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1.
Rutenko AN Borisov SV Gritsenko AV Jenkerson MR 《Environmental monitoring and assessment》2007,134(1-3):21-44
A 3D marine seismic survey of the Odoptu license area off northeastern Sakhalin Island, Russia, was conducted by DalMorNefteGeofizika
(DMNG) on behalf of Exxon Neftegas Limited and the Sakhalin-1 consortium during mid-August through early September 2001. The
key environmental issue identified in an environmental impact assessment was protection of the critically endangered western
gray whale (Eschrichtius robustus), which spends the summer–fall open water period feeding off northeast Sakhalin Island in close proximity to the seismic
survey area. Seismic mitigation and monitoring guidelines and recommendations were developed and implemented to reduce impacts
on the feeding activity of western gray whales. Results of the acoustic monitoring program indicated that the noise monitoring
and mitigation program was successful in reducing exposure of feeding western gray whales to seismic noise. 相似文献
2.
Yazvenko SB McDonald TL Blokhin SA Johnson SR Meier SK Melton HR Newcomer MW Nielson RM Vladimirov VL Wainwright PW 《Environmental monitoring and assessment》2007,134(1-3):45-73
Exxon Neftegas Limited, operator of the Sakhalin-1 consortium, is developing oil and gas reserves on the continental shelf
off northeast Sakhalin Island, Russia. DalMorNefteGeofizika (DMNG), on behalf of the Sakhalin-1 consortium, conducted a 3-D
seismic survey of the Odoptu license area during 17 August–9 September 2001. A portion of the primary known feeding area of
the endangered western gray whale (Eschrichtius robustus) is located adjacent to the seismic block. The data presented here were collected as part of daily monitoring to determine
if there was any measurable effect of the seismic survey on the distribution and abundance of western gray whales. Mitigation
and monitoring program included aerial surveys conducted between 19 July and 19 November using the methodology outlined by
the Southern California High Energy Seismic Survey team (HESS). These surveys provided documentation of the distribution,
abundance and bottom feeding activity of western gray whales in relation to seismic survey sounds. From an operations perspective,
the aerial surveys provided near real-time data on the location of whales in and outside the feeding area, and documented
whether whales were displaced out of an area normally used as feeding habitat. The objectives of this study were to assess
(a) temporal changes in the distribution and abundance of gray whales in relation to seismic survey, and (b) the influence
of seismic survey, environmental factors, and other variables on the distribution and abundance of gray whales within their
preferred feeding area adjacent to Piltun Bay. Multiple regression analysis revealed a limited redistribution of gray whales
southward within the Piltun feeding area when the seismic survey was fully operational. A total of five environmental and
other variables unrelated to seismic survey (date and proxies of depth, sea state and visibility) and one seismic survey-related
variable (seg3d, i.e., received sound energy accumulated over 3 days) had statistically significant effects on the distribution and abundance
of gray whales. The distribution of two to four gray whales observed on the surface (i.e., about five to ten whales in total)
has likely been affected by the seismic survey. However, the total number of gray whales observed within the Piltun feeding
area remained stable during the seismic survey.
M. W. Newcomer, Deceased. 相似文献
3.
The introduction of anthropogenic sounds into the marine environment can impact some marine mammals. Impacts can be greatly
reduced if appropriate mitigation measures and monitoring are implemented. This paper concerns such measures undertaken by
Exxon Neftegas Limited, as operator of the Sakhalin-1 Consortium, during the Odoptu 3-D seismic survey conducted during 17
August–9 September 2001. The key environmental issue was protection of the critically endangered western gray whale (Eschrichtius robustus), which feeds in summer and fall primarily in the Piltun feeding area off northeast Sakhalin Island. Existing mitigation
and monitoring practices for seismic surveys in other jurisdictions were evaluated to identify best practices for reducing
impacts on feeding activity by western gray whales. Two buffer zones were established to protect whales from physical injury
or undue disturbance during feeding. A 1 km buffer protected all whales from exposure to levels of sound energy potentially
capable of producing physical injury. A 4–5 km buffer was established to avoid displacing western gray whales from feeding
areas. Trained Marine Mammal Observers (MMOs) on the seismic ship Nordic Explorer had the authority to shut down the air guns if whales were sighted within these buffers.
