Stream Health Research Articles

Analysis of the Effects of Securing Baseflow and Improving Water Quality through the Introduction of LID Techniques

Rapid climate change and increasing water use have led to various problems in small- and medium-sized urban streams during dry periods, such as stream drying, water pollution, and ecological degradation, reducing their physical and ecological functions. Ensuring adequate baseflow and improving water quality during these critical periods are essential for maintaining urban stream health. While previous studies have explored the effects of Low Impact Development (LID) techniques (e.g., green roof, rainwater harvesting system, permeable pavement, infiltration trench) on infiltration and groundwater recharge, they have primarily focused on general flow regimes rather than dry and low-flow periods. This study specifically evaluates the effects of LID techniques on securing baseflow and improving water quality during dry periods, utilizing the SWAT-MODFLOW model and the Web-based Hydrograph Analysis Tool (WHAT) system. The results show that LID techniques reduce peak flow by an average of 27% and secure an additional 43% of baseflow during dry periods. Suspended solids (SS) and total phosphorus (T-P) concentrations were reduced by 15% and 41%, respectively. These findings demonstrate the effectiveness of LID techniques not only in managing stormwater runoff during flood events but also in maintaining baseflow and water quality during dry periods, thus providing valuable insights for sustainable urban watershed management.

Temporal analysis of water chemistry and smallmouth bass (Micropterus dolomieu) health at two sites with divergent land use in the Susquehanna River watershed, Pennsylvania, USA

Monitoring wild fish health and exposure effects in impacted rivers and streams with differing land use has become a valuable research tool. Smallmouth bass (Micropterus dolomieu) are a sensitive, indicator species that exhibit signs of immunosuppression and endocrine disruption in response to water quality changes and contaminant exposure. To determine the impact of agriculture and development on smallmouth bass health, two sites (a developed/agriculture site and a forested site) in the Susquehanna River watershed, Pennsylvania were selected where bass and water chemistry were sampled from 2015 to 2019. Smallmouth bass were sampled for histopathology to assess parasite and macrophage aggregate density in the liver and spleen, condition factor (Ktl), hepatic gene transcript abundance, hepatosomatic index (HSI), and a health assessment index (HAI). Land use at the developed/agriculture site included greater pesticide application rates and phytoestrogen crop cover and more detections and higher concentrations of pesticides, wastewater-associated contaminants, hormones, phytoestrogens, and mycotoxins than at the forested site. Additionally, at the developed/agriculture site, indicators of molecular changes, including oxidative stress, immune/inflammation, and lipid metabolism-related hepatic gene transcripts, were associated with more contaminants and land use variables. At both sites, there were multiple associations of contaminants with liver and/or spleen macrophage aggregate density, indicating that changes at the molecular level seemed to be a better indicator of exposures unique to each site. The findings illustrate the importance of timing for land management practices, the complex mixtures aquatic animals are exposed to, and the temporal changes in contaminant concentration. Agricultural practices that affect hepatic gene transcripts associated with immune function and disease resistance were demonstrated which could negatively affect smallmouth bass populations.

Water purification – an essential service from forest ecosystems, and farming practices in the Pong River Basin, Northeast Thailand

Deforestation often results in biodiversity depletion, land degradation, and loss of forest ecosystem services such as water purification. This research examined the relationship between natural forest areas in the Pong River Basin (PRB), northeast Thailand, and water quality in the Pong River system, one of the country's most polluted rivers. Water parameters were measured in 15 tributaries where samples were collected 500 m upstream from the outlets, and 2–5 m from the streambanks during summer, rainy, and winter seasons in 2021. Land use and land cover (LULC) were classified by a supervised classification method in QGIS using LANDSAT8 satellite imagery and USGS SRTM data. Vegetative surveys were conducted near the sampling locations which included species richness and density. Water characteristics at all the sites were under Thailand's Water Quality Standard, except a level of biological oxygen demand (avg. BOD = 3.52 mg/L). The upper PRB, covered with more forested areas with higher tree densities along streambanks (∼43 % of the basin, 619 trees/ha), revealed better water quality including a higher concentration of dissolved oxygen (avg. DO = 7.57 mg/L) and a lower level of fecal coliform bacteria (avg. FCB = 642 MPN/100 mL). In contrast, the lower PRB having larger areas of farmlands and smaller forests (∼63 % and 23 %, respectively) yielded higher concentrations of FCB (avg. = 1,353 MPN/100 mL) and phosphates (avg. PO43- = 0.34 mg/L). Positive correlations were found between the amount of forestlands (% of the sub-basin) with DO and nitrate concentrations (r = 0.468 and 0.409, p-value < 0.05, respectively), while agricultural areas were correlated with FCB (r = 0.414, p-value < 0.05). Amounts of forests determine water purity, while farmlands denoting dirtiness. These findings show that water purification is an essential forest ecosystem service, critical for stream health.

