Week in Review 3

The third week is the halfway point for the PSD training. The first field retrieval went well, though there were issues with cage positioning and air exposure. Modifications were made and the remaining cages successfully redeployed.

We recognized that the bench sheets should be in French as well as English, not necessarily one or the other, but bilingual would be best. Locustox staff are working on this. Also, we are working on collecting more information in the bench sheets.

After retrieval Locustox extracted the PSD and prepared the field and quality control samples for GC analysis (9 samples total). The lab equipment was well suited to the procedure, though a TurboVap LV is preferable for high sample throughput (greater than 10 - 15 samples at a time).

The GC successfully ran the OC pesticide standards (using OSU's OCPQUANT.M method), though neither a calibration curve nor data analysis was completed. The GC was loaded with the extracts to run over the weekend. We attempted to perform the analysis in a manner consistent with OSU's approach to facilitate future data comparisons.

Next week we will again travel to Saint Louis for the second of three retrievals. This next retrieval is particularly important as two sets of PSDs will be collected with one going back to OSU for analysis and comparison with Locustox's analysis.

We are a couple days behind on lab work, but as this is the first such training attempt we will use it to frame future training schedules.

Field retrieval 1 extractions

Oct. 4^th 2007

The sample extractions were started first thing in the morning (~8:00 am). Adama and Anna added 100 mL of hexanes to the samples and prepared a reagent blank and lab OC pesticide spike. The OCP spike consisted of 200uL of a 1,000 ppb concentration standard prepared from the Chemservice OC pesticide standard OSU provided. Adama, Marie, Anna, and Sokhna worked on the second dialysis.

Dialysis of retrieved PSDs.

Cheikh ran the standards on the GC using the OSU methods. Results should be available Friday.

A review of the field bench sheets revealed substantial deviations, mostly in the form of unrecorded data. I discussed this with Cheikh and we will work with the staff on the next retrieval to increase completion.

Oct. 5^th 2007

The standards finished without incident on the GC but there was not time for anything but a cursory review of the runs. Background was low, many of the 5 ppb peaks were identified, but specifics will not be available until Monday at the earliest, possibly Wednesday due to the field work at Saint Louis.

Today Locustox performed the sample blow down on Rotavaps and the Techne Dri-block. In attendance: Adama, Marie, Sokhna and Cheikh.

Adama performing the the initial sample blow down with a Rotavap.

Transfer from round bottom flask to smaller tube.

One sample, the trip blank, became contaminated with water on the Rotavap blow down. We used it as an example on how to remove water from a sample and where to keep accurate notes on the bench sheet.

After the extraction the samples were loaded onto the GC with the standards for analysis over the weekend.

Pont Gendarme field sites map

This is a modification to an existing slide. The field sampling sites are represented by the white circles with red outline. We have had poor luck with our GPS receiver, so coordinates are pending.

PSD cleanup

We performed the field cleanup steps for the samples collected yesterday. For the UN-GEF project, this cleanup is performed in the lab, not in the field. The following Locustox staff were in attendance: Cheikh, Adama, Anna, and Marie.

I demonstrated the proper PSD cleanup procedure using the field and trip blanks from yesterday’s retrieval. Note that these blanks do not normally get this cleanup, but this was for demonstration purposes. The staff then completed the remaining sample cleanup including an extraction blank. These samples will be extracted tomorrow.

The OSU field benchsheets have a location to record the manufacturer and lot numbers of the cleanup reagents. I neglected to move this information from the field to the extraction benchsheet and as a result it was not recorded. I will rectify the problem when Cheikh and I review the benchsheets.

The PSD dialysis portion of the extraction needs to be completed in a single day; therefore, the extraction will not begin until Thursday morning. The entire extraction should be complete by Friday afternoon.

The prep blank, lab spike, and field and trip blanks from the deployment will not be extracted this round. This first extraction will familiarize the staff with the procedures. As the mentioned samples are valuable and irreplaceable quality control, they will be part of the second extraction to take place after retrieval of the Locustox/OSU duplicates next week.

One thing has become clear: It would be preferable to have the SOPs and SAMs translated into French. This is something that is important not just to Locustox, but to future partner labs.

