38 research outputs found
Acid mine drainage: streambed sorption of copper, cadmium and zinc
January 10, 1990.Includes bibliographical references.Grant no. 14-08-0001-1551, Project no. 04; financed in part by the U.S. Department of the Interior, Geological Survey, through the Colorado Water Resources Research Institute
Quantification and Characterization of Nanoparticulate Zinc in an Urban Watershed
The recent expansion in the use of nanomaterials in consumer and industrial applications has led to a growing concern over their behavior, fate, and impacts in environmental systems. However, engineered nanoparticles comprise only a small fraction of the total nanoparticle mass in aquatic systems. Human activities, particularly in urban watersheds, are increasing the population of incidental nanoparticles and are likely altering the cycling of more abundant natural nanoparticles. Accurate detection, quantification, characterization, and tracking of these different populations is important for assessing both the ecological risks of anthropogenic particles, and their impact on environmental health. The urban portion of the South Platte watershed in Denver, Colorado (United States) was sampled for zinc to identify and quantify different nanomaterial sources. Single particle ICP-QMS was employed, to provide single elemental (Zn) signals arising from particle detection events. Coupling spICP-QMS to sample pre-fractionation (sedimentation, filtration) provided some insights into Zn association with nanoparticulate, colloidal, and suspended sediment phases. Single particle ICP-TOFMS (spICP-TOFMS) provided quantification across a large atomic mass range, yielding an even more detailed characterization (elemental ratios) on a particle-by-particle basis, providing some delineation of multiple sources of particles. Across the watershed, on average, 21% of zinc mass was present as zinc-only particles with a rather uniform mean size of 40.2 nm. Zinc that was detected with one or more other elements, primarily Al, Fe, and Si, is likely to be present as heteroagglomerates or within mineral colloids. Although spICP-TOFMS provides a substantial amount of information, it is still in its early stages as an analytical technique and currently lacks the requisite sensitivity to study the smallest of nanoparticles. As this technique continues to develop, it is anticipated that this methodology can be broadly applied to study sources, behavior and effects of a disparate variety of nanoparticles from both geogenic and anthropogenic origins
Quantification of Bioaccessible and Environmentally Relevant Trace Metals in Structure Ash from a Wildland鈥揢rban Interface Fire
Wildfires at the wildland鈥搖rban interface (WUI)
are increasing
in frequency and intensity, driven by climate change and anthropogenic
ignitions. Few studies have characterized the variability in the metal
content in ash generated from burned structures in order to determine
the potential risk to human and environmental health. Using inductively
coupled plasma optical emission spectroscopy (ICP-OES) and inductively
coupled plasma mass spectrometry (ICP-MS), we analyzed leachable trace
metal concentration in soils and ash from structures burned by the
Marshall Fire, a WUI fire that destroyed over 1000 structures in Boulder
County, Colorado. Acid digestion revealed that ash derived from structures
contained 22 times more Cu and 3 times more Pb on average than surrounding
soils on a mg/kg basis. Ash liberated 12 times more Ni (mg/kg) and
twice as much Cr (mg/kg) as soils in a water leach. By comparing the
amount of acid-extractable metals to that released by water and simulated
epithelial lung fluid (SELF), we estimated their potential for environmental
mobility and human bioaccessibility. The SELF leach showed that Cu
and Ni were more bioaccessible (mg of leachable metal/mg of acid-extractable
metal) in ash than in soils. These results suggest that structure
ash is an important source of trace metals that can negatively impact
the health of both humans and the environment
Adsorption of copper, cadmium and zinc on suspended sediments in a stream contaminated by acid mine drainage: the effect of seasonal changes in dissolved organic carbon
January 1, 1991.Bibliography: pages 13-14.Grant no. 14-08-0001-G1551-01, Project no. 04; financed in part by the U.S. Department of the Interior, Geological Survey
Acute Toxicity of Ternary Cd鈥揅u鈥揘i and Cd鈥揘i鈥揨n Mixtures to <i>Daphnia magna</i>: Dominant Metal Pairs Change along a Concentration Gradient
Multiple
metals are usually present in surface waters, sometimes
leading to toxicity that currently is difficult to predict due to
potentially non-additive mixture toxicity. Previous toxicity tests
with <i>Daphnia magna</i> exposed to binary mixtures of
Ni combined with Cd, Cu, or Zn demonstrated that Ni and Zn strongly
protect against Cd toxicity, but Cu鈥揘i toxicity is more than
additive, and Ni鈥揨n toxicity is slightly less than additive.
