High-concentrations diel-fluctuations of Plants Protection Products in dry periods

2021 ◽  
Author(s):  
Daniele la Cecilia ◽  
Anne Dax ◽  
Daniel Odermatt ◽  
Heinz Singer ◽  
Christian Stamm
Keyword(s):  
Surface Water ◽  
Expert Knowledge ◽  
Plant Protection ◽  
Parent Compound ◽  
Early Morning ◽  
Mitigation Strategies ◽  
High Temporal Resolution ◽  
Contamination Sources ◽  
Tile Drains ◽  
Diel Fluctuations

<p>Modern agriculture routinely uses Plant Protection Products (PPPs) to guarantee food security. However, PPPs can reach surface waters where they pose a threat to susceptible non-target organisms. Understanding the contamination sources and flowpaths is of utmost importance to design optimal pollution mitigation strategies. While highest concentration peaks typically occur during rainfalls following PPPs applications, a monitoring campaign in a small Swiss agricultural stream in 2019 detected several compounds in concentrations exceeding the precautionary limit of 100 ng/l by up to 14 times during a dry period. The further exploration of the time series revealed for the first time diel fluctuations of some PPPs. Such peculiar patterns excluded the occurrence of known contamination pathways including spray drift, wind erosion and dry deposition. Despite the availability of an unprecedented high-temporal resolution dataset, we were not able to disentangle the source-flowpath combination driving the observed peculiar dynamics.</p><p>Here we present the results of the follow-up 1-day field campaign aiming to close this knowledge gap. The campaign was carried out on the dry day of August 12<sup>th</sup> 2020 and we collected water samples every 6 hours from the stream at 6 different locations and from 4 outlets of active tile drains.</p><p>The results revealed widespread contamination by the fungicide fluopyram; its transformation product fluopyram-benzamide followed identical dynamics but its concentration was 10 times lower than the parent compound. This result is in line with the high DT50 of fluopyram and its broad use in the catchment. The data showed that diel fluctuations were a reoccurring phenomenon; concentrations were higher in the early morning and lower in the early evening at the most downstream location. However, the fluctuating PPPs showed a concentration peak in the upstream location at midday. We were able to narrow down the contamination sources of napropamide, clothianidin, and oxadixyl; the first is a current herbicide, the second is an insecticide not reapproved since 2020, while the third is an old fungicide banned in Switzerland in 2005, which we measured at approximately 200 ng/l. Finally, the investigated tile drains delivered PPPs at lower concentrations compared to the levels measured in the surface water, with the exception of the herbicide metamitron, which was measured at nearly 20 ng/l only at the outlet of 1 tile drain.</p><p>The presented research suggested that contamination sources can be localized by means of grab samples collected along the stream. However, it was not conclusive on the flowpath delivering PPPs to the stream. We hypothesize that 2 processes may explain the reported patterns: (i) irrigation at the upstream locations in the early morning; (ii) intra-daily exchanges at the interface between surface water and contaminated shallow groundwater. We will complement the study with expert knowledge by local stakeholders, satellite-derived soil moisture indices, high-resolution land use data and regulatory information to establish a methodology to optimally identify critical source areas in dry periods, where mitigation strategies should be put in place.</p>

scholarly journals Improved Automated Detection of Subpixel-Scale Inundation—Revised Dynamic Surface Water Extent (DSWE) Partial Surface Water Tests

2019 ◽  
Vol 11 (4) ◽  
pp. 374 ◽  
Author(s):  
John Jones
Keyword(s):  
Surface Water ◽  
Mixture Models ◽  
Model Development ◽  
Depth Estimation ◽  
High Temporal Resolution ◽  
Commission Error ◽  
Dynamic Surface ◽  
In Situ Data ◽  
The Us ◽  
Spectral Mixture

In order to produce useful hydrologic and aquatic habitat data from the Landsat system, the U.S. Geological Survey has developed the “Dynamic Surface Water Extent” (DSWE) Landsat Science Product. DSWE will provide long-term, high-temporal resolution data on variations in inundation extent. The model used to generate DSWE is composed of five decision-rule based tests that do not require scene-based training. To allow its general application, required inputs are limited to the Landsat at-surface reflectance product and a digital elevation model. Unlike other Landsat-based water products, DSWE includes pixels that are only partially covered by water to increase inundation dynamics information content. Previously published DSWE model development included one wetland-focused test developed through visual inspection of field-collected Everglades spectra. A comparison of that test’s output against Everglades Depth Estimation Network (EDEN) in situ data confirmed the expectation that omission errors were a prime source of inaccuracy in vegetated environments. Further evaluation exposed a tendency toward commission error in coniferous forests. Improvements to the subpixel level “partial surface water” (PSW) component of DSWE was the focus of this research. Spectral mixture models were created from a variety of laboratory and image-derived endmembers. Based on the mixture modeling, a more “aggressive” PSW rule improved accuracy in herbaceous wetlands and reduced errors of commission elsewhere, while a second “conservative” test provides an alternative when commission errors must be minimized. Replication of the EDEN-based experiments using the revised PSW tests yielded a statistically significant increase in mean overall agreement (4%, p = 0.01, n = 50) and a statistically significant decrease (11%, p = 0.009, n = 50) in mean errors of omission. Because the developed spectral mixture models included image-derived vegetation endmembers and laboratory spectra for soil groups found across the US, simulations suggest where the revised DSWE PSW tests perform as they do in the Everglades and where they may prove problematic. Visual comparison of DSWE outputs with an unusual variety of coincidently collected images for locations spread throughout the US support conclusions drawn from Everglades quantitative analyses and highlight DSWE PSW component strengths and weaknesses.