Additional mitigation measures were also incorporated: Temporal mitigation was provided by rescheduling the program from June–August
to August–September to avoid interference with spring arrival of migrating gray whales. The survey area was reduced by 19%
to avoid certain waters <20 m deep where feeding whales concentrated and where seismic acquisition was a lower priority. The
number of air guns and total volume of the air guns were reduced by about half (from 28 to 14 air guns and from 3,390 in3 to 1,640 in3) relative to initial plans. “Ramp-up” (=“soft-start”) procedures were implemented.
Monitoring activities were conducted as needed to implement some mitigation measures, and to assess residual impacts. Aerial
and vessel-based surveys determined the distribution of whales before, during and after the seismic survey. Daily aerial reconnaissance
helped verify whale-free areas and select the sequence of seismic lines to be surveyed. A scout vessel with MMOs aboard was
positioned 4 km shoreward of the active seismic vessel to provide better visual coverage of the 4–5 km buffer and to help
define the inshore edge of the 4–5 km buffer. A second scout vessel remained near the seismic vessel. Shore-based observers
determined whale numbers, distribution, and behavior during and after the seismic survey. Acoustic monitoring documented received
sound levels near and in the main whale feeding area.
Statistical analyses of aerial survey data indicated that about 5–10 gray whales moved away from waters near (inshore of)
the seismic survey during seismic operations. They shifted into the core gray whale feeding area farther south, and the proportion
of gray whales observed feeding did not change over the study period.
Five shutdowns of the air guns were invoked for gray whales seen within or near the buffer. A previously unknown gray whale
feeding area (the Offshore feeding area) was discovered south and offshore from the nearshore Piltun feeding area. The Offshore
area has subsequently been shown to be used by feeding gray whales during several years when no anthropogenic activity occurred
near the Piltun feeding area.
Shore-based counts indicated that whales continued to feed inshore of the Odoptu block throughout the seismic survey, with
no significant correlation between gray whale abundance and seismic activity. Average values of most behavioral parameters
were similar to those without seismic surveys. Univariate analysis showed no correlation between seismic sound levels and
any behavioral parameter. Multiple regression analyses indicated that, after allowance for environmental covariates, 5 of
11 behavioral parameters were statistically correlated with estimated seismic survey-related variables; 6 of 11 behavioral
parameters were not statistically correlated with seismic survey-related variables. Behavioral parameters that were correlated
with seismic variables were transient and within the range of variation attributable to environmental effects.
Acoustic monitoring determined that the 4–5 km buffer zone, in conjunction with reduction of the air gun array to 14 guns
and 1,640 in3, was effective in limiting sound exposure. Within the Piltun feeding area, these mitigation measures were designed to insure
that western gray whales were not exposed to received levels exceeding the 163 dB re 1 μPa (rms) threshold.
This was among the most complex and intensive mitigation programs ever conducted for any marine mammal. It provided valuable
new information about underwater sounds and gray whale responses during a nearshore seismic program that will be useful in
planning future work. Overall, the efforts in 2001 were successful in reducing impacts to levels tolerable by western gray
whales. Research in 2002–2005 suggested no biologically significant or population-level impacts of the 2001 seismic survey.
M. W. Newcomer is deceased. 相似文献
4.
