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1.
The Distribution and Sources of Polycyclic Aromatic Hydrocarbons in Surface Sediments Along the Egyptian Mediterranean Coast 总被引:2,自引:0,他引:2
El Nemr A Said TO Khaled A El-Sikaily A Abd-Allah AM 《Environmental monitoring and assessment》2007,124(1-3):343-359
Coastal marine sediment samples were collected from 31 sampling stations along the Egyptian Mediterranean Sea coast. All sediment
samples were analyzed to determine aliphatic and polycyclic aromatic hydrocarbons (PAHs) as well as total organic carbon (TOC)
contents and grain size analysis. Total concentrations of 16 EPA-PAHs in the sediments were varied from 88 to 6338 ng g−1 with an average value of 154 ng g−1 (dry weight). However, the concentrations of total aliphatic were varied from 1.3 to 69.9 ng g−1 with an average value of 15.6 ng g−1 (dry weight). The highest contents of PAHs were found in the Eastern harbor (6338 ng g−1), Manzala (5206 ng g−1) and El-Jamil East (4895 ng g−1) locations. Good correlations observed between a certain numbers of PAH concentrations allowed to identify its origin. The
average total organic carbon (TOC) percent was varied from 0.91 to 4.54%. Higher concentration of total pyrolytic hydrocarbons
(∑COMB) than total fossil hydrocarbons (∑PHE) declared that atmospheric fall-out is the significant source of PAHs to marine
sediments of the Egyptian Mediterranean coast. The selected marked compounds, a principal component analysis (PCA) and special
PAHs compound ratios (phenanthrene/anthracene vs fluoranthene/pyrene; ∑COMB/∑EPA-PAHs) suggest the pyrogenic origins, especially
traffic exhausts, are the dominant sources of PAHs in most locations. Interferences of rather petrogenic and pyrolytic PAH
contaminations were noticed in the harbors due to petroleum products deliveries and fuel combustion emissions from the ships
staying alongside the quays. 相似文献
2.
Seasonal variation of the concentrations of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured by ICP-AES
in the water and sediment from the Saricay Stream, Geyik Dam and Ortakoy Well in the same basin. Comparisons between trace
metal concentrations in water and sediment in three sources (Stream, Dam and Well) were made. The concentrations of a large
number of trace metals in the water and sediment were generally higher in the Stream than in the Well and Dam, particularly
in summer. Trace metal concentration ranges in sediments of the Saricay Stream and its sources showed very wide ranges (as
mass ratio): Co: 5–476 μg g−1, Cr: 15–1308 μg g−1, Cu: 7–128 μg g−1, Fe: 1120–13210 μg g−1, Mn: 150–2613 μg g−1, Ni: 102–390 μg g−1, Pb: 0.7–31.3 μg g−1 and Zn: 18–304 μg g−1, whereas Cd was not detected. Trace metal concentration ranges found in waters were: Co: 9.5–20.7 μg L−1, Cr: 20.3–284 μg L−1, Cu: 170–840 μg L−1, Fe: 176–1830 μg L−1, Mn: 29.3–387 μg L−1, and Ni: 4.3–21.9 μg L−1. Among the trace metals studied, Cd and Zn in two seasons and Pb in winter were usually not detected or in the recommended
levels. In addition, Cd was not detected in the sediment during the winter season. The analysis of variance (one-way ANOVA)
and correlation matrix was employed for the sediment and water samples of the two field surveys (summer and winter) comparison.
The three sources showed differences in metal contents. The metal levels in sediments displayed marked seasonal and regional
variations, which were attributed to anthropogenic influences and natural processes. In the Saricay Stream, high values of
metals during the dry season showed an anthropological effect from small industry firms, e.g.: an olive mill and a dairy farm
or water dilution during summer seasons. Finally, the pollution in this basin probably originated from small industrial, low
quality coal-burned thermal power plants, and particularly agricultural and domestic waste discharges. 相似文献
3.
In this work, water and sediment samples were collected from three different stations located along the Sakarya river between
May and September 2003. Lead, copper, chromium, zinc, nickel and cadmium concentrations were determined by using solvent extraction
and flame atomic absorption spectrometric method. The results show that differences based upon sampling times, regions, sediment
and water samples were observed. The mean levels of copper, nickel, chromium, lead, cadmium, zinc for sediment samples are;
4.630 μg g−1, 13.520 μg g−1, 8.780 μg g−1, 2.550 μg g−1, 9.990 μg g−1 and for water samples are; 0.851 μg g−1, 1.050 μg g−1, 0.027 μg g−1, 1.786 μg g−1, 0.236 μg g−1, 0.173 μg g−1, respectively. 相似文献
4.
