共查询到20条相似文献,搜索用时 31 毫秒
1.
This study was carried out to determine the occurrence, prevalence and contributing factors to the incidence of goitre in
Yewa north local government area of Ogun state, southwestern Nigeria. To achieve these objectives, soil, water, and cassava
tubers were collected from four villages – Igbogila, Egua, Sawonjo and Imoto and from Lagos (about 250 m to the ocean) as
a reference location, in order to determine their iodine concentrations. The results of the analyses indicated a soil mean
iodine range of 2.1–5.8 μg g−1; a cassava mean iodine value of 2.3–3.5 μg g−1 and a drinking water mean iodine value of generally <1.0 μg L−1 in all the four villages. These values of iodine in soil and water of the four villages are considered low when compared
with the soil iodine value of 7.4 μg g−1 and water iodine value of 6.1 μg L−1 obtained from Lagos. The limestone unit of the study area remains an inhibiting factor in the bioavailability of the iodine
because of its alkalinity. Statistical analysis has shown that there was significant difference between iodine concentration
in the soils and the drinking water, and a correlation between the soil iodine and organic matter content at p < 0.05. The correlation between soil iodine and granulometric fractions occurred at p < 0.01. Potential goitrogens in the commonly consumed cassava products might also have contributed to the prevalence of goitre
in the study area. Both the females and the adults (i.e., less mobile groups) were found to be vulnerable to goitre development
in these villages. 相似文献
2.
The geochemical characteristics of arsenic in the soil of the Western Hunan mining area of P.R. China were systematically
studied. The results show that the strata of Western Hunan are rich in arsenic and that Western Hunan is a geochemically abnormal
region for arsenic. The experimental study on speciation in the strata also indicates that the speciation of arsenic in the
Neoproterozoic-Cambrian strata are mainly easily transferred speciation (exchangeable, carbonate-bound, sulfides-bound), which
are approaching or exceed 60%. Arsenic content in the main soil of Western Hunan is in the range of 8.8–22.8 μg g−1, the mean value is 16.1 μg g−1, which is larger than the arsenic background value of Hunan soil. The distribution of rock with high arsenic content or high
easily transferred arsenic speciation is consistent with the distribution of high arsenic content soil. In the mining region,
part soils and river/brook waters were polluted by mine tailings and mining/smelting waste water. The arsenic content in polluted
paddy soils and river/brook water is 46.26–496.19 μg g−1, 0.3–16.5 mgL−1, respectively. The positive abnormality and pollution of arsenic in the soil and water affects the arsenic content of the
crop and the inhabitants’ health. 相似文献
3.
Smyth PP Burns R Huang RJ Hoffman T Mullan K Graham U Seitz K Platt U O'Dowd C 《Environmental geochemistry and health》2011,33(4):389-397
Thyroid hormone levels sufficient for brain development and normal metabolism require a minimal supply of iodine, mainly dietary.
Living near the sea may confer advantages for iodine intake. Iodine (I2) gas released from seaweeds may, through respiration, supply a significant fraction of daily iodine requirements. Gaseous
iodine released over seaweed beds was measured by a new gas chromatography–mass spectrometry (GC–MS)-based method and iodine
intake assessed by measuring urinary iodine (UI) excretion. Urine samples were obtained from female schoolchildren living
in coastal seaweed rich and low seaweed abundance and inland areas of Ireland. Median I2 ranged 154–905 pg/L (daytime downwind), with higher values (~1,287 pg/L) on still nights, 1,145–3,132 pg/L (over seaweed).
A rough estimate of daily gaseous iodine intake in coastal areas, based upon an arbitrary respiration of 10,000L, ranged from
1 to 20 μg/day. Despite this relatively low potential I2 intake, UI in populations living near a seaweed hotspot were much higher than in lower abundance seaweed coastal or inland
areas (158, 71 and 58 μg/L, respectively). Higher values >150 μg/L were observed in 45.6% of (seaweed rich), 3.6% (lower seaweed),
2.3% (inland)) supporting the hypothesis that iodine intake in coastal regions may be dependent on seaweed abundance rather
than proximity to the sea. The findings do not exclude the possibility of a significant role for iodine inhalation in influencing
iodine status. Despite lacking iodized salt, coastal communities in seaweed-rich areas can maintain an adequate iodine supply.
This observation brings new meaning to the expression “Sea air is good for you!” 相似文献
4.
High concentrations of arsenic were determined in sediments from the Kouhsorkh area, Khorasan province, NE Iran. The main
rock formations in the area consist of Tertiary volcanic rocks as Tuffaceous sandstone, polymictic conglomerate and andesite.
