Researchers alarmed by levels of mercury and arsenic in Chinese freshwater ecosystem

Jan 09, 2008

A team of researchers, led by biologists at Dartmouth, has found potentially dangerous levels of mercury and arsenic in Lake Baiyangdian, the largest lake in the North China Plain and a source of both food and drinking water for the people who live around it.

The researchers studied three separate locations in Lake Baiyangdian, all at varying distances from major sources of pollution, such as coal emissions, agricultural runoff, and sewage discharge. They found concentrations of arsenic and mercury in fish were above the threshold considered by the U.S. Environmental Protection Agency (EPA) to pose a risk to humans and wildlife.

The findings were published online on Dec. 24, 2007, in the journal Water, Air, and Soil Pollution.

“It’s important to study this system because it is typical of many throughout China where human activity and industrialization are having detrimental effects on the environment with major human health implications,” says Celia Chen ’78, a research associate professor of biological sciences. “It makes perfect sense to apply what we’re learning about lakes in the U.S. to other places in the world, like China, that have a growing global impact.”

Chen and her team were curious to learn how arsenic and mercury, two toxic environmental metals, moved through the food web in a freshwater ecosystem known to be polluted and contaminated. In a process called bioaccumulation, mercury and arsenic were found throughout the food web, from the water, into the algae, through the tiny algae-eating zooplankton, to the fish. As expected, the researchers found that more nutrient-rich environments supported larger algal blooms, which resulted in lower concentrations of mercury and arsenic in the water due to uptake by the algae.

In their previous work, the researchers found that when there is a lot of algae present, mercury and arsenic are biodiluted, or more dispersed, so zooplankton that eat the algae are exposed to lower levels of the metals and transfer less to fish.

“Despite this potential interaction – a decrease in bioaccumulation due to high algal biomass – the mercury and arsenic in this system are high enough to be of concern to humans and wildlife that drink the water and consume fish,” says Chen. “For example, we saw arsenic levels in the water that represent more than fifty times the EPA-recommended limit for consumption of fish and shellfish.”

Source: Dartmouth College

Explore further: Alaska fisheries and communities at risk from ocean acidification

add to favorites email to friend print save as pdf

Related Stories

Hoverbike drone project for air transport takes off

7 hours ago

What happens when you cross a helicopter with a motorbike? The crew at Malloy Aeronautics has been focused on a viable answer and has launched a crowdfunding campaign to support its Hoverbike project, "The ...

Study indicates large raptors in Africa used for bushmeat

8 hours ago

Bushmeat, the use of native animal species for food or commercial food sale, has been heavily documented to be a significant factor in the decline of many species of primates and other mammals. However, a new study indicates ...

'Shocking' underground water loss in US drought

8 hours ago

A major drought across the western United States has sapped underground water resources, posing a greater threat to the water supply than previously understood, scientists said Thursday.

Recommended for you

Malaysia air quality 'unhealthy' as haze obscures skies

1 hour ago

Air quality around Malaysia's capital Kuala Lumpur and on Borneo island was "unhealthy" on Tuesday, with one town reaching "very unhealthy" levels as haze—mostly from forest fires in Indonesia—obscured skies.

Worldwide water shortage by 2040

1 hour ago

Two new reports that focus on the global electricity water nexus have just been published. Three years of research show that by the year 2040 there will not be enough water in the world to quench the thirst of the world population ...

Regulations only a first step in cutting emissions

3 hours ago

Intensifying calls for action on climate change have led to a variety of proposed regulations to cut greenhouse gas emissions from specific sources of the economy, including, most recently, the environmental ...

User comments : 0