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211.
The technique of diffusion gradient in thin films (DGT) for assessing bioavailable metals has not been tested under field
conditions. We assessed the relationships of DGT- and cation exchange resin-membrane-measured concentrations of Cd, Cu, Pb,
and Zn with plant uptake of the metals under greenhouse and field conditions. In the greenhouse, the effective concentrations
of Cu, Pb, and Zn by DGT correlated significantly with uptake by sorghum (Sorghum bicolor), but cation exchange resin-membrane-measured concentrations of Cd, Pb, and Zn did not correlate with sorghum uptake. In
the field, the DGT-measured concentrations of Cd, Pb, and Zn were not linearly related to uptake Cd, Pb, and Zn by lettuce
(Lactuca sativa) except for Cu uptake (r = 0.87, p < 0.05). Similarly, it was only the resin-membrane-extractable Pb that correlated with Pb uptake by lettuce (r = 0.77; p < 0.05). However, fitting non-linear regression models improved the plant metal uptake predictions by DGT-measured bioavailable
Cd, Cu, Pb, and Zn under field conditions. In conclusion, the DGT technique was fairly predictive of bioavailability in the
greenhouse, but not in the field. 相似文献
212.
Singh HP Sharma VP Batish DR Kohli RK 《Environmental monitoring and assessment》2012,184(4):1813-1821
Indiscriminate adoption and use of cell phone technology has tremendously increased the levels of electromagnetic field radiations
(EMFr) in the natural environment. It has raised the concerns among the scientists regarding the possible risks of EMFr to
living organisms. However, not much has been done to assess the damage caused to plants that are continuously exposed to EMFr
present in the environment. The present study investigated the biochemical mechanism of interference of 900 MHz cell phone
EMFr with root formation in mung bean (Vigna radiata syn. Phaseolus aureus) hypocotyls, a model system to study rhizogenesis in plants. Cell phone EMFr enhanced the activities of proteases (by 1.52
to 2.33 times), polyphenol oxidases (by 1.5 to 4.3 times), and peroxidases (by 1.5 to 2.0 times) in mung bean hypocotyls over
control. Further, EMFr enhanced malondialdehyde (an indicator of lipid peroxidation), hydrogen peroxide, and proline content,
indicating a reactive oxygen species-mediated oxidative damage in hypocotyls. It was confirmed by the upregulation in the
activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, catalase, and glutathione
reductase) suggesting their possible role in providing protection against EMFr-induced oxidative damage. The study concluded
that cell phone radiations affect the process of rhizogenesis through biochemical alterations that manifest as oxidative damage
resulting in root impairment. 相似文献
213.
Chaudhary P Singh SB Chaudhry S Nain L 《Environmental monitoring and assessment》2012,184(2):1145-1156
The present study is aimed at analysing and comparing different soil enzymes in soil samples of native contaminated sites
of a Mathura refinery and adjoining agricultural land. Enzyme activities are considered as indicators of soil quality and
changes in biogeochemical function due to management or perturbations. Soil samples were collected from the premises and nearby
area of Mathura refinery, India. Biological health parameters (dehydrogenase, aryl esterase, aryl sulphatase,
\upbeta \upbeta -glucosidase, alkaline phosphatase, acid phosphatase, lipase, laccase and catalase activity) were estimated in the soil samples.
Among all the samples, sewage sludge soil showed maximum activity of enzymes, microbial biomass carbon and most probable number
of polycyclic aromatic hydrocarbon (PAH) degraders in soils spiked with three- to four-ring PAHs at 50 ppm. Available phosphorus,
potassium and nitrogen was also exceptionally high in this sample, indicating maximum microbial bioconversion due to presence
of nutrients stimulating potent PAH-degrading microorganisms. 相似文献
214.
Warren C Duzgoren-Aydin NS Weston J Willett KL 《Environmental monitoring and assessment》2012,184(2):1107-1119
Hurricanes are relatively frequent ecological disturbances that may cause potentially long-term impacts to the coastal environment.