Also, a number of the details are lab specific, which is to be expected for a SOP, but they need to be modified for Locustox and the UN-GEF project in general (such as the cleanup reagents info). I can help consult on the specifics and Cheikh could translate but we are limited on time; therefore, we are assigning the staff the documents to translate. This should help familiarize them with the procedures and benchsheets.

After the translation we will review the documents and make necessary changes. All the translated documents will be emailed to OSU for further review and backup.

Field retrieval 1

The first retrieval at Pont Gendarme went well, though there were some unexpected issues with the cage positioning. In attendance for the retrieval training were Adama, Marie, Anna, Sokhna, Cheikh and Makhfousse. Abdoulaye Djiop again joined us and helped significantly during retrieval.

We left for Saint Louis Monday, the 1^st in the afternoon and arrived that evening. We left the hotel at about 7 am (first light) and headed to the field site.

At the first site, the main drainage pumping station, we found the cages exposed to air (about 15 cm above the water line). The water level had been lowered to facilitate fishing, which was ongoing when we arrived (the fishermen declined to allow photos). Exposure to air prevents water sampling and, in fact, allows for air sampling; neither condition is suitable for this project.

The PSD cages as we found them at the first site.

Also, a cage had clearly been tampered with, the shell removed and the retention nuts missing. The shell had been dented, but the PSDs were still intact. We collected this cage for analysis.

The cage that had been tampered with lost it's shell on retrieval.


A rusted spring and accompanying discoloration on the PSD.


The dented shell.

The cages were repositioned lower in the water column.

The retention springs on the cages are not stainless steel and had rusted. These should be replaced with stainless springs.

Staff washed the two PSD in local water and packaged them in a clip-sealed Teflon bag according to the SOP. (Note: this project necessitates a deviation from the OSU SOP. The OSU SOP requires the local water rinse, then subsequent rinses in HCL, 18 Mohm/cm water, acetone, and finally isopropanol. For the UN-GEF project, the PSDs are washed in local water and then sealed in a Teflon bag. The rinses are performed at the laboratory. This modification is a logistical requirement and has been vetted by OSU/ Locustox work from the summer of 2006.) A trip blank accompanied our retrieval and a field blank remained exposed for the entire operation at this site.

At the second site, the main irrigation canal, the cages were again exposed, this time about 20cm above the water line. Staff retrieved, cleaned and stored the PSD without incident and according to the SOP. After retrieval, the cages were repositioned so they rested horizontally in the water column.

The cages as we found them at the second site.

Removing the PSDs for the local water wash (L to R: Anna, Marie, Sokhna).

Cheikh and Mr. Djiop helping to reposition the cages horizontally in the water column.

We discussed the possibility of manufacturing new shell retention nuts with an eye hook on them. This would allow easy horizontal deployment, prevent the nut from inadvertently unscrewing, and may help prevent tampering.

The PSDs at this site had about the same amount of fouling as those at the first site.

The third site is the main irrigation pumping station with the cages deployed in the Goron-Lampsor tributary. The cage and PSDs here were extremely clean; no signs of rusting or fouling. Additionally, the cages remained completely submerged. Staff retrieved, cleaned and stored the PSDs without incident in accordance with the SOP.

We again witnessed local household water collection and fishing in the area.

Retrieval of the cages and water quality data collection at site 3

(L to R: Anna, Adama, Mr. Djiop).

At the fourth site, the main drainage canal, the cages remained well positioned. Again, staff retrieved, cleaned and stored the PSDs without incident in accordance with the SOP.

Cage retrieval at site 4 (L to R: Marie, Sokhna, Mr. Djiop, Anna, Makhfousse).

After the final collection we returned to Dakar and deposited the samples at the laboratory that afternoon.

The staff have become comfortable with handling the PSDs and benchsheets. While I was initially disappointed that the first two sites’ cages were partially exposed, Makhfousse pointed out that the incident helps training. It also underscores the fact that these data should be limited to training purposes only.

The PSD extraction, GC analysis and data evaluation steps remain and we will accomplish as much as we can in the remainder of the week.