scholarly journals Monitoring monthly surface water dynamics of Dongting Lake using Sentinal-1 data at 10 m

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4992 ◽  
Author(s):  
Liwei Xing ◽  
Xinming Tang ◽  
Huabin Wang ◽  
Wenfeng Fan ◽  
Guanghui Wang
Keyword(s):  
Surface Water ◽  
Water Distribution ◽  
Remote Sensing Data ◽  
Water Area ◽  
Dongting Lake ◽  
Water Dynamics ◽  
High Temporal Resolution ◽  
Backscattering Coefficient ◽  
Distribution Maps ◽  
Lower Accuracy

High temporal resolution water distribution maps are essential for surface water monitoring because surface water exhibits significant inner-annual variation. Therefore, high-frequency remote sensing data are needed for surface water mapping. Dongting Lake, the second-largest freshwater lake in China, is famous for the seasonal fluctuations of its inundation extents in the middle reaches of the Yangtze River. It is also greatly affected by the Three Gorges Project. In this study, we used Sentinel-1 data to generate surface water maps of Dongting Lake at 10 m resolution. First, we generated the Sentinal-1 time series backscattering coefficient for VH and VV polarizations at 10 m resolution by using a monthly composition method. Second, we generated the thresholds for mapping surface water at 10 m resolution with monthly frequencies using Sentinel-1 data. Then, we derived the monthly surface water distribution product of Dongting Lake in 2016, and finally, we analyzed the inner-annual surface water dynamics. The results showed that: (1) The thresholds were −21.56 and −15.82 dB for the backscattering coefficients for VH and VV, respectively, and the overall accuracy and Kappa coefficients were above 95.50% and 0.90, respectively, for the VH backscattering coefficient, and above 94.50% and 0.88, respectively, for the VV backscattering coefficient. The VV backscattering coefficient achieved lower accuracy due to the effect of the wind causing roughness on the surface of the water. (2) The maximum and minimum areas of surface water were 2040.33 km2in July, and 738.89 km2in December. The surface water area of Dongting Lake varied most significantly in April and August. The permanent water acreage in 2016 was 556.35 km2, accounting for 19.65% of the total area of Dongting Lake, and the acreage of seasonal water was 1525.21 km2. This study proposed a method to automatically generate monthly surface water at 10 m resolution, which may contribute to monitoring surface water in a timely manner.

Inorganic nitrogen, sterols and bacterial source tracking as tools to characterize water quality and possible contamination sources in surface water

2012 ◽  
Vol 46 (4) ◽  
pp. 1079-1092 ◽  
Author(s):  
Vesna Furtula ◽  
Heather Osachoff ◽  
George Derksen ◽  
Hafizan Juahir ◽  
Al Colodey ◽  
...  
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Inorganic Nitrogen ◽  
Source Tracking ◽  
Bacterial Source Tracking ◽  
Contamination Sources

scholarly journals Modelling the Fate of Pesticide Transformation Products From Plot to Catchment Scale—State of Knowledge and Future Challenges

2021 ◽  
Vol 9 ◽  
Author(s):  
Matthias Gassmann
Keyword(s):  
Preferential Flow ◽  
Prediction Models ◽  
Environmental Fate ◽  
Plant Protection ◽  
Formation Rate ◽  
Regional Scale ◽  
Parent Compound ◽  
Transformation Products ◽  
Model Complexity ◽  
Catchment Scale

