Dear EarthTalk: I always thought eating fish was healthy, but now I’m concerned about mercury in tuna and other fish. Are there any fish that are still safe to eat? – Brit Brundage, Fairfield, CTYou should be concerned about contaminants in certain fish, including some kinds of tuna. The non-profit Environmental Defense Fund (EDF) recommends minimizing consumption of albacore (white) tuna, a large fish that accumulates moderate amounts of mercury in its fatty tissue. But other kinds of (smaller) tuna, such as skipjack (usually canned as "light"), which accumulates a third the amount of mercury as albacore, are OK to eat in moderation, though consumption by those under age seven should be limited.
To further complicate the issue, some canned light tuna may contain yellowfin tuna, which has mercury levels similar to those of albacore; these products are sometimes but not always labeled as "gourmet" or "tonno"â€”and their consumption should be limited, even by adults.
Mercury, a known "neurotoxin" (a poison that affects the nervous system), is particularly insidious because it is widespread in our oceans, primarily due to emissions from coal-burning power plants. These smokestacks deposit mercury into waterways, which carry it to the ocean where bacteria convert it into methylmercury. Fish then ingest it with their food and from water passing over their gills.
Generally speaking, bigger, older and large predatory fish (such as sharks, swordfish, tilefish, king mackerel and some tuna) near the top of marine food chains are more likely to have high levels of mercury than fish lower in the marine food chain. People exposed to high levels or frequent doses of mercury can suffer nervous system disorders, impaired mental development and other health problems.
An April 2003 study, published in Environmental Health Perspectives, found that 89 percent of study subjects, chosen because they ate a significant amount of fish, had blood mercury levels above the U.S. Environmental Protection Agency’s (EPA’s) safety threshold of five micrograms per liter. Even though there are health benefits to eating fish (including the intake of healthy omega-3 fatty acids), the EPA advises that young children, pregnant women, nursing mothers and women of childbearing age limit their intake of high-mercury fish to one serving per week at most, while limiting their overall intake of any fish or shellfish to no more than two to three servings, or 12 ounces total, per week.
Mercury isn’t the only harsh pollutant lurking in the ocean. Industrial chemicals like PCBs and pesticides like DDT are awash in marine food chains around the world. According to EDF, it can take five years or more for women of childbearing age to rid their bodies of PCBs, and 12-18 months to appreciably reduce their mercury levels. EDF adds that moms who eat toxic fish before becoming pregnant may have children who are slower to develop and learn because fetuses are exposed to stored toxins through the placenta.
To learn more, visit the EPA’s Fish Advisories website. It includes links to individual state advisories, which have details on what fish should or shouldn’t be eaten from nearby lakes or coastal areas. Catfish, Pollock, salmon, shrimp and canned light tuna are currently on the EPA’s safe list, as they feed toward the bottom of the food chain and thus have less opportunity to accumulate mercury and other contaminants.
Dear EarthTalk: What does it mean when one uses the phrase, "building a green economy?" I’ve heard it repeated a few times lately and would like to have a better understanding of the concept. – Rosie Chang, Islip, NY
The phrase "building a green economy" means different things to different people, but in general it refers to encouraging economic development that prioritizes sustainabilityâ€”that is, working with nature and not against it in the quest to meet peoples’ needs and wantsâ€”instead of disregarding environmental concerns in the process of growing the economy. The primary way governments around the world are trying to "green" their own economies today is by increasing investment inâ€”and, by extension, creating jobs inâ€”industries on the cutting edge of non-polluting renewable forms of energy, such as solar and wind power.
President Obama has repeatedly invoked his vision of a green economy as a tool for helping the U.S. lift itself out of recession and position itself as an economic powerhouse in a carbon-constrained future. The American Recovery and Reinvestment Act (ARRA) of 2009, the $787.2 billion stimulus package that Congress signed into law in 2009, was chock full of provisions to boost renewable energy, energy efficiency and environmental restoration initiatives. Examples include $4.5 billion to convert government buildings into high-performance green buildings, $8.4 billion for investments in public transportation, and tens of billions of dollars more for research into new technologies to amplify existing efforts. ARRA also earmark $11 billion for the implementation of the "smart grid," a new approach to power distribution that will bring more clean energy sources into the mix and promote energy efficiency.
Infusing such huge amounts of cash into sustainability-oriented projects is one way the Obama administration hopes to "green" the U.S. economy while simultaneously pulling the country out of recession. "To truly transform our economy, protect our security, and save our planet from the ravages of climate change, we need to ultimately make clean, renewable energy the profitable kind of energy," Obama told Congress a few months ago.
Of course, Americans aren’t the only ones bent on building a green economy. During the 1980s and 1990s, while the American government was largely asleep at the wheel on environmental issues, countries such as Denmark, Germany, Spain and Japan were already busy investing in wind and solar research and implementation. And while these nations’ ongoing efforts are nothing to sneeze at, economists point out that what is most needed is action on the part of the world’s fastest growing economiesâ€”China and India.
A recent report by the consulting firm McKinsey & Company found that Chinaâ€”which surpassed the U.S. as the world’s largest generator of greenhouse gases three years agoâ€”has great potential for building a green economy over the coming decades. According to McKinsey, by 2030 China could reduce its oil and coal imports by up to 40 percent and its greenhouse gas emissions by 50 percent by investing upwards of 1.5 trillion yuan ($220 billion in U.S. dollars) per year in both existing and new green technologies. China has begun to see the light with regard to reducing emissions, increasing energy efficiency and embracing renewable alternative energy, but it has yet to make significant financial commitments, which will be key to both warding off catastrophic climate change and building a truly global green economy.
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