News
California rivers have more dangerous chemicals than previously believed, environmental officials reported this month.
The increase in reported toxicity levels is largely due to increased monitoring and better assessment tools, rather than unchecked pollution, said Nahal Mogharabi, a spokesman with the Environmental Protection Agency.
For instance, samples of fish tissue indicating unsafe levels of mercury increased 24 percent from 2006 to 2010, with the greatest increases seen in mercury, Mogharabi said in a prepared statement.
Mercury contamination of fish is found in many of Nevada County's waterways, including the South Fork of the Yuba River.
“The most notable issue identified with waters in Nevada County are mercury contamination of fish tissue that make fish unsafe for humans and wildlife to consume,” Mogharabi said in an e-mail to The Union.
According to a recent EPA study, one out of nine Rainbow Trout were shown to have trace mercury amounts in excess of the recommended federal and state standards (3 milligrams of methylmercury per 1 kilogram of fish tissue). The samples were taken from one mile downstream of the town of Washington, according to the study. Only fish above 150 millimeters were sampled as that is the length of fish most often taken home and consumed by sport fishermen, the study reported.
The reach of Deer Creek beginning at Deer Creek reservoir to Lake Wildwood, Little Deer Creek, Hum Bug Creek and Gold Run were other waterways within county that were found to have unsafe mercury levels in fish samples.
Additionally, the upper reach of Bear River (from Combie Lake to Camp Far West Reservoir), which also extends into Placer County, showed fish contamination.
In nearby waterways in neighboring counties, the Middle Fork of the Yuba River and Rollins Reservoir displayed similar mercury problems.
The danger to humans comes when mercury becomes biologically available in the form of methylmercury, which accumulates in the food chain and reaches harmful levels in the sport-fish that people most regularly consume, Mogharabi said.
She said that installing best management practices and oxygenation of lakes and reservoirs are two immediate ways to reduce mercury levels found in fish.
“In a historic mining area, many best management practices can be implemented to retain sediment rich in mercury on site such that rain events won't wash it into creeks, rivers and lakes,” Mogharabi said.
Relating to oxygenation, Mogharabi said the state has begun to develop a statewide “Mercury Total Maximum Daily Load for reservoirs which will serve as a pollution clean up plan for many of the waters in Nevada County currently impaired by mercury.”
Chris Shutes, president of the California Sportfishing Protection Alliance, said the presence of mercury in fish is a concern for those who consume what they catch and is hopeful state and federal officials continue to search for solutions.
“I know it is a long-term process, but remediation efforts are underway in a lot of areas and I hope it continues,” he said.
The EPA listed 2021 as the date when mercury levels will drop below hazardous efforts if recommended best management practices are implemented.
To contact Staff Writer Matthew Renda, e-mail mrenda@theunion.com or call (530) 477-4239.
The increase in reported toxicity levels is largely due to increased monitoring and better assessment tools, rather than unchecked pollution, said Nahal Mogharabi, a spokesman with the Environmental Protection Agency.
For instance, samples of fish tissue indicating unsafe levels of mercury increased 24 percent from 2006 to 2010, with the greatest increases seen in mercury, Mogharabi said in a prepared statement.
Mercury contamination of fish is found in many of Nevada County's waterways, including the South Fork of the Yuba River.
“The most notable issue identified with waters in Nevada County are mercury contamination of fish tissue that make fish unsafe for humans and wildlife to consume,” Mogharabi said in an e-mail to The Union.
According to a recent EPA study, one out of nine Rainbow Trout were shown to have trace mercury amounts in excess of the recommended federal and state standards (3 milligrams of methylmercury per 1 kilogram of fish tissue). The samples were taken from one mile downstream of the town of Washington, according to the study. Only fish above 150 millimeters were sampled as that is the length of fish most often taken home and consumed by sport fishermen, the study reported.
The reach of Deer Creek beginning at Deer Creek reservoir to Lake Wildwood, Little Deer Creek, Hum Bug Creek and Gold Run were other waterways within county that were found to have unsafe mercury levels in fish samples.
Additionally, the upper reach of Bear River (from Combie Lake to Camp Far West Reservoir), which also extends into Placer County, showed fish contamination.
In nearby waterways in neighboring counties, the Middle Fork of the Yuba River and Rollins Reservoir displayed similar mercury problems.
The danger to humans comes when mercury becomes biologically available in the form of methylmercury, which accumulates in the food chain and reaches harmful levels in the sport-fish that people most regularly consume, Mogharabi said.
She said that installing best management practices and oxygenation of lakes and reservoirs are two immediate ways to reduce mercury levels found in fish.
“In a historic mining area, many best management practices can be implemented to retain sediment rich in mercury on site such that rain events won't wash it into creeks, rivers and lakes,” Mogharabi said.
Relating to oxygenation, Mogharabi said the state has begun to develop a statewide “Mercury Total Maximum Daily Load for reservoirs which will serve as a pollution clean up plan for many of the waters in Nevada County currently impaired by mercury.”
Chris Shutes, president of the California Sportfishing Protection Alliance, said the presence of mercury in fish is a concern for those who consume what they catch and is hopeful state and federal officials continue to search for solutions.
“I know it is a long-term process, but remediation efforts are underway in a lot of areas and I hope it continues,” he said.
The EPA listed 2021 as the date when mercury levels will drop below hazardous efforts if recommended best management practices are implemented.
To contact Staff Writer Matthew Renda, e-mail mrenda@theunion.com or call (530) 477-4239.
Health tips
For most people, the risk from mercury by eating fish and shellfish is not a health concern. Yet, some fish and shellfish contain higher levels of mercury that may harm an unborn baby or young child's developing nervous system.
The risks from mercury in fish and shellfish depend on the amount of fish and shellfish eaten and the levels of mercury in the fish and shellfish. Therefore, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) are advising women who may become pregnant, pregnant women, nursing mothers, and young children to avoid some types of fish and eat fish and shellfish that are lower in mercury. By following these 3 recommendations for selecting and eating fish or shellfish, women and young children will receive the benefits of eating fish and shellfish and be confident that they have reduced their exposure to the harmful effects of mercury. 1. Do not eat: • Shark • Swordfish • King Mackerel • Tilefish They contain high levels of mercury. 2. Eat on average up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury. Shrimp, canned light tuna, salmon, pollock and catfish are acceptable low-mercury alternatives. 3. Check local advisories about the safety of fish caught by family and friends in your local lakes and rivers. -Source: The U.S. Food and Drug Administration |