Furthermore, some As–Sb–Au mineralization occurred in this area. Concentrations of arsenic in sediments were determined to
range between 4.2 and 268.2 ppm, exceeding US EPA (2004) limits. It seems that young volcanic activity is one of the most important factors for arsenic contamination in this area.
The first stage of this medical geology study was done at 2 villages in the Kouhsorkh area in which the arsenic concentration
in water is high. People in this residential area suffer from skin diseases including hyperpigmentation, hypopigmentation,
keratosis on head, hands, and feet. The 24-h urine specimens were tested for arsenic, the level of total arsenic in urine
were determined to range between 13.66 and 75.92 μg/l day, exceeding permissible limits from 5 to 40 μg/day. More systematic
studies are needed to determine the link between As exposure and its related diseases. 相似文献
5.
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
6.
Ali Akbar Safari Sinegani Hossein Mirahamdi Araki 《Environmental Chemistry Letters》2010,8(4):323-330
Sequential extraction has been used as a suitable method for fractionation of chemical forms of trace elements and study of
their plant availability. Surface soils were sampled from Guilan and Hamadan provinces in north and northwest of Iran with
temperate and semiarid climates. The chemical forms of Pb in the Pb(NO3)2-treated (400 μg Pb g−1) soils have been studied in solid state incubation (FC) at 27°C in sterile and unsterile conditions. After 20 min and 3600 h
a sequential extraction scheme was also used to fractionate Pb of incubated samples into soluble-exchangeable (Sol-Exch),
carbonates associated (ACar), organic matter associated (AOM), Mn oxide associated (AMnOx), Fe oxide associated (AFeOx), and
residual (Res) forms. Temperate soil samples had higher clay content, cation exchange capacity (CEC), dichromate oxidable
organic carbon (OC), total Kjeldahl-nitrogen (TN), biological activity, amorphous and crystalline Fe and Al, but semiarid
soil samples had higher sand content, pH, equivalent calcium carbonate (ECC), available P and K. Soil lead fractionation revealed
that in both groups of soils Pb largely changed to exchangeable, carbonates associated and organic associated forms after
20 min. The chemical forms of Pb differed widely among soils after 3600-h incubation. The conversion rate of Pb from more
available forms to less available forms was higher in temperate soils with higher Fe–Mn oxides and OM contents compared to
semiarid soils. In temperate soils after 3600-h incubation, greater content of Pb was observed in Res (68%), AOM (14%), ACar
(7%), and AMnOx (5%) fractions. However, in semiarid soils greater content of Pb was observed in Res (61%), ACar (16%), Sol-Exch
(8%), and AOM (8%) fractions. The sum of AMnOx and AFeOx chemical forms for Pb in semiarid soils compared to temperate soils
was lower. It was only 7% against 9% in temperate soils. Soil microorganisms in unsterile soils had significant effect on
AOM, AFeOx and Res fractions of Pb. They not only increased AOM and AFeOx fractions of Pb in soils but also decreased Res
fraction of Pb significantly. 相似文献
7.
Polycyclic aromatic hydrocarbon (PAH) concentrations were determined in 16 topsoils (0–10 cm) collected across the site of
a former tar works in NE England. The soils were prepared in the laboratory to two different particle size fractions: <250 μm
(fraction A) and >250 μm to <2 mm (fraction B). Sixteen priority PAHs were analysed in the soils using in situ pressurised
fluid extraction (PFE) followed by gas chromatography—mass spectrometry (GC–MS). The average total PAH concentration in the
soils ranged from 9.0 to 1,404 mg/kg (soil fraction A) and from 6.6 to 872 mg/kg (soil fraction B). These concentrations are
high compared with other industrially contaminated soils reported in the international literature, indicating that the tar
works warrants further investigation/remediation. A predominance of higher-molecular-weight compounds was determined in the
samples, suggesting that the PAHs were of pyrogenic (anthropogenic) origin. Statistical comparison (t-test) of the mean total PAH concentrations in soil fractions A and B indicated that there was a significant difference (95%
confidence interval) between the fractions in all but two of the soil samples. Additionally, comparisons of the distributions
of individual PAHs (i.e. 16 PAHs × 16 soil samples) in soil fractions A and B demonstrated generally higher PAH concentrations
in fraction A (i.e. 65.8% of all individual PAH concentrations were higher in soil fraction A). This is important because
fraction A corresponds to the particle size thought to be most important in terms of human contact with soils and potential
threats to human health. 相似文献
8.
