG-H radical cation and hydrated electrons (eaq−). Then eaq− reacts with L-α-PG-H to form the L-α-PG-H radical anion. Decaying rate constants of eaq− observed at 720 nm is to be 8.9 × 108 dm3 mol−1 s−1. The rate constant for oxidation of L-α-PG-H by SO4
− is calculated as 4.5 × 108 and 4.3 × 108 s−1 mol−1 dm3, respectively. The dissociation constants (pKa) of L-α-PG-H is 3. Excited triplet of L-α-PG-H in solution is formed by laser
flash photolysis. The quench rate constant of L-α-PG-H excited triplet (k
s) is determined to be 1.3 × 107 dm3 mol−1 s−1 and k
0 is equal to 1.7 × 105 s−1. 相似文献
15.
Maria do Socorro S. Pereira Eduardo Winter Jose Roberto Guimarães Susanne Rath Anne Hélène Fostier 《Environmental Chemistry Letters》2007,5(3):137-141
Here, we show a fast and sensitive method for the determination of inorganic arsenic in natural waters using differential
pulse cathodic stripping voltammetry. All the arsenite determinations were done in 2.0 mol L−1 HCl + 3.15 × 10−4 mol L−1 Cu(II) supporting electrolyte. 1 × 10−3 mol L−1 sodium thiosulphate was used as As(V) reducing agent. The detection limit was 0.5 μg L−1 for both species. The method has been applied to water samples collected in an arsenic-contaminated region of Brazil, in
particular, to verify the efficiency of the solar oxidation and removal of arsenic process applied to these waters. 相似文献
16.
Andrew McMinn Andrew Pankowskii Chris Ashworth Ranjeet Bhagooli Peter Ralph Ken Ryan 《Marine Biology》2010,157(6):1345-1356
Primary production at Antarctic coastal sites is contributed from sea ice algae, phytoplankton and benthic algae. Oxygen microelectrodes
were used to estimate sea ice and benthic primary production at several sites around Casey, a coastal area in eastern Antarctica.
Maximum oxygen export from sea ice was 0.95 mmol O2 m−2 h−1 (~11.7 mg C m−2 h−1) while from the sediment it was 6.08 mmol O2 m−2 h−1 (~70.8 mg C m−2 h−1). When the ice was present O2 export from the benthos was either low or negative. Sea ice algae assimilation rates were up to 3.77 mg C (mg Chl-a)−1 h−1 while those from the benthos were up to 1.53 mg C (mg Chl-a)−1 h−1. The contribution of the major components of primary productivity was assessed using fluorometric techniques. When the ice
was present approximately 55–65% of total daily primary production occurred in the sea ice with the remainder unequally partitioned
between the sediment and the water column. When the ice was absent, the benthos contributed nearly 90% of the primary production. 相似文献
17.
The annual population dynamics (nauplii, old copepodites CIV–CV and adults) and seasonal variations in reproductive parameters
of the cyclopoid copepod Oithona similis were investigated on the basis of the data 1999–2006 in Kola Bay, a large subarctic fjord in the Barents Sea. Population
density of O. similis ranged from 110 to 9,630 ind m−3 and averaged 1,020 ± 336 ind m−3. The relative abundance of adults was high during winter (~60%). At the end of winter (mid-March), the population included
a large percentage of later-stage copepodites (stage CIV 23% and stage CV 57%). There were two periods of mass spawning, in
late June and September. Autumn and summer generations strongly differed in abundance, average prosome length (PL), clutch
size (CS), egg diameter (D), egg production rates (EPR and SEPR) and female secondary production. Average PL decreased with increasing water temperature,
while D and CS were strongly correlated with PL but unaffected by temperature. Annual average EPR and SEPR were 0.55 ± 0.18 eggs female−1 day−1 and 0.0011 ± 0.003 day−1, respectively. Female secondary production averaged 0.8 ± 0.3 μg C m−3 day−1 (range 0.001–3.58). There were positive relationships between abundance, EPR, SEPR, production and water temperatures. Reproductive
parameters appeared to be controlled by hydrological factors and food conditions. 相似文献
18.