Total mercury concentrations in different tissues of frigate tuna fish (Auxis thazard thazard) was determined by the cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer. A mixture
of HNO3, HClO4 and H2SO4 was used for complete oxidation of organic tissue. The concentration of mercury obtained was in the order Gills < Stomach
< Gonads < Intestine < Heart < Duodenum < Liver < Muscle. The concentration of total mercury detected in the edible muscle
tissue of the tuna fish tested ranged from 0.044 to 0.201 μg g−1 (mean = 0.108 μg g−1) wet weight. These levels are all within the maximum allowed/recommended level in fish (0.5 μg g−1 wet weight) set by the Food and Agriculture Organisation/World Health Organisation (FAO/WHO) and are therefore unlikely to
constitute any significant mercury exposure to the general population because of consumption of tuna fish. The results of
the study suggest a relatively clean marine environment that has not been significantly impacted by mercury contamination
probably due to minimal industrial activity in the region. 相似文献
5.
In this study, the relationship between some physico-chemical properties of soils and lead contamination in soil due to emission
from industrial operations in Samsun province of Turkey was investigated. The extent of timely contamination was studied by
comparing the obtained results with the results of the study conducted in the same region in 1998. An area of 225 km2 (15 km × 15 km), which was divided into 1000 × 1000 m grid squares (16 lines in the east and south directions), was selected
within the industrial area. The total of 256 grid points was obtained and soil samples were collected from three depths (0–5,
5–15, and 15–30 cm) of each grid center in 2004. The total Pb concentrations of soil samples were determined as 65.84–527.04
μg g−1 at 0–5 cm in depth, 58.50 – 399.54 μg g−1 at 5–15 cm in depth, and 44.65–330.07 μg g−1 at 15–30 cm in depth. DTPA-extractable Pb concentrations of soils were found to be in the range of 1.52–9.03 μg g−1, 0.54–7.09 μg g−1, 0.19–6.13 μg g−1 at 0–5, 5–15, and 15–30 cm depths, respectively. There were significant relationships between both total or DTPA-extractable
Pb concentrations and selected physico-chemical properties of soil. According to enrichment factor (EF) values calculated
from the total Pb concentrations, 11.3% of the study area (225 km2) was enriched with Pb in high level, but 77% of the area was in significant enrichment level with Pb. The average total and
DTPA-extractable Pb concentrations increased as 11 and 13%, respectively in comparison with the results of 1998. 相似文献
6.
Twelve samples each of soil and ground water were collected from paddy-wheat, paddy-cotton, sugarcane fields and tube wells
from same or near by fields around Hisar, Haryana, India during 2002–2003 to monitor pesticide residues. Residues were estimated
by GC-ECD and GC-NPD systems equipped with capillary columns for organochlorine, synthetic pyrethroid and organophosphate
insecticides. In soil, HCH (0.002–0.051 μg g−1), DDT (0.001–0.066 μg g−1), endosulfan (0.002–0.039 μg g−1) and chlordane (0.0002–0.019 μg g−1) among organochlorines, cypermethrin (0.001–0.035 μg g−1) and fenvalerate (0.001–0.022 μg g−1) among synthetic pyrethroids and chlorpyriphos (0.002–0.172 μg g−1), malathion (0.002–0.008 μg g−1), quinalphos (0.001–0.010 μg g−1) among organophosphates were detected. Dominant contaminants were DDT, cypermethrin and chlorpyriphos from the respective
groups. In water samples, HCH, DDT, endosulfan and cypermethrin residues were observed frequently. Only chlorpyriphos among
organophosphates was detected in 10 samples. On consideration of tube well water for drinking purpose, about 80% samples were
found to contain residues above the regulatory limits. 相似文献
7.
