Source:
Geological Society of America
Summary:
Microplastics (plastics <5mm) and their negative health impacts have been studied in oceans, rivers, and even soils, and scientists are beginning to grapple with the myriad human health impacts their presence might have. One understudied, but critical, link in the cycle is groundwater, which is often a source of drinking water. Share: FULL STORY ________________________________________ Microplastics (plastics <5mm) and their negative health impacts have been studied in oceans, rivers, and even soils, and scientists are beginning to grapple with the myriad human health impacts their presence might have. One understudied, but critical, link in the cycle is groundwater, which is often a source of drinking water. While microplastics in groundwater likely affect human health, only a handful of studies have examined the abundance and movement of microplastics in groundwater. This gap means the potential for adverse health effects remains largely unknown. At the Geological Society of America's 2020 Annual Meeting today at 1:30, Teresa Baraza Piazuelo, a Ph.D. candidate at Saint Louis University, will help fill that knowledge gap by presenting new research on groundwater microplastics in a karst aquifer. "There hasn't been that much research looking at [micro]plastics and groundwater," Baraza says. "It's a very new topic. There's been a boom of research on microplastics in the ocean, even in soils... but to fully understand something, you have to explore it in all its aspects." Microplastics pose multiple physical and chemical risks to the ecosystems where they're present, and those risks are exacerbated by plastics' longevity in natural environments. "Since they're plastic, they're very durable," Baraza says, "which is why plastic is great. But it doesn't degrade easily." Microplastics' ability to linger in their environments for decades or longer likely has cumulative detrimental effects on both the organisms and quality of the ecosystem. Their chemical threat stems largely from their ability to transport harmful compounds on their surfaces; when organisms at the base of the food chain ingest microplastics, they ingest the toxins, too. As larger organisms consume the smaller ones, the toxins can build up (a process called bioaccumulation), eventually resulting in responses like organ dysfunction, genetic mutation, or death. "Cave ecosystems are known for being super fragile to begin with," she explains. "All the cave organisms -- salamanders, blind fish -- are sensitive, so any contaminants that are introduced could damage those ecosystems." Groundwater can stay in the same aquifer for tens to hundreds of years, or even longer. Combining that long residence time with plastics' resistance to degradation means that those chemical effects could effectively build up in the water and in any organisms within it, increasing the likelihood of toxic bioaccumulation. Together, these could result in long-term contamination of water sources with poorly-understood health effects and ecosystem damage. To understand where microplastics in groundwater come from and how they move through aquifers, Baraza and her Ph.D. advisor have been sampling groundwater from a Missouri cave weekly, all year long, and analyzing its chemistry and microplastics load. Because previous groundwater-microplastics studies have been limited to low-rainfall conditions, they're also studying how flooding events affect microplastics concentrations in groundwater. So far, they've found that while microplastics do increase in groundwater during a flood event, there's also a second peak in microplastics after the flooding has begun to wane. Their explanation is that there are two sources of microplastics for groundwater: those that are already in the subsurface, and those that are newly delivered from the surface. "Finding so much plastic later on in the flood, thinking that it could be coming from the surface... is important to understand the sourcing of microplastics in the groundwater," Baraza says. "Knowing where the plastic is coming from could help mitigate future contamination." Their current flood results are only based on one event, but Baraza will continue sampling through the rest of the year -- weather permitting. "Flood sampling is hard," she says, "especially in St. Louis, where the weather is so unpredictable. Sometimes we think it's going to rain and then it doesn't rain, and then sometimes it doesn't seem like it's going to rain, but it does... we caught a flood a week ago, and we are expecting to catch a couple more floods." The effort is worth it to determine if flooding events -- which are becoming more common under climate change -- are highly-effective deliverers of microplastics in groundwater reservoirs. make a difference: sponsored opportunity ________________________________________ The Biggest Environmental Problems Of 2020 • The climate crisis is accelerating at an unprecedented rate, and we are not ready for it. While the crisis has many factors that play a role in its exacerbation, there are some that warrant more attention than others. ... • Poor Governance. • Food Waste. • Biodiversity Loss. • Plastic Pollution. • Deforestation. • Air Pollution. Environmental law From 1 January 2020, ships will only be permitted to use fuel oil with a very low sulfur content. The International Maritime Organization estimates that the new limit of 0.5% sulfur content, down from 3.5%, will cut sulfur dioxide emissions from ships by about 8.5 million tonnes.