The amphipod Hyalella azteca as a biomonitor in field deployment studies for metal mining

Overcoming water quality effects in biological monitoring: a case study of amphipod in situ exposures in Ontario agricultural streams

Bioindicators add valuable understanding of biological impacts to contaminant monitoring programs. However, attributing effects (e.g., mortality and growth impairment) to contaminant exposures is challenging because of potential confounding by environmental variables. We assessed the influence of four water quality variables (temperature, dissolved oxygen, pH, and conductivity) on contaminant effects assessments during in situ exposures of the amphipod Hyalella azteca in six agricultural and urban watersheds in southern Ontario, Canada (2005-06, 2008-10). We further tested whether sampling in specific months of the growing season would minimize confounding effects. While high toxicity from organophosphate and carbamate pesticides increased mortality and reduced growth in caged amphipods, warmer stream temperatures also affected endpoints, increasing mortality and improving growth. Seasonal patterns indicated early summer (June) as optimal for detecting impacts when: (1) stream pesticide concentrations were highest, (2) acetylcholinesterase (AChE) inhibition (a biomarker of organophosphate/carbamate exposure) was highest, and (3) stream temperature was below its seasonal peak. Specifically, higher correlations among organophosphate pesticide concentrations, AChE inhibition, and mortality indicated better attribution of cause in this month (r = 0.53-0.76, p < 0.05). Ability to discriminate between pesticide-impacted sites and reference sites was also greater than other months (June = 100% correct assignment as high-impact or reference site). Considering sampling times of stream bioindicators that maximize pesticide responses and limit confounding effects of water quality may improve the accuracy and resource-efficiency of biological monitoring programs.

Laboratory and In situ Selenium Bioaccumulation Assessment in the Benthic Macroinvertebrates Hyalella azteca and Chironomus dilutus

Selenium (Se) bioaccumulation and toxicity in aquatic vertebrates have been thoroughly investigated. Limited information is available on Se bioaccumulation at the base of aquatic food webs. In this study, we evaluated Se bioaccumulation in two benthic macroinvertebrates (BMI), Hyalella azteca and Chironomus dilutus raised in the laboratory and caged in-situ to a Canadian boreal lake e (i.e., McClean Lake) that receives continuous low-level inputs of Se (< 1 μg/L) from a uranium mill. Additional Se bioaccumulation assays were conducted in the laboratory with these BMI to (i) confirm field results, (ii) compare Se bioaccumulation in lab-read and native H. azteca populations and (iii) identify the major Se exposure pathway (surface water, top 1 cm and top 2-3 cm sediment layers) leading to Se bioaccumulation in H. azteca. Field and laboratory studies indicated overall comparable Se bioaccumulation and trophic transfer factors (TTFs) in co-exposed H. azteca (whole-body Se 0.9-3.1 µg/g d.w; TTFs 0.6-6.3) and C. dilutus (whole-body Se at 0.7-3.2 µg Se/g d.w.; TTFs 0.7-3.4). Native and lab-reared H. azteca populations exposed to sediment and periphyton from McClean Lake exhibited similar Se uptake and bioaccumulation (NLR, p = 0.003; 4.1 ± 0.8 µg Se/g d.w), demonstrating that lab-reared organisms are good surrogates to assess on-site Se bioaccumulation potential. The greater Se concentrations in H. azteca exposed to the top 1-3 cm sediment layer relative to waterborne exposure, corroborates the importance of the sediment-detrital pathway leading to greater Se bioaccumulation potential to higher trophic levels via BMI.

Invertebrate metal accumulation and toxicity from sediments affected by the Mount Polley mine disaster

On August 4, 2014, a tailings dam failed at the Mount Polley copper and gold mine near Likely, British Columbia, Canada, releasing approximately 25 M m[Formula: see text] of contaminated water and solid tailings material into Polley and Quesnel lakes. Water, sediment, freshwater scuds (Hyalella azteca), and mayfly larvae (Ephemeroptera) were collected during the summer of 2018 from Polley Lake, affected and unaffected sites in Quesnel Lake, and both mine-contaminated and clean far-field sites as references. Analytical results indicated that invertebrates from sites affected by the tailings breach had elevated metal concentrations relative to those from non-affected or reference sites. We conducted a controlled laboratory exposure to determine if laboratory-reared Hyalella azteca metal concentrations were related to field-collected water or sediments from the same sites as the field study. Half of the replicates prevented amphipods from directly contacting sediments (water-only exposure), while the other half allowed them direct access (sediment and water exposure). Whole-body Cu concentration was highest in Hyalella exposed to substrate from the most contaminated sites as well as in treatments where they were allowed direct access to sediments. Hyalella having direct access to metal-contaminated sediments showed reduced survival and growth relative to those in reference or control treatments. These results suggest that metals from the fine sediments associated with the Mount Polley mine disaster are bioavailable and potentially toxic to epibenthic invertebrates, even several years after the initial breach.

