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1.
Residues of organochlorine pesticides in water and suspended particulate matter from the Yangtze River catchment of Wuhan, China 总被引:6,自引:0,他引:6
The residues of 13 organochlorine pesticides (OCPs) in surface water and HCHs and DDTs in suspended particulate matter (SPM)
from rivers and lakes in Yangtze River catchment of Wuhan, China, were investigated. The concentration of total OCPs in surface
water varied from 1.01 to 46.49 ng l−1 (mean 10.55 ng l−1). The levels of total HCHs (ΣHCH) and total DDTs (ΣDDT) in surface water were in the range of 0.55–28.07 ng l−1 and lower than detection limit to 16.71 ng l−1, respectively, which was lower than Chinese standards on the whole. For OCPs residues in SPM, the mean levels varying from
0.20 to 34.72 ng l−1 and 0.46 to 2.72 ng l−1 for ΣHCH and ΣDDT, respectively, which ranked the relatively higher levels among Chinese studied rivers. Results from this
investigation showed that previous excessive usage of technical OCPs was the main reason for the residues of HCHs and DDTs
both in surface water and SPM, although some new sources were likely to occurred in the region. Apart from the OCPs in SPM
originated from upstream in flood season, one of the important sources of OCP residues both in water and SPM in Yangtze River
was supposed to be the inputs of its tributaries. Additionally, in situ water-SPM phase distributions of OCPs indicated that
HCHs tended totransport with water as well as DDTs was prone to combine with SPM in Yangtze River catchment of Wuhan. 相似文献
2.
Wang H He M Lin C Quan X Guo W Yang Z 《Environmental monitoring and assessment》2007,133(1-3):231-242
Surface sediment samples from 12 sites of the three selected rivers in Daliaohe River watershed (Hunhe River, Taizihe River
and Daliaohe River) were analyzed with the objective of establishing sources and hazard of the organochlorinae pesticides
(OCPs) and polychlorinated biphenyl (PCBs) in surface sediments. The total concentrations of OCPs varied from 3.06 to 23.24
ng g−1. ∑HCH (α-HCH, β-HCH, δ-HCH, γ-HCH), ∑DDT (p, p′-DDE, p, p′-DDD, o, p′-DDT, p, p′-DDT) and ∑Cyclodiene (Heptachlor, Aldrin,
Heptachlor epoxide, Dieldrin, Endrin) ranged from 1.86 to 21.48, 0.5 to 2.81 and 0.56 to 1.53 ng g−1, respectively. Results of OCPs also illustrate that the most dominant pollutants among the OCPs was ∑HCH, and γ-HCH was the
most dominant isomer in HCH, which was evidence of recent input of lindane. It possibly came from the runoff of polluted soils
and long-scale transportation. Total PCB concentrations ranged between 1.88 and 16.88 ng g−1. The peak concentrations of PCBs were found in sediments from station T5 and D3, which are in the vicinity of industrial
areas and ferry, respectively. These data show a moderate level of OCPs and PCBs contaminations compared to that in other
countries. 相似文献
3.
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
4.
Achanthobrama marmid (thorn-bream) (n:24), Chondrostoma regium (nose-carp) (n:33) and Silurus glanis (wels) (n:21), and Cyprinus carpio (carp) (n:30) were collected from Sır Dam Lake in Kahramanmaraş Province. The iron (Fe), manganese (Mn), cobalt (Co), nickel
(Ni), and lead (Pb) levels were determined in the total of 108 fish samples by Atomic Absorption Spectrophotometer. The concentrations
of heavy metals were expressed as mg kg−1 wet weight of tissue. The mean Fe and Mn levels of muscle and gill of C. carpio were 0.8–5.71 and 0.30–1.96, respectively. The mean of the Fe and Mn levels of muscle and gill of A. marmid were 1.22, 5.07 and 0.38, 0.85 mg kg−1, respectively. The ranges of mean concentrations of Fe and Mn levels in muscle and gill of C. regium were 0.91, 5.61 and 0.27, 3.42 mg kg−1, respectively. The mean value of Fe in S. glanis gill was 1.03, which of Mn was 0.17 mg kg−1. Fe, Mn, Co, Ni, and Pb were not detected in the muscle of S. glanis. The mean values for Co in muscle of thorn-bream, carp, and nose-carp were 0.005, 0.01, 0.0 mg kg−1, respectively. Nickel values in the muscle were ranged between 0.38 and 1.93 in thorn-bream, 0.06 and 1.34 in carp, 0.14
and 1.89 in nose-carp, in that order. The mean Pb levels of muscle and gill of A. marmid were 0.14 and 0.29 mg kg−1, respectively. The mean values of Pb concentration of muscle and gill for C. carpio were 0.13 and 0.50 mg kg−1, respectively. In C. regium mean values for Pb in muscle and gill were 0.06 and 0.06 mg kg−1, respectively. The mean value of Pb in S. glanis gill was 0.42, ranged between 0.0–0.92 mg kg−1. 相似文献
5.
