Long-term trends of chemical and modelled photochemical parameters in four Alpine lakes

Minella, Marco; Leoni, Barbara; Salmaso, Nico; Savoye, Liliane; Sommaruga, Rubén; Vione, Davide

doi:10.1016/j.scitotenv.2015.08.149

Cited by 20 publications

(26 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, an examination of Figure 1 suggests that a variation in DOC by one order of magnitude (from 1 to 10 mg C L −1 ) induced a twofold variation in the pseudo-first-order k(CBZ) ( Figure 1 a,b). However, seasonal DOC variations in a lake are very unlikely to go beyond a factor of two [ 30 ]. More important variations in k(CBZ) (up to fourfold, Figure 1 c,d) were observed when water depth varied by an order of magnitude.…”

Section: Resultsmentioning

confidence: 99%

Insights into the Time Evolution of Slowly Photodegrading Contaminants

Vione

2021

Molecules

Self Cite

View full text Add to dashboard Cite

Photochemical degradation plays an important role in the attenuation of many recalcitrant pollutants in surface freshwaters. Photoinduced transformation kinetics are strongly affected by environmental conditions, where sunlight irradiance plays the main role, followed by water depth and dissolved organic carbon (DOC). Apart from poorly predictable weather-related issues, fair-weather irradiance has a seasonal trend that results in the fastest photodegradation in June and the slowest in December (at least in temperate areas of the northern hemisphere). Pollutants that have first-order photochemical lifetimes longer than a week take more than one month to achieve 95% photodegradation. Consequently, they may experience quite different irradiance conditions as their photodegradation goes on. The relevant time trend can be approximated as a series of first-order kinetic tracts, each lasting for one month. The trend considerably departs from an overall exponential decay, if degradation takes long enough to encompass seasonally varying irradiance conditions. For instance, sunlight irradiance is higher in July than in April, but increasing irradiance after April and decreasing irradiance after July ensure that pollutants emitted in either month undergo degradation with very similar time trends in the first 3–4 months after emission. If photodegradation takes longer, pollutants emitted in July experience a considerable slowdown in photoreaction kinetics as winter is approached. Therefore, if pollutants are photostable enough that their photochemical time trend evolves over different seasons, degradation acquires some peculiar features than cannot be easily predicted from a mere analysis of lifetimes in the framework of simple first-order kinetics. Such features are here highlighted with a modelling approach, taking the case of carbamazepine as the main example. This contaminant is almost totally biorecalcitrant, and it is also quite resistant to photodegradation.

show abstract

Section: Resultsmentioning

confidence: 99%

Insights into the Time Evolution of Slowly Photodegrading Contaminants

Vione

2021

Molecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…In summer, water temperature and light decrease with depth, while nutrients usually increase. In Lake Iseo, chemical parameters and inorganic nutrient concentrations showed a typical pattern for monomictic lakes, with low values of conductivity, phosphorus, nitrogen, and silica compounds in the surface layer in summer (Diehl, 2002;Minella et al, 2016;Salmaso et al, 2012). A combination of field observations and 3D hydrodynamic simulations were used to identify phytoplankton species, and estimate the various time scales of the dominant physical and biological processes in Lake Iseo during a stratified period, deriving phytoplankton patch categorization and growth interpretation that provides a general framework for the spatial distri- bution of phytoplankton concentration in Lake Iseo (Marti et al, 2015).…”

Section: Phytoplankton Community and Cyanobacteriamentioning

confidence: 98%

Long-term studies for evaluating the impacts of natural and anthropic stressors on limnological features and the ecosystem quality of Lake Iseo

et al. 2019

Self Cite

View full text Add to dashboard Cite

We review the state of the art of limnological studies in Lake Iseo and provide updated data concerning long-term investigations (from 1993 to 2018) carried out on chemical and physical parameters (e.g., oxygen, phosphorus, silicon). Changes observed in Lake Iseo were compared with those reported in other Deep South alpine Lakes (DSLs) to highlight analogies and differences of long-term chemical, physical, and biological patterns. Until the 1960s, Lake Iseo and other DSLs were oligotrophic. The increase of anthropogenic pressure and global warming has led to a progressive and unrecovered process of eutrophication. Moreover, the decrease in frequency of full mixing episodes has induced a state of temporary meromixis. Other changes have been identified over the last two decades, especially concerning the phytoplankton and zooplankton communities, and new emerging chemical pollutants were detected. Given the important ecological and socioeconomic role of Lake Iseo, long-term investigations are of paramount importance to understand the response of the lake ecosystem to climatic and anthropogenic stressors. These two factors can also act coupled with new combined and synergic effects.

show abstract

“…The case of HCO 3 − and CO 3 2− may be more complex, because their concentration data are often not available (unless dedicated water titration is carried out, which is relatively rare). In contrast, alkalinity (Alk) and pH are more commonly found [26]. The procedure to derive [HCO 3 − ] and [CO 3 2− ] from Alk and pH is based on the thermodynamic theory of equilibria in aqueous solution [41,42].…”