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
9.
Particle size distribution and pollutants in road-deposited sediments in different areas of Zhenjiang,China 总被引:2,自引:0,他引:2
An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant
washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were
collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City,
China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations
of pollutants. The samples are found to consist predominantly of fine particles (60–80%, <250 μm). The maximum mean concentrations
of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in
samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus
(5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest
particle size fraction analysed (63 μm). The organic matter and nitrogen content generally increased with decreasing particle
sizes in the <500-μm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the
finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer
particles (down to 125 μm for TN). 相似文献
10.
Rogan N Serafimovski T Dolenec M Tasev G Dolenec T 《Environmental geochemistry and health》2009,31(4):439-451
This research focuses on the heavy metal contamination of the paddy soils and rice from Kočani Field (eastern Macedonia) resulting
from irrigation by riverine water impacted by past and present base-metal mining activities and acid mine drainage. Very high
concentrations of As, Cd, Cu, Pb and Zn were found in the paddy soils (47.6, 6.4, 99, 983 and 1,245 μg g−1) and the rice (0.53, 0.31, 5.8, 0.5 and 67 μg g−1) in the western part of Kočani Field, close to the Zletovska River, which drains the mining facilities of the Pb–Zn mine
in Zletovo. In terms of health risk, the observed highest concentrations of these elements in the rice could have an effect
on human health and should be the subject of further investigations. 相似文献
11.
In this study, the content and speciation of arsenic in coal waste and gas condensates from coal waste fires were investigated,
respectively, using the digestion and sequential extraction methods. The fresh and fired-coal waste samples were collected
from Yangquan, which is one of the major coal production regions in northern China. High-performance liquid chromatography-inductively
coupled plasma-mass spectrometry (HPLC-ICP-MS) was used to determine the concentrations of four major arsenic species [As(III),
As(V), monomethylarsonic acid (MMA) and dimethylarsenic acid (DMA)] in the extracts, while ICP-MS was used to measure total
As content. Arsenic content in the investigated coal wastes and the condensate ranges between 23.3 and 69.3 mg/kg, which are
higher than its reported average content in soils. Arsenic in coal waste exists primarily in the residual fraction; this is
followed in decreasing order by the organic matter-bound, Fe–Mn oxides-bound, exchangeable, carbonates-bound, and water-soluble
fractions. The high content of arsenic in the condensates indicates that combustion or spontaneous combustion is one of the
major ways for arsenic release into the environment from coal waste. About 15% of the arsenic in the condensate sample is
labile and can release into the environment under leaching processes. The water extractable arsenic (WEA) in the fresh coal
waste, fired coal wastes, and the condensate varied between 14.6 and 341 μg/kg, with As(V) as the major species. Furthermore,
both MMA and DMA were found in fresh coal wastes, fired coal wastes, and the condensate. 相似文献
12.
Mohammad Mahmudur Rahman Gary Owens Ravi Naidu 《Environmental geochemistry and health》2009,31(Z1):179-187
Chronic exposure to arsenic (As) causes significant human health effects, including various cancers and skin disorders. Naturally
elevated concentrations of As have been detected in the groundwater of Bangladesh. Dietary intake and drinking water are the
major routes of As exposure for humans. The objectives of this study were to measure As concentrations in rice grain collected
from households in As-affected villages of Bangladesh where groundwater is used for agricultural irrigation and to estimate
the daily intake of As consumed by the villagers from rice. The median and mean total As contents in 214 rice grain samples
were 131 and 143 μg/kg, respectively, with a range of 2–557 μg/kg (dry weight, dw). Arsenic concentrations in control rice
samples imported from Pakistan and India and on sale in Australian supermarkets were significantly lower (p < 0.001) than in rice from contaminated areas. Daily dietary intake of As from rice was 56.4 μg for adults (males and females)
while the total daily intake of As from rice and from drinking water was 888.4 and 706.4 μg for adult males and adult females,
respectively. From our study, it appears that the villagers are consuming a significant amount of As from rice and drinking
water. The results suggest that the communities in the villages studied are potentially at risk of suffering from arsenic-related
diseases. 相似文献
13.
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
14.
The concentration of uranium was determined in 944 samples from stream water by the inductively coupled plasma quadrupole
mass spectrometry (ICP-QMS) method and represented on a color-shaded contour map. Uranium concentrations in surface water
were determined to be between 0.007 μg/l and 43.7 μg/l with median of 0.33 μg/l. The regional distribution of uranium is influenced
primarily by lithological and anthropogenic factors. In Mecklenburg, northern Brandenburg, and eastern Schleswig-Holstein,
elevated uranium concentrations coincide with the extent of the last Weichselian ice sheet. The maximum concentrations are
observed in the surface waters of the old mining districts in the western part of the Ore Mountains and in eastern Thuringia.
