Paradigma complejo-evolucionista

DATE SITE NEOCHETINA BRUCHI NEOCHETINA EICHHORNIAE February 26, 1995 April 1, 1995 May 6, 1995 June 10, 1995 July 8, 1995 August 12, 1995 * March 5, 1994 March 5, 1994 August 20, 1994 August 20, 1994 V VI V VII VII V I II II IV 244 139 735 259 276 250 727 - 221 - 192 149 283 464 576 607 - 899 - 320

GROUP DISCUSSION

Pieterse The 2,4-D test has not been cleared by your EPA, right? I see that you have the tested paraquat, on what basis was this decided?

de Graft Johnson We have tested this on very small areas within Ghana. Now for next year's testing we hope that glyphosate and 2,4-D will be used. These will be very limited, on some small streams and applied from a craft. Now, before this we haven't attempted using Gramoxone (paraquat) on any large scale. In fact it wouldn't be cleared for use. But we saw a situation where we thought we must get rid of water hyacinth quickly and those infestations were in a small stream. So we quickly went in for the easiest available chemical. In addition, the stream was not being used for anything like drinking purposes. So we quickly went out there and used paraquat to wipe out water hyacinth in that stream. It is not implicit that paraquat would be used on any trials next year by the project.

As regards the problem with 2,4-D, I still can't understand. It appears that the Technical team of the Environmental Protection Agency, may have their own biases. I presume that is why there is the delay in clearing it. I have given the agency some available literature on the herbicides. It appears that someone insists that there is some literature which states that 2,4-D has something to do with haemoglobin or combines in the blood. I can't be too sure about that now. However, this person is insisting that there should be more information on that. Because of that the other members in the Technical Group cannot find their way to say, "O.K., go ahead and use it." I presume that is the result and you can't go ahead and use that herbicide.

There is also a possible use of some harvesters. We have in Ghana about 3 harvesters, 2 of British make. One is used on the Lake Volta and one on the reservoirs that provides water for Kumasi. That kind of harvester is not very efficient. You fix the cutter and after the cutting is done you have to remove the cutter and put on the rake. This harvester is called a Water Devil - it's British made. There is a harvester of German origin (Navalis) which is used in the lower water Volta River to clear landing sites for the ferries that ply the river.

Regarding the question of repairs to these crafts, the crafts have been imported, and the spares are not easily available. The Navalis harvester was out of order for months during the rehabilitation of one of the bridges in the lower Volta. The company undertaking the bridge repairs rehabilitated the harvester and is using it to clear the weeds in the area.

Otherwise it was out of use because the blades were blunt and they couldn't have replacements.

I believe there is a program between the Ghana Government and the Japanese Government. If it is approved, the Japanese Government would provide some harvesters, which we hope to use in the Tano/Abbey lagoon to clear access to villages and the Jewi Wharf that has often been blocked by these floating weeds, until certain other management practices could be put in place. But as far as I am concerned the agreement is not being signed and it's supposed to be harvesters plus barges, spares and some trucks.

Charudattan What are the health effects of 2,4-D?

de Graft Johnson We would appreciate having documents that detail the health effects of 2,4-D because we don't have access to that much information. So, if this is available and we have them either through the course of our stay here or later on, we could give it to the technical people who are in the process of having these chemicals. The information can help these people with their assessment.

Haller There was a Swedish study and a study done in the mid-western United States on nontoxic nymphoma - a type of cancer. Those studies were reported about 5 years ago. And now the National Cancer Institute has done a thorough survey as well as the American College of Toxicology and we have a publication on that. Also the EPA is re-registering 2,4-D, glyphosate, and the entire aquatic group of herbicides. Re-registration of 2,4-D was supposed to happen, all brought up to standards by January of 1996. There have been some delays; maybe by January of 1997 it will be fully re-registered with all of the studies that have to be done before the registration. The word on the street, among the people that are using the materials, and the industry as well, is that there is no red flag, there is no major problems, and the availability 2,4-D to use in water in the U.S. will be continued.

Labrada What about the formulation?

Haller There will be 2 formulations used in the U.S.; actually 3 formulations. 1) 2-4,D acid - when the salt hits the water the acid, breaks down and you end up dealing with the acid. So, all of the registration studies had to be done with the acid. 2) The amine salt and the other salt that we used in submerged weed control is the butoxy form, used in the Tennessee valley and on up into Canada. So there are 3 and really 2 that are commercially available. The amine and the butoxy are both used in U.S. and Canada.

The maximum contamination level that is allowed in water in the U.S., 0.1 mg per litre, in potable water. The typical half-life in water ranges from 3 to 7 days for the amine. This number is established by the Environmental Protection Agency and it is at least 100 fold less than in the no-effect level.

De Graft Johnson As I said earlier, it would be good to have publications to be given to our Environmental Protection Agency to have a look at. Then they will decide for or against allowing 2,4-D to be used. If there is anything that we are going to do, it has to be on a small scale, until the time that 2,4-D is approved.

Charudattan Where from do you normally get all of your information or literature? de Graft Johnson Sometimes from the companies themselves, if they are willing to give it;

sometimes they don't. I think its the agents who really know. Once the company wants to sell anything to Ghana, it has to seek clearance from the Agency. So I am surprised that they (Agency) doesn't have that much information. They should have more information on these things or they should insist that all the chemical companies give them as much details as possible if they don't have the right access to them.

THE WATER HYACINTH PROBLEM IN WEST AFRICA