Exploring potential mechanisms linking urban landscapes to instream stressors and macroinvertebrates in the Southeast Piedmont: Implications for watershed management

Urbanization has greatly degraded stream health, particularly in the rapidly urbanizing southeastern United States. Recent studies identified primary instream stressors affecting biological communities along urban gradients in the Southeast Piedmont. However, a comprehensive understanding of the complex mechanisms is still lacking, which impedes effective management actions. To improve our understanding, we investigated the potential pathways by which urbanization, as represented by the landscape development intensity index (LDII), and important environmental characteristics affected instream stressors and macroinvertebrate communities using structural equation modeling (SEM) and the U.S. Geological Survey Southeast Stream Quality Assessment dataset. We investigated the direct, indirect, and total effects of LDII and environmental characteristics on instream stressors and macroinvertebrate communities as well as the interactions of instream stressors. Moreover, we explored alternative reasonable relationships between variables by using an alternative model approach. We found that LDII had moderate to strong total effects on all instream stressors and macroinvertebrates with complex impact pathways revealed in SEM models, demonstrating the dominant impact of urban landscape development on stream ecosystems in the Southeast Piedmont. Flow disturbance and pesticides were major mediators transmitting most of LDII’s effects on macroinvertebrates. Furthermore, we found potential interactions among instream stressors, which were not widely discussed in previous studies. Compared with agricultural watersheds, urban watersheds represented different land use impact mechanisms. Our findings contributed to an improved understanding of urbanization’s impact on stream ecosystems and demonstrated the usefulness of an alternative model approach that provided insights into the underlying mechanisms. In addition, we demonstrated the utility of LDII in characterizing landscape development and improving SEM models. Finally, we explored the potential of SEM in global watershed management activities by discussing the practical implications of impact pathways and the innovative use of SEM as a decision-making tool.

Analysis of irregularly sampled stream temperature time series: challenges and solutions

Water temperature is a key physical indicator of stream health, and as such, is commonly measured as part of long-term river health monitoring programs. However, analysis of long-term stream water temperature time series can be challenging, due to typically low frequencies of sampling combined with common characteristics of data collection from streams – such as observations unevenly spaced across seasons, changes to routine sampling frequencies, or improvements in the accuracy of measurements over time – known as sampling artifacts. While there are many models regularly used to estimate trends and summary statistics in long-term stream temperature datasets, there is limited understanding of the impact that commonly encountered sampling artifacts have on the accuracy and uncertainty of their estimates. This study constructed Monte-Carlo simulations to examine the influence that common sampling artifacts and the choice of analysis model can have on trend and mean estimates from long-term stream temperature time series covering tropical, temperate and cold climates. We found that, if not appropriately accounted for during analysis, sampling artifacts may obscure true trends or summary statistics, such as site means, and lead to inaccurate or misleading estimates. However, models that included components to account for seasonal variation within the model structure could estimate trends and means with high confidence, in the presence of almost all of the sampling artifacts commonly found in long-term stream temperature datasets. Structural biases in the time-of-day of sampling, such as always sampling in the morning, or where the start and end of the record are sampled at different times of day, could make estimates highly inaccurate and uncertain, and should be avoided in data collection strategies. This work aims to facilitate the analysis of historical stream temperature datasets with confidence, through identifying models that perform reliably in the presence of common sampling artifacts. The findings will enable further global insights into stream temperature, support management decisions based on accurate analysis and assist the design of future stream sampling programs using cost-effective, low-frequency sampling strategies.