Bergasa O Ramírez R Collado C Hernández-Brito JJ Gelado-Caballero MD Rodríguez-Somozas M Haroun RJ 《Environmental monitoring and assessment》2007,127(1-3):127-133
In order to assess the extent of metal contamination at rocky shores of the Canarian Archipelago, metal concentrations have
been measured in Patella piperata (Gould, 1846), using the standard atomic absorption spectrophotometer technique. Ranges of elements concentrations measured
(in μg g−1) found in the biota were: Cd (0.36 ± 0.26 μg g−1 dry wt.), Cu (2.05 ± 0.91 dry wt.), Pb (1.57 ± 1.14 μg g−1dry wt.) and Zn (10.37 ± 4.60 μg g−1 dry wt.). Variation in metal concentrations in Patella, was tested by using non-parametric statistical methods. Cd content had a maximum in the Archipelago Chinijo, northward of
Lanzarote Island. The metal concentrations recorded at the clean stations may be considered carefully if they are used like
background levels. 相似文献
8.
Elevated levels of selenium have been found in water and aquatic biota downstream from two open-pit coal mines in the Rocky Mountain foothills of Alberta. Birds are particularly sensitive to excessive dietary selenium. However, there is relatively little information on selenium accumulation in birds' eggs on fast-flowing mountain streams. We determined levels of selenium in water samples, caddisfly larvae and eggs of American dippers (Cinclus mexicanus) nesting on the Gregg River, downstream from the mines, and on reference streams in the same general vicinity. Selenium levels (mean, 95% confidence limits) in water samples and caddisflies collected from sites near dipper nests on the Gregg River (water: 4.26, 1.90–9.56 μg L−1; caddisflies: 8.43, 7.51–9.46 μg g dry wt−1) were greater than those collected from sites near nests on reference rivers (water: 0.38, 0.21–0.71 μg L−1; caddisflies: 4.65, 4.35–4.97 μg g dry wt−1). The mean (± 1SE) selenium level in dipper eggs from the Gregg River (6.3 ± 0.2 μg g−1 dry wt) was significantly higher than it was in eggs from reference streams (4.9 ± 0.2 μg g−1 dry wt). Concentrations of selenium in eggs were significantly correlated with those in water samples (r = 0.45). The maximum selenium level in eggs from the Gregg River (9.0 μg g−1) may have been high enough to warrant concern from an ecotoxicological perspective. The American dipper can serve as a useful bioindicator of selenium contamination in mountainous, lotic ecosystems. 相似文献
9.
Dere S Dalkiran N Karacaoğlu D Elmaci A Dülger B Sentürk E 《Environmental monitoring and assessment》2006,115(1-3):1-22
The implications of metal contamination of agricultural soils due to long term irrigation with treated industrial wastewater and their subsequent accumulation in the vegetables/crops growing on such soils has been assessed in an area of industrial complex, Jajmau, Kanpur (India). Physico-chemical properties of the soil were also studied. The soil and vegetables/crops were sampled from an area of 2100 acre agricultural land and analyzed for physico-chemical properties and metal accumulation in different parts of the plants. The comparison of the data of physico-chemical properties of control and contaminated soil showed that salinity, electrical conductivity, available phosphorous, sodium and potassium content (both water soluble and exchangeable) were found high in contaminated soil. The analysis of plant available metal content in the soil showed the highest level of Fe, which ranged from 529.02 to 2615 μg g−1 dw and lowest level of Ni (3.12 to 10.51 μg g−1 dw). The analysis of the results revealed that accumulation of toxic metal Cr in leafy vegetables was found more than fruit bearing vegetables/crops. Thus, it is recommended that the leafy vegetables are unsuitable to grow in such contaminated sites. It is important to note that toxic metal, Ni was not detected in all the plants. The edible part of the vegetables (under ground) such as, garlic (19.27 μg g−1 dw), potato (11.81 μg g−1 dw) and turmeric (20.86 μg g−1 dw) has accumulated lowest level of toxic metal, Cr than leafy and fruit bearing vegetables. In some fruit part of vegetables such as, bitter gourd, egg plant, jack tree, maize and okra, the accumulation of Cr was not detected and may be grown in this area. 相似文献
10.
