Biochar derivation at low temperature: A novel strategy for harmful resource usage of antibiotic mycelial dreg.

Antibiotic mycelial dreg (AMD) has been categorized as hazardous waste due to the high residual hazardous contaminants. Inappropriate management and disposal of AMD can cause potential environmental and ecological risks. In this study, the potential of pleuromutilin mycelial dreg (PMD) as a novel feedstock for preparing tetracycline hydrochloride (TC) adsorbent was explored to achieve safe management of PMD. The results suggested that residual hazardous contaminants were completely eliminated after pyrolysis. With the increase of pyrolysis temperature, the yields, H/C, O/C, (O + N)/C, and pore size in PMD-derived biochars (PMD-BCs) decreased, while BET surface area and pore volume increased, resulting in the higher stability of the PMD-BCs prepared from higher temperatures. The TC adsorption of the PMD-BCs increased from 27.3 to 46.9 mg/g with the increase of the pyrolysis temperature. Surprisingly, pH value had a strong impact on the TC adsorption, the adsorption capacity of BC-450 increased from 6.5 to 71.1 mg/g when the solution pH value increased from 2 to 10. Lewis acid-base interaction, pore filling, π-π interaction, hydrophobic interaction, and charge-assisted hydrogen bond (CAHB) are considered to drive the adsorption. This work provides a novel pathway for the concurrent detoxification and reutilization of AMD.

Effect-based monitoring of two rivers under urban and agricultural influence reveals a range of biological activities in sediment and water extracts.

Chemical contaminants, such as pesticides, pharmaceuticals and industrial compounds are ubiquitous in surface water and sediment in areas subject to human activity. While targeted chemical analysis is typically used for water and sediment quality monitoring, there is growing interest in applying effect-based methods with in vitro bioassays to capture the effects of all active contaminants in a sample. The current study evaluated the biological effects in surface water and sediment from two contrasting catchments in Aotearoa New Zealand, the highly urbanised Whau River catchment in Tamaki Makaurau (Auckland) and the urban and mixed agricultural Koreti (New River) Estuary catchment. Two complementary passive sampling devices, Chemcatcher for polar chemicals and polyethylene (PED) for non-polar chemicals, were applied to capture a wide range of contaminants in water, while composite sediment samples were collected at each sampling site. Bioassays indicative of induction of xenobiotic metabolism, receptor-mediated effects, genotoxicity, cytotoxicity and apical effects were applied to the water and sediment extracts. Most sediment extracts induced moderate to strong estrogenic and aryl hydrocarbon (AhR) activity, along with moderate toxicity to bacteria. The water extracts showed similar patterns to the sediment extracts, but with lower activity. Generally, the polar Chemcatcher extracts showed greater estrogenic activity, photosynthesis inhibition and algal growth inhibition than the non-polar PED extracts, though the PED extracts showed greater AhR activity. The observed effects in the water extracts were compared to available ecological effect-based trigger values (EBT) to evaluate the potential risk. For the polar extracts, most sites in both catchments exceeded the EBT for estrogenicity, with many sites exceeding the EBTs for AhR activity and photosynthesis inhibition. Of the wide range of endpoints considered, estrogenic activity, AhR activity and herbicidal activity appear to be the primary risk drivers in both the Whau and Koreti Estuary catchments.

The relationships between specific dynamic action, nutrient retention and feed conversion ratio in farmed freshwater Chinook salmon (Oncorhynchus tshawytscha).

Improving the feed conversion ratio (FCR; the amount of feed consumed relative to the amount of weight gain) can reduce both production costs and environmental impacts of farmed fish. The aim of this study was to investigate what drives FCR to understand how nutrients are retained, as well as the amount of oxygen consumed for digestion, absorption and assimilation (a metabolic process known as specific dynamic action, SDA). Feed-efficient and inefficient Chinook salmon (Oncorhynchus tshawytscha) in fresh water were identified using ballotini beads and X-radiography that tracked individual feed intake across three assessment periods under satiated feeding. This allowed a comparison of physiological traits and body composition between the two FCR phenotypes over two time points as Chinook salmon grew from 305 to 620 g. Fish with higher daily feed intake (DFI) had higher daily weight gain (DWG) as expected. Nonetheless, the relationship between FCR and DFI as well as FCR and DWG was variable between time points. FCR and DWG were not correlated at the first time point and were negatively correlated at the second time point. In contrast, FCR and DFI were positively correlated at the first time point but not the second. Despite this, efficient fish ate smaller meals and retained more protein, lipid and energy in their body tissues. There was no detectable difference in metabolism between the two FCR phenotypes with respect to minimal resting metabolic rate, maximum metabolic rate, aerobic scope, or SDA parameters. In conclusion, FCR is not consistently associated with growth and metabolic differences in freshwater Chinook salmon, but FCR-efficient fish retain more nutrients and consume smaller meals.