Elevated concentrations are found in areas of agriculturally used loess soils. These concentrations correlate with the use
of phosphate fertilizers. There is a zone of elevated concentrations up to 10.0 μg U/l in the Keuper Sandstone area south
of the Thuringian Forest and from northwest of Stuttgart as far as Coburg. The distribution of elevated values in mineral
water shows a clear correlation with the elevated values in surface water and the geology of those locations. Bunter and Keuper
strata are the most important uranium source. 相似文献
15.
In the present article, a simple, rapid, sensitive and economical method has been developed for the simultaneous separation
and preconcentration of the trace amounts of copper, nickel, cobalt and manganese in water samples by using modified XAD-4
resins. The sorption was quantitative in the pH range 6.0–9.0, whereas quantitative desorption occurred instantaneously with
5.0 mL of 2 M HNO3, and selected elements have been determined by using flame atomic absorption spectrometry. Dynamic ranges were 0.04–3.5,
0.1–6.0, 0.04–4.5 and 0.04–4.0 μg/mL for copper, nickel, cobalt and manganese, respectively. The detection limits were 9.2,
28.6, 12.3 and 5.7 ng/mL for Cu(II), Ni(II), Co(II) and Mn(II), respectively. The effects of the experimental parameters,
including the sample pH, eluent type, interference ions and breakthrough volume, were studied for separation and preconcentration
of Cu(II), Ni(II), Co(II) and Mn(II) ions. Determination of these ions in standard samples confirmed that the proposed method
has good accuracy. The proposed method was used for the determination of these ions in water samples. 相似文献
16.
Debapriya Mondal Mayukh Banerjee Manjari Kundu Nilanjana Banerjee Udayan Bhattacharya Ashok K. Giri Bhaswati Ganguli Sugata Sen Roy David A. Polya 《Environmental geochemistry and health》2010,32(6):463-477
Remediation aimed at reducing human exposure to groundwater arsenic in West Bengal, one of the regions most impacted by this
environmental hazard, are currently largely focussed on reducing arsenic in drinking water. Rice and cooking of rice, however,
have also been identified as important or potentially important exposure routes. Quantifying the relative importance of these
exposure routes is critically required to inform the prioritisation and selection of remediation strategies. The aim of our
study, therefore, was to determine the relative contributions of drinking water, rice and cooking of rice to human exposure
in three contrasting areas of West Bengal with different overall levels of exposure to arsenic, viz. high (Bhawangola-I Block,
Murshidibad District), moderate (Chakdha Block, Nadia District) and low (Khejuri-I Block, Midnapur District). Arsenic exposure
from water was highly variable, median exposures being 0.02 μg/kg/d (Midnapur), 0.77 μg/kg/d (Nadia) and 2.03 μg/kg/d (Murshidabad).
In contrast arsenic exposure from cooked rice was relatively uniform, with median exposures being 0.30 μg/kg/d (Midnapur),
0.50 μg/kg/d (Nadia) and 0.84 μg/kg/d (Murshidabad). Cooking rice typically resulted in arsenic exposures of lower magnitude,
indeed in Midnapur, median exposure from cooking was slightly negative. Water was the dominant route of exposure in Murshidabad,
both water and rice were major exposure routes in Nadia, whereas rice was the dominant exposure route in Midnapur. Notwithstanding
the differences in balance of exposure routes, median excess lifetime cancer risk for all the blocks were found to exceed
the USEPA regulatory threshold target cancer risk level of 10−4–10−6. The difference in balance of exposure routes indicate a difference in balance of remediation approaches in the three districts. 相似文献
17.