Concentrations of heavy metals were determined in the water column (including the sea-surface microlayer, subsurface, mid-depth
and bottom water) and sediments from Singapore’s coastal environment. The concentration ranges for As, Cd, Cr, Cu, Ni, Pb
and Zn in the seawater dissolved phase (DP) were 0.34–2.04, 0.013–0.109, 0.07–0.35, 0.23–1.16, 0.28–0.78, 0.009–0.062 and
0.97–3.66 μg L−1 respectively. The ranges for Cd, Cr, Cu, Ni, Pb and Zn in the suspended particulate matter (SPM) were 0.16–0.73, 6.72–53.93,
12.87–118.29, 4.34–60.71, 1.10–6.08 and 43.09–370.49 μg g−1, respectively. Heavy metal concentrations in sediments ranged between 0.054–0.217, 37.48–50.52, 6.30–21.01, 13.27–26.59,
24.14–37.28 and 48.20–62.36 μg g−1 for Cd, Cr, Cu, Ni, Pb and Zn, respectively. The lowest concentrations of metals in the DP and SPM were most frequently found
in the subsurface water while the highest concentrations were mostly observed in the SML and bottom water. Overall, heavy
metals in both the dissolved and particulate fractions have depth profiles that show a decreasing trend of concentrations
from the subsurface to the bottom water, indicating that the prevalence of metals is linked to the marine biological cycle.
In comparison to data from Greece, Malaysia and USA, the levels of metals in the DP are considered to be low in Singapore.
Higher concentrations of particulate metals were reported for the Northern Adriatic Sea and the Rhine/Meuse estuary in the
Netherlands compared to values reported in this study. The marine sediments in Singapore are not heavily contaminated when
compared to metal levels in marine sediments from other countries such as Thailand, Japan, Korea, Spain and China. 相似文献
11.
Sediment and suspended particulate matter samples from 24 stations in the Gulf of Kavala have been examined for lead contamination. Grain size analysis and organic matter content were also performed. Total – anthropogenic sediment lead concentrations and enrichment factors at stations close to harbors and chemical industries were found higher (up to 209–135μg/g and 4.12 respectively), in relation to concentrations from the rest of the coastal zone. In the above areas, increased suspended particulate lead in the bottom of the water column was also recorded (up to 109μg/g). Total sediment lead concentrations composed of high natural Pb background increased with decreasing grain size, suggesting their association with the fine fractions of the sediments (31.1–66.0% mud presence) and the organic matter content (6–9% higher values). Overall, higher total lead concentrations in the sediments, determined by this work, appear to be significantly different from those reported for the Gulf of Kavala in previous studies and similar to those detected in other highly contaminated eastern Mediterranean coastal areas. 相似文献
12.
Incineration of acrylic waste solution in a lab scale quartz tube vertical incinerator showed the presence of 12–15 polycyclic
aromatic hydrocarbons (PAHs) from a list of 16 priority pollutants at 700–1100˚C after an interval of 50˚C. The amount of total 16 PAHs at 900 and 1100˚C was about 8.5 and 1.25 times higher than those at 700˚C (739.48 μg g−1) respectively. The amount of total probable (2A) and possible (2B) human carcinogenic PAHs was minimum at 700˚C. 相似文献
13.
This is the first comprehensive study of sources of variation in metal concentrations within the whole tissues of a shallow burrowing, filter-feeding intertidal clam, Austrovenus stutchburyi. Samples were collected from 12 sites in April, August, November and February in 1993–1994 in the vicinity of Otago Harbour and Peninsula, New Zealand. Total tissue trace metal concentrations (μg g−1 dry weight) were measured in individual animals for the essential metals : Mn, Cu, Zn, Ni and the non-essential Cr using trace-metal clean acid-digestion and ICP-OAES techniques. Average metal concentrations were 3–60 μg g−1 for Cu, 40–118 μg g−1 for Zn, 2–12 μg g−1 for Mn, 5–35 μg g−1 for Ni and 1–44 μg g−1 for Cr. These levels decreased with body weight and differed amongst sites except for Cr in February (mid-summer). Highest concentrations occurred at sites close to a city (Dunedin) and within the central harbour region although the Cu, Zn, Ni and Cr concentrations did not correlate with the environmental gradient or season. At one coastal site, samples of both the blue mussel Mytilus galloprovincialis and cockles gave similar trends in trace metal levels. These results suggest that the cockle could be a useful trace metal biomonitor within NZ estuaries. 相似文献
14.