[254] The Pacific nation of Palau bans sun cream that is harmful to corals and sea life in January 2020.[255] Climate change, tropical fisheries and prospects for sustainable development Abstract Tropical fisheries substantially contribute to the well-being of societies in both the tropics and the extratropics, the latter through ‘telecoupling’ — linkages between distant human–natural systems. Tropical marine habitats and fish stocks, however, are vulnerable to the physical and biogeochemical oceanic changes associated with rising greenhouse gases. These changes to fish stocks, and subsequent impacts on fish production, have substantial implications for the UN Sustainable Development Goals. In this Review, we synthesize the effects of climate change on tropical marine fisheries, highlighting the socio-economic impacts to both tropical and extratropical nations, and discuss potential adaptation measures. Driven by ocean warming, acidification, deoxygenation and sea-level rise, the maximum catch potential of tropical fish stocks in some tropical exclusive economic zones is projected to decline by up to 40% by the 2050s under the RCP8.5 emissions scenario, relative to the 2000s. Climate-driven reductions in fisheries production and alterations in fish-species composition will subsequently increase the vulnerability of tropical countries with limited adaptive capacity. Thus, given the billions of people dependent on tropical marine fisheries in some capacity, there is a clear need to account for the effects of climate change on these resources and identify practical adaptations when building climate-resilient sustainable-development pathways. Key points • Tropical oceans will be where many of the first anthropogenic signals in physical and biogeochemical variables will exceed natural variability, with resulting impacts on socioecological systems. • Maximum catch potential in some tropical exclusive economic zones is projected to decline by up to 40% by the 2050s under continued high greenhouse gas emissions. • Climate change impacts on tropical fisheries will affect sustainable development of both local economies and communities, and extratropical regions through ‘telecoupling’ of human–natural systems such as seafood trade and distant-water fishing. • The key impacts for developing tropical nations will be reduced capacity to achieve the UN Sustainable Development Goals related to food security (SDG2), poverty alleviation (SDG1) and economic growth (SDG8). • Effective and practical adaptation solutions for both small-scale and industrial fisheries, built on the involvement of all appropriate stakeholders and supporting policies, are needed to sustain fisheries productivity in the tropics. • Many substantial predicted biological and socio-economic impacts on tropical fisheries would be prevented if greenhouse gas-mitigation actions keep global atmospheric warming below 1.5 °C relative to pre-industrial levels. Metal contamination and bioremediation of agricultural soils for food safety and sustainability Abstract Agricultural soil is a non-renewable natural resource that requires careful stewardship in order to achieve the United Nations’ Sustainable Development Goals. However, industrial and agricultural activity is often detrimental to soil health and can distribute heavy metal(loid)s into the soil environment, with harmful effects on human and ecosystem health. In this Review, we examine processes that can lead to the contamination of agricultural land with heavy metal(loid)s, which range from mine tailings runoff entering local irrigation channels to the atmospheric deposition of incinerator and coal-fired power-plant emissions. We discuss the relationship between heavy metal(loid) biogeochemical transformations in the soil and their bioavailability. We then review two biological solutions for remediation of contaminated agricultural land, plant-based remediation and microbial bioremediation, which offer cost-effective and sustainable alternatives to traditional physical or chemical remediation technologies. Finally, we discuss how integrating these innovative technologies with profitable and sustainable land use could lead to green and sustainable remediation strategies, and conclude by identifying research challenges and future directions for the biological remediation of agricultural soils. Key points • Agricultural soil is a non-renewable natural resource that requires careful stewardship in order to achieve the United Nations’ Sustainable Development Goals. • Global agricultural soil pollution by heavy metal(loid)s represents one of the biggest challenges to sustainable development, particularly in developing countries. • Bioremediation, including phytoremediation and microbially mediated bioremediation, is a promising nature-based solution for treating heavy metal(loid) contamination. • It is imperative that the international community realizes the seriousness of the heavy metal(loid)s contamination in soils, takes actions to prevent further pollution and instigates the remediation of contaminated sites with environmentally friendly techniques. • Policymakers should foster a bioremediation-enabling environment through policy instruments and increased field-based research funding.