Spatial and temporal analysis of physical and chemical properties of Short Creek

Freshwater systems are vitally important. Ecologically, rivers and streams are responsible for immense biodiversity, providing habitat for terrestrial and aquatic flora and fauna. Freshwater systems benefit humans in innumerable ways, providing drinking water to millions of people, means of transportation, food sources, and recreation areas. Nevertheless, the degradation of freshwater ecosystems continues to worsen at alarming rates. Long-term water quality monitoring can help determine the best management practices to improve and restore waterways. This study assessed changes in water chemistry in the Short Creek tributary located in Wheeling, WV, comparing historical data to current, focusing on physical and chemical water quality parameters data recorded from single monthly points obtained from historical data and averaged monthly points from current data. Short Creek represents 4 of 11 sites where data is collected weekly year-round. This data collection has been ongoing since 2018 and is part of a more extensive compilation hosted by Three Rivers Quest and the WVU Water Resource Research Institute. Water temperature, dissolved oxygen, chloride, specific conductivity, pH, and turbidity were recorded and analyzed utilizing Excel and RStudio. The increased frequency of monitoring provides a more accurate representation of Short Creek's overall condition. Both historical and current datasets were incomplete but generally did not show declines. A concerted effort in long-term water quality monitoring is necessary for understanding stream health. Current and historical data combined give us more resolution to estimate trends in water chemistry, better determine stream health progress, and assist in implementing best management practices.

Assessing the Health of Dachigam Stream: A Water Quality Analysis

As global populations rise and climate change impacts water cycles, the importance of water resources becomes increasingly critical for human sustenance. Streams, characterized by their unidirectional flow, are valuable systems for studying ecological phenomena across spatial and temporal scales. Maintaining good water quality is crucial for preserving biodiversity and ensuring individual and public health, environmental protection, and sustainable development. Analyzing water chemistry is a valuable tool for monitoring stream health, offering insights into pollutant levels and potential issues. This study assesses the spatiotemporal changes in water quality in the Dachigam stream in Kashmir, India. Data on various water quality parameters were collected over a year at six different sampling locations within the Dachigam National Park and surrounding areas up to the mouth of Dal lake. Parameters such as pH, dissolved oxygen, electrical conductivity, and nutrient concentrations were analyzed to evaluate stream health and identify potential sources of pollution. Results revealed significant spatiotemporal variability was evident in the sampled parameters, revealing notable differences in element concentrations across various sites. There was an observable trend of increasing concentrations from upstream to downstream locations. The observed escalation in pollution levels from upstream to downstream sites underscores heightened anthropogenic impacts in the downstream regions.

Longitudinal stream synoptic (LSS) monitoring to evaluate water quality in restored streams.

Impervious surface cover increases peak flows and degrades stream health, contributing to a variety of hydrologic, water quality, and ecological symptoms, collectively known as the urban stream syndrome. Strategies to combat the urban stream syndrome often employ engineering approaches to enhance stream-floodplain reconnection, dissipate erosive forces from urban runoff, and enhance contaminant retention, but it is not always clear how effective such practices are or how to monitor for their effectiveness. In this study, we explore applications of longitudinal stream synoptic (LSS) monitoring (an approach where multiple samples are collected along stream flowpaths across both space and time) to narrow this knowledge gap. Specifically, we investigate (1) whether LSS monitoring can be used to detect changes in water chemistry along longitudinal flowpaths in response to stream-floodplain reconnection and (2) what is the scale over which restoration efforts improve stream quality. We present results for four different classes of water quality constituents (carbon, nutrients, salt ions, and metals) across five watersheds with varying degrees of stream-floodplain reconnection. Our work suggests that LSS monitoring can be used to evaluate stream restoration strategies when implemented at meter to kilometer scales. As streams flow through restoration features, concentrations of nutrients, salts, and metals significantly decline (p < 0.05) or remain unchanged. This same pattern is not evident in unrestored streams, where salt ion concentrations (e.g., Na+, Ca2+, K+) significantly increase with increasing impervious cover. When used in concert with statistical approaches like principal component analysis, we find that LSS monitoring reveals changes in entire chemical mixtures (e.g., salts, metals, and nutrients), not just individual water quality constituents. These chemical mixtures are locally responsive to restoration projects, but can be obscured at the watershed scale and overwhelmed during storm events.

