Page 15 - EER-2-3

Explora: Environment
and Resource Environmental contamination of titanium

Ti and hinder mobility. Under reducing conditions, concentrations ranged from 0.1 to 10 mg/L, with a mean
Ti becomes more soluble and mobile. Sedimentation level of 21.1 mg/L. Additionally, TiO NP contamination
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leads to the accumulation of Ti in certain areas. Aquatic has been reported in other freshwater locations, including
organisms accumulate Ti from the water column or forest brooks, agricultural streams, urban streams, and urban
sediments; this accumulation may vary depending watersheds (Table 3).
on the species and their trophic level. Local climate, Ti is detected in aquatic habitats, such as freshwater
weather patterns, and seasonal variations can all and marine ecosystems, mostly in the form of TiO NPs. 108
significantly impact the mobility and behavior of Ti in The accumulation of Ti in these water bodies is caused by
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both soil and water.
a complex interaction of natural geological processes and
There is a range of different Ti chemical (polymorphic) human activities. TiO contents in surface waters have been
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forms and speciation stages, such as Ti oxocation (titanyl estimated to range from 2 to 700 ng/L, 102 demonstrating
TiO ) andTi(IV) dihydroxideion (Ti[OH] ), each with that the distribution of Ti in aquatic environments is not
2+
2+
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a distinct set of features and environmental implications homogeneous and varies from place to place (Table 3).
(Table S2). Being aware of Ti speciation is essential for Minerals such as ilmenite, rutile, and anatase in rocks
comprehending its behavior, mobility, and potential impact and soils weather and degrade over time, releasing TiO
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on the environment. In general, in aqueous (acidic) solutions, particles into surface water bodies, including rivers,
Ti forms different complexes with hydroxyl groups (the lakes, and oceans. The richness of these minerals in the
dominance of di/tetra-valent ions). The general formula surrounding geology could have a direct influence on the
for these complexes is [Ti(OH) (H O) (6-n) ] (4−n)+ (0≤n≤4). 95 concentration of Ti in the water bodies, and anthropogenic
n
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Kumar et al. and Migaszewski and Gałuszka discussed activities based on these minerals could aggravate the
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that TiO exists in different polymorphs in nature, including release of Ti into surface waters. 102
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tetragonal anatase, tetragonal rutile, nanocrystalline TiO , Kiser et al. reported that the raw sewage of a wastewater
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and orthorhombic brookite. Amorphous TiO is a non- treatment facility in Central Arizona, US, contained Ti
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crystalline type of TiO . Thermodynamically, rutile is as 1 – 30 × 10 ng/L, and the effluents of the treatment
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5
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more stable due to its formation under high pressures facility still exhibited 5 – 15 × 10 ng/L of Ti. Aside from
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and temperatures (>500°C), while brookite and anatase wastewater treatment plants, surface water bodies canbe
are often created under low pressures. This increases the directly or indirectly exposed to TiO NPs via landfills,
likelihood of anatase and brookite conversion to the rutile 2
form rather than the reverse process. Notably, Ti mobility combustion processes, product applications, rainwater
and solubility usually increase when complexed with deposition, agricultural non-point sources, surface runoff,
organic and inorganic ligands. 92,93,95 underground leaching, and accidental release during
production and transportation. Azimzada et al. found
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4. Distribution and biogeochemistry of Ti in that the Ti content of river water samples collected from
the aquatic environment the Netherlands, Germany, Italy, and the US were 5.8 ± 5.6,
75.1 ± 11.5, 143 ± 114, and 524 ± 255 ng/L, respectively,
4.1. Distribution while in Brazil, the levels were reported at 2,262 ± 423 ng/L.
Similar values were observed in lake water samples from
Sanitary sewer overflows are a major issue in the US, which China (6.4 ± 4.8 ng/L) and the United Kingdom (135 ±
often leads to the release of contaminants, such as TiO NPs, 45.9 ng/L). Meanwhile, the Tamsui River basin in Taiwan
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into water. Sousa et al. reported that TiO NPs are not removed showed high Ti levels (1,040 ± 40.0–31,700 ± 600 ng/L). 102
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during the sewage treatment process, and the particles enter Importantly,the intensification of industrialization and the
surface waters along with the treated sewage at estimated applicationof Ti-nanomaterials are expected to increase
concentrations of 20 – 10,000 ng/L. Surface water samples
collected from Crane Creek, Stoop Creek, and Gills Creek NP release and dispersion in river systems.
in Columbia, South Carolina, US, demonstrated TiO -NP Due to the protonation–deprotonation equilibria
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concentrations ranging from 1 to 95 mg/L, with a mean of of the surface hydroxyl groups, TiO surfaces present a
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25 mg/L. TiO -NP concentrations in the beach shorelines pH-dependent charge. More specifically, there is a negative
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close to the bathing zones in the French Mediterranean ranged charge in higher pH environments and a positive charge
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from 100 to 900 mg/L; this presence was attributed to the use in acidic environments. The pHat which the particle’s
of sunscreens that contain TiO NPs. TiO -NP concentrations total charge is zero, or the point of zero charge, divides
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downstream of the Thurriver, France, were found to be 133 – these regimes. 115,116 Since the Derjaguin–Landau–Verwey–
260 mg/L, which was attributed to the nearby nanomaterial Overbeek force typically controls the aggregation of TiO
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manufacturing industry. In Taihu Lake, China, TiO -NP particles, the strength of the repulsive forces coming
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Volume 2 Issue 3 (2025) 9 doi: 10.36922/EER025130027