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In situ oxygen analysis of garnet in eclogite and related rocks is increasingly being used to probe the composition of subduction fluids. However, in many cases, these samples contain textural signs of both fluid flow and retrograde metamorphism, some of which may take place outside the garnet stability field. In order to test the connection between polymetamorphism and fluid infiltration, rutile rimmed by titanite from high‐grade tectonic blocks of the Franciscan Formation (California, USA) was analysed for oxygen isotope ratios and trace element concentrations. Zirconium concentrations in rutile yield temperatures of ~600°C for eclogite and hornblende eclogite from three well‐studied localities (Junction School, Tiburon and Ward Creek). Rutile trace element concentrations are generally low and consistent with a mafic protolith. Titanite surrounding rutile has inherited much of its trace element content from rutile, and Zr‐in‐titanite temperatures are spuriously high. Titanite in rutile‐free samples (blueschist and eclogite from Jenner beach) have similar compositions suggesting that they were formed at the expense of rutile as well. Oxygen isotope ratios from rutile and titanite in the same sample are fortuitously similar, indicating disequilibrium between these minerals, which formed at different times and temperatures but in equilibrium with the same oxygen reservoir. Rutile in blocks with garnets zoned in oxygen isotopes are generally in equilibrium with the rims rather than the cores. Slow oxygen diffusion in rutile and the low temperatures of formation require that rutile recrystallized after fluid interaction and before blueschist facies metamorphism. External fluid interaction of Franciscan eclogites took place near the peak of metamorphism. [ABSTRACT FROM AUTHOR]

This document focuses on models in relation to the discharge of chemical active ingredients associated with bath pesticide treatments used in net-pen finfish aquaculture operations. The document includes a brief overview of the context and associated conceptual processes to be modelled, specific modelling challenges, a review of modelling efforts to date, and a description of some simple models. In general, modelling for bath pesticides for discharge and dispersal is in an early stage of development. There have been few modelling efforts and few extensively calibrated or validated models. Furthermore, few models have been incorporated into pesticide management considerations. Models range in complexity from models that make many simplifying assumptions, such as a constant current, to models that use more realistic representations, for example temporally and spatially varying currents. In general, outputs from models which use non-spatially varying currents may not be representative when displacement distances are greater than 500 m. This is problematic since displacement distances of bath pesticide discharges are often greater than 500 m. Hydrodynamic models are one potential solution; however, their implementation and operation is resource intensive and predictions are imperfect representations of real-world situations. Nevertheless, their use should be considered when predicted displacement distances exceed 500 m. All models have uncertainties and sensitivities associated with them. In general, models for predicting exposure to bath pesticides have not been extensively explored and quantified, including sensitivities to hydrographic detail and resolution, initial condition specification, and active ingredient behaviour. Predictive models, whether they are forecast or hindcast models, are subject to the validity of the assumptions made about future and past conditions; since these are often not well known, any model output needs to be interpreted cautiously and with appropriate respect for the uncertainties. Calibration and validation of models are challenging due to the difficulties in obtaining spatially and temporally extensive observations associated with discharges from multiple farm sites and multiple treatment scenarios. Despite the uncertainties, models can be useful for regulatory decision support. Model selection depends on the decision maker's needs; and the interpretation of model results requires clearly defined decision rules. Specific recommendations on model selection will require further clarification of management needs, more detailed evaluations of model uncertainties and sensitivities, as well as verification and validation of chosen models. [ABSTRACT FROM AUTHOR]