Spatiotemporal Variation Analyses of Water Quality, Fish Ecological Guilds, and the Longitudinal Connectivity in Musim Stream

The main objectives of this study were to analyze the spatiotemporal variations of water quality, fish ecological guilds and longitudinal connectivity in the weirs of Musim Stream. Fish were collected at 44 sites during spring and fall seasons for the analysis of trophic guilds, tolerance guilds, and the ecological stream health, based on FAI model. Total 33 species were observed in the stream and the dominant species were &lt;i&gt;Zacco platypus&lt;/i&gt; and &lt;i&gt;Squalidus qracilis majimae&lt;/i&gt;. Mean values of BOD and COD, as an indicator of organic matter pollution, showed high in the drought spring and low in fall (post-monsoon season). Also, TP showed same pattern with the BOD and COD pattern. The hierarchical clustering, based on the fish compositions, classified as three groups (up-stream, mid-stream and the down-stream). Based on the NMDS (Non-metric Multidimensional Scaling) analysis of fish abundance, high similarity was observed between S1-S5 sites, which were consistent with the results of hierarchical cluster analysis. Fish ecological guilds in the upper stream showed a high similarity between the insectivore and sensitive species, while in the middle and lower reaches, high similarity was found between the omnivore and intermediate species. Evaluations of longitudinal connectivity, based on the structural and hydrological characteristics of the weir, indicated all disconnections by the weirs, except for S15, in the spring. Stream ecological health, based on the FAI model, was significantly (&lt;i&gt;p&lt;/i&gt; &lt; 0.05, n=37) influenced by the height of overflow (&lt;i&gt;Hu1&lt;/i&gt;). Overall, our study suggests that the longitudinal connectivity, based on the weir structures, flow regime and fish swimming capacity, were blocked off by the weirs in the stream. The results provide valuable insights for securing river management strategies and served as the fundamental data for stream restoration in the future.

Top 5 Things Health Professions Students Should Know About Ecology and Waste Management.

The environments in which we live affect individual and community risk for disease transmission and illness severity. Communities' and neighborhoods' waste stream management designs and health care organizations' spatial and structural architecture also influence individuals' and communities' pathogenic vulnerabilities and how well health sector industrial hygiene practices support them. This article describes a One Health approach to planetary environmental health and suggests strategies for implementing a One Health or Planetary Health approach in the context of climate change.

Construction and assessment of an indicator system of stream conditions in a typical mountain landscape in Northeast China.

Stream ecosystem health assessments are crucial for the effective management of aquatic ecosystem service functions and the assessment of anthropogenic and climatic impacts on aquatic ecosystems. However, there is still a lack of comprehensive assessment methods based on complete ecosystem structures. This study improved an ecological health assessment system, which consists of 13 indicators based on ecosystem structure. The assessment system was applied to 30 streams on Changbai Mountain. The results showed that the comprehensive index of stream health (ISH) in Changbai Mountain was relatively high, and the ISH increased with the elevation gradient. The dominant factors controlling the ecosystem health level were water pH, water flow, vegetation coverage, total phosphorus (TP), and vegetation diversity index. All these results indicated that the damage caused by excessive deforestation and farmland occupation in recent years has not been fully reversed and that human disturbance from tourism may be the main reason for the low stream health at lower elevations. Our results suggest that the key to future work is to increase quantitative research on disturbance sensitivity and to develop economically viable restoration measures.