Ryan R. P. Noble Robert M. Hough Ronald T. Watkins 《Environmental geochemistry and health》2010,32(3):193-205
Stawell Gold Mine in NW Victoria, Australia, mines ores that contain large concentrations of As and significant quantities
of the metals Pb and Cr. The aim of this research was to understand the dispersion, enrichment and probable exposure of these
potentially hazardous elements around the mine site. Fifty-five surface soil samples were collected near the mine (<15 km)
and analysed by ICP-MS/OES following bioavailable and four-acid extractions. Soils near the mine show greater concentrations
of As, Cr and Pb than those near a regionally determined background. This is attributed to the combination of a natural geochemical
halo around mineralization and anthropogenic dispersion due to mining and urbanization. Total As concentrations were between
16 and 946 mg kg−1 near the mine in a regional background of 1–16 mg kg−1. Total Cr concentrations were between 18 and 740 mg kg−1 near the mine in a regional background of 26–143 mg kg−1. Total Pb concentrations were between 12 and 430 mg kg−1 near the mine in a regional background of 9–23 mg kg−1. Dispersion of contaminant elements from the present ore processing is <500 m. The most enriched soils occur close to the
town and are unrelated to present mining practices. The bioavailable As, Cr and Pb, soil ingestion rates and Risk Reference
Doses were used to estimate health risks. An average toddler (12 kg) would need to consume at least 1.5 g, and most likely
12 g, of soil per day to show some symptoms of As toxicity. The maximum measured bioavailable As would pose a risk at average
ingestion rates of 200 mg per day. Individuals with soil-eating disorders would exceed the safe daily consumption limits for
As, and potentially Cr and Pb. Small children are not typically exposed to soil everyday, very few have soil eating disorders,
and, therefore, the health risk from the soils around the mine is minimal. 相似文献
19.
Ravi Naidu Euan Smith S. M. Imamul Huq Gary Owens 《Environmental geochemistry and health》2009,31(Z1):61-68
The bioavailability of arsenic (As) in the soil environment is largely governed by its adsorption–desorption reactions with
soil constituents. We have investigated the sorption–desorption behaviour of As in four typical Bangladeshi soils subjected
to irrigation with As-contaminated groundwater. The total As content of soils (160 samples) from the Laksham district ranged
from <0.03 to approximately 43 mg kg−1. Despite the low total soil As content, the concentration of As in the pore water of soils freshly irrigated with As-contaminated
groundwater ranged from 0.01 to 0.1 mg l−1. However, when these soils were allowed to dry, the concentration of As released in the pore water decreased to undetectable
levels. Remoistening of soils to field moisture over a 10-day period resulted in a significant (up to 0.06 mg l−1) release of As in the pore water of soils containing >10 mg As kg−1 soil, indicating the potential availability of As. In soils containing <5 mg As kg−1, As was not detected in the pore water. A comparison of Bangladeshi soils with strongly weathered long-term As-contaminated
soils from Queensland, Australia showed a much greater release of As in water extracts from the Australian soils. However,
this was attributed to the much higher loading of As in these Australian soils. The correlation of pore water As with other
inorganic ions (P, S) showed a strongly significant (P < 0.001) relationship with P, although there was no significant relationship between As and other inorganic cations, such
as Fe and Mn. Batch sorption studies showed an appreciable capacity for both AsV and AsIII sorption, with AsV being retained in much greater concentrations than AsIII. 相似文献
20.
An assessment of exposure to mercury in Changchun city has been undertaken. We estimated Hg exposure to members of the general population based on currently available information and our research. We also studied the Hg concentrations in scalp hair of adults. Adults have an estimated intake of all Hg species via all routes of 6.780 μg day−1 (excluding dental amalgam), which equates to an absorbed dose of 1.718 μg day−1. Fish consumption was the most important exposure route (12% of intake, 43% of absorbed dose). Furthermore, air, cereals and vegetables were important exposure routes, and these exposure were estimated for absorbed dosed at 0.296, 0.209 and 0.318 μg day−1, respectively. The mean Hg concentration in hair was 0.448 μg g−1 (range 0.092–10.463 μg g−1). Hg concentration in the hair of males was 0.422 μg g−1 (0.105–2.665 μg g−1), and was 0.474 μg g−1(0.092–10.463 μg g−1) in the hair of females. Neither place of residence nor age had any significant effect on hair Hg concentrations. 相似文献