Portal de Periódicos da CAPES

Dispatches

2015; Wiley; Volume: 13; Issue: 2 Linguagem: Inglês

10.1890/1540-9295-13.2.68

1540-9309

ESA,

Recycling and Waste Management Techniques

A new report, Top Ten Countries Turning the Corner on Toxic Pollution (www.worstpolluted.org/2014-report.html), released by the Blacksmith Institute for a Pure Earth, the Global Alliance on Health and Pollution, and Green Cross Switzerland, announces these organizations' choices for the best efforts made by low-middle income countries in cleaning up polluted sites during 2014. And the winners – often local projects – are: Ghana, for replacing the burning of electronic waste by a mechanized recycling system that employs local people; Senegal, for replacing artisanal lead battery recycling with a hydroponic garden project; Peru, for introducing legislation on soil pollution plus reclamation deadlines; Uruguay, for cleaning up electronic waste hotspots; Mexico, for turning polluted refinery land into urban parkland; Indonesia, for returning a lead battery dump to its soccer field origins; The Philippines, for introducing aquaculture pond filtering in a polluted river system; Vietnam, for implementing an inexpensive soil remediation project reducing pollution from lead battery smelting; collectively, various republics of the former Soviet Union, for hunting down tons of old, toxic pesticides; and Kyrgyzstan, for filtering out radionuclides and heavy metals from drinking water. A Ghanaian worker dismantling e-waste. Dealing with entrenched pollution problems demands cooperation between different stakeholders if remediation efforts are to be successful. The project in Agbogbloshie, Accra, Ghana, is a good example of such cooperation. For years the world has dumped its electronic waste here. People burn the plastic components to get at the metals inside, covering the area in toxic smoke. But a partnership – including the City University of New York, Ghanaian government departments, the local scrap dealers' association, and individual recyclers, plus a little funding from NGOs and EU and UN bodies – led to a low-tech wire stripping facility being set up. Local recyclers bring the cables and wire they collect to the facility, which now has some 50 employees. Here, all the plastic is stripped off and the wire baled. The recyclers get better prices for this cleaner wire and can also sell the plastic coating, which used to be burned. Plans exist to increase the size of the facility, further reducing smoke levels, and to extend it to deal with plastic casings and sheet metals. “These projects demonstrate that it's possible to overcome barriers to environmental progress in developing countries”, says Allen Blackman (Resources for the Future, Washington, DC). “The challenge going forward will be to determine whether and how they should be scaled up to address national and regional problems as well as local ones.” The Chinese Government has promoted potatoes (Solanum tuberosum) as a fourth major staple food in China – joining wheat, rice, and corn – and aims to increase potato production and consumption nationwide. Until now, the potato has simply been considered as a vegetable side dish. Its elevation to “major staple food” will likely be accompanied by a series of policy changes, including increased research on seed hybridization, expanded potato growing areas, and improved methods for making processed foods out of potatoes. As compared with the US and Russia, China has traditionally consumed fewer of the tubers, but governmental officials hope that greater production and consumption will lead to better health for consumers, more income for farmers, and more food for the population as a whole. Obesity and diabetes are increasingly common in China, so replacing a portion of milled rice with potatoes may contribute to weight control and general well-being. China currently grows 5.33 million hectares of potatoes and plans to increase the potato growing area by 80%, to reach 10 million hectares. “Growing potatoes is relatively easy. It doesn't require much water”, says Lifeng Huang (Zhangjiakou, China), an organic potato grower. “[They are] not picky about soil either. The only thing that's important is the day–night temperature difference, which affects the potatoes' taste.” One of the target areas for increased production is northwest China, where most other crops struggle to survive due to the poor soil and limited water resources. Rice fields in southern China, where an extra growing season can be added during the winter, represent another target area. Such efforts will also bring more income to rural farmers in these regions. Some Chinese commentators have interpreted this move as evidence of food shortages. With its huge population and limited arable lands, China has been making a serious effort to grow most of the food needed to feed its people. A spokesperson for the Ministry of Agriculture denied that there was a food shortage but confirmed that expanding potato production is part of a plan to meet