Determination of imazosulfuron persistence in rice crop and soil 总被引:1,自引:0,他引:1
Sondhia S 《Environmental monitoring and assessment》2008,137(1-3):205-211
Imazosulfuron is a new post-emergence sulfonylurea herbicide. It is highly active at low application rates to control annual
and perennial broad-leaf weeds and sedges in rice. There is increasing concerned about the persistence of pesticide residues
in soils, crop produce and subsequent contamination of groundwater. Thus persistence of imazosulfuron residues under field
condition was evaluated. Imazosulfuron was applied at 30, 40, 50 and 60 a. i. g ha −1 rates, 4 days after transplanting of rice as post-emergence herbicide. Soil and plant samples treated with imazosulfuron
were collected at 60, 90 and 120 days after herbicide application and analyzed for residues. Rice grains and straw samples
were sampled at harvest (120 days). Residues of imazosulfuron in soil were not found after 90 and 120 DAS (days after spraying).
Rice grains contained 0.006, 0.009 μg g−1 residues at 50 and 60 g ha −1 application rates. 0.009 and 0.039 μg g−1 residues of imazosulfuron were detected at 50 and 60 g/ha rates respectively in rice straw. Residues of imazosulfuron were
not detected applied at 30 and 40 g ha−1 in rice grains and straw, respectively and can be safely applied to the transplanted rice. 相似文献
15.
Cristiane Rossi de Oliveira Luiz Augusto dos Santos Madureira 《Environmental monitoring and assessment》2011,173(1-4):91-105
Nonaromatic hydrocarbons and geochemical parameters from 17 sediment?Cwater interface samples were used to assess sources of organic matter in three harbors, located in Santa Catarina State, southern Brazil. The evaluation was based on the molar C/N/P ratios, abundance of resolved nonaromatic hydrocarbons (3.0?C25.9 ??g g???1), unresolved complex mixture, and two indexes: the carbon preference index (CPI) and the low molecular weight to high molecular weight ratio. The results indicate that the organic matter is predominantly of terrestrial origin (C/N > 10 and CPI > 2). Variations in the total organic carbon from 0.43 to 2.98 mmol g???1 and total phosphorus from 82.4 to 464.3 ??g g???1 showed no clear correlation with the silt and clay fractions of the sediments possibly due to anthropogenic input. In contrast to the low level of contamination based on the acyclic hydrocarbon distribution, the results obtained from a series of geologically stable hopanes and steranes reveal the presence of less degradable petroleum derivatives. 相似文献
16.
The aim of this study is to determine the possibility of using Rinodina sophodes (Ach.) Massal., a crustose lichen as polycyclic aromatic hydrocarbons (PAHs) bioaccumulator for evaluation of atmospheric
pollution in tropical areas of India, where few species of lichens are able to grow. PAHs were identified, quantified and
compared to evaluate the potential utility of R. sophodes. The limit of detection for different PAHs was found to be 0.008–0.050 μg g − 1. The total PAHs in different sites were ranged between 0.189 ± 0.029 and 0.494 ± 0.105 μg g − 1. The major sources of PAHs were combustion of organic materials, traffic and vehicular exhaust (diesel and gasoline engine).
Significantly higher concentration of acenaphthylene and phenanthrene indicates road traffic as major source of PAH pollution
in the city. Two-way ANOVA also confirms that all PAHs content showed significant differences between all sampling sites (P
1%). This study establishes the utility of R. sophodes in monitoring the PAHs accumulation potentiality for development of effective tool and explores the most potential traits
resistant to the hazardous environmental conditions in the tropical regions of north India, where no such other effective
way of biomonitoring is known so far. 相似文献
17.
Montes AM González-Farias FA Botello AV 《Environmental monitoring and assessment》2012,184(3):1359-1369
The lagoon system of Navachiste-Macapule is located in northern Mexico, in the state of Sinaloa, with an area of 24,000 ha.