Determination of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey 总被引:1,自引:0,他引:1
The concentrations of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey were investigated. Soil samples
were collected at distances of 0, 25 and 50 m from the roadside. The concentrations of lead, cadmium and copper were measured
by Flame Atomic Absorption Spectrophotometry (FAAS). A slotted tube atom trap (STAT) was used to increase the sensitivity
of lead and cadmium in FAAS. Lead concentrations in soil samples varied from 1.3 to 45 mg kg−1 while mean lead levels in plants ranged from120 ng g−1 for grape in point-4 to 866 ng g−1 for apple leaves in point-2. Lead analyses showed that there was a considerable contamination in both soil and plants affected
from traffic intensity. Overall level of Cd in soil samples lies between 78 and 527 ng/g while cadmium concentration in different
vegetations varied in the range of 0.8–98.0 ng g−1. Concentrations of copper in soil and plant samples were found in the range of 11.1–27.9 mg kg−1 for soil and 0.8–5.6 mg kg−1 for plants. Standard reference material (SRM) was used to find the accuracy of the results of soil analyses. 相似文献
6.
The levels and composition of persistent organic pollutants in alluvial agriculture soils affected by flooding 总被引:1,自引:0,他引:1
Barbara Maliszewska-Kordybach Bozena Smreczak Agnieszka Klimkowicz-Pawlas 《Environmental monitoring and assessment》2013,185(12):9935-9948
The concentrations and composition of persistent organic pollutants (POPs) were determined in alluvial soils subjected to heavy flooding in a rural region of Poland. Soil samples (n?=?30) were collected from the upper soil layer from a 70-km2 area. Chemical determinations included basic physicochemical properties and the contents of polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and polycyclic aromatic hydrocarbons (PAHs, 16 compounds). The median concentrations of Σ7PCB (PCB28?+?PCB52?+?PCB101?+?PCB118?+?PCB138?+?PCB153?+?PCB180), Σ3HCH (α-HCH?+?β-HCH?+?γ-HCH) and Σ3pp′(DDT?+?DDE?+?DDD) were 1.60?±?1.03, 0.22?±?0.13 and 25.18?±?82.70 μg kg?1, respectively. The median concentrations of the most abundant PAHs, phenanthrene, fluoranthene, pyrene, benzo[b]fluoranthene and benzo[a]pyrene were 50?±?37, 38?±?27, 29?±?30, 45?±?36 and 24?±?22 μg kg?1, respectively. Compared with elsewhere in the world, the overall level of contamination with POPs was low and similar to the levels in agricultural soils from neighbouring countries, except for benzo[a]pyrene and DDT. There was no evidence that flooding affected the levels of POPs in the studied soils. The patterns observed for PAHs and PCBs indicate that atmospheric deposition is the most important long-term source of these contaminants. DDTs were the dominant organochlorine pesticides (up to 99 %), and the contribution of the parent pp′ isomer was up to 50 % of the ΣDDT, which indicates the advantage of aged contamination. A high pp′DDE/pp′DDD ratio suggests the prevalence of aerobic transformations of parent DDT. Dominance of the γ isomer in the HCHs implies historical use of lindane in the area. The effect of soil properties on the POP concentrations was rather weak, although statistically significant links with the content of the <0.02-mm fraction, Ctotal or Ntotal were observed for some individual compounds in the PCB group. 相似文献
7.
Animal products like milk and meat are often found to be contaminated with residues of persistent pesticides and other toxic substances. The major source of entry of these compounds to animal body is the contaminated feed and fodder. So, unless the residues are managed at this stage, it is very difficult to prevent contamination in milk and meat. Therefore, the status of residue level of most persistent organochlorinated pesticides (OCP) in feed and fodder should be monitored regularly. The frequency of occurrence and contamination levels of OCP residues in different kinds of animal concentrate feed and straw samples collected from Bundelkhand region of India were determined. Out of 533 total samples, 301 i.e. 56.47% samples were positive containing residues of different OCPs like hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) complex, endosulfan and dicofol. Among different HCH isomers, the mean concentration of ??-HCH was highest, and total HCH varied from 0.01 to 0.306 mg kg???1. In case of DDT complex, i.e. DDD, DDE and DDT, the concentration ranged between 0.016 and 0.118 mg kg???1 and the pp| isomers were more frequently encountered than their op| counterparts. Endosulfan was also found in some samples in concentration ranging from 0.009 to 0.237 mg/kg, but dicofol could be recorded in very few samples. Although feed samples were found to contain OC residues, after comparing their levels in positive samples with the limiting values of respective pesticides, only very few were found to exceed the threshold level. Otherwise, they were mostly within safe limits. 相似文献
8.