A geophysical seismic survey was conducted in the summer of 2001 off the northeastern coast of Sakhalin Island, Russia. The
area of seismic exploration was immediately adjacent to the Piltun feeding grounds of the endangered western gray whale (Eschrichtius robustus). This study investigates relative abundance, behavior, and movement patterns of gray whales in relation to occurrence and
proximity to the seismic survey by employing scan sampling, focal follow, and theodolite tracking methodologies. These data
were analyzed in relation to temporal, environmental, and seismic related variables to evaluate potential disturbance reactions
of gray whales to the seismic survey. The relative numbers of whales and pods recorded from five shore-based stations were
not significantly different during periods when seismic surveys were occurring compared to periods when no seismic surveys
were occurring and to the post-seismic period. Univariate analyses indicated no significant statistical correlation between
seismic survey variables and any of the eleven movement and behavior variables. Multiple regression analyses indicated that,
after accounting for temporal and environmental variables, 6 of 11 movement and behavior variables (linearity, acceleration,
mean direction, blows per surfacing, and surface-dive blow rate) were not significantly associated with seismic survey variables,
and 5 of 11 variables (leg speed, reorientation rate, distance-from-shore, blow interval, and dive time) were significantly
associated with seismic survey variables. In summary, after accounting for environmental variables, no correlation was found
between seismic survey variables and the linearity of whale movements, changes in whale swimming speed between theodolite
fixes, mean direction of whale movement, mean number of whale exhalations per minute at the surface, mean time at the surface,
and mean number of exhalations per minute during a whales surface-to-dive cycle. In contrast, at higher received sound energy
exposure levels, whales traveled faster, changed directions of movement less, were recorded further from shore, and stayed
under water longer between respirations. 相似文献
5.
Distribution and abundance of western gray whales off northeastern Sakhalin Island, Russia, 2001’003
Meier SK Yazvenko SB Blokhin SA Wainwright P Maminov MK Yakovlev YM Newcomer MW 《Environmental monitoring and assessment》2007,134(1-3):107-136
In 2001–2003, >60,000 km of aerial surveys and 7,700 km of vessel surveys were conducted during June to November when critically
endangered Korean–Okhotsk or western gray whales (Eschrichtius robustus) were present off the northeast coast of Sakhalin Island, Russia. Results of surveys in all years indicated gray whales occurred
in predominantly two areas, (1) adjacent to Piltun Bay, and (2) offshore from Chayvo Bay, hereafter referred to as the Piltun
and offshore feeding areas. In the Piltun feeding area, the majority of whales were observed in waters shallower than 20 m
and were distributed from several hundred meters to ∼ 5 km from the shoreline. In the offshore feeding area during all years,
the distribution of gray whales extended from southwest to northeast in waters 30–65 m in depth. During all years, the distribution
and abundance of whales changed in both the Piltun and offshore feeding areas, and both north–south and inshore–offshore movements
were documented within and between feeding seasons. The discovery of a significant number of whales feeding in the offshore
area each year was a substantial finding of this study and raises questions regarding western gray whale abundance and population
levels, feeding behavior and ecology, and individual site-fidelity. Fluctuations in the number of whales observed within the
Piltun and offshore feeding areas and few sightings outside of these two areas indicate that gray whales move between the
Piltun and offshore feeding areas during their summer–fall feeding season. Seasonal shifts in the distribution and abundance
of gray whales between and within both the Piltun and offshore feeding areas are thought, in part, to be a response to seasonal
changes in the distribution and abundance of prey. However, the mechanism driving the movements of whales along the northeast
coast of Sakhalin Island is likely very complex and influenced by a multitude of factors.
*Deceased 相似文献
6.
An enhanced dual coil 2,4-dinitrophenylhydrazine (DNPH) derivatization method (dual coil/DNPH) allowed the quantitative determination
of formaldehyde (HCHO) in ambient air. In this method, traceable HCHO was collected using a coil sampler connected in series
and lacking a long sampling tube. It was then analyzed using liquid chromatography followed by UV detection of the DNPH derivatives.
The method is based on the reaction of formaldehyde with DNPH to produce 2,4-dinitrophenylhydrazone. The detection limits
(3σ) were 0.10–0.40 ppbv with a precision ranging from 0.84 to 4.09% RSD. The results of dual coil/DNPH and conventional DNPH
cartridge methods were generally well correlated: HCHO (dual coil/DNPH) = 0.97 (±0.13) vs. HCHO (DNPH Cartridge) + 0.33 (±0.33),
r = 0.82. The dual coil/DNPH method was used to measure gaseous HCHO in the atmosphere of Metropolitan Seoul during the summer
2000 and 2001, and in Gwangju during the fall of 2001 and 2002. The daytime mean concentration of HCHO was 4.52 (±5.69) and
3.21 (±1.27) ppbv in Metropolitan Seoul for 10–12 August 2000 and 29–31 May 2001, respectively, and 1.73 (±0.98), 3.04 (±2.25),
2.70 (±1.70), and 2.01 (±2.28) ppbv in Gwangju City during 22–27 September 2001, 17–24 October 2001, 9–13 October 2002, and
28 October to 2 November 2002, respectively. The HCHO in Seoul from 10–12 August 2000 was mainly the result of photochemical
processes, while direct emissions from vehicles and long-range transport of air from China contributed during 29–31 May 2001.