Prokaryotic Community Composition and Diversity in Sediments from Choctafaula, Uphapee, and Cubahatchee Creeks in the Lower Tallapoosa River Basin, Macon County, Alabama: An Observational Study

Sedimentary prokaryotes are primarily responsible for metabolic activity in rivers. They are subjected to a variety of natural and anthropogenic pressures, allowing us to use the composition and diversity of their communities as indicators of ecological health. For our investigation, we looked at sediments from three ecologically critical streams in the Lower Tallapoosa River Basin (Choctafaula, Uphapee, and Cubahatchee Creeks). The prokaryotic community was characterized using molecular approaches, and elemental concentrations were determined by inductively coupled plasma atomic emission spectrometry. This research demonstrated that Proteobacteria (45.02–80.73%), Bacteroidetes (1.98–26.52%), Firmicutes (1.36–50.67%), Actinobacteria (1.55–16.81%), and Acidobacteria (0.13–8.77%) were the most prevalent phyla. Key physicochemical parameters, core communities at multiple taxonomic levels, and several pathogenic genera shifted radically between streams. Weighted and unweighted unifrac distance metrics based PCoA plots indicated the structural and membership similarity of samples from specific creek ecosystems. Based on our research findings, it is evident that the composition and diversity of prokaryotic communities in sediment could serve as significant indicators in stream ecosystems. Further investigation and application of these indicators could prove valuable in assessing the health of streams, particularly in light of the accelerated changes resulting from climate change within a condensed timeframe.

Toxicity Assessment on Odonata Larvae Survivability in Monitoring Heavy Metal Contaminations

The aquatic ecosystem has been suffering a continuous increase of metal contamination such as Cadmium (Cd), Zinc (Zn), and Manganese (Mn) due to their inadequate high potential to disturb the aquatic organism population. Meanwhile, some insects such as Pseudagrion microcephalum and Ischnura senegalensis can be used as biological indicators to determine stream health. Therefore, this study was conducted to determine the relationship between the heavy metal concentration and its effect on the survivability of two different species of damselfly larvae from the family Coenagrionidae; Pseudagrion microcephalum and Ischnura senegalensis. In this study, there is a significant effect of three heavy metal exposures on the survivability of P.microcephalum (F11,180=14.50, P=0.00) and I.senegalensis (F11,180 =15.10, P=0.00). Pseudagrion microcephalum is more tolerable towards Mn (F3,60=13.19, P=0.00) and Zn (F3,60=16.07, P=0.00) at different concentrations compared to I.senegalensis. In the meantime, I.senegalensis was tolerable to Cd exposure. The LC50 value of Cd was much lower than other heavy metals. Besides, the LT50 value of Cd at 200 mg/L was the lowest on P. microcephalum (31 hr) and I. senegalensis (36 hr) compared to other heavy metals. Cd was the most toxic to P.microcephalum and I.senegalensis larvae followed by zinc and manganese (LC50 &amp; LT50=Cd &gt; Zn &gt; Mn). It is concluded that I.senegalensis was tolerant towards Cd, Mn, and Zn compared to P.microcephalum and Cd had the fastest-acting toxicity and significantly reduced the lethal time of mortality on both species.

Integrating Earth Observation with Stream Health and Agricultural Activity

Integrating Earth Observation with Stream Health and Agricultural Activity

Monthly sampling reveals seasonal fine sediment fluctuations and riverine invertebrate community responses