The Odiel salt marshes (Marismas del Odiel) are an important nature area declared a Biosphere Reserve, but they are greatly
affected by pollution from the Odiel River. Surface sediments from this area were analysed using the latest version of the
BCR sequential extraction procedure to determine the fractionation of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn among four geochemical
phases (acid-soluble, reducible, oxidisable and residual). The total content of each of the metals and As was also determined.
The results showed high concentrations of As, Cd, Cu, Pb and Zn, with maximums of 791 mg kg−1 of As, 8.5 mg kg−1 of Cd, 2,740 mg kg−1 of Cu, 1,580 mg kg−1 of Pb and 3,920 mg kg−1 of Zn. The concentrations of Cr, Mn and Ni were low since there are no sources of pollution by them in the area. A comparison
of the metal and As levels with the sediment quality guidelines showed that the pollution is sufficient to produce noxious
effects in aquatic organisms in most of the Odiel salt marshes. Based on the chemical distribution of the elements, it was
found that Cd and Zn were the most mobile (i.e., elements that can pass easily into the water under changing environmental
conditions). However, Cr, Fe, Ni and As were present in the greatest percentages in the residual fraction, which implies that
these elements are strongly linked to the sediments. 相似文献
9.
The activity concentrations of soil samples collected from thirty different locations of Malwa region of Punjab were determined
by using HPGe detector based on high-resolution gamma spectrometry system. The range of activity concentrations of 226Ra, 232Th and 40K in the soil from the studied areas varies from 18.37 Bq kg−1 (Sangrur) to 53.11 Bq kg−1 (Sitoguno), 57.28 Bq kg−1 (Dhanola) to 148.28 Bq kg−1 (Sitoguno) and 211.13 Bq kg−1 (Sunam) to 413.27 Bq kg−1 (Virk Khera) with overall mean values of 35 Bq kg−1, 80 Bq kg−1and 317 Bq kg−1 respectively. The absorbed dose rate calculated from activity concentration of 226Ra, 232Th and 40K ranges between 8.47 and 24.48, 35.68 and 92.38, and 8.74 and 17.11 nGy h−1, respectively. The total absorbed dose in the study area ranges from 58.08 nGy h−1 to 130.85 nGy h−1 with an average value of 79.11 nGy h−1. The calculated values of external hazard index (Hex) for the soil samples of the study area range from 0.35 to 0.79. Since these values are lower than unity, therefore, according
to the Radiation Protection 112 (European Commission. Radiation Protection 112 1999) report, soil from these regions is safe and can be used as a construction material without posing any significant radiological
threat to population. 相似文献
10.
Wetherbee GA Gay DA Brunette RC Sweet CW 《Environmental monitoring and assessment》2007,131(1-3):49-69
The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of
mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification
of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in
two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury
concentration are approximately 11% of the median mercury concentration for all valid 1999–2004 MDN data. Median absolute
differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15%
of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between
NADP/MDN measurements by ±2 ng·l−1 and ±2 μg·m−2·year−1, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively. 相似文献
11.
Persistent Organochlorine Pesticide Residues in Soil and Surface Water of Northern Indo-Gangetic Alluvial Plains 总被引:1,自引:0,他引:1
This study reports the concentration levels and distribution pattern of the organochlorine pesticide (OCPs) residues in the
soil and surface water samples collected from the northern Indo-Gangetic alluvial plains. A total of 31 soil and 23 surface
water samples were collected from the study region in Unnao district covering an area of 2150 km2 and analyzed for aldrin, dieldrin, endrin, HCB, HCH isomers, DDT isomers/metabolites, endosulfan isomers (α and β), endosulfan
sulfate, heptachlor and its metabolites, α-chlordane, γ-chlordane and methoxychlor. In both the soil and surface water samples
β- and δ-isomers of HCH were detected most frequently, whereas, methoxychlor was the least detected pesticide. The results
showed contamination of soil and surface water of the region with several persistent organic pesticides. The total OCPs level
ranged from 0.36–104.50 ng g–1 and 2.63–3.72 μg L–1 in soil and surface water samples, respectively. 相似文献
12.
