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Since the 1970s, several formal biomonitoring programs have been initiated to monitor temporal and spatial trends of persistent, bioaccumulative, and (or) toxic chemicals (PBTs) in the Great Lakes. Researchers have used a variety of approaches to deal with common issues that arise in these programs and there is considerable debate in the literature as to the most appropriate methods to use. Here, we critically review factors of importance in biomonitoring programs and common methods used for dealing with them under three main categories: organism-specific factors (lipid, age, size, sex, growth and bioenergetics, diet, and chemical biotransformation), study design (choice of tissue type, compositing, replication and length of monitoring program, sampling frequency, selection of contaminants to include in monitoring programs, and use of specimen banks for retrospective studies), and data analysis (accounting for changes in analytical methodology, treatment of censored data, assessment of compound classes, comparison of empirical models, mechanistic models, and spatial assessments). We use data from the literature as well as longterm measurements of polychlorinated biphenyls (PCBs) in lake trout (Salvelinus namaycush) collected in Lake Ontario as part of monitoring programs run by Environment Canada, the Ontario Ministry of the Environment, and the United States Environmental Protection Agency to illustrate these factors. We find that, in general, there are several defensible methods, ranging from simple to complex, to deal with the issues considered here, with each having specific advantages and disadvantages. The optimal approach depends largely on the program objectives, particularly if the results are meant for the public (understandable without a scientific background) or for research purposes (balance between complexity versus simplicity). Given that data analysis typically requires fewer resources compared to other aspects of monitoring programs, it may be feasible to use more than one data analysis approach to increase credibility of the results and to improve comparability of data among studies. The importance of conducting preliminary surveys and (or) pilot studies and regular review of ongoing programs (e.g., through a power analysis) is emphasized. Key words: environmental contaminants, biomonitoring programs, Great Lakes, data analysis, study design, temporal and spatial trend analysis. Depuis les annees 1970, plusieurs programmes formels de suivi biologique ont ete mis en place pour suivre les tendances spatio-temporelles de la persistance et de la bioaccumulation des produits et/ou toxiques (<< BPTs >>) dans les Grands Lacs. Les chercheurs ont utilise une gamme d'approches pour tenir compte des problcmes courants provenant de ces programmes, et l'on constate un debat anime dans la litterature sur les methodes les plus adequates. Dans cette perspective, les auteurs revisent de facon critique l'importance des suivis biologiques et les methodes usuelles pour composer avec elles, selon trois categories principales: facteurs specifiques aux organismes (lipide, age, dimension, sexe, croissance et bioenergetique, dicte, et biotransformation), conception de l'etude (choix du type de tissus, composition, replication et duree du programme de suivi, frequence des echantillonnages, selection des contaminants a inclure dans les programmes de suivi, et utilisation de banques de specimens pour les etudes retrospectives) et finalement l'analyse des donnees (tenant compte des modifications de la methodologie analytique, du traitement des donnees retenues, de l'evaluation des classes de composes, de la comparaison de modcles empiriques, des modcles mecanistes, et des evaluations spatiales). Les auteurs ont utilise des donnees de la litterature ainsi que les mesures a long terme des biphenyls polychlores (<< BPCs >>), recoltees chez la truite de lac (Salvelinus namaycush), dans le lac Ontario dans le cadre de programmes de suivis conduits par Environnement Canada, le Ministcre ontarien de l'environnement, et l'Agence de protection de l'environnement des Etats-Unis, afin d'illustrer ces facteurs. Les auteurs ont constate, en general, qu'il existe plusieurs methodes defendables, allant de la plus simple a la plus complexe, pour tenir compte des problematiques ici considerees, chacune ayant des avantages et des desavantages specifiques. L'approche optimale depend grandement des objectifs du programme, surtout si les resultats sont destines au public (comprehensibles sans formation scientifique) ou pour des fins de recherche (balance entre complexite et simplicite). Sachant que les analyses de donnees necessitent moins de ressources comparativement aux autres aspects des programmes de suivi, il serait pensable de conduire plus d'une approche d'analyse des donnees afin d'augmenter la credibilite des resultats et d'ameliorer la comparabilite des donnees entre les etudes. Les auteurs mettent l'emphase sur l'importance de conduire des etudes preliminaires de suivi/pilote ainsi qu'une revision regulicre des programmes en marche (e.g. par une analyse de puissance). Mots-cles : contaminants environnementaux, programmes de suivi biologique, Grands Lacs, analyse de donnees, conception d'etude, analyse des tendances spatio-temporelles., Introduction The Laurentian Great Lakes have experienced major stressors that have acted to damage the integrity of the system (Swackhamer 2005). One such group of stressors are persistent, bioaccumulative, and [...]

Triclosan is widely used in personal care products (skin creams, toothpastes, soaps, deodorants, body spray) and cleaning products (dishwashing detergent and all-purpose cleaners) (Halden in Environ Sci Technol 48:3603-3611, 2014). In 2001, it was selected for screening-level risk assessment under the Canadian Environmental Protection Act (HC and EC in Preliminary assessment. Triclosan. Chemical abstracts Service Number 3380-34-5, 2012. http://www.ec.gc.ca/ese-ees/default.asp?lang=En&n=6EF68BEC-1), and its physicochemical and toxicological characteristics indicate that there may be a risk to aquatic environments due to releases of the chemical in Canada. A surveillance initiative across Canada has included sampling at 44 sites from July 2012 to March 2018. Triclosan was detected in 226 of 918 samples; concentrations ranged from less than 6 to 874 ng L−1, and the detections averaged 54.23 ng L−1 (standard deviation; 97.6 ng L−1). However, using the entire dataset (including censored data estimated with the Kaplan-Meier model), the mean triclosan concentration was 17.95 ng L−1, and the standard deviation was 52.84 ng L−1. Three samples at Wascana Creek (downstream), Saskatchewan, had concentrations above the Federal Environmental Quality Guidelines of 470 ng L−1, indicating a potential risk to the aquatic ecosystem. In this study, triclosan in samples collected downstream from municipal wastewater treatment plant discharges usually demonstrated higher concentrations than upstream samples. Based on the results of this study, it is hypothesized that triclosan concentration have fluctuated between years of this study but not in an overall or significant increase or decreasing trend. Triclosan concentrations and detections also are more prevalent in urban than in rural or mixed development rivers. Performance evaluation of triclosan concentrations in the Canadian environment is scheduled to be reassessed by 2024. Therefore, a 3-year sampling program should be in place across Canada by 2021. [ABSTRACT FROM AUTHOR]