Potential environmental pollution from copper metallurgy and methods of management

This paper presents the latest overview of the environmental impact of wastes from the non-ferrous metallurgical industry. Ashes, slags and dusts - by-products from mining and metal processing - are sources of toxic metals, such as Pb, Cd, Hg, As, Al, as well as particulate matter. Physical, chemical and biological processes transform industrial wastes and cause water, soil and air pollution. Improperly protected heaps are subject to wind erosion and rain water leaching. Heavy metals and particulate matter are transported over long distances, contaminating the soil, living areas, watercourses, while in combination with mist they create smog. Water erosion releases heavy metals, which are leached into groundwater or surface runoff. This paper focuses on the range of pollution emissions from non-ferrous metallurgy wastes, hazards, mechanisms of their formation and fallouts, on the current state of technology and technological risk reduction solutions. The impact of pollution on human health and the biosphere, and methods of waste reduction in this industry sector are also presented. A sustainable and modern mining industry is the first step to cleaner production.

The Impact of Metal-Rich Sediments Derived from Mining on Freshwater Stream Life

Metal-rich sediments have the potential to impair life in freshwater streams and rivers and, thereby, to inhibit recovery of ecological conditions after any remediation of mine water discharges. Sediments remain metal-rich over long time periods and have long-term potential ecotoxicological interactions with local biota, unless the sediments themselves are physically removed or replaced by less metal-rich sediment. Laboratory-derived environmental quality standards are difficult to apply to the field situation, as many complicating factors exist in the real world. Therefore, there is a strong case to consider other, field-relevant, measures of toxic effects as alternatives to laboratory-derived standards and to seek better biological tools to detect, diagnose and ideally predict community-level ecotoxicological impairment. Hence, this review concentrated on field measures of toxic effects of metal-rich sediment in freshwater streams, with less emphasis on laboratory-based toxicity testing approaches. To this end, this review provides an overview of the impact of metal-rich sediments on freshwater stream life, focusing on biological impacts linked to metal contamination.

Vanadium and thallium exhibit biodilution in a northern river food web

Trophic transfer of contaminants dictates concentrations and potential toxic effects in top predators, yet biomagnification behaviour of many trace elements is poorly understood. We examined concentrations of vanadium and thallium, two globally-distributed and anthropogenically-enriched elements, in a food web of the Slave River, Northwest Territories, Canada. We found that tissue concentrations of both elements declined with increasing trophic position as measured by δ¹⁵N. Slopes of log [element] versus δ¹⁵N regressions were both negative, with a steeper slope for V (-0.369) compared with Tl (-0.099). These slopes correspond to declines of 94% with each step in the food chain for V and 54% with each step in the food chain for Tl. This biodilution behaviour for both elements meant that concentrations in fish were well below values considered to be of concern for the health of fish-eating consumers. Further study of these elements in food webs is needed to allow a fuller understanding of biomagnification patterns across a range of species and systems.

Bioaccumulation of trace elements in the sandhopper Talitrus saltator (Montagu) from the Ionian sandy coasts of Sicily

The Ionian beaches of Sicily are of particular ecological interest because they include the basin of the largest active volcano in Europe and hosts both sites subject to natural protection constraints, as well as important industrial settlements. Consequently, the possibilities for these areas to become polluted are numerous. The sandhopper Talitrus saltator has proven to be a good bioindicator of contamination by numerous trace metals on some European coasts. Nevertheless, no data are available for the populations inhabiting the shores of the southern Mediterranean. Now, as metal accumulation has been shown to vary intraspecifically, the aim of this study was to evaluate trace metal accumulation in adults of T. saltator inhabiting Ionian coastal areas of Sicily and make an assessment of natural and anthropogenic metal pollution of this strip of coast. We also extended our survey to As, Co, Mo, Se, Sn and V never investigated before in this species. Significant differences in metal concentration among sites were found in both sand samples and amphipod tissues. The highest metal content was observed near the mouth of Simeto, the longest river of Sicily which collects waters coming from the volcanic territory of Mount Etna. The bioaccumulation of Cd, Cu, Hg and Zn in T. saltator is fully confirmed; it is also proven for As and Mo and assumed for Cr, Fe, Mn and V. Our outcomes let us to evaluate the prevailing influence of telluric contamination of the Ionian sandy shores of Sicily by trace metals. We also come to the conclusion that in the northern sites, pollution originates from volcanic emission while anthropogenic influence prevails in the southern ones.