This document focuses on modelling in relation to the discharge of active ingredients associated with in-feed drugs used in marine net-pen aquaculture farming operations in Canada. The document includes an overview of the context and associated conceptual processes to be modelled, specific modelling challenges, a review of modelling efforts to date, and a description of some simple models for potential use. In general, modelling for in-feed drug discharges and depositions is in an early stage of development. Few models have been developed specifically to predict the benthic deposition of in-feed drugs and these range in complexity. Model results are sensitive to input parameters, including treatment details, hydrographic conditions, drug partitioning specifics, and sinking rates and timing of discharges. Many of these parameters are poorly understood, difficult to measure, and hence, not well quantified. Thus, determining the quantification of uncertainties and sensitivities of model results remain challenging. Many models for predicting the deposition of organic waste produced by net-pen fish farms have been developed. Although similarities exist between the underlying assumptions of these models and those for in-feed drugs, their adaptation to use for modelling the deposition of infeed drugs is not necessarily simple or straightforward. Of particular importance is the inclusion of drug partitioning specifics which is necessary in order to correctly model in-feed drug deposition dynamics; simple conversion factors between organic waste deposition and in-feed drug deposition are likely not a suitable approach as the ratio between carbon and drug in the released feces varies with time. The objectives of modelling must be specified before a model is selected and assessed for its adequacy and sufficiency. Once models have been selected and/or developed, models must be validated before being used. In general, existing models of in-feed drug deposition have not been extensively calibrated or validated. Of the few validations that have been done, the literature suggests that, regardless of complexity, existing models give, at best, an order of magnitude estimate of seabed drug concentrations. Despite the uncertainties surrounding model precision and validity, models can be useful for regulatory decision support. Model selection depends on the decision maker's objectives. Precision and accuracy of the model cannot be estimated until the chosen model is verified and validated. Existing validation studies indicate that available models are only able to provide order of magnitude estimates of in-feed drug depositions. At this time, simple models may be sufficient for decision support. This sentiment may change as science better characterizes model inputs and processes, and conducts more validation studies. [ABSTRACT FROM AUTHOR]

In this document, we describe a simple model, the Potential Exposure Zone (PEZ), that estimates the area exposed to discharges (feed, feces, in-feed drugs, and bath pesticides) resulting from finfish aquaculture activities. The PEZ provides an estimate of the spatial scale over which examination of information concerning the presence of species, habitats, and human activities should be examined for interactions of potential concern as part of an initial screening process for Fisheries and Oceans Canada aquaculture site assessments. The PEZ is a circle centred on the cage array with a radius equal to half the length scale of the cage array and a transport distance which is determined from a current speed and a transport time. PEZs are calculated for fourteen proposed Newfoundland marine finfish aquaculture sites. Benthic PEZs for waste feed, feces, and in-feed drugs are calculated using mid-depth current speeds and transport times based on the time required for particles to sink to the seabed. Pelagic PEZs for azamethiphos and hydrogen peroxide are calculated using 15 m sub-surface current speeds and a transport time based on the time required for the treatment dose concentration to dilute to a specified threshold. All calculated PEZs have radii ranging from O(100) to O(1,000) m with the exception of the PEZ associated with well-boat discharges for hydrogen peroxide which has a radius of 0 m since the assumed effective treatment concentration is less than the threshold concentration. Length scales estimated from the predicted deposition areas provided by the proponent were consistent with the length scales of the benthic PEZs estimated using mean current speeds. It should be emphasized that the entire domain within a PEZ is unlikely to be exposed but with proper selection of the input variables (i.e., current speed, sinking rate, depth, dilution rate, and threshold concentration), the PEZs should encompass all exposed areas. [ABSTRACT FROM AUTHOR]

Ion microprobe analysis with a sub-micrometer diameter spot reveals a sharp, 2 [micro]m gradient in oxygen isotope ratio proving that oxygen diffusion in zircon is slow even under prolonged high-grade metamorphism. The data are consistent with an oxygen diffusion coefficient of [10.sup.-23.5[+ or -]1] [cm.sup.2]/s. Furthermore, this gradient is found in a zircon that contains clear textural evidence of recrystallization in nearby regions. This finding shows that through careful textural and chemical analysis, primary information can be extracted from a zircon that has also undergone partial recrystallization. The oxygen isotope ratios found in zircon have been used to infer magmatic and pre-magmatic histories, including the presence of liquid water on the surface of earliest Earth. Recently, these interpretations have been questioned with the assertion that zircon may not retain its primary oxygen isotope signature through metamorphism. The slow diffusion confirmed by these results supports interpretations that assume preservation of magmatic compositions. Keywords: Ion microprobe, SIMS, zircon, diffusion, oxygen isotopes, stable isotopes, granulites facies, migmatites

