According to a Nova Scotia Environment report, the heavily saturated wetlands are beginning to recover despite the effluent’s impact on dissolved oxygen supplies in the area and the presence of dioxins and furans.
“After the initial cleanup, we have inspected the wetlands on numerous occasions and it’s showing signs of recovery,” said Kathleen Johnson, an environmental engineer with the Environment Department. “It was impacted the most during the leak.”
At the high point of the leak, when effluent was gushing out of the pipe, Northern Pulp was at more than double the approved levels of biochemical oxygen demand (BOD), the amount of dissolved oxygen available for micro-organisms. While 3960 kg/day is the approved level for BOD, levels hit 7920 kg/day at Indian Cross Point.
Johnson noted that because the effluent stopped flowing shortly after the leak was discovered the levels of BOD are returning to normal.
“For any long-term negative impacts, a spill needs to be concentrated and over a period of time,” she said. “Thankfully, it wasn’t the case here.”
Also measured were total suspended solids (TSS), which measure water quality. Predictably, the wetlands showed TSS around 7380 kg/day and the East River at the point of release contained TSS of 5850 kg/day, far more than the approved 4100 kg/day.
“High TSS would have a short term impact to things like the vision of fish, since their vision would be clouded,” said Johnson. “They wouldn’t be able to distinguish between their food, the smallest of species, and the TSS. At this point, fish would not still be experiencing the effects of release.”
Of most concern was the presence of certain dioxins and furans, considered by Health Canada to be toxic and persistent organic pollutants. While there are minute trace amounts in wood, water and even the human body, federal regulations state they should not be in any measurable concentration.
Five different dioxins and furans were identified in concentrations between the East River point of release and the wetlands. OCDD, a dioxin, was even found in concentrations of 3.93 pg/litre at Melmerby Beach. While a pictogram (pg) is only one trillionth of a gram, Johnson noted the fact they were detected has resulted in further investigation.
“Based on federal regulations, by the time the water gets through the process, dioxins and furans shouldn't be detected. That's the standard,” she said. “Those results are under further investigation, because they shouldn't be showing up at all.”
The study, commissioned by Nova Scotia Environment and conducted by Strum Environmental, collected samples and delivered to a lab. Strum was given the parameters of what is contained in pulp mill effluent after discharge for good measure.
According to Johnson, the samples were taken the day after leak was reported around noon. Categories examined include acute toxicity, and biochemical oxygen demand (BOD). The testing also looked for a variety of dioxins and furans.
The first samples were taken at Melmerby Beach.
“We had heard that there were dead fish at the beach so we wanted to sample there first,” she said. “NSE, Department of Natural Resources and Fisheries and Oceans didn't witness any dead fish.”
Other testing locations included the wetlands at Indian Cross Point and the East River at the point of release. The samples weren’t vial sized.
“We need more 20 litres from each sample area,” said Johnson. “It’s needed for the Environment Canada testing methodology, which states a certain percentage of species must remain alive fully immersed in 100 per cent effluent.”
This test works well when the right fish are used. This wasn’t the case when two toxicity results from the East River and Melmerby Beach were invalid because technicians used fresh water fish in salt-water tests. The report does indicate that
materials likely did not reach Melmerby Beach and other points downstream from where the leak occurred.
During the leak, the test results established that Northern Pulp exceeded the NSE approval levels for BOD and TSS. Inspector specialist Marc Theriault hasn’t determined the consequences from government yet.
“Nothing has been decided at this point,” said Theriault. “Initially, we focused on repair and monitoring activities.”
He noted that he would follow Environment Department compliance procedures though there is no timeline at this point.
Johnson noted that, in her opinion, it was better for the wetlands that only the effluent and not the saturated soil was removed for disposal in Boat Harbour.
“You have to let nature take its course. It would have taken the wetlands longer to recover because once that soil is gone, it takes a long time to come back.”
On Twitter: @NGNewsJohn