The Department of Environment (DOE) has come up with a plan to start the process of rehabilitating the New River in the Orange Walk District. They want to replenish its dissolved oxygen stores that were depleted by the pollution currently afflicting it. There are some inherent risks to their planned course of action, and so, the DOE is testing their oxygenation plan in a secluded part of the river first.
Readers may be aware that part of the nutrient pollution of a waterway, such as a river, the run-off from the land, or wastewater from any human activity, causes the body of water to be concentrated with nutrients that don’t naturally occur in its aquatic environment. That causes a phenomenon called eutrophication, which occurs when the saturated nutrients cause algae to grow in excessively large amounts to feed on it. The algae then die and deplete the water body’s important dissolved oxygen stores, which is needed to maintain the aquatic life. It is the cause of those mass numbers of dead fish that was seen in the river several weeks ago
That excess algae death then causes the release of toxic chemicals such as hydrogen sulfide, as well as methane. In large concentrations, hydrogen sulfide is harmful to humans, and most likely, this was what was making the students and teachers at La Immaculada Primary School sick last week. Their school’s compound is very close to the riverbank in Orange Walk Town, and during the midday heat, those toxic gases from the sick river go wafting unto their property.
Explaining the danger of this chemical, Edgar Ek, the Deputy Chief Environmental Officer, told the press, “At very low levels, you’ll start to smell it. Less than one part per million, you’ll start to smell that rotten egg smell. Once you reach up, I think less than 100 parts per million, you’ll have some minor effects on humans, like irritation to the throat, nausea, irritation to the eyes – things like that. But, other segments of the population might be more susceptible to it. For example, those that suffer from asthma, because it causes the closure of the bronchioles. So, some situations like that will happen. But, from the information that we have right now, we are not reaching that level. Once you reach like 500 parts per million, then it’s where you need to be concerned because, at that point in time, there is no smell, the concentration is higher. And then, you could have seizures and death within hours.”
In order, to counteract the excess hydrogen sulfide and other toxic gases coming from the river, the DOE has install aerators. These are a series of propellers placed on a rotating iron bar that is several feet long. That device is then floated on top of the river’s surface, and it is powered by a machine that spins the iron bar. That motion then spins the propellers, which are in contact with the river’s surface, and the water is stirred up. The constant movement and disturbance of the water’s surface then drives oxygen into it.
But, the aeration plan can have unintended consequences, and it is expected that the aerators will cause larger amount of hydrogen sulfide to be released into the air near to the aeration site. So, the DOE personnel has installed one in a part of the river that is directly accessible from the property belonging to El Gran Mestizo Resort. On Monday, September 9, Edgar Ek, the Deputy Chief Environmental Officer, and several other DOE representatives went to install the first aerator at that location, to test if this course of action will help to improve the river’s health.
The press came inquiring about this intervention, and he explained why they are only testing it out first.
Ek said, “There will be a phase where the situation will deteriorate. That’s supposed to be short-lived, We’re not expecting that it’s going to extend for a long period. And after that, it should – if things work out as we expect, then it should turn out to be normal.”
Since the immediate area will become inundated by hydrogen sulfide, the DOE is conducting this trial at the chosen location because it is a distance away from other residential parts of Orange Walk Town. They don’t want to harm the population of the town while trying to rehabilitate the river. If the aerators work as planned, the DOE will then install them at other strategic locations along the river that are the most negatively impacted by the pollution.
Conservationists are already expressing concern for this course of action. They indicate that if the aeration tactics cause the sediments of the river to be disturbed, larger quantities of hydrogen sulfide, as well as other toxic substances will be released that is trapped in the mud. If these things should happen, it will turn a bad situation even worse.
The DOE has assured that because this is surface aeration, the sediments will not be disturbed.