Development of acute and chronic toxicity bioassays using the pelagic copepod Gladioferens pectinatus.

Well validated and reliable biological assays using local and native species are required to characterise the impacts of pollution on ecosystem health. We identified a native estuarine pelagic copepod species suitable for assessing the ecotoxicological impact of anthropogenic contaminants. Gladioferens pectinatus fulfilled the necessary-selection criteria of: wide distribution and abundance across New Zealand estuaries, ease of maintenance in the laboratory, short life cycle, sensitivity to toxicants with different modes of action, and providing reproducibility of biological response to toxicants. Measured endpoints were survival and larval development rate for the nauplii, and survival, realized offspring and total potential offspring for adults. LC50 values for the survival of G. pectinatus exposed to copper, phenanthrene and chlorpyrifos were 170 (143-193), 181.3 (131.3-231.3) and 4.3 (3.8-4.9) µg/L, respectively. The most sensitive chronic endpoint identified for G. pectinatus was the larval development rate, with EC50 values of 49.8 (45-55.3), 31.3 (24.8-44.7) and 1.97 (1.6-2.31) µg/L for copper, phenanthrene and chlorpyrifos, respectively. The acute and chronic responses obtained for G. pectinatus against the three reference toxicants are comparable with those reported for other copepod species and confirm its sensitivity and suitability to assess the toxicity of New Zealand estuarine samples.

Antifouling activity of portimine, select semisynthetic analogues, and other microalga-derived spirocyclic imines.

A range of natural products from marine invertebrates, bacteria and fungi have been assessed as leads for nature-inspired antifouling (AF) biocides, but little attention has been paid to microalgal-derived compounds. This study assessed the AF activity of the spirocyclic imine portimine (1), which is produced by the benthic mat-forming dinoflagellate Vulcanodinium rugosum. Portimine displayed potent AF activity in a panel of four macrofouling bioassays (EC50 0.06-62.5 ng ml-1), and this activity was distinct from that of the related compounds gymnodimine-A (2), 13-desmethyl spirolide C (3), and pinnatoxin-F (4). The proposed mechanism of action for portimine is induction of apoptosis, based on the observation that portimine inhibited macrofouling organisms at developmental stages known to involve apoptotic processes. Semisynthetic modification of select portions of the portimine molecule was subsequently undertaken. Observed changes in bioactivity of the resulting semisynthetic analogues of portimine were consistent with portimine's unprecedented 5-membered imine ring structure playing a central role in its AF activity.

Assessment of cytotoxicity, genotoxicity and 7-ethoxyresorufin-O-deethylase (EROD) induction in sediment extracts from New Zealand urban estuaries.

Sediments represent a major sink for contaminants resulting from industrial and agricultural activities - especially lipophilic substances. This study exclusively used in vitro methodologies to characterize specific toxicity effects of contaminants in sediment extracts from two urban New Zealand estuaries. Sediment extracts were prepared and tested for a range of biological endpoints. The micronucleus and comet assays in V79 cells were used to assess genotoxicity. Induction of 7-ethoxyresorufin-O-deethylase in piscine RTL-W1 cells was determined to estimate dioxin-like toxicity. Cytotoxic potentials were analyzed by neutral red uptake and MTT reduction. There was evidence of strong dioxin-like toxicity and moderate cytotoxicity. Genotoxicity was distinct in the micronucleus assay, but low in the comet assay. The results indicate the presence of chemicals in the sediments with the potential to pose a risk through multiple mechanisms of toxicity, the identities and amounts of which will be disclosed in a parallel study alongside with in vivo toxicity data.

