The ecotoxicity of biosolids has been studied extensively using single-compound toxicity testing and ‘spiking’ studies; however, little knowledge exists on the ecotoxicity of biosolids as they are land-applied in the Canadian context. The purpose of this study is to elucidate the chronic, sublethal (i.e., behavioural), and lethal impacts of land- applying biosolids on the environmentally-relevant Folsomia candida (springtails) and Lumbricus terrestris (earthworms) and concomitantly ascertain whether the use of biosolids for nutrient amendment is a sustainable practice. This study is part of a larger multi-compartment program which includes terrestrial plants and aquatic arthropods. After an extensive review of government protocols and existing research in the literature, the current study attempted to elucidate the true nature of the potential ecotoxicity of land-applying biosolids, within a laboratory context. Protocols were developed or modified (e.g., using Evans’ boxes (Evans 1947) for chronic and sublethal testing on L. terrestris). Subsequently, two biosolids were tested on springtails and earthworms using avoidance and reproductive bioassay endpoints, at application rates that are standard (8 tonnes ha-1) and worst-case scenarios (22 tonnes ha-1). Results indicated no effect of biosolids at the environmentally-relevant concentration; the worst-case scenario exhibited a positive significantly significant relationship (indicating preference for treatment conditions). We suggest that further assessment of the potential ecotoxicological impact of biosolids employ i) environmentally-relevant organisms, ii) appropriate bioassays including the use of whole-organism endpoints, and iii) multi-kingdom testing (e.g., Kingdom Plantae, Animalia) to comprehensively elucidate answers. Lastly, in situ (field assays) are strongly encouraged in future studies.

Biosolids, the treated solid by-product of a WWPT, have been land-applied for decades as a means of disposal of an inexpensive form of fertilizer. However, research has shown that many chemicals such as pharmaceuticals, herbicides, pesticides, plasticizers, detergents, or heavy metals pass through the WWTP, often unaltered, and potentially end up in the biosolids. Therefore, a need to determine if the land-application of biosolids has an impact on terrestrial biota exists. In this work, six different organisms were used including Folsomia candida, Lumbricus terrestris, Zea mays, Glycine max, Phaseolus vulgaris, and Brassca rap. It was determined that government protocols were inadequate since they either prescribed organisms not environmentally-relevant or only looked at initial growth stages such as germination and emergence and not at effect, if any, on subsequent generations. Thus, new protocols were developed. Additionally, it was concluded that very little impact was seen on any of the terrestrial biota examined.

The scientific method paired with the practice of statistics is widely implemented to analyze, interpret and derive conclusions regarding a dataset. This laboratory exercise introduced first year biology students to the scientific method, applying it to evaluate how brown planaria (Dugesia tigrina) responds to light. In the laboratory setting, students were required to formulate a research question and hypothesis, design a study, record observations, gather data and perform statistical calculations (mean, median, standard deviation, ttests), receiving feedback from their peers and teaching assistants. When surveyed, less than half of the students felt they had a strong background in mathematics or were comfortable in the subject. To resolve this, we produced multiple videos enabling students to review the content to help recall the material. These resources introduced students to terminology, provided them opportunities to practice usage of these terms, as well as instructions on how to perform statistical calculations. We employed an analysis of covariance (ANCOVA) to determine if the students who viewed the videos performed better on the statistical analysis and interpretation portion. Based on ANCOVA, the wet laboratory experiments in conjunction with video resources, resulted in increased student performance in the laboratory component compared to previous iterations without video tools.

No abstract

No abstract

The uncertainty of potential toxicity when land-applying municipal biosolids to agricultural fields needs to be clarified considering the concomitant benefit for nutrient amendment and sustainability of resource recovery. This research is part of a larger program that assessed the toxicity of biosolids to terrestrial and aquatic organisms and this study specifically examined the toxicity of two biosolids when applied to four environmentally-relevant field crops. New bioassays were necessary to test the ecotoxicity of biosolids throughout the entire life cycle of each crop: Zea mays (corn), Glycine max (soybeans), Phaseolus vulgaris (common bean), and Brassica rapa (field mustard). It was hypothesized that biosolids would exhibit impact at both an environmentally-relevant application rate (8 tonnes ha-1) and a worst-case scenario (22 tonnes ha-1). The ecotoxicity of biosolids was tested using chronic, lethal, and multigenerational endpoints (i.e., F1 generation viability). Overall, study findings indicated a positive response to nutrient amendment using biosolids at either application rate. Negative responses to biosolids were seen in early growth stages of some cultivars (Zea mays) but disappeared or became positive as plants matured: these observations would have been made if existing protocols had been followed. Brassica rapa exhibited a negative germination rate when exposed to biosolids; however, further work is necessary to elucidate whether the effect is a result of nutrient additions or physical compaction on the small seed. The complete life-cycle bioassays of crops suggest that plants grown in the biosolids-amended soil were significantly larger and produced more seeds compared to reference assays. These results lend scientific support for their sustainable use in land-application strategies in Canada.

Biosolids, the treated solid by-product of a WWPT, have been land-applied for decades as a means of disposal of an inexpensive form of fertilizer. However, research has shown that many chemicals such as pharmaceuticals, herbicides, pesticides, plasticizers, detergents, or heavy metals pass through the WWTP, often unaltered, and potentially end up in the biosolids. Therefore, a need to determine if the land-application of biosolids has an impact on terrestrial biota exists. In this work, six different organisms were used including Folsomia candida, Lumbricus terrestris, Zea mays, Glycine max, Phaseolus vulgaris, and Brassca rap. It was determined that government protocols were inadequate since they either prescribed organisms not environmentally-relevant or only looked at initial growth stages such as germination and emergence and not at effect, if any, on subsequent generations. Thus, new protocols were developed. Additionally, it was concluded that very little impact was seen on any of the terrestrial biota examined.

No abstract