Distribution and ecotoxicology of bioavailable metals and As in surface sediments of Paraguaçu estuary, Todos os Santos Bay, Brazil

Surface sediments collected in the intertidal zone of Paraguaçu estuary in July, 2013, were analyzed for organic matter, nitrogen, phosphorus, grain size fractions and partial concentrations of 16 metals. The USEPA 3051A method and ICP-OES and CV-AAS techniques were chosen to metal analysis. Pollution indices (EF, Igeo and PIN) and a comparison with sediment quality guidelines (UET, ERL, ERM, TEL and PEL of NOAA) were conducted in order to evaluate the potential metal impacts over the area. Principal Component Analysis (PCA) and Pearson correlation results showed the importance of organic matter content and the fine-grained fraction of sediments on the control of the bioavailable metals distribution. The Paraguaçu estuary already has anthropogenic enrichment relative to the background level, especially for Mn, whose values exceeded almost 30 times the background at one site (Mn: 1197.30 mg kg(-1)). However, metal levels are still below the reference values with the exception of Hg at one site (Hg: 0.25 mg kg(-1), exceeded TEL and ERL).

Proteogenomic insights into the core-proteome of female reproductive tissues from crustacean amphipods

As a result of the poor genome sequence coverage of crustacean amphipods, characterization of their evolutionary biology relies mostly on phenotypic traits. Here, we analyzed the proteome of ovaries from five amphipods, all from the Senticaudata suborder, with the objective to obtain insights into the core-proteome of female reproductive systems. These amphipods were from either the Gammarida infraorder: Gammarus fossarum, Gammarus pulex, Gammarus roeseli, or the Talitrida infraorder: Parhyale hawaiensis and Hyalella azteca. Ovaries from animals sampled at the end of their reproductive cycle were dissected. Their whole protein contents were extracted and their proteomes were recorded by high-throughput nanoLC-MS/MS with a high-resolution mass spectrometer. We interpreted tandem mass spectrometry data with the protein sequence resource from G. fossarum and P. hawaiensis, both recently established by RNA sequencing. The large molecular biodiversity within amphipods was assessed by the ratio of MS/MS spectra assigned for each sample, which tends to diverge rapidly along the taxonomic level considered. The core-proteome was defined as the proteins conserved along all samples, thus detectable by the homology-based proteomic assignment procedure. This specific subproteome may be further enriched in the future with the analysis of new species and update of the protein sequence resource.

Metal mixture toxicity to aquatic biota in laboratory experiments: application of the WHAM-FTOX model

The WHAM-FTOX model describes the combined toxic effects of protons and metal cations towards aquatic organisms through the toxicity function (FTOX), a linear combination of the products of organism-bound cation and a toxic potency coefficient (αi) for each cation. Organism-bound, metabolically-active, cation is quantified by the proxy variable, amount bound by humic acid (HA), as predicted by the WHAM chemical speciation model. We compared published measured accumulations of metals by living organisms (bacteria, algae, invertebrates) in different solutions, with WHAM predictions of metal binding to humic acid in the same solutions. After adjustment for differences in binding site density, the predictions were in reasonable line with observations (for logarithmic variables, r(2)=0.89, root mean squared deviation=0.44), supporting the use of HA binding as a proxy. Calculated loadings of H(+), Al, Cu, Zn, Cd, Pb and UO2 were used to fit observed toxic effects in 11 published mixture toxicity experiments involving bacteria, macrophytes, invertebrates and fish. Overall, WHAM-FTOX gave slightly better fits than a conventional additive model based on solution concentrations. From the derived values of αi, the toxicity of bound cations can tentatively be ranked in the order: H<Al<(Zn-Cu-Pb-UO2)<Cd. The WHAM-FTOX analysis indicates much narrower ranges of differences amongst individual organisms in metal toxicity tests than was previously thought. The model potentially provides a means to encapsulate knowledge contained within laboratory data, thereby permitting its application to field situations.

Age differential response of Hyalella curvispina to a cadmium pulse: influence of sediment particle size

In Argentina periurban streams frequently receive agricultural, livestock and industrial discharges. Heavy metals have been found in the water column and sediments of numerous water bodies of the pampean region, at levels above the limits established for aquatic life protection. This study aimed to evaluate the effect of a contaminant pulse of cadmium discharged into a water-sediment system of different particle sizes, by means of laboratory tests using juveniles and adults of Hyalella curvispina, a native amphipod. We found that the substrate particle size was a determining factor in the toxicity of cadmium and that the adults of H. curvispina were more sensitive than juveniles. We also observed a temporal difference between the two ages for the same type of sediment. Given the nature of the sediments of regional water bodies, it is expected that a discharge of cadmium, even at concentrations as low as those tested here, will affect the survival of native amphipods.