Development of acute and chronic sediment bioassays with the harpacticoid copepod Quinquelaophonte sp.

Reliable environmentally realistic bioassay methodologies are increasingly needed to assess the effects of environmental pollution. This study describes two estuarine sediment bioassays, one acute (96 h) and one chronic (14 d), with the New Zealand harpacticoid copepod Quinquelaophonte sp. utilising behavioural and reproductive endpoints. Spiked sediments were used to expose Quinquelaophonte sp. to three reference compounds representing important categories of estuarine chemical stressors: zinc (a metal), atrazine (a pesticide), and phenanthrene (a polycyclic aromatic hydrocarbon). Acute-to-chronic ratios (ACR) were used to further characterise species responses. Acute sediment (sandy and low total organic content) 96 h EC50 values for the sublethal inhibition of mobility for zinc, atrazine and phenanthrene were 137, 5.4, and 2.6 µg/g, respectively. The chronic EC50 values for inhibition of reproduction (total offspring) were 54.5, 0.0083, and 0.067 µg/g for zinc, atrazine, and phenanthrene, respectively. For phenanthrene, a potentially novel mode of action was identified on reproduction. Quinquelaophonte sp. was found to be more sensitive than several other estuarine species indicating choice of test organism is important to characterising the effects of environmentally relevant levels of contamination. The bioassay sediment results demonstrate the sensitivity and suitability of Quinquelaophonte sp. as a tool for the assessment use of estuarine health.

A national survey of trace organic contaminants in Australian rivers.

Trace organic contaminant (TrOC) studies in Australia have, to date, focused on wastewater effluents, leaving a knowledge gap of their occurrence and risk in freshwater environments. This study measured 42 TrOCs including industrial compounds, pesticides, and pharmaceuticals and personal care products by liquid chromatography tandem mass spectrometry at 73 river sites across Australia quarterly for 1 yr. Trace organic contaminants were found in 92% of samples, with a median of three compounds detected per sample (maximum 18). The five most commonly detected TrOCs were the pharmaceuticals salicylic acid (82%, maximum = 1530 ng/L), paracetamol (also known as acetaminophen; 45%, maximum = 7150 ng/L), and carbamazepine (27%, maximum = 682 ng/L), caffeine (65%, maximum = 3770 ng/L), and the flame retardant (2-chloroethyl) phosphate (44%, maximum = 184 ng/L). Pesticides were detected in 28% of the samples. To determine the risk posed by the detected TrOCs to the aquatic environment, hazard quotients were calculated by dividing the maximum concentration detected for each compound by the predicted no-effect concentrations. Three of the 42 compounds monitored (the pharmaceuticals carbamazepine and sulfamethoxazole and the herbicide simazine) had a hazard quotient >1, suggesting that they may be causing adverse effects at the most polluted sites. A further 10 compounds had hazard quotients >0.1, indicating a potential risk; these included four pharmaceuticals, three personal care products, and three pesticides. Most compounds had hazard quotients significantly <0.1. The number of TrOCs measured in this study was limited and further investigations are required to fully assess the risk posed by complex mixtures of TrOCs on exposed biota.

Characterization of the transcriptional effects of the plastic additive dibutyl phthalate alone and in combination with microplastic on the green-lipped mussel Perna canaliculus.