the country's future food requirements. National campaigns to control malaria in Mali have increased the use of insecticide-treated bed nets (ITNs) from 50% of households in 2006 to 84% in 2012. However, a recent study suggests that the increased ITN applications have spawned a hybrid mosquito resistant to the nets' chemical effects (P Natl Acad Sci USA 2015; doi:10.1073/pnas.1418892112). Two malaria vectors, Anopheles gambiae and A coluzzii, are reproductively isolated through much of their respective ranges. When they do interbreed, the hybrid population usually does not persist, likely because the hybrids are relatively less fit. But in the summer of 2006, a hybridization event occurred in the town of Selinkenyi, Mali, producing a new type of mosquito that has all but erased the original insecticide-susceptible A coluzzii population, and “appears to be replacing A gambiae” as well, according to study co-author Gregory Lanzaro, a professor in the Department of Pathology, Microbiology, and Immunology in the School of Veterinary Medicine at the University of California, Davis (Davis, CA). Lanzaro and his collaborators have discovered that the “unusual mechanism” at work here, known as adaptive introgression, imparted a gene for insecticide resistance from the A gambiae genome to the previously pure population of A coluzzii. While adaptive introgression of insecticide resistance has been described in these species before, Lanzaro emphasizes that this study's longitudinal nature – and the coincidental overlap between the distribution of ITNs and the appearance of the hybrids – provides “compelling evidence that the increased use of ITNs was the driving force behind this event”. ITN deployment has previously been linked to insecticide resistance on the continent. “Treated nets are really the bulwark of malaria control in Africa”, says Lanzaro, “and as they start failing, we're going to have a big problem because we're not sure what's going to replace them”. In 2012, the World Health Organization issued a Global Plan for Insecticide Resistance Management in Malaria Vectors, which advocates the simultaneous use of multiple insecticides that work in different ways. “Since bed nets are still pyrethroid-based”, says Maureen Coetzee, Director of the Wits Research Institute for Malaria at the University of the Witwaters-rand (Johannesburg, South Africa), “indoor residual house spraying should use a different class – carbamates, organophosphates, or DDT – depending on the resistance profile of the local vectors”. Currently, Lanzaro and his colleagues are trying to explain precisely why these mosquitoes are doing so well, and investigating how this new hybrid may be affecting the health of Selinkenyi's residents. On January 29, 2015, the National Aeronautics and Space Administration (NASA) successfully launched a new satellite designed to measure soil moisture on the Earth's land surfaces, providing the highest resolution global measurements of both soil moisture and freeze/thaw cycles (whether soil is frozen or thawed) ever detected from space. The satellite, called the Soil Moisture Active Passive (SMAP) observatory (http://smap.jpl.nasa.gov), could revolutionize how scientists understand links between the cycling of water, energy, and carbon. “The science imperative of mapping surface soil moisture and landscape freeze/thaw state is derived from the amazing fact that the three principal cycles of the Earth system – water, energy, and carbon cycles over land – are linked together through these variables”, explains SMAP Science Team Leader, Dara Entekhabi (Massachusetts Institute of Technology, Cambridge, MA). Observers film the successful launch of the SMAP observatory from Vandenberg Air Force Base, CA. SMAP data are likely to benefit many disciplines, including hydrology, climatology, meteorology, and ecology, and will also contribute to global climate models that require high-resolution data to link different aspects of the Earth's water and carbon cycling. “The primary science goal of SMAP is to provide the needed observations to inform the true link between the cycles”, continues Entekhabi. “This will improve our Earth system models (whether used in short-term weather prediction or long-range climate projections) and reduce the uncertainty of how regional water, energy, and carbon cycles will respond to climate variability and global change.” Two primary instruments on SMAP combine to provide data that may open up exciting lines of research. One instrument is an active radar sensor that can measure vegetation water-content without the need to correct for clouds and other atmospheric “noise”. According to Entekhabi, “The measurements will allow high-resolution and frequently revisited mapping [every 2–3 days] of vegetation water-content. This is a whole new data source for global ecology that goes far beyond the traditional visible/near infrared vegetation indices. Clouds and solar illumination will no longer be constraints.” Scientists will be able to use the raw SMAP data, but