Managing the impacts of anthropogenically enhanced deposited fine sediment levels in lotic ecosystems requires understanding of how catchment land-use changes have altered the natural sediment regime (erosion, transport, deposition) of rivers. Unfortunately, no existing studies have employed an appropriate sampling frequency over a period encompassing the full range of seasonal flow conditions expected to influence in-stream sediment dynamics. We determined the short-term (monthly) dynamics of deposited fine sediment and invertebrate communities over 12-months in 15 fourth- and fifth-order rivers draining catchments of low, medium and high land-use intensity in Southland, New Zealand to determine when and where fine sediment threatens stream health. We compared the Quorer resuspension method (suspendable inorganic sediment, SIS) and the in-stream visual sediment cover assessment method, and evaluated the effectiveness of four commonly-used invertebrate stream health metrics against their newly developed sediment-specific counterparts. Monthly variability in SIS was substantial across all land-use categories, but became more pronounced as land-use intensity increased. All 15 sites experienced a prolonged period of relatively stable flow which coincided with the largest short-term increase in SIS at 14 of the 15 sites. However, variability in SIS was not mirrored in macroinvertebrate metrics. These findings suggest that controlling inputs of fine sediment to rivers and streams will be most effective when targeted at periods of prolonged stable flow, particularly within high land-use intensity catchments. The resuspension method consistently outperformed visual estimates when considering its relationship with macroinvertebrate metrics, while sediment-specific metrics demonstrated a stronger association with fine sediment than commonly employed metrics e.g. (%EPT). We conclude that restoration/mitigation practices cannot be based solely on short-term, or even long-term, reductions in fine sediment, or on physical measures alone, but should be based on long-term recoveries of sediment-impacted invertebrate communities using concurrent measurements of both biotic and abiotic conditions.

Restoring eastern hellbender (Cryptobranchus a. alleganiensis) populations through translocation of headstarted individuals

AbstractFreshwater biodiversity is declining at a fast pace despite significant efforts directed toward the management and conservation of aquatic systems. Eastern hellbenders are one of North America's most iconic stream amphibian species, a sentinel of stream health, and are experiencing rapid population declines throughout most of their range. Common conservation strategies include headstarting; however, the success of this strategy for rebuilding hellbender populations and the most optimal release scenarios have largely been unassessed. We use a cohort of 205 animals released in several Ohio watersheds to evaluate the success of headstarting and reintroduction efforts over 3 years. Using PIT‐tag surveys over 25 occasions between July 2018 and November 2021 and capture–recapture models, we found that 3‐year apparent survival post‐release was 0.162 ± 0.061, with lower survival in year 1 (0.383 ± 0.058) and greater in years 2 (0.696 ± 0.086) and 3 (0.609 ± 0.154). Using demographic simulations, we found that releasing cohorts of N = 100 individuals at fewer suitable sites several times (e.g., 3 releases, 2 or 3 years apart) would be a better strategy compared to single release events across multiple sites. Additional simulations showed that eastern hellbender headstarting programs using wild eggs can be highly beneficial in producing more animals reaching adulthood (up to 7 times, if survival in captivity is assumed to be 100%) compared to development in the wild. This study emphasizes the need to monitor the success of reintroduction programs and provides evidence that headstarting can be a viable strategy for rebuilding eastern hellbender populations.

Taxonomic and functional diversity of aquatic macroinvertebrate from natural forest as reference for streams health indicators in Lasolo Watershed, Southeast Sulawesi, Indonesia

Abstract. Nasaruddin N, Sabaruddin L, Analuddin K, Sudia LB. 2023. Taxonomic and functional diversity of aquatic macroinvertebrate from natural forest as reference for streams health indicators in Lasolo Watershed, Southeast Sulawesi, Indonesia. Biodiversitas 24: 5523-5538. Macroinvertebrates are known to play a crucial role in nutrient recycling and serve as valuable stream degradation indicators. Therefore, this study aimed to examine the structural and functional diversity of macroinvertebrate communities as a reference for stream health indicators in tropical Sulawesi, Indonesia. Spatial sampling using a multi-habitat method was conducted between September 2021 and March 2022 in five streams connected to natural forest and three from drainage areas in dryland farming. Data on forest cover, physical-chemical variables, and macroinvertebrate samples were collected, while the species richness and diversity trends across streams were analyzed using individual rarefaction curves. In addition, the composition of macroinvertebrate functional group was also evaluated. The results showed that 2474 individuals belonging to 77 genera were recorded throughout the area. We found a reduction in taxa composition by comparing the reference and impacted stream at the genus, family, and order levels with approximate values of 83.1%, 74.07%, and 55.6%, respectively. At least seven significantly different potential metrics that differentiated between reference and the impacted ecosystem were found, including the number of family taxa (#family), the number of insect taxa (#insect), the number of Ephemeroptera-Plecoptera-Trichoptera taxa (#EPT), the number of scraper taxa (#scraper), as well as Shannon-Wiener diversity, Simpson Evenness, and Margalef Richness index. These metrics offer a strong method for assessing land use change and their impact on freshwater biodiversity, emphasizing the importance of conservation efforts in the ecosystem.

