A detailed, documented report in The Narwhal magazines says nutritent-laced water from greenhouses is probably responsible for a resurgence of algae blooms in Lake Erie.
The blooms declined when municipalities invested in improved waste water treatment facilities and farmers adopted no-till and other soil conservation measures to reduce runoff nutrients.
But with more large greenhouses being built recently, algae blooms have returned, reported Matt McIntosh.
Leamington Mayor Hilda MacDonald, said the greenhouse pollution is real and is frustrated that the provincial government is doing so little to help.
She said called the lack of action inexcusable.
“Don’t tell me it’s just a few bad apples. Those bad apples are big bad apples and they’re ruining the whole bin,” MacDonald said. “We’re holding [the Environment Ministry’s] feet to the fire. They’re the ones who have fallen down on the job. Testing? That’s their job. Where the hell are they?”
The provincial government’s online report on enforcement said the highest was $62,500 in fines handed out to Kapital Produce in Windsor in April 2022 for mixing greenhouse water and stormwater. The ministry’s court bulletin said the levels of phosphorus were up to 40 times greater than the limit of 0.5 milligrams per litre specified in the company’s environmental compliance approval, a permit required to operate.
The ministry site listed only three other convictions in the region since 2019, resulting in a fine of $6,500 for Cielo Vista Farms for not maintaining proper logs of stormwater pond inspections; $31,250 charged to Golden Acres Farms for having over-limit phosphorus levels in a stormwater collection pond that discharges into a drain that leads to Lake Erie; and $50,000 imposed on Nature Fresh Farms for allowing greenhouse water to flow into Leamington’s Bailey Drain. All of the convictions listed on the ministry site were at operations that grow vegetables. None are for greenhouses growing cannabis and not all of them are within the four corners of cannabis-production laws.
Of 32 outfall locations at different greenhouses, 21 were found to have high levels of nitrates or phosphorus — indicative of nutrient water or process water from greenhouse production getting into municipal streams. Sturgeon Creek was found to have phosphorus concentrations nearing seven milligrams per litre. The provincial limit for a healthy waterway is 0.03 milligrams per litre. Nearby Lebo Drain was not much better.
The 2012 report categorized Sturgeon Creek and Lebo Drain as “the most polluted in the province of Ontario with respect to phosphorus and nitrate.” It concluded the ministry could not support further greenhouse development in either watershed “without appropriate treatment technology in place.”
No enforcement or fines are listed on the public record.
The nutrient-loading problem, similarly, has only become more acute. An August 2023 report by a team at the Essex Region Conservation Authority revealed that phosphorus loading in Leamington tributaries now ranges from 2.9 to 6.0 milligrams per litre, or 100 to 200 times greater than the provincial target.
With more than a decade of collected data, the report found “year over year, nutrient concentrations continue to be strikingly higher in greenhouse streams than non-greenhouse streams.”
“With greenhouse agriculture continuing to expand in this area, and elsewhere in the Great Lakes Basin, it is essential that we take heed of this canary in the coal mine,” the report said.
The lead author of the report said what’s most concerning is the apparent significant leakage from what should be totally enclosed, state-of-the-art, brand-new greenhouse constructions.
Regulations around the disposal of effluent water — water used in the production of crops — do recyle nutrients and besides reducing phosphorous pollution that nourish algae blooms also reduce growing costs.
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