Oriented quartz needles in clinopyroxene have become one of the diagnostic indicators of ultrahigh-pressure (UHP) metamorphism. The presence of apparently exsolved quartz is taken as evidence of decompression of a non-stochiometric Ca--Eskola component ([Ca.sub.0.5][[].sub.0.5]Al[Si.sub.2][O.sub.6], CaEs) that is presumed to be stable only at UHP conditions. Eclogite from the Eastern Blue Ridge, North Carolina, contains clinopyroxene ([Jd.sub.20]Ca[Ts.sub.5][Ac.sub.5]Ca[Es.sub.0][Di.sub.65][Hd.sub.5]) with oriented needles of quartz and calcic amphibole that appear to have exsolved together. The quartz + amphibole intergrowths are surrounded by 1-5 [micro]m haloes of neoformed pyroxene ([Jd.sub.10]Ca[Ts.sub.10][Ac.sub.5]Ca[Es.sub.0][Di.sub.70][Hd.sub.5]). The modes of quartz, amphibole, and clinopyroxene haloes were determined using BSE images, and reintegrated with the host clinopyroxene. Viewing the quartz and amphibole needles down the c-axis of the pyroxene host provides a better estimate of their proportions than in prismatic sections. Reintegrated pyroxene compositions were nearly identical to the analyzed host pyroxene with no CaEs component. Clinopyroxene with CaEs solid solution has been repeatedly synthesized at UHP conditions. However, examination of the phase equilibria usually cited as evidence for CaEs stability at conditions of [greater than or equal to] 25 kbar shows that clinopyroxene with 10 mol% CaEs is stable well within the quartz field, and provides a pressure minimum similar to the albite = jadeite + quartz barometer. Exsolution of quartz and associated amphibole is commonplace in clinopyroxene from the Blue Ridge eclogite that lacks coesite or other evidence for UHP metamorphism. The presence of a diluted (5-10%) CaEs component in clinopyroxene does not require UHP conditions.

Higher earthworm populations and Lumbricus biomass production were observed in corn plots sidedressed with solid dairy cattle manure. Significant changes were seen in the cocoon production between manure treatments indicating the potential effects of manure sidedressing on earthworm populations dynamics. Sidedressing of solid dairy cattle manure also increased Lumbricus populations, especially juveniles and adult L. terrestris. Population of Lumbricus and the population of Aporrectodea increased on treatment with manure.

