1 / 14

Detection & Monitoring of Carbamate Pesticides

Detection & Monitoring of Carbamate Pesticides. Content. Objective Case study background Introduction - Why use carbamate pesticides? Health impacts of carbamate pesticides. Measurement method Results and comments Advantages & disadvantages of systems used. Objective.

tala
Download Presentation

Detection & Monitoring of Carbamate Pesticides

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Detection & Monitoring of Carbamate Pesticides

  2. Content • Objective • Case study background • Introduction - Why use carbamate pesticides? • Health impacts of carbamate pesticides. • Measurement method • Results and comments • Advantages & disadvantages of systems used

  3. Objective A case study of twoflow-injection biosensor systems using semi disposable enzyme reactor have been developed to determine the presence and amount of Carbaryl, a type of Carbamate pesticide.

  4. Case Study Background Water samples collected from wells located in the Songkhla Province of Thailand. There are various vegetation farm found in that area. The six sampling wells that were chosen are all located near vegetable growing areas.

  5. Introduction - Why use carbamate pesticides? Increased use of Carbamate pesticides due to • its ability to kill of wide range of pest. • lowerenvironmental persistence • economicallyviable • pastresults visible While Organochlorine pesticides  are • environmentally persistent • bio-accumulative pesticides • genotoxic– (deleterious action on a cell’s genetic material affecting its integrity) • endocrine disruptors – ( interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body)

  6. Health impacts of Carbamate pesticides • Acetylcholinesterase, is an enzyme that degrades the neurotransmitter, acetylcholine. • Carbamatepesticides causes a inhibition/retardation of acetylcholinesterase(AChE) enzymatic activity when ingested. • Thus when there is a inhibition of AChE activity, there will tend to be an increase amount of acetylcholine • In there is high level of acetylcholine, it can cause convulsions, epilepsy and tremors.

  7. Measurement method Test was done with 2 different type of flow-injection biosensor systems: - Potentiometric ( ion analyzer – measures pH level) - Conductimetric (conductivity meter – measures conductivity level) • The acetic acid dissociated further to release hydrogen ions as shown: • The released hydrogen ions are then used by both the potentiometric & conductimetric system, which respectively uses pH electrode to detect the increase of hydrogen ions, and a lab-built conductivity meter to detect the increase of conductivity due to the increased number of ions.

  8. Measurement method • Step 1 : Immobilization of acetylcholinesterase on activate silica gel. • Step 2: Injection of Acetylcholine solution to determine initial enzymatic activity. • Step 3: Injection of water sample which may be containing carbamate pesticides. • Step 4: Stop flow when sample solution reaches enzyme reactor. ( Incubation period ) • Step 5: Wash out of pesticide containing solution,from system .injection of Acetylcholine solution again, and determine the enzymatic activities. • %Inhibition can then be calculated for the before & after results. • Inhibition, I (%) = [ (Ho - H1) / Ho ] x 100 Ho – Height difference given by enzyme reactor before Hi – Height difference given by enzyme reactor after

  9. Results and comments • Only samples from sampling site 1 and 2 contains carbaryl by using the two biosensor systems • Standard carbaryl was analyzed by the GC-MS first. • Incubation time is 5 and 10min for the potentiometric and conductimetric system respectively.

  10. Results and comments • Potentiometric system: Inhibition values 7.2% and 2.9% • Conductimetric System: Inhibition values 5.9% and 2.8% • Detection limit of system  10% inhibition  0.3ppm • US EPA standard  12% inhibition  0.7ppm

  11. Results and comments • Presence of carbaryl in water samples were double confirmed with gas chromatography–mass spectrometric (GS-MS) system Reasons for given results • two wells were nearer to the vegetable patches than the rest • vegetable patches near these two sites were just recently sprayed, a few days before the water collection • As half-life of carbaryl in surface water is about 8 days

  12. Advantages & disadvantages of systems used Advantages • Both systems are simple to construct and easy to operate - The potentiometric system uses pH electrode that is readily available - The conductivity cell in the conductimetric system is very easy to make, using a small section of a glass tube with two stainless steel tubes glued to the ends as electrodes • Both systems allow the analysis of a large number of samples • Can be used as a monitoring or a screening method for pesticides Disadvantages • Although the enzyme reactor is specific to one particular type of compound, the detection sensitivity is still not high enough to detect low concentrations of Carbaryl in the water sample.

  13. THE END http://detectionandmonitoring.wordpress.com/ Credits to: Prince of Songkla University, Hat Yai, Songkhla

More Related