NASA also provides data assimilation products that combine information from other sources to enhance SMAP measurements and provide even greater insight into Earth system processes. “I think we're looking at a whole new era for global ecology!”, says Entekhabi. It's not exactly pristine habitat: a tiny weed-infested wetland overshadowed by a Shell crude oil refinery in Sydney's western suburbs. Yet a tiny population of rare green and golden bell frogs (Litoria aurea) has persisted here for decades, thanks in large part to their industrial wasteland of a home. However, with the refinery now being decommissioned, every effort is being made to save the frogs. In a deal with the New South Wales Government, Shell subsidiary Viva Energy will build a specialized breeding space in the wetland. Workers dismantling 26 000 metric tons of pipes and storage tanks will be trained to spot frogs living among the waterlogged tank walls, and return them to the wetland. Amphibian biologist Jodi Rowley (Australian Museum Research Institute, Sydney) explains that green and golden bell frogs were once abundant. “They were used for classroom dissections”, she says. “People fed them to their pet snakes. They were just the frog in everybody's backyard.” But in the 1980s and 1990s, habitat loss, the aggressive plague minnow (Gambusia holbrooki, a North American fish introduced to control mosquitoes), and the chytrid fungus took a rapid toll. Green and golden bell frogs find refuge in industrial sites. The species now occurs in just a handful of locations, including three in Sydney. One, Olympic Park in Homebush, was a notorious, heavily polluted industrial dumping ground. Nevertheless the frogs were detected there, in a disused quarry; a successful habitat restoration effort, when the site was cleaned up for the 2000 Summer Olympics, provides a template for what they need to thrive. “They do tend to be found in these weird industrial places”, says Rowley. “They don't seem to mind slightly saline water, which the chytrid fungus can't handle at all, so it seems to give them an edge. [The frogs] love to colonize new places, so if you build something right, they can do really well.” Although well studied, the frogs remain a puzzle. “They should be a ‘weedy’ species”, continues Rowley. “They lay 4000 eggs a year, grow fast, can travel a kilometer a night, and are habitat generalists. Yet they are a threatened species, so why has this happened?” Cities are starting to capitalize on a previously untapped source of renewable energy – the water flowing through their own pipelines. For example, earlier this year, Portland, Oregon, started generating electricity from four 50-kilowatt turbines installed within one of the city's major water pipelines. Under an agreement between the city and local turbine provider Lucid Energy, the power generated by the 107-cm-wide turbines will be sold to a local utility, producing enough energy for about 150 homes and generating an estimated $2 million in revenue over 20 years. Though such turbines generate modest amounts of power as compared with hydroelectric dams, they offer a big advantage: “We produce energy without [negative] environmental impact”, says Gregg Semler, president and CEO at Lucid (Portland, OR). However, turbines like Lucid's are useful only in hilly areas, where the flow of water from reservoirs and other sources is driven by gravity rather than by mechanical pumps. Gravity creates more pressure in those pipelines than is required to distribute the water to the city's users. That pressure must be reduced to minimize leakage and avoid damage within the water system. While this is typically accomplished with valves, cities can instead use the pressure to drive turbines, generating electricity that can be fed into the grid or used to power local facilities. Semler notes that the turbines provide a stable power source that helps defray the huge energy costs associated with producing drinking water. According to the US Environmental Protection Agency, water and wastewater utilities are among the largest energy consumers in municipalities, accounting for 30–40% of the total energy consumed. Semler believes the turbines could be valuable for populations in remote mountainous areas that have good water resources but lack reliable electricity infrastructure. Paul O'Callaghan, CEO of market-research firm BlueTech Research (Vancouver, Canada), says that use of in-pipe turbines is part of a broader trend among water utilities to focus on sustainability while trying to reduce the usage and cost of energy. “Utilities are looking at every possible opportunity for energy recovery and reduction”, he says. Adoption of the turbines is increasing, but has taken time due to early technical hurdles and the need to educate utilities about the potential opportunities offered by the technology. So far, a handful of relatively small, independent companies offer in-pipe turbines, including Zeropex (Stavanger, Norway), which has installations in several European countries and the