During 22–27 September 2001, 17–24 October 2001, and 9–13 October 2002 in Gwangju, the HCHO came primarily from photochemical
processes, although some air affected by biomass burning admixed in the late afternoon. The increase in the HCHO concentration
on 20 October 2001 and from 28 October to 2 November 2002 was attributed mainly to direct emissions from biomass burning in
farmland near the measurement site. 相似文献
7.
This study deals with numerical simulation of flow fields and dispersion of model passive admixtures in the planetary boundary
layer in a 10 × 10 km square area, centered on the Czech Republic’s Temelín Nuclear Power Plant. Numerical calculations of
three-dimensional flow fields with eight basic wind directions given for the inlet boundary of the computational domain are
performed using the FLUENT CFD code with the standard k – ε turbulence model. The resultant modeling of the flow fields provides information as to probable local directions and velocities
of flow vectors on a horizontal scale of 100 m, which are consistent with the data given for the boundaries of the calculation
area in the framework of a scale of 10 km. The modeled flow fields generate the input data for related Lagrangian simulation
of the ground concentration and deposition fields of passive particles assumedly emitted at the site of the Temelín plant.
Simulated plumes describe eight cases of potential ground-level distribution of model passive admixtures in the area. 相似文献
8.
Delta-aminolevulinate dehydratase (ALAD) activity has been used in prokaryotes and eukaryotes as a biomarker for environmental
lead (Pb) exposure and toxicity. Microorganisms are sensitive indicators of toxicity at the fundamental level of ecological
organization, but bacterial biomarker studies are focused on the Pseudomonas strains in Group I and E coli. The objectives of the present work were to determine if Burkholderia gladioli belonging to group II, due to its 16SrRNA similarity, can be used as biomarker in metal contamination and compare its possible
usage with Pseudomonas aeruginosa and Citrobacter freundii (previously known as Esherichia freundii) and Bacterium freundii which are classified in Group I. In this study, ALAD activity in an environmental strains of Burkholderia gladioli, Pseudomonas aeruginosa, Citrobacter freundii were investigated to evaluate potential inhibition by Pb and other toxic metals. When the ALAD activity of Burkholderia gladioli was tested, Co and Pb decreased activity by 27 and 71%, respectively. In addition to these findings, Zn increased the activity
up to 26%. These effects were found to be statistically meaningful (p < 0.05). It was determined that the increase of lead concentration inhibites the ALAD activity at each of the three strains.
There was a statistically significant dose–response relationship between ALAD activity in cells of Burkholderia gladioli and Pb (Pearson correlation coefficent = −0.665; r
2 = 0.665, and p < 0.001). The strongest ALAD inhibition which was measured was 90% at Burkholderia gladioli when protein extracts were incubated with 750 μM of Pb. The relationship between Pb and ALAD activity was statistically described
by [ALAD Activity] = 0.476−0.000597 × [Pb]. According to the obtained results, we suggest that the ALAD of Burkholderia gladioli can be used as a biomarker for lead contamination in the environment. 相似文献
9.
Bulgaroni V Rovedatti MG Sabino G Magnarelli G 《Environmental monitoring and assessment》2012,184(5):3307-3314
A pilot study was conducted to evaluate the usefulness of salivary cholinesterase and carboxylesterase as biomarkers of exposure
to environmental organophosphate pesticides. Ninety samples were obtained from women and 62 samples from their preschool-aged
children who live near an agricultural area of the Upper Valley of the Negro River (Patagonia, Argentina) where pesticides
are applied 6 months a year. Each participant donated two samples under similar conditions: one in the pre-exposure period
and another during the pulverization period. Demographic information, potential confounders, and risk behaviors were registered.