The case for expanding the range of subject specialists used in farm planning.

We explored the merit of expanding the range of subject specialists used in farm planning. We document the outcomes for sheep and beef farmers to improve water quality and promote climate change awareness as part of the wider planning process in two community catchment groups (Hurunui District Landcare Group and King Country River Care group). We found that subject specialists added value. A land resource specialist contributed to greater precision and a more detailed description of the farms natural and built capital. This contributed to a more robust analysis and better targeting of the actions in the work programme. The terrestrial ecologist activated the link between the management of indigenous biodiversity and stream health, with resilience to future climate events. The carbon specialist created the link between tree planting and water quality outcomes because of where tree plantings were located on most farms. The carbon specialist also highlighted the option to register existing soil conservation plantings under the emissionstrading scheme, adding a revenue stream. With the subject specialist(s) as part of the wider farm team, environmental concerns are more likely to be integrated into the business plan with mitigation actions better tailored and targeted in the work programme.

Systematic evidence mapping informs a class-based approach to assessing personal care products and pubertal timing

BackgroundPersonal care products (PCPs) contain many different compounds and are a source of exposure to endocrine disrupting chemicals (EDCs), including phthalates and phenols. Early-life exposure to EDCs commonly found in PCPs has been linked to earlier onset of puberty. ObjectiveTo characterize the human and animal evidence on the association between puberty-related outcomes and exposure to PCPs and their chemical constituents and, if there is sufficient evidence, identify groups of chemicals and outcomes to support a systematic review for a class-based hazard or risk assessment. MethodsWe followed the OHAT systematic review framework to characterize the human and animal evidence on the association between puberty-related health outcomes and exposure to PCPs and their chemical constituents. ResultsNinety-eight human and 299 animal studies that evaluated a total of 96 different chemicals were identified and mapped by key concepts including chemical class, data stream, and puberty-related health outcome. Among these studies, phthalates and phenols were the most well-studied chemical classes. Most of the phthalate and phenol studies examined secondary sex characteristics and changes in estradiol and testosterone levels. Studies evaluating PCP use and other chemical classes (e.g., parabens) had less data. ConclusionsThis systematic evidence map identified and mapped the published research evaluating the association between exposure to PCPs and their chemical constituents and puberty-related health outcomes. The resulting interactive visualization allows researchers to make evidence-based decisions on the available research by enabling them to search, sort, and filter the literature base of puberty-related studies by key concepts. This map can be used by researchers and regulators to prioritize and target future research and funding to reduce uncertainties and address data gaps. It also provides information to inform a class-based hazard or risk assessment on the association between phthalate and phenol exposures and puberty-related health outcomes.

End-Point Predictors of Water Quality in Tropical Rivers

End-point evaluation of stream health is essential for the quantification of water quality. To this end, many Multi-Metric Indices (MMIs) have been developed to quantify water quality. The most extensive work has occurred in North America and Europe, while other areas of the world are in development. In this study, we compared the use of relevant physical, chemical and biological parameters in MMIs to various other stream health indicators to assess water quality throughout a three-river corridor along the north central Pacific slope of Costa Rica. Analysis of the data suggested MMIs were the best indicators of water quality and, more specifically, insect MMIs were the most predicative. MMIs were also best at pinpointing anthropomorphic impact throughout the corridor. Further, less complex insect MMIs such as compilations of family diversity using Ephemeroptera, Plecoptera and Trichoptera (EPT) orders were equally as predictive as the more complex models. With a need to better understand and use citizen monitors to predict water quality in these tropical environments, less complex insect MMIs show promise as a solution.