Peat moss has been a standard carrier of inoculum for experimentation and in agriculture. Peat moss is, however, a non-renewable resource. Alternatively, biochar could serve as an inoculum carrier. Here, we tested the effect of biochar-based seed coatings as a carrier for the phosphorous-solubilizing Pseudomonas libanensis inoculum, on corn growth after soluble and insoluble P addition. The survival of P. libanensis was determined based on the measure of colony-forming units from samples of four inoculated guar gum-based biochar coatings and was compared to peat. Storage experiments were performed on inoculated biochars for 22 weeks at 25 °C and on coated corn seeds for 16 weeks at 4 °C. Seed coatings were prepared with inoculated and uninoculated biochars (100 seeds treatment⁻¹), and effects of these treatments are reported on indices of seed germination after 7 days. A greenhouse experiment investigated the effects of the inoculated and uninoculated biochar seed coating on corn plants. The parameters measured from the greenhouse-grown corn plants were germination, fresh weight, dry weight, height, root length, basal stem diameter, leaf area, chlorophyll content, and tissue phosphorous. Our results show that corn plants grown from seeds coated with a biochar from hardwood feedstock are 2 to 10 g heavier than controls and that controls are 4 to 26 % shorter than the plants grown from biochar-coated seeds, where soluble phosphorous is applied. Moreover, corn seeds that were coated with a biochar produced from softwood feedstock germinated more quickly, based on the speed of germination index. Overall, we show that a biochar-based seed coating can benefit sustainable agriculture by carrying P. libanensis and enhancing the growth of corn, but according to parametric statistical tests, it does so without increasing the phosphorous content of the plants.

Cyanotoxins have been shown to be highly toxic for mammalian cells, including brain cells. However, little is known about their effect on inflammatory pathways. This study investigated whether mammalian brain and immune cells can be a target of certain cyanotoxins, at doses approximating those in the guideline levels for drinking water, either alone or in mixtures. We examined the effects on cellular viability, apoptosis and inflammation signalling of several toxins on murine macrophage-like RAW264.7, microglial BV-2 and neuroblastoma N2a cell lines. We tested cylindrospermopsin (CYN), microcystin-LR (MC-LR), and anatoxin-a (ATX-a), individually as well as their mixture. In addition, we studied the neurotoxins β-N-methylamino-l-alanine (BMAA) and its isomer 2,4-diaminobutyric acid (DAB), as well as the mixture of both. Cellular viability was determined by the MTT assay. Apoptosis induction was assessed by measuring the activation of caspases 3/7. Cell death and inflammation are the hallmarks of neurodegenerative diseases. Thus, our final step was to quantify the expression of a major proinflammatory cytokine TNF-α by ELISA. Our results show that CYN, MC-LR and ATX-a, but not BMAA and DAB, at low doses, especially when present in a mixture at threefold less concentrations than individual compounds are 3-15 times more potent at inducing apoptosis and inflammation. Our results suggest that common cyanotoxins at low doses have a potential to induce inflammation and apoptosis in immune and brain cells. Further research of the neuroinflammatory effects of these compounds in vivo is needed to improve safety limit levels for cyanotoxins in drinking water and food.

In Canada, the presence of pharmaceuticals and pesticides in municipal drinking water has been examined primarily in larger urban centres which draw their supplies from surface water. However, few studies have examined this issue in smaller and rural communities, which represent nearly one-third of the Canadian population and which draw their drinking water mainly from groundwater. This study presents a regional-scale assessment of the presence of these contaminants in the drinking waters of 17 smaller rural communities, compared with two larger urban communities, in south-central Quebec. From a total of 70 chemicals examined, 15 compounds (9 pharmaceuticals and 6 pesticides) were detected. The three most frequently detected contaminants were caffeine, atrazine and naproxen, respectively, in 29%, 24% and 21% of the samples. Detections reported here for the first time in Quebec drinking water include the known human carcinogen cyclophosphamide and the fungicide thiabendazole. Maximum concentrations of pharmaceuticals ranged from 30 to 1,848 ng L⁻¹ and of pesticides from 21 to 856 ng L⁻¹. This study provides direct evidence that drinking water in smaller, rural communities of Quebec, Canada, whether sourced from groundwater or surface water, can contain measurable levels of pharmaceuticals and pesticides, indicative of their susceptibility to source contamination.