The main economic activity in the area is agriculture, and the lagoon lies next to the irrigation district ID-063 which covers
116,615 ha. The purpose of this study is to evaluate the levels of pollution generated by organochlorine pesticides (OC) in
the surface sediments of the lagoon and in the agricultural drains of the ID-063 that are supposedly transported into the
system as a result of agricultural activities and runoff from adjacent land. For this, between 2006 and 2007, 45 surface sediment
samples were collected (warm dry, rainy and cold dry) from 15 sampling sites, during the three climatic seasons. Of these,
eight were located inside the lagoon in marine conditions (salinity >31 PSU) and seven in the agricultural drains of the ID-063
in freshwater conditions (salinity <5 PSU). The average concentration of the OC in the sediments was 44.75 ng g − 1, among which the group of the alicyclic compounds presented the greatest concentrations. The average value of the total organic
carbon (TOC) in the sediments of the system was 0.90%. The sediments collected inside the lagoon had an average OC concentration
of 18.97 ng g − 1, and the predominant type of sediment was fine to very fine sand. The average OC concentration in the sediments collected
in the agricultural drains was 75.69 ng g − 1, where fine sediments (silt) were predominant. The presence of methoxychlor, endrin and heptachlor suggested that these compounds
were continuously used in the system, even though their use is forbidden in Mexico. 相似文献
18.
Anthropogenic nexus on organochlorine pesticide pollution: a case study with Tamiraparani river basin,South India 总被引:2,自引:0,他引:2
Kumarasamy P Govindaraj S Vignesh S Rajendran RB James RA 《Environmental monitoring and assessment》2012,184(6):3861-3873
The levels of 17 organochlorine pesticides residues (OCPs) in surface water and sediments from Tamiraparani river basin, South
India were investigated to evaluate their potential pollution and risk impacts. A total of 96 surface water and sediment samples
at 12 sampling stations were collected along the river in four seasons during 2008–2009. The ΣOCP concentrations in surface
water and sediments were in the range of 0.1 to 79.9 ng l−1 and 0.12 to 3,938.7 ng g−1 dry weight (dw), respectively. Among the OCPs, the levels of dichlorodiphenyltrichloroethanes (DDTs), aldrin, dieldrin, cis-chlordane, trans-chlordane, and mirex were dominant in the sediments. The dominant OCPs in water samples are heptachlor, o,p′-DDE, dieldrin,
o,p′-DDD, and mirex, which show different source of contamination pattern among sampling seasons. The distribution pattern
of DDTs, hexachlorocyclohexane, and other OCPs in the present study shows heterogenic nature of nonpoint source of pollution.
Notable contamination of water and sediment sample that was observed in upstream (S2) 58 ng l−1 and downstream (S11) 1,693 ng g−1 dw explains agricultural and municipal outfalls, whereas frequent damming effect reduces the concentration level in the midstream.
The overall spatial–temporal distribution pattern of ΣOCP residues are illustrated by GIS package. 相似文献
19.
Presence of pesticide residues was studied in rain water during 2002 employing multi residue analysis method by gas liquid
chromatography equipped with ECD and NPD detectors and capillary columns. The presence of pesticide residues in surface aquatic
system triggered the investigation of the presence of pesticides in rain water. A total of 13 pesticides were detected in
rain water samples. Among the different groups of pesticides, organochlorines were present in the range of 0.041–7.060 ppb
with maximum concentration of p,p’-DDT up to 7.060 μg l−1. Synthetic pyrethroids were present ranging from 0.100 to 1.000 μg l−1 and organophosphates in the range of 0.050–4.000 μg l−1 showing maximum contamination with cypermethrin (1.000 μg l−1) and monocrotophos (4.000 μg l−1) of the respective groups. Almost 80% samples showed the residues above MRL of 0.5 ppb fixed for multi residues and on the
basis of single pesticide, 16–50% samples contained residues above the MRL value of 0.1 ppb. 相似文献
20.
Total selenium (Se) and water-soluble Se in soil, and Se in a shallow groundwater were hydrogeochemically researched in an
alluvial fan area in Tsukui, Central Japan. The water-soluble Se was estimated at average level of 2.6 ± 1.2μg Se kg−1 dry soil (± SD, n = 25), showing less than 1% of the total Se (349–508μg Se kg−1 dry soil) in soil. The monthly Se concentration in groundwater was average 2.2μg,L−1, ranging 1.6–2.4μg,L−1 during 2001–2003. The Se in groundwater significantly decreased with increasing groundwater level after rainfall. This result
indicated that Se-bearing water percolated with relatively low Se concentration through the soil layer. According to our prediction
model of linear regression curve on the observation data, Se concentration in the groundwater was estimated to be increasing
with the very low rate of 4.35 × 10−3μg Se L−1,yr−1. The hydrogeochemical research and the result of the prediction model showed that any explosive increase of Se will hardly
occur in this groundwater without an anthropogenic Se contamination. 相似文献