Active or passive smoking had no effect on these enzyme activities in either group. During the pulverization period, cholinesterase
activity was not detectable in 76% of the children's samples and 23% of the mothers' samples. Comparing samples collected
during the pulverization period with respect to the pre-pulverization period, the average mother and child cholinesterase
activity decreased by 65.7% (p < 0.001) and 85.8% (p < 0.001), respectively. Also, mother and child carboxylesterase activity decreased by 27.5% (p < 0.001) and 41.9% (p < 0.01), respectively. Child carboxylesterase activity in the pulverization period was associated to the habit of eating
dust outdoors (p < 0.01). The most frequent inhibition levels observed for cholinesterase and carboxylesterase activity were between 70–100%
and 0–29%, respectively, in both groups studied. This shows that at the same level of exposure, cholinesterase was more sensitive
to inhibition than carboxylesterase. Therefore, carboxylesterase might more properly reflect the degree of environmental organophosphate
exposure and may have potential as a novel tool for biomonitoring. 相似文献
10.
Shihe Fan Igor Burstyn Ambikaipakan Senthilselvan 《Environmental Modeling and Assessment》2010,15(2):137-146
The provinces of Saskatchewan, Alberta, and British Columbia are major oil- and gas-producing regions in western Canada. With
increasing oil and gas production activities, there has been a growing concern of the effect of oil and gas industry emissions
on health. Nevertheless, lack of proper tools to estimate the exposure to these emissions has been a hindrance to epidemiological
studies and risk assessment. This paper presents a spatiotemporal modeling approach to estimating ambient sulfur dioxide (SO2) levels based on environmental monitoring data (N = 10,295), which were collected at rural sites (591 per month on average) of this region from June 1, 2001 to May 31, 2002.
Based on the model, illustrative maps consistently revealed high and low SO2 concentration sub-regions. The sub-regions with elevated SO2 concentrations had increased levels during the winter months from December 2001 to March 2002 and then decreased during the
spring of 2002. This statistical modeling approach may help researchers estimate the SO2 levels within the study area for their epidemiological studies or risk assessment. 相似文献
11.
Atmospheric surface aerosol radiative forcing (SARF) ΔF, forcing efficiency ΔFe and fractional forcing efficiency ΔFFe evaluated from cloud-screened narrowband spectral and thermal-offset-corrected radiometric observations during the Asia dust
outbreak episodes in Gwangju, Republic of Korea are reported in this study. Columnar aerosol optical properties (aerosol optical
depth (AOD), τ
aλ, Angstrom exponent α, mass concentration of fine and coarse mode particles) were also reported for the station between January
2000 and May 2001 consisting of 211cloud-free days. Results indicate that majority of the AOD were within the range 0.25–0.45
while some high aerosol events in which AODs ≥ 0.6 were observed during the severe dust episodes. For example, AOD increases
from annual average value of 0.34 ± 0.13 at 501 nm to values >0.60 during the major dust events of March 27–30 and April 7–9,
2000, respectively. The α
501–870 nm which is often used as a qualitative indicator of aerosol particle size had values ranging from 0.01 to 1.77. The diurnal
forcing efficiency ΔDFe at Gwangju was estimated to be −81.10 ± 5.14 W m −2/τ
501 nm and −47.09 ± 2.20 W m −2/τ
501 nm for the total solar broadband and visible band pass, respectively while the fractional diurnal forcing efficiency ΔFDFe were −15.8 ± 0.64%/τ
501 nm and −22.87 ± 1.13%/τ
501 nm for the same band passes. Analyses of the 5-day air-mass back trajectories were further developed for Gwangju in order to
classify the air-mass and types of aerosol reaching the site during the Asia dust episodes. 相似文献
12.
Pasture selection by livestock is an essential topic for rangeland management, especially in trace element-contaminated soils.
