We begin our current review of the aquatic literature with the extremely topical issue of the negative impact of cross-barriers on rivers on fish populations. Chinese scientists describe how a cascade of dams on the Yangtze River has contributed to the decline of five key species on the river. We also present the results of a study on the rate of carbon accumulation in small boiler bogs in Poland. These ecosystems are important sites for sequestration of the element, but their role in this process is still underestimated.
Also, the problem of perennial pollutants, such as PFAS compounds, continues to occupy scientists – it turns out that atmospheric deposition is an important source of these substances in surface waters, as evidenced by studies of Great Lakes waters. Two other articles presented talk about the impact of changes in temperature patterns and water availability occurring as a result of climate change on insects – one in the context of the threat to pollinators, the other of changes in the extent of areas convenient for the proliferation of malaria-carrying mosquitoes in Africa. We conclude the review with two articles on wastewater management. It is very interesting to review the current knowledge of wastewater sanitation methods other than combined sewers in urban areas.
The use of non-sewer systems is necessary in situations where wastewater management goals cannot be met with a single technological solution. The second article is an introduction to a thematic issue on the use of wastewater to analyze epidemiological risks based on biomarkers.
1. dams trigger exponential population declines of migratory fish
Huang Z., Li H. (2024). Dams trigger exponential population declines of migratory fish. Sci. Adv. 10, eadi6580.
The impact of transverse bulkheads on global migratory fish stocks is enormous and seriously underestimated. If anyone doesn’t believe this is the case, I recommend the work of Chinese scientists on the impact of the Yangtze River dams on the populations of the river’s five flagship species: the Chinese sturgeon(Acipenser sinensis), the Chinese paddlefish (Psephurus gladius), the Yangtze sturgeon (j. Dabry’s, Acipenser dabryanus), the Chinese feeler(Myxocyprinus asiaticus) and Coreius guichenoti. China has initiated more than a dozen programs to save these fish, but despite 40 years of efforts, the species is now on the verge of extinction.
Scientists see the reasons for this state of affairs as insufficient recognition of the actual impact of hydromorphological changes in rivers on the functioning of fish. They proposed an analytical tool that takes into account a range of models, including a three-level migration classification system, six descriptive life-cycle models, the concept of abnormal stocks (those that cannot reproduce due to barriers), the dam impact coefficient(DIC) and a simplified population model. Based on it, they determined the migration pattern and life cycle of each analyzed species, the impact of dams on its life cycle, and the mechanisms underlying population decline. They also outlined six scientific misjudgments behind the failures of the programs implemented so far, as well as the recommended direction for reforming China’s fish salvage strategy. A must-read for all water managers.
2. kettle-hole peatlands as carbon hot spots: unveiling controls of carbon accumulation rates during the last two millennia
Karpińska-Kołaczek M., Kołaczek P., Marcisz K. et al. (2024). Kettle-hole peatlands as carbon hot spots: Unveiling controls of carbon accumulation rates during the last two millennia. CATENA, 237, 107764.
Recognizing patterns of carbon sequestration over time and space is crucial to developing models and future predictions of carbon dioxide absorption. Peatlands play an essential role in the Earth’s carbon cycle. A group of Polish scientists has reconstructed peat carbon accumulation rates(PCAR from peat carbon accumulation rates) over the last ±1500 years in three Polish peat bogs (Jaczno, Głęboczek and Pawski Ług). The goal of their work was to determine the factors responsible for changes in carbon accumulation in these ecosystems. The PCAR results were linked to data on pollen residues, crustacean amoebae, plant macro-pebbles and charcoal.
The study showed that the peatlands analyzed varied in terms of local environmental conditions (e.g., water levels), the degree of peat development, vegetation dynamics and fire activity. In general, PCAR values were higher in sections of profiles dominated by mosses of the genus Sphagnum, with a high proportion of myxotrophic crustose amoebae, and without fire incidents. The results indicate almost three times higher PCAR (average >70 g C/m2/year) in the profiles of the Jaczno and Pawski Lug peatlands compared to the European average carbon accumulation for the Holocene (22.9±2.0 g C/m2/year according to literature data).
This can be explained by the unique local conditions of these peatlands, which have been characterized by stable and high water levels for the past 1,500 years. Such small, scattered in the European landscape, but well-preserved blanket bogs can be important carbon sinks, and therefore deserve more attention in terms of research, monitoring and protection. The work highlights the enormous potential of small peatlands (<10 ha) as specific hot spots for carbon accumulation.
3 The Ins and Outs of Per- and Polyfluoroalkyl Substances in the Great Lakes: The Role of Atmospheric Deposition
Xia Ch., Capozzi S.L., Romanak K.A., et al. (2024). The Ins and Outs of Per- and Polyfluoroalkyl Substances in the Great Lakes: The Role of Atmospheric Deposition. Environmental Science & Technology.
Perfluoroalkyl and polyfluoroalkyl substances, also known as PFAS or perennial chemicals, have become persistent and permanent contaminants of water, soil and air. Because they are very stable, they circulate throughout the water cycle and enter drinking water sources with precipitation. Consumption of PFASs is associated with negative health effects, so monitoring their quantity in reservoirs that provide drinking water supply is particularly important. Such a study was conducted by researchers at Indiana University and Environment and Climate Change in Ontario for the Great Lakes, which are the main source of water for residents of their catchment areas in the US and Canada.
According to the findings, published in the journal Environmental Science & Technology, precipitation introduces similar amounts of PFAS into each of the Great Lakes, but individual reservoirs eliminate the chemical at different rates. The results of the 2021-2023 study indicate that atmospheric deposition is the main source of PFAS in lakes. The highest concentrations of these compounds were found in Lake Ontario (11.0 ng/l), followed by Lake Michigan, Lake Erie and Lake Huron (3.5-8.5 ng/l), and the lowest in Upper Lake (1.3 ng/l).