This document is part of a CSAS process in support of the development of a post-deposit monitoring program for drug and pesticide use at Canadian marine finfish farms. This report focusses on the usage (number of farms treated and amount of active ingredient used) of drugs and pesticides at Canadian marine finfish farms during 2016-2018. Total Canadian marine finfish aquaculture production showed a slight decrease during these years: 148 900 t in 2016; 140 500 t in 2017; and 138 400 t in 2018. By province, 61-63% of the annual production was in British Columbia (BC), 17-20% in New Brunswick (NB), 11-17% in Newfoundland & Labrador (NL), and 4-8% in Nova Scotia (NS); production was >95% Atlantic salmon. The Government of Canada has required marine finfish farms to report their usage of drugs and pesticides on an annual basis since 2016. Data on drug and pesticide use in 2016-2018 were obtained from the National Aquaculture Public Reporting Data (NAPRD) and the Aquaculture Integrated Information System (AQUIIS). The reported drugs (applied in-feed) and pesticides (applied in bath treatments) included antibiotic drugs (oxytetracycline, florfenicol, erythromycin, ormetoprim, and trimethoprim), pest control drugs (emamectin benzoate, ivermectin, and selamectin for sea louse control; and praziquantel for parasitic worm control), and pesticides (azamethiphos and hydrogen peroxide; both for sea louse control). Individual farms used from zero to six drugs and pesticides in 2016, and zero to five in 2017 and 2018. Of the 136-152 active marine finfish farms in each year during 2016-2018, 108-128 (74-84%) used at least one drug or pesticide in each year. By province, 52-58% of treated farms were in BC, 26-30% in NB, 13-18% in NL, and 0-3% in NS. The percentage of active farms that used at least one drug or pesticide was: 83-86% in BC; 69-86% in NB; 74-95% in NL; and 0-38% in NS. Of the five antibiotic drugs reported, florfenicol was used at the most farms (47-50 farms per yr), followed by oxytetracycline (17-24 farms per yr); the other three were used by =5 farms per yr. BC had the largest number of farms treated with florfenicol and the highest quantity used in each year (34-35 farms per yr). The largest number of farms treated with oxytetracycline was in NB in 2016 (10 farms) and in BC in 2017 (7 farms) and 2018 (10 farms); the highest quantity used was in NL in 2016 and 2017, and in BC in 2018. Of the pest control drugs, emamectin benzoate was used at the most farms in all three years (56-70 farms per yr). BC had the largest number of farms treated with emamectin benzoate in all three years (32-38 farms per yr), while NL used the largest quantity in all three years. Ivermectin was used at 14-20 farms per yr and was only used in NB and NL, with NB having the larger number of farms treated and the larger quantity used in each year. Selamectin was used on a trial basis only (one NB farm in 2017 and one NB farm in 2018). Praziquantel was used only in NL, and only in 2016 and 2017. One other sea louse control drug, lufeneron, was used in freshwater hatcheries in BC, NB, and NL. The pesticide azamethiphos was used at 20-42 farms per yr; it was used only in NB and NL. In 2016, NB had the larger number of farms treated with azamethiphos (29 farms) and the larger quantity used; in 2017 and 2018, NB and NL had equal numbers of farms treated (20 farms each in 2016, 10 farms each in 2017), while NL used the larger quantity in both years. Hydrogen peroxide was used at 25-37 farms per yr; it was used in BC, NB, and NL. In 2016, NB had the largest number farms treated with hydrogen peroxide (14 farms) and also used the largest quantity; in 2017 and 2018, BC had the largest number of treated farms (17 in 2017; 22 in 2018) and also used the largest quantity in both years. There were differences in usage between salmon year-classes for some of the chemicals: florfenicol and ivermectin were used primarily on smolts, while emamectin benzoate and azamethiphos were used more on pre-market fish. In BC, treatments with drugs and pesticides occurred throughout the year, while in NB and NL, treatments did not occur in winter and early spring; in NS, the only treatments were in August 2016 and in June-August 2018 (all NS treatments were antibiotics). The three years of data were insufficient to discern clear interannual trends in drug and pesticide use. [ABSTRACT FROM AUTHOR]

The finfish aquaculture industry utilises a wide spectrum of chemotherapeutants ranging from anti-sea lice treatments to antibiotics in the production of their marketed products. The impact of these compounds to non-target organisms coupled to their potential for environmental persistence is of major concern and the minimisation of their usage is the target for a regulatory regime under development by Fisheries and Oceans Canada (DFO). Accurate quantification of contaminant levels is essential to determine if Environmental Quality Standards (EQS) have been exceeded. Typically, sea lice treatments and antibiotics used in aquaculture have been adopted from terrestrial farming practices. This is reflected in the number of analytical methods available for the analysis of their active ingredients (a.i.) in soil and freshwater media compared to the marine environment. Traditional extraction methods either use large volumes of solvents harmful to human health and the environment, are labour intensive and time consuming, or are expensive due to instrument costs. Recently, a new technique has been developed called QuEChERS, an acronym for quick, easy, cheap, effective, rugged and safe which is gaining popularity for multi-class and multi-residue extractions from a variety of matrices due to its simplistic methodology. No matter what analytical method is developed or selected for routine analysis of samples, it should undergo a validation procedure to demonstrate its robustness and suitability for the intended purpose. For regulatory decision-making and enforcement where analytical results could be presented in court as part of a prosecution case it is critical that the analytical method is also accredited to ISO/IEC 17025 which would give confidence that procedures employed by the analytical laboratory adhered to a set of strict regulatory guidelines. If the analytical method is to be used solely for the purpose of monitoring, validation is still considered essential but accreditation is not. [ABSTRACT FROM AUTHOR]