The presence and persistence of microplastics (MPs) in diverse aquatic environments are of global concern. Microplastics can impact marine organisms via direct physical interaction and the release of potentially harmful chemical additives incorporated into the plastic. These chemicals are physically bound to the plastic matrix and can leach out. The hazards associated with chemical additives to exposed organisms is not well characterized. We investigated the hazards of plastic additives leaching from plastic. We used the common plasticizer dibutyl phthalate (DBP) as a chemical additive proxy and the New Zealand green-lipped mussel (Perna canaliculus) as a model. We used early-adult P. canaliculus exposed to combinations of virgin and DBP-spiked polyvinyl chloride (PVC), MPs, and DBP alone for 7 days. Whole transcriptome sequencing (RNA-seq) was conducted to assess whether leaching of DBP from MPs poses a hazard. The differences between groups were evaluated using pairwise permutational multivariate analysis of variance (PERMANOVA), and all treatments were significantly different from controls. In addition, a significant difference was seen between DBP and PVC MP treatment. Transcriptome analysis revealed that mussels exposed to DBP alone had the most differentially expressed genes (914), followed by PVC MP + DBP (448), and PVC MP (250). Gene ontology functional analysis revealed that the most enriched pathway types were in cellular metabolism, immune response, and endocrine disruption. Microplastic treatments enriched numerous pathways related to cellular metabolism and immune response. The combined exposure of PVC MP + DBP appears to cause combined effects, suggesting that DBP is bioavailable to the exposed mussels in the PVC MP + DBP treatment. Our results support the hypothesis that chemical additives are potentially an important driver of MP toxicity. Environ Toxicol Chem 2024;43:1604-1614. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Monitoring the Health of Coastal Environments in the Pacific Region-A Review.

Coastal areas provide important ecological services to populations accessing, for example, tourism services, fisheries, minerals and petroleum. Coastal zones worldwide are exposed to multiple stressors that threaten the sustainability of receiving environments. Assessing the health of these valuable ecosystems remains a top priority for environmental managers to ensure the key stressor sources are identified and their impacts minimized. The objective of this review was to provide an overview of current coastal environmental monitoring frameworks in the Asia-Pacific region. This large geographical area includes many countries with a range of climate types, population densities and land uses. Traditionally, environmental monitoring frameworks have been based on chemical criteria set against guideline threshold levels. However, regulatory organizations are increasingly promoting the incorporation of biological effects-based data in their decision-making processes. Using a range of examples drawn from across the region, we provide a synthesis of the major approaches currently being applied to examine coastal health in China, Japan, Australia and New Zealand. In addition, we discuss some of the challenges and investigate potential solutions for improving traditional lines of evidence, including the coordination of regional monitoring programs, the implementation of ecosystem-based management and the inclusion of indigenous knowledge and participatory processes in decision-making.

Comparison between droplet digital PCR and reverse transcription-quantitative PCR methods to measure ecotoxicology biomarkers.

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is currently the gold-standard technique for detecting and quantifying messenger RNA. However, without proper validation, the method may produce artefactual and non-reproducible cycle threshold values generating poor-quality data. The newer droplet digital PCR (ddPCR) method allows for the absolute quantification of targeted nucleic acids providing more sensitive and accurate measurements without requiring external standards. This study compared these two PCR-based methods to measure the expression of well-documented genes used in ecotoxicology studies. We exposed Mediterranean mussels (Mytilus galloprovincialis) to copper and analyzed gene expression in gills and digestive glands using RT-qPCR and ddPCR assays. A step-by-step methodology to optimize and compare the two technologies is described. After ten-fold serial complementary DNA dilution, both RT-qPCR and ddPCR exhibited comparable linearity and efficiency and produced statistically similar results. We conclude that ddPCR is a suitable method to assess gene expression in an ecotoxicological context. However, RT-qPCR has a shorter processing time and remains more cost-effective.

Development of a harpacticoid copepod bioassay: selection of species and relative sensitivity to zinc, atrazine and phenanthrene.

Worldwide, estuaries are under increasing pressure from numerous contaminants. This study aimed to identify a suitable marine harpacticoid copepod species for toxicity testing of New Zealand estuaries. Multiple aspects were considered for species selection and included: a broad regional distribution, ease of culture, reproductive rate under laboratory conditions, sexual dimorphism, and sensitivity to contaminants. Five species were evaluated and two (Robertsonia propinqua and Quinquelaophonte sp.) were able to be cultured. The relative sensitivity of these copepods to three reference toxicants was assessed by determining the medial lethal values following a 96 h exposure (96 h LC(50)) to these toxicants in the aquatic phase. LC(50) values for zinc, phenanthrene, and atrazine respectively were 2.0, 0.89, and 7.58 mg/L in R. propinqua and 0.64, 0.75, and 20.8 mg/L in Quinquelaophonte sp. After evaluating all factors involved in choosing a bioassay species for New Zealand, Quinquelaophonte sp. was selected as the most suitable bioassay species.