Mass budget calculations indicate that the northernmost lakes (Superior, Michigan and Huron) accumulate PFAS, while the other two eliminate them from the waters by sedimentation or with runoff. These studies confirm the ubiquity of perennial pollutants, but recognizing the pathways of their circulation in the environment can help shape actions to reduce their future presence.
4. what are the main reasons for the worldwide decline in pollinator populations?
Brunet J., Fragoso F.P. (2024). What are the main reasons for the worldwide decline in pollinator populations? CABI Reviews.
We recently celebrated World Bee Day, which was an opportunity to remind readers about these beneficial insects. Unfortunately, bees, like many other pollinators, are particularly vulnerable to the negative effects of climate change, two scientists report in a review published on CABI Reviews. Production of 85 percent. flower species and 87 of the world’s leading crops rely on the work of pollinators. Scientific studies confirm the decline of pollinators worldwide, which affects biodiversity conservation, reduces crop yields and threatens food security. According to the Intergovernmental Science-Policy Platform on the Future of Science. The report also calls for a review of the Intergovernmental Panel on Biological Diversity and Ecosystem Services (IPBES) of about 16 percent. Vertebrate pollinators, such as birds and bats, and 40 percent. invertebrate pollinators, such as bees and butterflies, are threatened with extinction.
The paper synthesizes the diversity of pollinators, discusses the main factors causing a decline in their numbers (such as habitat loss, pesticide use, major pests and pathogens, environmental pollution or climate change) and various strategies to reduce these impacts. It also addresses the problem of the negative impact of honey (farmed) bees on wild pollinators. The results of the review indicate that the effects of climate change are the most important, yet most difficult to control, threat to this group of organisms. Changes in temperature patterns and water availability can reduce the quantity and quality of resources available to them, modify their habitat, and reduce the survival of larvae or adults. Understanding the factors driving pollinator decline can help develop strategies and action plans to protect them and preserve the ecosystem services they provide.
5. future malaria environmental suitability in Africa is sensitive to hydrology
Smith M.W., Willis T., Mroz E., et al. (2024). Future malaria environmental suitability in Africa is sensitive to hydrology. Science 384, 697-703.
With climate change, the geographic ranges of species, and thus the areas exposed to the pathogens they carry, are changing. Previous predictions of malaria distribution in Africa have been made on the basis of rainfall and temperature models, without taking into account many of the relevant hydrological processes. Including information on where and how water flows and retains, creating favorable breeding sites for various species of malaria-carrying mosquitoes, is a prerequisite for improving future scenarios against the spread of the disease.
British researchers at the University of Leeds have used a set of hydrological and climate models to estimate current and future scenarios for the distribution of areas conducive to mosquito breeding and malaria transmission in West Africa. The models used indicate that after an initial moderate increase in the extent of these areas (<0.5 million km2 in the period 2006-2025), from 2075 to 2100. They are expected to shrink. The transmission time per season will also change, extending up to nine months in some areas. The research underscores the role of hydrological phenomena in the distribution patterns of species whose life cycles depend on water. If the range of malarial mosquitoes in Africa is shrinking as a result of climate change, will it expand in other parts of the world?
6. integrating recent scientific advances to enhance non-sewered sanitation in urban areas
Strande L. Integrating recent scientific advances to enhance non-sewered sanitation in urban areas. Nat Water (2024).
Nearly half of the world’s population is currently not connected to a sewage system, and this number is growing twice as fast as the connected population. In urban areas around the world, the percentage reaches 37 percent, with higher rates in low- and middle-income countries (60-90 percent) and lower rates in highly developed countries (5-30 percent). A paradigm shift from sewerage to alternative options for wastewater collection and disposal has been under discussion for more than 20 years. An overview of the issue published in Nature Water presents the state of the art in non-sewer sanitation in urban areas.
It focuses on issues relating to wastewater properties, various biological processes occurring during storage, treatment methods and monitoring. In dense urban areas, global goals for safely managed sanitation will not be achieved with a single technological solution. The overview presented here is a good starting point for organizing the available knowledge on a variety of wastewater treatment solutions, technologies and processes other than through the sewage system.
7. wastewater-based epidemiology to assess environmentally influenced disease
Bowes D.A., Driver E.M., Choi P.M. et al. (2024). Wastewater-based epidemiology to assess environmentally influenced disease. J Expo Sci Environ Epidemiol.
While we’re on the subject of wastewater, here’s a brief preview of an interesting series. The Journal of Exposure Science and Environmental Epidemiology has prepared a special issue on Wastewater-based Epidemiology to Assess Environmentally Influenced Disease. WBE, or wastewater-based epidemiology, is a rapidly growing scientific discipline that uses municipal wastewater to assess the health of a population in near real time. The method involves analyzing biomarkers that indicate various aspects of human health, behavior, exposure and activity. Since the beginning of the 21st century. WBE is being used as a useful tool for monitoring the psychoactive substances used in the population, and has recently gained widespread use for early disclosure of SARS-CoV-2 infection outbreaks during the COVID-19 pandemic.
The journal will publish a series of articles prepared by experts in the fields of wastewater and environmental epidemiology, exposure science, engineering, water management or environmental microbiology. It will cover a range of topics, exploring the interrelationship between humans and the environment using wastewater analysis. Topics covered include. the problem of setting new targets for assessing risks from municipal wastewater, particularly for infectious diseases; simultaneous monitoring of chemical and biological indicators of exposure and associated human impact; and assessing the utility of wastewater data for taking appropriate action. An enlightening read that can set directions for expanding wastewater and surface water monitoring to include new indicators related to public health.