Annotation for dataset of publication <Pesticide Risks in Small Streams – How to Get as Close as Possible to the Stress Imposed on Aquatic Organisms>

[Abstract] 
The dataset contains concentrations profiles of 213 agricultural pesticides in surface water samples. Half-day composite samples were taken from five small streams in Switzerland from the beginning of March to the end of August 2015. Half-day samples from discharge events were measured individually, whereas half-day samples taken during dry weather periods between discharge events were pooled to samples of variable lengths (five days on average) and then measured resulting in 34 to 60 measured samples per site. 

Studies using the data and describing the methods: 
+ Doppler et al., 2017: Aqua & Gas, 4, 46-56 (in German) and Doppler et al., 2017: Aqua & Gas, 12, 42-52 (in French)
+ Spycher et al., 2018: Environ. Sci. Technol.  52, 8, 4526-4535. https://pubs.acs.org/doi/10.1021/acs.est.8b00077


[Dataset Organization]
There are two comma-separated text-files: 
+ NAWA_Spez_2015_original_samples.csv: measurements of the original samples
+ NAWA_Spez_2015_time_weighted_averages_each_halfday.csv: measured and calculated concentrations for each half-day of the sampling campaign. Half-days with missing samples (7% of the total time covered) are also reported, but all variables are set to NA apart from the compound identifiers (Name and CAS) and the half-day identifier (ID and time)

[Scientific Context]
The goal of the study was to maximize both the number of compounds measured and the temporal resolution and that over a full growing season. All details on sampling, analytical methods and data evaluation are given in the methods section of the publication of Spycher et al. (2017). 

+ There are 12 variables in NAWA_Spez_2015_original_samples.csv (213 cpds x 298 Sample IDs = 63'474 rows)
	- Sample_ID: ID of sample in chronological order. First digit indicates stream (1: Mooskanal, 2: Weierbach, 3: Eschelisbach, 4: Canale Piano di Magadino, 5: Tsatonire)
	- Samplename_measured_sample: Samplename of measured sample. Can be either a single half-day sample or a pooled sample consisting of several half-days. Can differ from sample_ID if pooled samples were interrupted by single half-days with separate measurements (due to rain events). In such cases the data have different Sample_IDs, but the same Samplename_measured_sample. Total number of measured samples is 249.
	- Stream: Name of five small streams of monitoring campaign
	- ID_Begin: First half-day of measured sample
	- ID_End: Last half-day of measured sample
	- Date_Begin_CET: Begin of first half-day of sample (time given as Central European Time during daylight saving time, i.e. UTC + 2 h)
	- Date_End_CET: End of last half-day of sample (time given as Central European Time during daylight saving time, i.e. UTC + 2 h)
	- Name: Name of compound
	- CAS-Number: CAS-Number of compound
	- Concentration_ng_L: Concentration of compound [ng/L]. Concentrations < LOQ are denoted with zero.
	- LOQ_ng_L: LOQ of compound [ng/L]. Specific for site and measurement run (potentially 23 different LOQs)
	- Type: Type of pesticide, i.e. F: Fungicide, H: Herbicide, H(S): Herbicide Safener, I: Insecticide, B: also registered as biocide

+ There are 15 variables in NAWA_Spez_2015_time_weighted_averages_each_halfday.csv (128 cpds x 1805 ID.halfday = 231'040 rows)
	- ID.halfday: ID of half-day from first half-day of campaign to last half-day. First digit indicates the stream (1: Mooskanal, 2: Weierbach, 3: Eschelisbach, 4: Canale Piano di Magadino, 5: Tsatonire).
	- Samplename_measured_sample: Samplename of measured sample. Can be either a single half-day sample or a pooled sample consisting of several half-days. Total number of measured samples is 249.
	- Stream: Name of five small streams of monitoring campaign.
	- Date_CET: Date and time at beginning of half-day sample (time given as Central European Time during daylight saving time, i.e. UTC + 2 h)
	- Name: Name of compound
	- CAS-Number: CAS-Number of compound
	- Type: Type of pesticide, i.e. F: Fungicide, H: Herbicide, H(S): Herbicide Safener, I: Insecticide, B: also registered as biocide
	- Original_Concentration_ng_L: Concentration of compound at given half-day [ng/L]. Concentrations < LOQ are denoted with zero.
	- LOQ_ng_L: LOQ of compound [ng/L]. Specific for site and measurement run (potentially 23 different LOQs)
	- C_twa_14d_fixed_steps: 14d-time weighted average concentration. Calculation starts with first half-day of campaign. Missing samples ignored for interruptions up to 1 day. For interruptions > 1 day the calculation is restarted on first half-day after the interruption.
	- LOQ_mean_over_14d: 14d-time weighted LOQ (LOQs can vary as the different water samples were measured in more than one run)
	- C_twa_14d_moving: 14d-time weighted average concentration calculated with a moving window approach. On each half-day the concentration was calculated as the mean of the corresponding half-day and the 13.5 previous and the 13.5 following half-days.
	- C_twa_3d_fixed_steps: 3d-time weighted average concentration. Calculation starts with first half-day of campaign. Missing samples ignored for interruptions up to 1 day. For interruptions > 1 day the calculation is restarted on first half-day after the interruption.
	- LOQ_mean_over_3d: 3d-time weighted LOQ (LOQs can vary as the different water samples were measured in more than one run)
	- C_twa_3d_moving: 3d-time weighted average concentration calculated with a moving window approach. On each half-day the concentration was calculated as the mean of the corresponding half-day and the 2.5 previous and the 2.5 following half-days.


[Citation]
Spycher et al. 2018: https://pubs.acs.org/doi/10.1021/acs.est.8b00077

<DOI dataset>

Questions: simon_lukas.spycher@alumni.ethz.ch, heinz.singer@eawag.ch