We have studied the composition (nutrients and trace elements) of a grass-based diet from soils affected by a mine spill at
different growth stages (October 2008 to May 2009). A diet based on other plants (mainly Compositae species) was also studied (May 2009) for comparison. Faeces and mane hair of horses feeding on these pastures were also analysed.
Micronutrient (Cu, Fe, Mn and Zn) and potentially toxic trace element (As, Cd, Pb, Tl) concentrations were below the maximum
tolerable levels (MTL) for horses, except for Fe (at early growth of pastures) and Cd (in the diet based on ‘other’ plants).
Values of potential ingestion of Fe by horses were higher than 10 mg kg body weight − 1 day − 1. Cadmium concentrations in some pasture samples (those composed of Compositae species) were higher than 3 mg kg − 1. Potential toxicity of such Cd levels in pastures is uncertain, since a high disparity of criteria about MTL by cattle exists
(between 0.5 and 10 mg kg − 1 diet). Nutrient concentrations were adequate for horses, which could counteract possible harmful effects derived from trace
element ingestion. The analyses of excreta and mane hair point to the low risk of toxicity derived from the consumption of
these contaminated pastures. However, the ingestion of regenerating pastures (autumnal samples) should be avoided due to the
greater risk of ingestion of contaminated soil attached to the plant material. Management of these pastures by grazing requires
periodic monitoring. Special attention should be given to Fe and particularly Cd (non-essential element) which accumulates
in animal organs, where it could provoke uncertain long-term effects. 相似文献
13.
Eutrophication and Sedimentation Patterns in Complete Exploitation of Water Resources Scenarios: An Example from Northwestern Semi-arid Mexico 总被引:1,自引:0,他引:1
Sánchez-Carrillo S Alatorre LC Sánchez-Andrés R Garatuza-Payán J 《Environmental monitoring and assessment》2007,132(1-3):377-393
Water requirements to supply human needs lead water stakeholders to store more water during surplus periods to fulfil the
demand during – not only – scarcity periods. At the reservoirs, mostly those in semi-arid regions, water level then fluctuates
extremely between rises and downward during one single year. Besides of water management implications, changes on physical,
chemical and biological dynamics of these drawdown and refilling are little known yet. This paper shows the results, throughout
a year, on solids, nutrients (N and P), chlorophyll-a, and sedimentation changes on the dynamics, when the former policy was applied in a reservoir from the semi-arid Northwestern
Mexico. Water level sinusoidal trend impinged changes on thermal stratification and mixing, modifying nutrient cycling and
primary producer responses. According to nitrogen and phosphorus concentration as well as chlorophyll-a, reservoir was mesotrophic, becoming hypertrophic during drawdown. Nutrient concentrations were high (1.22 ± 0.70 and 0.14 ± 0.12 mg
P l−1), increasing phosphorus and lowering N:P significantly throughout the study period, although no intensive agricultural, no
urban development, neither industrial activities take place in the watershed. This suggests nutrient recycling complex mechanisms,
including nutrient release from the sediment–water interface as the main nutrient pathway when shallowness, at the same time
as mineralization, increases. Outflows controlled nitrogen and phosphorus availability on the ecosystem while organic matter
depended on river inflows. As on other subtropical aquatic ecosystems, nitrogen limited primary productivity (Spearman correlation
R = 0.75) but chlorophyll-a seasonal pattern showed an irregular trend, prompting other no-nutrient related limitants. Shallowness induced a homogeneous
temporal pattern on water quality. This observed temporal variability was mainly explained statistically by changes on solids
(mineral and organic), chlorophyll-a and flows (62.3%). Annual sedimentation rates of total solids ranged from 11.73 to 16.29 kg m−2 year−1 with organic matter comprising around 30%. N:P ratio on sedimentation rates were as high as could be expected in a resuspension
dominated ecosystem, and spatially inverse related with N:P ratio on bottom sediments. Distance from river inlet into the
reservoir reveals a marked spatial heterogeneity on solid and nitrogen sedimentation, showing the system dependence on river
inflows and supporting resuspension as the main phosphorus pathway. Accretion rates (2.19 ± 0.40 cm year−1) were not related to hydrological variability but decreased with the distance to the river input. Total sediment accumulation
(9,895 tons km−2 year−1) denotes siltation as other serious environmental problem in reservoirs but possibly not related with operational procedures. 相似文献
14.