Key Challenges to the Effective Management of Pollutants in Water and Sediment.

The intensification of human activities is placing increasing pressure on the ecosystems of riverine, estuarine, and coastal waters, as these compartments are sinks for many anthropogenic contaminants [...].

Enhancing consumption responsibility to address global plastic pollution.

Plastic pollution is a global crisis, especially in the marine environment. Excessive consumption and unsound disposal are responsible for the constant accumulation of plastic waste, resulting in plastic litter and microplastic contamination on a global scale. Establishing a new global framework is regarded as a promising tool to address plastic pollution, including marine plastic litter. However, there is a need to raise awareness of the role of consumers at individual and national levels in reducing the use of unnecessary plastics and increasing the recycling of plastic waste. The global framework should incorporate aspects of the importance of consumption responsibility in solutions addressing the issue of plastic pollution.

Disentangling the influence of microplastics and their chemical additives on a model detritivore system.

Microplastics (MPs) can negatively impact freshwater organisms via physical effects of the polymer itself and/or exposure to chemicals added to plastic during production to achieve desired characteristics. Effects on organisms may result from direct exposure to plastic particles and/or chemical additives or effects may manifest as indirect effects through ecological interactions between organisms (e.g., reduced food availability that impairs a consumer). To disentangle these issues, we used a simplified freshwater food web interaction comprising microbes and macroinvertebrate detritivores to evaluate the toxicity of 1) polyvinyl chloride (PVC) MPs without added chemicals (virgin), 2) the common chemical additive dibutyl phthalate (DBP), and 3) PVC MPs with incorporated DBP. Exposure to virgin PVC MPs (0.33 and 3.3 mg/L) caused negligible ecological effect with the exception of reduced macroinvertebrate feeding rates at 3.3 mg/L. Exposure to DBP (1 mg/L) both individually and when incorporated into the PVC MPs negatively impacted all tested endpoints, including microbial and macroinvertebrate respiration, feeding rate and assimilation efficiency. DBP leached rapidly from the MPs into the water, and also accumulated in macroinvertebrates and their food, providing multiple routes of exposure. Our findings suggest that additives which are intentionally incorporated into MPs could play a key role in MP toxicity and contribute to the disruption of key ecological interactions underpinning ecosystem processes, such as leaf litter decomposition.

Characterization of the effects of triclosan on sperm and embryos of Mytilus and Perna mussel species.

The Greenshell™ mussel (GSM), Perna canaliculus, is a culturally and commercially important species in New Zealand. Declines in spat settlement of GSM have been observed in important growing areas and the cause(s) have not been identified. One hypothesis is that chemical contaminants could be a contributing factor. The aim to this study was to investigate the effects of acute exposure on early life stages using the anti-microbial triclosan (TCS) as a benchmark toxicant and the blue mussel (BM), Mytilus galloprovincialis, as a reference species. Sperm and embryos of BM and GSM were exposed to TCS for 1 h and 48 h, respectively. Following exposures, a range of parameters were investigated including spermatozoa cellular characteristics via flow cytometry, fertilization success, larval mortality and size. Exposure to TCS negatively impacted functional parameters of sperm, reduced the fertilization success and larval size, and increased larval mortality in both BM and GSM with LC5048h of 94.3 and 213 µg L-1, respectively. Triclosan increased sperm ROS production in both species, which could cause destabilisation of mitochondrial and other cellular membranes, resulting in reduced mitochondrial membrane potential (BM) and increased sperm size (GSM), leading to apoptosis in both species. Fertilization success of GSM was only affected at the highest TCS concentration tested (391 µg L-1), but development of larvae derived from exposed sperm was affected from the lowest concentrations tested (0.5 and 5.2 µg L-1) in both species. This highlights the importance of assessing the sensitivity of contaminants across developmental stages. Results of this study confirm that TCS causes oxidative stress and has membranotropic effects, and that early life stages of the endemic GSM are suitable to assess ecotoxicity of contaminants such as TCS.

Investigating the Ecotoxicity of Select Emerging Organic Contaminants Toward the Marine Copepod Gladioferens pectinatus.