US, and Rentricity (New York, NY). A team of students at the Maseno School in Maseno, Kenya, found a way to power their school's kitchen with biogas derived from sewage from their new dormitory's faulty sewer system, in an effort to help alleviate odor and prevent the waste from polluting nearby waterways in the surrounding community. Through the national competition known as Innovate Kenya, the students' proposed design won funding to build two prototype systems, one of which is now in use. The design relies on a bioreactor – an underground storage chamber where microorganisms ultimately break down human waste, producing biogas composed of carbon dioxide and methane that can be used as fuel. This also saves the school from having to burn wood for cooking and heating, thereby reducing the strain on forest resources and resulting in cleaner air in the vicinity. The team leader, 17-year-old Leroy Mwasaru, presented the design at the Techonomy Conference (9–11 Nov 2014; Half Moon Bay, CA). According to Mwasaru, “The project idea came up as a result of a pressing need to fill a social, environmental, and economic niche right from our school. We had learned about bioreactors at school and it was the perfect opportunity to make what we learned a reality.” The idea of converting animal and human waste to biogas is not new, and both for-profit companies and non-profit organizations are already implementing such projects globally. Hannes Muntingh, founder of Biogas Energy Solutions Ltd (Nairobi, Kenya), says, “The technology certainly holds fantastic potential for the developing world, particularly since there is little distributed energy or centralized sewage treatment [in these areas], and because so many households keep some livestock, which holds good methane generation potential”. Big obstacles remain, however – primarily the high cost of installation and a lack of technical knowledge in local communities regarding system setup and upkeep. Mwasaru and his team have held local workshops about the technology and hope to expand their project to process waste school-wide. They hope to fund this project with a crowdsourcing campaign and are looking into how best to do this. “It's all about convincing the world that today's youth are tomorrow's future”, says Mwasaru. Mass die-offs of animals are hardly a new phenomenon, but they are woefully understudied. When events occur, such as tens of thousands of dead Cassin's auklets (Ptychoramphus aleuticus) littering US West Coast beaches – most devastatingly between November and January – the first order of business is to uncover the cause. In this case, it's still unknown – as is whether the event will make it out of the newspapers and into the scientific literature. A report appearing in January (P Natl Acad Sci USA 2015; doi:10.1073/pnas.1414894112) – the first analysis of 727 mass mortality events that have been published in scholarly journals – suggests that the magnitude of these events is increasing, at least for birds, fish, and marine invertebrates. As the authors note, however, it's not clear if this is a real pattern or merely the result of heightened awareness. It's a complicated issue to tease apart. “These are rare events – you have to be in the right place at the right time to study them”, says co-lead author Adam Siepielski, an ecologist at the University of San Diego (San Diego, CA). For the third year in a row, The Marine Mammal Center (Sausalito, CA) is seeing unusual numbers of young, emaciated California sea lion strandings. “The paper's observations reflect what many of us suspect – that we are seeing an increase in large mortality events”, explains Jonathan Sleeman, director of the US Geological Survey's National Wildlife Health Center (Madison, WI). Unfortunately, he says, fragmented data collection systems and incomplete geographic coverage have hampered efforts. Sleeman aims to help change that. Two online databases – one focused on terrestrial animals, the other on marine mammals – will soon serve as coordinated repositories for these types of data, allowing scientists to study events over time and, hopefully, respond more quickly to future events. Sleeman and colleagues are in the final stages of testing WHISPers (the Wildlife Health Information Sharing Partnership event reporting system), an online, interactive database for tracking basic information about past (back to the 1970s) and present wildlife mortality events. Records can be sorted by geographic area, date range, species, or disease diagnosis. The Marine Mammal Health MAP (Monitoring and Analysis Platform) will pull data from national networks that report stranding events, as well as ocean biogeographic data. Once the team finalizes the data structure and standardization needs, they will begin an implementation phase, likely by the end of this year. “We hope to provide a way to collect and visualize marine mammal health, to identify hotspots and trends in disease”, says Claire Simeone, a veterinarian at the non-profit Marine Mammal Center (Sausalito, CA). The