Калифорния вводит запрет на использование гербицида параquat из-за связи с болезнью Паркинсона

California officials have announced the phase out of a widely-used herbicide that has been linked to serious health conditions, including Parkinson’s disease. Last month the California Department of Pesticide Regulation (CDPR) said all manufacturers of products containing paraquat-dichloride, or paraquat, have voluntarily canceled their product registrations in the Golden State. The move comes after state regulators began reevaluating paraquat in November 2024, and preliminary reports identified potential ties between paraquat exposure, thyroid impacts and birth defects. CDPR also said its reports showed the herbicide may have adverse effects on other organisms, particularly birds. California becomes only the second state in the U.S. behind Vermont to ban paraquat. Licensed dealers can still possess and sell voluntarily-cancelled pesticides, like those containing paraquat, for up to two years after the cancellation, per state law. But this decision has drawn criticism from organizations like the California Farm Bureau. A spokesperson for the organization told CapRadio the move removes an important tool for farmers, “and its loss raises a broader concern about California’s increasingly difficult marketplace,” citing increasing costs and complexity within the state. Dr. Olukayode Jegede is a professor with the UC Davis Department of Environmental Toxicology. He spoke with Insight Host Vicki Gonzalez about how paraquat is used, and some of the reasoning behind the state’s ban. This interview has been edited for length and clarity. Interview highlights What exactly is paraquat, and how is it used? Paraquat is a herbicide, designed to attack weeds [and] plants. Paraquat is also a broad spectrum herbicide, so it can be used to disrupt or destroy weeds of different classes or types.  It’s used on a number of crops — almond, pistachio, alfalfa. It’s usually used before planting, so you can clear the weeds, and it works very, very well.  It's affordable, and it’s been around for a long time. We're talking about California, but is this a widely-used herbicide? It’s used globally, although there are jurisdictions where [paraquat] is being banned now like the European Union. I think it’s been banned in China as well, despite the fact that China produces most of the [paraquat] we use in the U.S. It’s cheap, it’s effective, so why not? Can you just talk about the health issues that have been tied to paraquat? Any pesticide whatsoever will have some toxic abilities — that’s why they are pesticides. The same thing goes with paraquat. It has this mode of action where it generates a lot of reactive oxygen species, which causes oxidative stress. It does this at a very high rate compared to many other chemicals; it’s concerning in that regard. That's why it works effectively for plants. Epidemiological studies have linked it with Parkinson's disease, and that's why it's been in the news. But in terms of lab studies, we don’t have a lot actually showing these relationships. In terms of the effect on soil ecosystems… one thing I would say as a toxicologist is sometimes a pesticide might not be as toxic as you think it is, but my whole issue is with the persistence. It’s persistent in the soil, about 3,000 days in terms of DT50 [degradation time 50%, or half-life], that’s about eight years.   If you have any pesticide or chemical that's persistent in the environment, then there's a chance that it can cause effects, or they can react with other things that cause effects. That might be the reason when you do these studies, and find most people in these areas where we spray paraquat have high incidence of Parkinson’s, we can relate it and say "okay, maybe this pesticide is causing it.”  Almonds, still in their green hulls, hang on a tree at an orchard owned by farmer Joe Del Bosque in Firebaugh, Calif., on July 9, 2021AP Photo/Terry Chea And the more paraquat gets sprayed, the more it sticks around?  Yeah, it sticks around. One good thing about paraquat is it binds strongly with organic matter and clay in the soil. So it’s not an issue when it comes to groundwater; it doesn’t leach into groundwater, which is very good. [But] there are some soil organisms that feed on organic matter, and then they are exposed to paraquat that is bound there. One probable pathway to humans is because it binds to clay, clay tends to cake out, dry and [turn to] dust. It can spread through that. That’s probably how people get into contact with paraquat. Epidemiological studies have linked it, but in terms of lab studies you don't have a lot to actually pin it to paraquat. And the reason is simple; nobody funds those kinds of studies. Nobody wants to look at how it is effective on some cells. It’s an issue, but I also understand when people come up with, “we have paraquat here, we have more Parkinson’s disease here.” That’s probably the reason why the states were like, “maybe we should phase it out.” How significant is this decision for California to phase out paraquat? It's pretty significant. People have just two years to use whatever they have. Manufacturers are not manufacturing anything for California now. There won't be sales after two years.  Of course, farmers might have to start looking out for alternatives. It’s now about economics; that’s usually the case with these trade-offs. You have to look at costs, because paraquat is effective, but then if there are issues with health we also have to look at that. Does this decision come easy for the state? Do they often phase out chemicals and herbicides like this? No, I won't say that often. It’s a very tough decision for the state, because the state wants to protect human health, as well as take care of farmers. California is the biggest agricultural state, [making] a lot of money from agriculture. You have to say, "we should listen to the farmers as well." Even as a toxicologist, I like to listen to them and learn from them. But then when you have a lot of clamor, and people have been able to show these studies. You don’t have other parallel studies to compare and say “lab studies don’t show this link.” If we had that maybe the state would have been able to take different directions, but this is what they have and it’s in the public interest. They want to do the right thing. The California Farm Bureau pushed back on California’s plan, saying paraquat is an important tool for farmers and the loss raises bigger concerns about the state’s agricultural marketplace. As a toxicologist, how is this about trying to strike the right balance? I think the Farm Bureau speaks for a generality of farmers. There will be some farmers that will be like, “it’s good for us to face it out.” But I understand what the farmers are saying; it’s an important tool for them. And for them, it’s very hard — you need to convince them. If we had more research, more data, it would have been easy and everybody would know, "oh, this is clear. We need to get this out.” But the data we have is epidemiological studies; it's still debatable. That's where the farmers are leaning towards, “this is debatable, so why should you ban it?” If you have a replacement [that] is good, as effective as paraquat, not as concerning as paraquat, then farmers might say “we’ll go with this, and it’s not too expensive.” I understand the farmers, and I think they have a point. They have a right to be angry. But the state has to look policy-wise, is it good for us to take this route? They might look at it from health costs, what’s the health cost of Parkinson’s disease vis-a-vis what you get from agriculture. They have reasons why they took that direction, and [made] those decisions. I get the Farm Bureau, but I don’t know if it’s going to be reversed.