Estuarine ecosystems are recipients of anthropogenic stressors released from land-based activities. The aim of the present study was to investigate the ecotoxicological hazards of organic contaminants toward the estuarine copepod Gladioferens pectinatus using acute and chronic testing. Most chemicals demonstrated acute toxicity and influenced development of the copepods. Further research should be conducted to investigate these chemicals and their mixtures using long-term, multigenerational testing to characterize mechanisms of toxicity. Environ Toxicol Chem 2022;41:792-799. © 2022 SETAC.

First transcriptome of the copepod Gladioferens pectinatus subjected to chronic contaminant exposures.

Contaminants are often at low concentrations in ecosystems and their effects on exposed organisms can occur over long periods of time and across multiple generations. Alterations to subcellular mechanistic pathways in response to exposure to contaminants can provide insights into mechanisms of toxicity that methods measuring higher levels of biological may miss. Analysis of the whole transcriptome can identify novel mechanisms of action leading to impacts in exposed biota. The aim of this study was to characterise how exposures to copper, benzophenone and diclofenac across multiple generations altered molecular expression pathways in the marine copepod Gladioferens pectinatus. Results of the study demonstrated differential gene expression was observed in cultures exposure to diclofenac (569), copper (449) and benzophenone (59). Pathways linked to stress, growth, cellular and metabolic processes were altered by exposure to all three contaminants with genes associated with oxidative stress and xenobiotic regulation also impacted. Protein kinase functioning, cytochrome P450, transcription, skeletal muscle contraction/relaxation, mitochondrial phosphate translocator, protein synthesis and mitochondrial methylation were all differentially expressed with all three chemicals. The results of the study also suggested that using dimethyl sulfoxide as a dispersant influenced the transcriptome and future research may want to investigate it's use in molecular studies. Data generated in this study provides a first look at transcriptomic response of G. pectinatus exposed to contaminants across multiple generations, future research is needed to validate the identified biomarkers and link these results to apical responses such as population growth to demonstrate the predictive capacity of molecular tools.

Does plastic type matter? Insights into non-indigenous marine larvae recruitment under controlled conditions.

Marine plastic debris (MPD) are a global threat to marine ecosystems. Among countless ecosystem impacts, MPD can serve as a vector for marine 'hitchhikers' by facilitating transport and subsequent spread of unwanted pests and pathogens. The transport and spread of these non-indigenous species (NIS) can have substantial impacts on native biodiversity, ecosystem services/functions and hence, important economic consequences. Over the past decade, increasing research interest has been directed towards the characterization of biological communities colonizing plastic debris, the so called Plastisphere. Despite remarkable advances in this field, little is known regarding the recruitment patterns of NIS larvae and propagules on MPD, and the factors influencing these patterns. To address this knowledge gap, we used custom-made bioassay chambers and ran four consecutive bioassays to compare the settlement patterns of four distinct model biofouling organisms' larvae, including the three notorious invaders Crassostrea gigas, Ciona savignyi and Mytilus galloprovincialis, along with one sessile macro-invertebrate Spirobranchus cariniferus, on three different types of polymers, namely Low-Linear Density Polyethylene (LLDPE), Polylactic Acid (PLA), Nylon-6, and a glass control. Control bioassay chambers were included to investigate the microbial community composition colonizing the different substrates using 16S rRNA metabarcoding. We observed species-specific settlement patterns, with larvae aggregating on different locations on the substrates. Furthermore, our results revealed that C. savignyi and S. cariniferus generally favoured Nylon and PLA, whereas no specific preferences were observed for C. gigas and M. galloprovincialis. We did not detect significant differences in bacterial community composition between the tested substrates. Taken together, our results highlight the complexity of interactions between NIS larvae and plastic polymers. We conclude that several factors and their potential interactions influenced the results of this investigation, including: (i) species-specific larval biological traits and ecology; (ii) physical and chemical composition of the substrates; and (iii) biological cues emitted by bacterial biofilm and the level of chemosensitivity of the different NIS larvae. To mitigate the biosecurity risks associated with drifting plastic debris, additional research effort is critical to effectively decipher the mechanisms involved in the recruitment of NIS on MPD.