This study investigated the presence of total mercury (Hg) and organic mercury levels in the muscle of 19 common fresh water
fish species captured from river Ganges, West Bengal, India. The total mercury level found in our study may not cause any
toxic effect, but the methyl mercury (MeHg) level in some freshwater fish species was surprisingly very high and toxically
unacceptable. The results of mercury analysis in various specimens indicated that some fish muscles tended to accumulate high
levels of Hg, and approximately 50–84% of Hg was organic mercury. A strong positive correlation between mercury levels in
muscle with food habit and fish length (age) was found. Wallago attu possessed the highest amount of organic mercury in their muscle tissues, and it was 0.93 ± 0.61 μg Hg/g of wet weight. Whereas
in small-sized fishes Eutropiichthys murius, Puntius sarana, Cirrhinus mrigala, Mystus vittatus or Mystus gulio, and Tilapia mossambicus, it was below the detection limit. Contamination in Catla catla (0.32 ± 0.11), Anguilla bengalensis bengalensis (0.26 ± 0.07 μg Hg/g), Chitala chitala (0.25 ± 0.18), Rita rita (0.34 ± 0.14), and Ompok pabda (0.26 ± 0.04) was also above the 0.25 μg Hg/g of wet weight, the limit set by the PFA for the maximum level for consumption
of fish exposed to MeHg. Though in Labeo rohita (0.12 ± 0.03), Mastacembelus armatus (0.17 ± 0.02), Pangasius pangasius (0.12 ± 0.16), Bagarius bagarius (0.12 ± 0.01), and Clupisoma garua (0.1 ± 0.01), concentration was below the recommended level, in Lates calcarifer (0.23 ± 0.0) and Mystus aor (0.23 ± 0.1), it was threatening. Interestingly, a low concentration of Hg was found in post-monsoon samples. 相似文献
15.
Wigand C McKinney RA Cole ML Thursby GB Cummings J 《Environmental monitoring and assessment》2007,131(1-3):71-81
The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this
study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ
15N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ
15N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ
15N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ
15N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas,
the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ
15N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R
2 = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ
15N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ
15N of Spartina relates with the integrated, watershed-sea nitrogen inputs. 相似文献
16.
Pore waters play an important role in phosphorus dynamics in aquatic ecosystems. Phosphorus concentrations in pore waters
are much higher than above the bottom. This is confirmed by the results of this study concerning the hypereutrophic lake.
Pore water was analyzed at 11 sampling stations in the upper layer of bottom sediments. This water was separated by centrifugation
and phosphorus level was measured spectrophotometrically with ascorbic acid as a reducer. Total phosphorus concentration in
pore waters ranged from 0.5 to 8.1 mgP l − 1 (mean 3.2 mgP l − 1). Mean phosphorus concentration in pore water samples of this lake was the highest in summer and the lowest in winter. High
concentrations were observed in samples from the pelagial and low from the macrophyte zone. 相似文献
17.
Boyacioglu H Haliki A Ates M Guvensen A Abaci O 《Environmental monitoring and assessment》2007,135(1-3):327-334
This study aims to investigate the differences in the concentrations of airborne fungi and pollens between the towns located
in the province of Izmir and to determine the factors contributing to these differences. Five stations in each of four towns
(Buca, Konak, Bornova, and Karsiyaka) were randomly selected as the research areas. Fungus (cfu/m3) and pollen counts (cm2/pollen count) in the air samples collected from each station between June 2003 and May 2004 were measured. The results revealed
that whereas Karsiyaka had the highest fungus concentration (521.33 ± 777.1), Buca and Bornova had the lowest concentration
(482.67 ± 308.44). The mean fungus concentration in the province of İzmir was 501.5 ± 486.7. Pollen concentration was the
highest in Konak (486.67 ± 839.06) and the lowest in Bornova (369.83 ± 551.13). Fungus and pollen concentrations revealed
no difference between the towns (p > 0.05). The relationship between pollen-fungus concentrations and temperature-dust-humidity-sulphurdioxide was investigated
but it was found statistically insignificant (p > 0.05). As a result of regression analysis, it was determined that correlation of atmospheric parameters had no effects
on pollen and fungus concentrations (p > 0.05). 相似文献
18.