Robert E. Foley 《Environmental monitoring and assessment》1992,21(1):37-48
Thirteen organochlorine compounds were detected in fat and breast muscle tissues of Canada goose and five species of ducks that were shot by sportsman in New York. Residues of DDE and PCB occurred most frequently and were positively identified along with DDT, heptachlor epoxide, trans-nonachlor, and hexachlorobenzene. Compounds that were detected but not positively confirmed by mass spectrometry were dieldrin, mirex, heptachlor, chlordane, oxychlordane, and endrin. Wood duck (Aix sponsa) and Canada goose (Branta canadensis) had significantly lower levels of DDE and PCB than black duck (Anas rubripes), mallard (Anas platyrhynchos), scaup (Athya sp.), and bufflehead (Bucephala albeola). Birds collected from Long Island and the Hudson River-Lake Champlain corridor carried highest concentrations. 相似文献
13.
One hundred forty seven samples of bovine milk were collected from 14 districts of Haryana, India during December 1998–February
1999 and analysed for the presence of organochlorine pesticide (OCPs) residues. ∑HCH, ∑DDT, ∑endosulfan and aldrin were detected
in 100%, 97%, 43% and 12% samples and with mean values of 0.0292, 0.0367, 0.0022 and 0.0036 μg/ml, respectively. Eight percent
samples exceeded the maximum residue limit (MRL) of 0.10 mg/kg as recommended by WHO for ∑HCH, 4% samples of 0.05 mg/kg for
α-HCH, 5% samples of 0.01 mg/kg for γ-HCH, 26% samples of 0.02 mg/kg for β-HCH as recommended by PFAA and 24% samples of 0.05 mg/kg
as recommended by FAO for ∑DDT. Concentrations of β-HCH and p,p′-DDE were more as compared to other isomers and metabolites
of HCH and DDT. 相似文献
14.
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
15.
Assessment of water pollution in different bleaching based paper manufacturing and textile dyeing industries in India 总被引:3,自引:0,他引:3
Paper industries using different raw materials such as hard wood, bamboo, baggase, rice-straw and waste papers and bleaching
chemicals like chlorine, hypochlorite, chlorine dioxide, hydrogen peroxide, sulphite and oxygen were studied to estimate organic
pollution load and Adsorbable Organic Halides (AOX) per ton of production. The hard wood based paper industries generate higher
Chemical Oxygen Demand (COD) loads (105–182 kg t−1) and Biochemical Oxygen Demand (BOD) loads (32.0–72 kg t−1) compared to the agro and waste paper based industrial effluents. The bleaching sequences such as C–EP–H–H, C–E–H–H, C–E–Do–D1
and O–Do–EOP–D1 are adopted in the paper industries and the molecular elemental chlorine free bleaching sequence discharges
low AOX in the effluent. The range of AOX concentration in the final effluent from the paper industries was 0.08–0.99 kg t−1 of production. Water consumption was in the range of 100–130 m3 t−1 of paper production for wood based industries and 30–50 m3 for the waste paper based industries. Paper machine effluents are partially recycled after treatment and pulp mill black
liquor are subject to chemical recovery after evaporation to reduce the water consumption and the total pollution loads. Hypochlorite
bleaching units of textile bleaching processes generate more AOX (17.2–18.3 mg l−1) and are consuming more water (45–80 l kg−1) whereas alkali peroxide bleaching hardly generates the AOX in the effluents and water consumption was also comparatively
less (40 l kg−1 of yarn/cloth). 相似文献
16.
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
17.
Determination and Assessment of HCHs and DDTs Residues in Sediments from Lake Dongting, China 总被引:5,自引:0,他引:5
The contamination of organochlorine pesticides hexachlorocyclohexane (HCH) and Dichlorodiphenyltrichloroethane (DDT) and their
eco-environmental assessment in surface sediments from Lake Dongting, the second-largest freshwater lake in China, were studied.
Concentrations of ∑HCH (=α-HCH + β-HCH + γ-HCH +δ-HCH) were 0.21--9.59 ng/g dry weight and those of ∑ DDT = p,p'-DDD+p,p'-DDE+o,p'-DDT+p,p'-DDT)
ranged from under detectable limit to 10.15 ng/g dry weight. The ratios of α-HCH to γ-HCH were above 7 at most sampling sites
while no or a small amount of β-HCH were found at all sites, suggesting the degradation of HCH used in the history and possibly
current use of HCH in the region. The low ratios (below 2.0 in most cases) of (p,p'-DDE+p,p'-DDD) to p,p'-DDT and high levels
of individual isomers of DDT at some sites also suggested that there have still been fresh inputs of DDT into Lake Dongting.