Assessment of bioaccessibility and exposure risk of arsenic and lead in urban soils of Guangzhou City,China 总被引:5,自引:0,他引:5
Ying Lu Wei Yin Longbin Huang Ganlin Zhang Yuguo Zhao 《Environmental geochemistry and health》2011,33(2):93-102
Soil ingestion is an important human exposure pathway of heavy metals in urban environments with heavy metal contaminated
soils. This study aims to assess potential health risks of heavy metals in soils sampled from an urban environment where high
frequency of human exposure may be present. A bioaccessibility test is used, which is an in vitro gastrointestinal (IVG) test
of soluble metals under simulated physiological conditions of the human digestion system. Soil samples for assessing the oral
bioaccessibility of arsenic (As) and lead (Pb) were collected from a diverse range of different land uses, including urban
parks, roadsides, industrial sites and residential areas in Guangzhou City, China. The soil samples contained a wide range
of total As (10.2 to 61.0 mg kg−1) and Pb (38.4 to 348 mg kg−1) concentrations. The bioaccessibility of As and Pb in the soil samples were 11.3 and 39.1% in the stomach phase, and 1.9
and 6.9% in the intestinal phase, respectively. The As and Pb bioaccessibility in the small intestinal phase was significantly
lower than those in the gastric phase. Arsenic bioaccessibility was closely influenced by soil pH and organic matter content
(r
2 = 0.451, p < 0.01) in the stomach phase, and by organic matter, silt and total As contents (r
2 = 0.604, p < 0.001) in the intestinal phase. The general risk of As and Pb intake for children from incidental ingestion of soils is
low, compared to their maximum doses, without causing negative human health effects. The exposure risk of Pb in the soils
ranked in the order of: industrial area/urban parks > residential area/road side. Although the risk of heavy metal exposure
from direct ingestion of urban soils is relatively low, the risk of inhalation of fine soil particulates in the air remains
to be evaluated. 相似文献
18.
Moreno Rodriguez MJ Cala Rivero V Jiménez Ballesta R 《Environmental geochemistry and health》2005,27(5-6):513-519
Selenium was determined from 25 topsoils and 25 plants in the semi-arid Central Spain where large extents of soils are developed
on evaporitic materials. Some species of vegetation associated with them are of the genera Astragalus, Salsola, Mercurialis, Phlomis, Thymus and Atriplex. Total selenium in soils was determined and its bioavailability assessed by chemical sequential fractionation. Se content
in soils was adequate (in the range 0.17–0.39 mg kg−1) or large (in the range 0.50–4.38 mg kg−1) and appeared in highly and/or potentially available forms. Several plant species showed high Se levels (in the range 5–14.3 mg kg−1), which can be a potential risk of toxicity to animals. Data obtained from the study area can be used as a guide to the range
of values in soils and plants of the European Mediterranean area that are relatively unpolluted from industrial sources, allowing
comparison with more polluted areas. 相似文献
19.
An evaluation of ~250 samples of groundwater in the Amman Zarqa Basin for selenium along with other major and trace elements
showed that concentrations of Se ranged between 0.09 and 742 μg/L, with an average value of about 24 μg/L. Selenium concentrations
exceeded the recommended threshold for drinking water of the World Health Organization (WHO; 10 μ/L of Se) in 114 samples,
with greater than 50 μg/L (quantity equivalent to the Jordanian standard of the allowed concentration of the element in water)
of Se in nine cases. The average concentrations of Se in the lower, middle, and upper aquifers of the basin were 3.41, 32.99,
and 9.19 μg/L, respectively. Based on the correlation with geologic formations and the statistical analysis of major/minor
constituents and Piper tri-linear diagrams, we suggest that carbonate/phosphate dissolution, oxidation–reduction processes,
and fertilizers/irrigation return flow are, together, the primary factors affecting the chemistry of the groundwater. Factor
analysis helped to define the relative role of limestone-dolomitic dissolution in the aquifers (calcium, magnesium, and bicarbonate),
agricultural activities (sulfate, nitrates, phosphorus, and potassium), oxidation–reduction factor (Eh, Fe, Mn, Cu, Zn, and
Se), and anthropogenic (industrial) factor (EC, Fe, Cr, Co, Zn, and As). The high variability in Se concentrations might be
related to the possibility of a multi-source origin of Se in the area. 相似文献
20.
Eric Lichtfouse Valérie Sappin-Didier Laurence Denaix Giovanni Caria Laure Metzger Najat Amellal-Nassr Jens Schmidt 《Environmental Chemistry Letters》2005,3(3):140-144
We studied polycyclic aromatic hydrocarbons (PAHs) in crop soils amended with 1000 tonnes dry weight of sewage sludges per
10,000 m2 from 1974 to 1992, then after sludges addition from 1993 to 1999. The absence of variations of total PAHs levels of control
soils, averaging at 123 μg/Kg, shows the absence of horizontal contamination. During sludges addition, the total PAHs levels
in amended soils increased from 232 to 402 μg/Kg. Seven years after sludges addition, it decreased to 275 μg/Kg, which is
still more than twice –the levels of control soils. This finding shows that sludges PAHs are preserved in crop soils for long
periods of time, on a human scale. 相似文献