Section: Savetable/plotgraphmentioning

confidence: 99%

“…For instance, excess alcohol addition as an • OH scavenger, coupled with monitoring of the alcohol transformation products as • OH probes, can result in an over-prediction of the nitrate photolysis quantum yield [53]. The addition of bicarbonate salts at sufficiently high concentration values can also inhibit geminate recombination, because of the scavenging of cage O •− (reactions 25,26). This process enhances the production of CO 3…”

Section: •−mentioning

confidence: 99%

“…Validation has been obtained in the cases of carbamazepine [18], ibuprofen [19], diclofenac and naproxen [20], atrazine [21], and 2-methyl-4-chlorophenoxyacetic acid (MCPA) [22], as well as pesticide phototransformation intermediates such as 2,4-dichloro-6-nitrophenol [23], 2-nitro-4-chlorophenol [24], and 3,4-dichloroaniline [25].After several years of using APEX, a number of clear advantages and disadvantages have come to light. The main advantage is probably the software's flexibility, which has not only allowed for the modeling of pollutant phototransformation, but has also provided important insights into the photochemical functioning of natural surface waters [26]. Moreover, it has been possible to extend the model applications from the originally foreseen simple systems (stationary and well mixed ones, such as overturning lakes) to more complex environments such as stratified lakes, rivers, and to include additional phenomena such as evaporative water concentration [27].…”

mentioning

confidence: 99%

See 1 more Smart Citation

A Critical View of the Application of the APEX Software (Aqueous Photochemistry of Environmentally-Occurring Xenobiotics) to Predict Photoreaction Kinetics in Surface Freshwaters

Vione

2019

Molecules

Self Cite

View full text Add to dashboard Cite

The APEX (aqueous photochemistry of environmentally occurring xenobiotics) software computes the phototransformation kinetics of compounds that occur in sunlit surface waters. It is free software based on Octave, and was originally released in 2014. Since then, APEX has proven to be a remarkably flexible platform, allowing for the addressing of several environmental problems. However, considering APEX as a stand-alone software is not conducive to exploiting its full potentialities. Rather, it is part of a whole ecosystem that encompasses both the software and the laboratory protocols that allow for the measurement of substrate photoreactivity parameters. Coherently with this viewpoint, the present paper shows both how to use APEX, and how to experimentally derive or approximately assess the needed input data. Attention is also given to some issues that might provide obstacles to users, including the extension of APEX beyond the simple systems for which it was initially conceived. In particular, we show how to use APEX to deal with compounds that undergo acid-base equilibria, and with the photochemistry of systems such as stratified lakes, lakes undergoing evaporation, and rivers. Hopefully, this work will provide a reference for the smooth use of one of the most powerful instruments for the modeling of photochemical processes in freshwater environments. All authors have read and agreed to the published version of the manuscript. Molecules 2020, 25, 9 2 of 34 the main ones in surface waters being chromophoric dissolved organic matter (CDOM), nitrate, and nitrite [3,4]. The irradiation of all the mentioned photosensitizers yields the photoreactive transient • OH (hydroxyl radical), which can produce another transient (CO 3 •− , the carbonate radical) upon reaction with inorganic carbon species (HCO 3 − and CO 3 2− ) [5]. Irradiated CDOM can also produce reactive triplet states ( 3 CDOM*), and the latter yield singlet oxygen ( 1 O 2 ) upon reaction with dissolved O 2 [3,6]. All the mentioned transient species ( • OH, CO 3 •− , 3 CDOM*, and 1 O 2 ) are involved to some extent in indirect pollutant phototransformation, depending on the reactivity of the given pollutant towards each transient [7,8]. Although they play a key role in indirect phototransformation of pollutants, the transients are mostly scavenged/quenched by natural water components. The latter include: (i) dissolved organic matter (DOM, either chromophoric or not), HCO 3 − and CO 3 2− in the case of • OH (plus Br − , which plays the main role in some saltwaters and in seawater); (ii) DOM again in the case of CO 3 •− ; (iii) dissolved O 2 for 3 CDOM*; and (iv) the water solvent for 1 O 2 [7]. The main mentioned formation and scavenging processes are summarized by the reactions below [3-7]: Molecules 2020, 25, 9 3 of 34 to validate this approach by comparing the predicted kinetics with known field data of pollutant phototransformation. Validation has been obtained in the cases of carbamazepine [18], ibuprofen [19], diclofenac and naproxen [20], atrazine [2...

show abstract

Long-term trends of chemical and modelled photochemical parameters in four Alpine lakes

Cited by 20 publications

References 60 publications

Insights into the Time Evolution of Slowly Photodegrading Contaminants

Insights into the Time Evolution of Slowly Photodegrading Contaminants

Long-term studies for evaluating the impacts of natural and anthropic stressors on limnological features and the ecosystem quality of Lake Iseo

A Critical View of the Application of the APEX Software (Aqueous Photochemistry of Environmentally-Occurring Xenobiotics) to Predict Photoreaction Kinetics in Surface Freshwaters

Contact Info

Product

Resources

About