To consider multiple metal鈥搈etal interactions, we exposed <i>D. magna</i> neonates to Cd, Cu, Ni, or Zn alone and in ternary
Cd鈥揅u鈥揘i and Cd鈥揘i鈥揨n combinations in
standard 48 h lethality tests. In these ternary mixtures, two metals
were held constant, while the third metal was varied through a series
that ranged from nonlethal to lethal concentrations. In Cd鈥揅u鈥揘i
mixtures, the toxicity was less than additive, additive, or more than
additive, depending on the concentration (or ion activity) of the
varied metal and the additivity model (concentration-addition or independent-action)
used to predict toxicity. In Cd鈥揘i鈥揨n mixtures, the
toxicity was less than additive or approximately additive, depending
on the concentration (or ion activity) of the varied metal but independent
of the additivity model. These results demonstrate that complex interactions
of potentially competing toxicity-controlling mechanisms can occur
in ternary-metal mixtures but might be predicted by mechanistic bioavailability-based
toxicity models
Multiple Method Analysis of TiO\u3csub\u3e2\u3c/sub\u3e Nanoparticle Uptake in Rice (\u3ci\u3eOryza sativa\u3c/i\u3e L.) Plants
Understanding the translocation of nanoparticles (NPs) into plants is challenging because qualitative and quantitative methods are still being developed and the comparability of results among different methods is unclear. In this study, uptake of titanium dioxide NPs and larger bulk particles (BPs) in rice plant (Oryza sativa L.) tissues was evaluated using three orthogonal techniques: electron microscopy, single-particle inductively coupled plasma mass spectroscopy (spICP-MS) with two different plant digestion approaches, and total elemental analysis using ICP optical emission spectroscopy. In agreement with electron microscopy results, total elemental analysis of plants exposed to TiO2 NPs and BPs at 5 and 50 mg/L concentrations revealed that TiO2 NPs penetrated into the plant root and resulted in Ti accumulation in above ground tissues at a higher level compared to BPs. spICP-MS analyses revealed that the size distributions of internalized particles differed between the NPs and BPs with the NPs showing a distribution with smaller particles. Acid digestion resulted in higher particle numbers and the detection of a broader range of particle sizes than the enzymatic digestion approach, highlighting the need for development of robust plant digestion procedures for NP analysis. Overall, there was agreement among the three techniques regarding NP and BP penetration into rice plant roots and spICP-MS showed its unique contribution to provide size distribution information
Distribution and mode of occurrences of radionuclides in phosphogypsum from the Aqaba and Eshidiya fertilizer plants, Jordan
Bioavailability, Toxicity, and Bioaccumulation of Quantum Dot Nanoparticles to the Amphipod <i>Leptocheirus plumulosus</i>
Understanding the relative toxicities of different modes
of nanoparticle
exposure as compared with their dissolved metal ions are emerging
areas in ecotoxicology. Here, we report on bioavailability, toxicity,
and bioaccumulation of carboxyl-functionalized CdSe/ZnS quantum dots
(QDs) to the amphipod <i>Leptocheirus plumulosus</i> exposed
to equivalent Cd concentrations via dissolved Cd, QDs in water, or
QDs in algal food. Both modes of QD exposure were accumulated to greater
extent than dissolved Cd. Exposure to QDs via algae resulted in high
amphipod mortality. Cadmium and Se in amphipods exposed to QDs in
water were highly correlated and spatially localized within the amphipod.
In contrast, when exposed to QDs via algae the metals were more disperse
and not highly correlated suggesting QD dissolution and resultant
metal ion toxicity. This study suggests QDs are accumulated to a greater
extent than the dissolved ion and could lead to trophic transfer.
QDs ingested with algae are bioavailable and result in toxicity, which
is not observed in the absence of algae