fates of humans and wildlife are often linked during hard economic times, which are characterized by a greater likelihood of poaching, over-exploitation of natural resources, and diminished funding for conservation. Indeed, a new study has revealed that the social and economic turmoil of the Soviet Union's dissolution was mirrored by declines in the region's large mammal populations (Conserv Biol 2015; doi:10.1111/cobi.12450). Relying on 30 years of data collected by the Russian Federal Agency of Game Mammal Monitoring, the researchers divided the time-series into three parts: before the collapse (1981–1991), from the Union's collapse until the Russian Republic's economy showed initial signs of growth (1991–2000), and the period of economic recovery (2000–2010). They found that population growth rates of three of the eight species examined – wild boar, moose, and brown bear – had significantly decreased in the years post collapse, partially due to poaching. As lead author Eugenia Bragina (University of Wisconsin, Madison) puts it, “when people are very hungry, they just don't care about wildlife; they have to feed their kids”. Moose (Alces alces) declined following the breakup of the USSR. During the same period, the numerical abundance of another species – the gray wolf – increased by 80%. So, wolf predation might also be partially responsible for the concomitant declines in other mammals. Bragina explains that in the Soviet era “people put bounties on wolf pelts”, a practice that halted in the 1990s because of a lack of funds available to wildlife managers. In the period of Russia's economic recovery, researchers noted signs of recovery in several species, particularly wild boar. To explain this finding, the authors point out that almost half of the farmland in European Russia was abandoned during the USSR's collapse, fostering the recovery of large swaths of forest and offering new potential habitat for mammals. Times of economic turmoil can thus both complicate and facilitate conservation efforts. Bragina also sees these socioeconomic shocks as a potential for the international conservation community to step up: “these times of change really provide opportunities to offer something new”. Stormwater runoff – rainwater that carries toxic chemicals from impervious surfaces into streams and marine waters – poses a serious threat to water quality and aquatic life worldwide, particularly around urban areas. Now, a new study (Chemosphere 2015; doi:10.1016/j.chemosphere.2014.12.052) has shown that small-scale systems that filter runoff through a basic soil mixture can remove lethal chemicals remarkably well. An estimated 6.3 million kilograms of oil, heavy metals, pesticides, and other toxins enter Washington State's Puget Sound annually. Stormwater draining from the watershed that encompasses a dozen surrounding counties contributes the lion's share of this chemical burden. In response, regional scientists and planners have engineered “bioretention” technologies – green roofs, permeable pavements, and other systems that mimic the filtration ability of undeveloped landscapes – to curb toxic runoff, as mandated by water-quality regulations. Measurements of the efficacy of such approaches have mostly concentrated on the resulting changes in water chemistry rather than impacts on aquatic life, notes ecotoxicologist Jenifer McIntyre (Puyallup Research & Extension Center, Washington State University, Puyallup, WA). To shift the focus to living organisms, McIntyre and her colleagues turned to coho salmon (Oncorhynchus kisutch), one of several prized but regionally threatened and endangered salmonids in the Northwest. “Coho are a sentinel for stormwater pollution”, McIntyre explains. “Their long rearing time in freshwater and preference for spawning in streams that often overlap with human developments makes them especially vulnerable.” The researchers collected stormwater runoff from a major highway and exposed juvenile coho, as well as mayflies and daphnia (common salmon prey), to the contaminated water. All perished within 12 hours. But when coho were exposed to runoff filtered through soil columns – composed primarily of sand, compost, and shredded bark – all the fish and invertebrates survived. The treatment reduced toxic metals by up to 99%, polycyclic aromatic hydrocarbons to levels at or below detection, and organic matter by more than 40%. “Installing similar bioretention systems along transportation corridors could help decrease the harmful effects of urban runoff”, McIntyre continues. Meanwhile, another stormwater management strategy – building rain gardens – is already underway across the Northwest. The most effective of these rain gardens use native plants in amended soil; placed below roof downspouts and driveways, they capture, hold, and strip pollutants from runoff. “The more we can use various means in developed areas to direct runoff through soil and slow its entry into surface waters, the better our chances of improving water quality”, McIntyre concludes.