Transformation products (TP) of pesticides are found everywhere in the aquatic environment. Their dynamic formation and subsequent transport from agricultural fields to adjacent water bodies can be estimated by using environmental fate models, which is done in the registration process for plant protection products in the European Union. In this study, peer-reviewed applications of such models, the model complexity and their structure are documented and analysed. In total, 20 publications of 10 models – eight leaching models (GLEAMS, MACRO, RZWQM2, PEARL, PRZM, Pelmo, LEACHM, HYDRUS 1-D) and two catchment scale models (Zin-AgriTra, FRM) – were identified. The reviewed models greatly differ in their process complexity regarding the formation rate and the formation pathways of TPs.The major reason given for models failing to reproduce sampled TP concentrations in case studies was an erroneous substance transport, especially missing preferential flow simulation in soil. However, the contribution of TP formation processes to simulation uncertainty was not analysed at all in most of the studies. By comparing the structure of existing models, the state of knowledge on TP fate and requirements of TP fate assessment, the following recommendations were drawn: i) It is suggested that the models should be updated to reflect the current state of knowledge in process research, especially more complex transformation schemes and the formation of different TPs in different compartments, which was not included in most of the models. ii) Even though there are pesticide parent compound fate models at the catchment scale with a temporal resolution of one day, none of these models is able to simulate TP fate. Such models would enable scientists and authorities to estimate the environmental fate of TPs at the larger catchment scale or the regional scale. iii) To get over the assessment of the huge number of TPs formed in the environment, an integration of Quantitative Structure Properties Relationship models predicting TP fate characteristics, TP pathway prediction models and environmental fate models is suggested. This would allow for a largely automated and comprehensive assessment of the fate of a pesticide parent compound and all its TPs for regulatory purposes.

scholarly journals Surface Water and Contamination Sources in Urban River Watersheds (Northern Portugal)

2021 ◽  
Vol 22 (2) ◽  
pp. 67-74
Author(s):  
Isabel Horta Ribeiro Antunes ◽  
Ana Brás ◽  
Amelia Paula Reis
Keyword(s):  
Surface Water ◽  
Urban River ◽  
Contamination Sources ◽  
Northern Portugal

scholarly journals Prevalence of pesticides in Krško-Brežice polje aquifer

Geologija ◽  
2021 ◽  
Vol 64 (2) ◽  
pp. 267-288
Author(s):  
Nina MALI ◽  
Anja KOROŠA ◽  
Janko URBANC
Keyword(s):  
Surface Water ◽  
Passive Sampling ◽  
Sampling Method ◽  
Agricultural Land ◽  
Plant Protection ◽  
Degradation Products ◽  
Plant Protection Products ◽  
The Past ◽  
Groundwater Samples ◽  
The World

Groundwater pollution with pesticides is a problem that occurs all over the world as well as in Slovenia. Considering the past high loads of groundwater with pesticides, the purpose of the presented research was to determine the presence of pesticides in the groundwater of Krško-Brežiško polje in the period 2018-2019 and to check the applicability of the passive sampling method. A total of 21 groundwater samples were taken at 11 locations and 2 samples each in the Sava and Krka rivers. We identified 15 pesticides and their degradation products. Atrazine and its degradation product desethylatrazine were most frequently determined in groundwater samples. They are followed by desethylterbutylazine, terbutylazine, metolachlor and simazine. Atrazine, desethylatrazine, chlortoluron, metolachlor and terbuthylazine were detected in surface water. A total of 24 samples were taken in groundwater and surface water using the qualitative passive sampling method. We singled out 8 pesticides that appear in two campaigns. The frequency and occurrence of individual pesticides by both methods are comparable. Passive sampling has proven to be an appropriate method of identifying the presence of pesticides. The highest loads in the Krško-Brežiško field arise from the agricultural land areas. Groundwater is more contaminated with pesticides in the central part of the field in the direction of groundwater flow from west to east. In the groundwater of the Krško-Brežice field, atrazine and desethylatrazine are still the most frequently detected pesticides with higher concentrations, despite a 20 years long ban on the use of atrazine-based plant protection products.

scholarly journals Mobile Sensing Around the Globe: Considerations for Cross-Cultural Research

2022 ◽  
Author(s):  
Le Vy Phan ◽  
Nick Modersitzki ◽  
Kim Karen Gloystein ◽  
Sandrine Müller
Keyword(s):  
Cultural Psychology ◽  
Real Life ◽  
Mobile Sensing ◽  
Cross Cultural ◽  
Mitigation Strategies ◽  
High Temporal Resolution ◽  
Cross Cultural Differences ◽  
Cultural Research ◽  
Cross Cultural Research ◽  
Research Findings

The ubiquity of mobile devices allows researchers to assess people’s real-life behaviors objectively, unobtrusively, and with high temporal resolution. As a result, psychological mobile sensing research has grown rapidly. However, only very few cross-cultural mobile sensing studies have been conducted to date. In addition, existing multi-country studies often fail to acknowledge or examine possible cross-cultural differences. In this chapter, we illustrate biases that can occur when conducting cross-cultural mobile sensing studies. Such biases can relate to measurement, construct, sample, device type, user practices, and environmental factors. We also propose mitigation strategies to minimize these biases, such as the use of informants with expertise in local culture, the development of cross-culturally comparable instruments, the use of culture-specific recruiting strategies and incentives, and rigorous reporting standards regarding the generalizability of research findings. We hope to inspire rigorous comparative research to establish and refine mobile sensing methodologies for cross-cultural psychology.

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