Hurricane Katrina hit the Mississippi Gulf Coast in August 2005, and caused a storm surge with the potential to change the
trace element content of coastal surface sediments. In this study, surface estuarine and marine sediments were collected monthly
following the storm from ten sites along the Mississippi Gulf Coast (Mobile Bay, Grand Bay Bayous Heron and Cumbest, Pascagoula,
Ocean Springs, Biloxi Gulf, Back Biloxi Bay, Gulfport Gulf, Gulfport Courthouse Rd, and Gulfport Marina). Concentrations of
V, Cr, Mn, Fe, Co, Ni, Zn, As, Cd, and Pb were measured by inductively coupled plasma–mass spectrometry to evaluate their
temporal and spatial variations in the year following Hurricane Katrina. Sediments were characterized by pH, particle size
distribution and total carbon and nitrogen content. Trace element contents of the sediments were determined in both <2 mm
and <63 μm grain size fractions. Results revealed no significant temporal and spatial variability in trace element concentrations,
in either size fraction. Potential ecological risk of the sediments was assessed by using NOAA SQuiRTs’ guideline values;
most concentrations remained below probable adverse effects guidelines to marine organisms suggesting that trace elements
redistributed by Hurricane Katrina would not cause an adverse impact on resident organisms. Instead, the concentrations of
trace elements were site-dependent, with specific contaminants relating to the use of the area prior to Hurricane Katrina. 相似文献
215.
Sediment quality guidelines (SQGs) can be derived using different approaches and are commonly used in environmental management,
reclamation, and risk assessment. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive
lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety
Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and
Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal
and radionuclide concentrations in sediment, and corresponding benthic community composition data for a specific sampling
site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan
uranium operations were compiled and examined. Results indicate that the CNSC-derived SQGs had limited relationships to observed
effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. The LELs were found
to correctly align with effects at 95% of the sites that had effects, on a general basis, but on an element-specific basis
many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements
exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect
sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. It is suggested that alternatives
to the SLC approach be explored. 相似文献
216.
Mehmet Ates James Daniels Zikri Arslan Ibrahim O. Farah 《Environmental monitoring and assessment》2013,185(4):3339-3348
Aquatic stability and impact of titanium dioxide nanoparticles (TiO2 NPs, 10–30 nm) were investigated using Artemia salina. Acute exposure was conducted on nauplii (larvae) and adults in seawater in a concentration range from 10 to 100 mg/L TiO2 NPs for 24 and 96 h. Rapid aggregation occurred in all suspensions of TiO2 NPs to form micrometer size particles. Yet, both nauplii and adults accumulated the aggregates significantly. Average TiO2 content in nauplii ranged from 0.47 to 3.19 and from 1.29 to 4.43 mg/g in 24 and 96 h, respectively. Accumulation in adults was higher ranging from 2.30 to 4.19 and from 4.38 to 6.20 mg/g in 24 and 96 h, respectively. Phase contrast microscopy images revealed that Artemia were unable to excrete the particles. Thus, the TiO2 aggregates filled inside the guts. No significant mortality or toxicity occurred within 24 h at any dose. Lipid peroxidation levels characterized with malondialdehyde concentrations were not statistically different from those of the controls (p?>?0.05). These results suggested that suspensions of the TiO2 NPs were nontoxic to Artemia, most likely due to the formation of benign TiO2 aggregates in water. In contrast, both mortality and lipid peroxidation increased in extended exposure to 96 h. Highest mortality occurred in 100 mg/L TiO2 NP suspensions; 18 % for nauplii and 14 % for adults (LC50?>?100 mg/L). These effects were attributed to the particle loading inside the guts leading to oxidative stress as a result of impaired food uptake for a long period of time. 相似文献
217.
Carlee J. Wright Jan M. Sargeant Victoria L. Edge James D. Ford Khosrow Farahbakhsh RICG Inez Shiwak Charlie Flowers IHACC Research Team Sherilee L. Harper 《Environmental science and pollution research international》2018,25(33):32975-32987
One of the highest self-reported incidence rates of acute gastrointestinal illness (AGI) in the global peer-reviewed literature occurs in Inuit communities in the Canadian Arctic. This high incidence of illness could be due, in part, to the consumption of contaminated water, as many northern communities face challenges related to the quality of municipal drinking water. Furthermore, many Inuit store drinking water in containers in the home, which could increase the risk of contamination between source and point-of-use (i.e., water recontamination during storage). To examine this risk, this research characterized drinking water collection and storage practices, identified potential risk factors for water contamination between source and point-of-use, and examined possible associations between drinking water contamination and self-reported AGI in the Inuit community of Rigolet, Canada. The study included a cross-sectional census survey that captured data on types of drinking water used, household practices related to drinking water (e.g., how it was collected and stored), physical characteristics of water storage containers, and self-reported AGI. Additionally, water samples were collected from all identified drinking water containers in homes and analyzed for presence of Escherichia coli and total coliforms. Despite municipally treated tap water being available in all homes, 77.6% of households had alternative sources of drinking water stored in containers, and of these containers, 25.2% tested positive for total coliforms. The use of transfer devices and water dippers (i.e., smaller bowls or measuring cups) for the collection and retrieval of water from containers were both significantly associated with increased odds of total coliform presence in stored water (ORtransfer device = 3.4, 95% CI 1.2–11.7; ORdipper = 13.4, 95% CI 3.8–47.1). Twenty-eight-day period prevalence of self-reported AGI during the month before the survey was 17.2% (95% CI 13.0–22.5), which yielded an annual incidence rate of 2.4 cases per person per year (95% CI 1.8–3.1); no water-related risk factors were significantly associated with AGI. Considering the high prevalence of, and risk factors associated with, indicator bacteria in drinking water stored in containers, potential exposure to waterborne pathogens may be minimized through interventions at the household level. 相似文献
218.