Marvin C Charlton M Milne J Thiessen L Schachtschneider J Sardella G Sverko E 《Environmental monitoring and assessment》2007,130(1-3):149-161
Sediment traps were deployed in the three major basins of Lake Erie, and the central (Mississauga) basin of Lake Ontario,
and refurbished seasonally over the period 2000–2002. In Lake Ontario, sediment down-flux rates and corresponding contaminant
down-flux rates were highest in winter during periods of unstratified thermal conditions, and generally increased with depth
due to the influence of resuspended bottom sediments during all sampling periods. Lake Ontario suspended sediments exhibited
the highest concentrations of metals; concentrations of mercury and lead frequently exceeded guideline values for bottom sediments.
Contaminant levels in Lake Ontario suspended sediments were similar to concentrations in bottom sediments in the same area.
There was a spatial trend toward higher suspended sediment metals concentrations from the eastern basin to the western basin
of Lake Erie, which is similar to the trend in bottom sediment contamination. In the eastern basin of Lake Erie, which is
the deepest area of the lake, there was no trend in down-flux rate with depth in 2001; however, down-flux rates increased
with depth in 2002. Suspended sediments in the western basin of Lake Erie were determined to be largely resuspended bottom
sediments; all western basin samples collected in the study exceeded the guideline value for mercury (0.486 μg/g). 相似文献
19.
This study presents concentration levels of pollutants (lead, and cadmium) in tissues (livers, kidneys, muscles, and bones)
of shorebirds (Kentish Plovers (n = 5), Mongolian Plovers (n = 2), Dunlins (n = 6), Great Knots (n = 10), Terek Sandpipers (n = 10)) from Yeongjong Island, Korea in the East Asian–Australian migration flyways during the autumn migration in 1994–1995.
Lead concentrations in livers, in kidneys, in muscles, and in bones were significantly different among shorebird species.
Lead concentrations in livers of Kentish Plovers (4.76 ± 2.72 μg/wet g), Mongolian Plovers (2.05 μg/wet g), Dunlins (3.77 ± 1.07 μg/wet
g), and Great Knots (4.27 ± 3.19 μg/wet g) were less than the toxic level, and lead concentrations in livers of Terek Sandpipers
(1.20 ± 0.94 μg/wet g) were at the background level. Cadmium concentrations in livers, in kidneys, in muscles, and in bones
did not vary among shorebirds, and concentrations of cadmium in livers and in kidneys were at background level (respectively,
approximate 1 μg/wet g, approximate 2.67 μg/wet g) in all shorebird species. We suggest that interspecific differences of
lead and cadmium concentrations were attributed to differences in exposure time and differences of diet, microhabitats in
wintering ground. In livers and kidney of shorebirds from Yeongjong Island, lead and cadmium concentrations were higher than
other locations previously reported. 相似文献
20.
Total mercury distribution in different tissues of six species of freshwater fish from the Kpong hydroelectric reservoir in Ghana 总被引:1,自引:0,他引:1
Total mercury concentrations were determined in seven tissues of 38 fish samples comprising six species from the Kpong hydroelectric
reservoir in Ghana by cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer. Mercury concentration
in all the tissues ranged from 0.005 to 0.022 μg/g wet weight. In general, the concentration of mercury in all the tissues
were decreasing in the order; liver > muscle > intestine > stomach > gonad > gill > swim bladder. Mercury concentration was
generally greater in the tissues of high-trophic-level fish such as Clarotes laticeps, Mormyrops anguilloides and Chrysichthys aurutus whereas low-trophic-level fish such as Oreochromis niloticus recorded low mercury concentration in their tissues. The results obtained for total mercury concentration in the muscle tissues
analysed in this study are below the WHO/FAO threshold limit of 0.5 μg/g. This suggests that the exposure of the general public
to Hg through fish consumption can be considered negligible. 相似文献