Through the comparison between concentrations of HCH and DDT residues in sediments of Lake Dongting and those from other places
in China and also from the results of our eco-environmental assessment, it can be concluded that Lake Dongting is the water
body with high contamination of both HCH and DDT in its sediments in comparison with other water bodies in China. 相似文献
18.
Residues and ecological risks of organochlorine pesticides in Lake Small Baiyangdian, North China 总被引:3,自引:0,他引:3
Yan Wang Wen-Jing Wu Wei He Ning Qin Qi-Shuang He Fu-Liu Xu 《Environmental monitoring and assessment》2013,185(1):917-929
The levels of hexachlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) in the water, suspended particulate matter (SPM), and sediments from Lake Small Baiyangdian were measured by gas chromatograph with a 63Ni microelectron capture detector. The residual levels of the total HCHs in the water, SPM, and sediments were 1.59?±?2.24 ng L?1, 25.42?±?1.72 ng g?1 dw (dry weight), and 0.86?±?1.44 ng g?1 dw, respectively. DDTs were not detected in the water samples. The concentrations of total DDTs were 158.79?±?1.67 ng g?1 dw in SPM and 0.46?±?1.97 ng g?1 dw in the sediments. Compared to other areas in China and abroad, the levels of residual HCH and DDT were relatively low in the water and sediments, but they were moderate to high in the SPM. Organic carbon partition coefficient values for HCH in this study were higher than previously published values and may reflect new input in this area. The residual HCHs in this area could be derived from a mixture of technical HCH and lindane because ongoing lindane use may be occurring. DDT in the majority of the study area was primarily attributed to historical discharge, but some regions may be receiving new input. The ecological risks of γ-HCH in the water were very low according to species sensitivity distribution models. The concentrations of HCH and DDT in the sediments from the study area did not exceed the sediment quality guidelines, which indicate little risk for benthic organisms. 相似文献
19.
Advances in research on pollution of organic pesticides (OPs) in surface water, pollution survey and risk assessments of organochlorine
pesticides (OCPs) and organophosphorus pesticides (OPPs) of surface water in Hangzhou are conducted. Total concentrations
of dichloro-diphenyl-trichloroethane (DDT) and hexachloride-benzene (HCH) in surface water were observed to be 0–0.270 μg/L
and 0–0.00625 μg/L respectively. DDE, as a metabolite of DDT and many species of OPPS were determined in some samples of surface water. Parathion, the main pollutant among OPPs in surface water of Hangzhou,
was observed to be 0–0.445 μg/L. Based on these experimental results, health risk assessments on the organic pollution are
developed. It is observed that the total risk “R
T” at present time of surface water in Hangzhou is mainly contributed by organophosphorus pesticides, especially Parathion;
HCH and DDT are not the main contaminants; on the contrary, organophosphorous pesticides, especially Parathion, must be of
concern at the present time. 相似文献
20.
The chemical forms and ecological risk of As were characterized in the sediment of the Daliao River System (DRS), which has
been affected by long-term intensive industrial, urban, and agricultural activities. Twenty-seven samples of surface sediment
were collected and analyzed for total As content and that of its chemical forms. The results indicated that the average total
As content in the sediment was 9.83 mg kg − 1 but that the levels ranged from 1.57 to 83.09 mg kg − 1. At the sites near cities, mining sites, and the estuary of the DRS, it is likely that adverse effects on aquatic organisms
occur, due to As levels in the sediment that are often higher than the threshold effect level and occasionally higher than
the probable effect level. A selectively sequential extraction indicated that the majority of As in the sediment was bound
to Fe oxides (62.1%), with moderate proportions of residual As (19.8%), specifically adsorbed As (17.9%), and a low proportion
of non-specifically adsorbed As (1.1%). In addition, the content of Fe in the sediment was positively and significantly correlated
with the contents of amorphous and crystalline Fe oxide-bound As, confirming the crucial role of Fe oxides in immobilizing
high amounts of As in superficial environments. The average molar ratio of As to Fe was 1.18 × 10 − 4 in the surface sediment of the DRS, similar to that of natural Fe oxides, but much lower than that of synthesized Schwertmannite.
Therefore, the release of As under reduced and low pH conditions can cause serious problems for water resources and for living
organisms. 相似文献