James Silvanima Andy Woeber Stephanie Sunderman-Barnes Rick Copeland Christopher Sedlacek Thomas Seal 《Environmental monitoring and assessment》2018,190(7):435
Current wastewater treatment technologies do not remove many unregulated hydrophilic compounds, and there is growing interest that low levels of these compounds, referred to as emerging contaminants, may impact human health and the environment. A probabilistic-designed monitoring network was employed to infer the extent of Florida’s ambient freshwaters containing the wastewater (Includes reuse water, septic systems leachate, and wastewater treatment effluent.) indicators sucralose, acetaminophen, carbamazepine, and primidone and those containing the widely used pesticide imidacloprid. Extent estimates with 95% confidence bounds are provided for canals, rivers, streams, small and large lakes, and unconfined aquifers containing ultra-trace concentrations of these compounds as based on analyses of 2015 sample surveys utilizing 528 sites. Sucralose is estimated to occur in greater than 50% of the canal, river, stream, and large lake resource extents. The pharmaceuticals acetaminophen, carbamazepine, and primidone are most prevalent in rivers, with approximately 30% of river kilometers estimated to contain at least one of these compounds. Imidacloprid is estimated to occur in 50% or greater of the canal and river resource extents, and it is the only compound found to exceed published toxicity or environmental effects standards. Geospatial analyses show sucralose detection frequencies within Florida’s drainage basins to be significantly related to the percentage of urban land use (R2?=?0.36, p?<?0.001), and imidacloprid detection frequencies to be significantly related to the percentage of urban and agricultural land use (R2?=?0.47, p?<?0.001). The extent of the presence of these compounds highlights the need for additional emerging contaminant studies especially those examining effects on aquatic biota. 相似文献
219.
Kishore?Kumar?MahatoEmail author Krishna?Dutta Bankim?Chandra?Ray 《Journal of Polymers and the Environment》2018,26(3):1024-1050
The study of static and dynamic behavior of environmentally conditioned fibre reinforced polymeric (FRP) composites is necessary and crucial to examine the durability, reliability and sustainability of these noble materials. FRP composites are being used all around the globe and substituting the conventional materials, starting from mini toys to large aerospace components. Present review has introduced to accumulate and understand the disseminate literature in concentrating the significance of understanding the static and dynamic behavior of FRPs with changing environmental conditionings (hygrothermal, low and high temperature, salt solution, freeze thaw, UV light) and with the interaction of different nano-fillers. Their stability and integrity in diverse service environments may be reformed by their reactions against different nature of loadings i.e. static or dynamic and the components such as fibre, matrix and fibre/matrix interfaces in those environments. The static and dynamic states of loading may come with a possible weaker region to encounter the durability and integrity of the composites. To understand the exact failure modes that correlates the position of environmentally conditioned interfaces and dynamic state of loadings, thus confusing the estimation of its overall performance and mechanical behavior. Interface reliability and durability is vital since in-service environments the degradation in the interfacial region leads to complete composite failure. Therefore, the study of combined effects of various in-service environmental conditions and the role of static and dynamic behavior on the interface will be a crucial part related to the multiaxial dynamic states of failures occurring in FRP’s. 相似文献
220.
Cambodian subsistence communities within the Tonle Sap Great Lake area rely on resource extraction from the lake to meet livelihood needs. These fishing communities—many of which consist of dwellings floating on the lake—face potentially profound livelihood challenges because of climate change and changing hydrology due to dam construction for hydroelectricity within the Mekong Basin. We conducted interviews across five village communities, with local subsistence fisher people in the Tonle Sap in 2015, and used thematic analysis methods to reveal a fishery system that is undergoing rapid ecological decline, with local fishing communities increasingly experiencing reductions in available fish stocks. As a result, over 100 000 people living in these communities are experiencing a direct loss of well-being and livelihood. We discuss these losses and consider their implications for the future viability of Cambodian floating village communities. 相似文献