“I am not a guinea pig” – It’s the slogan of an Environmental Defense Fund initiative to raise awareness about all the synthetic chemicals in our life and what they may be doing to us.
By EDF’s estimate, more than 80,000 chemicals are available for use in the U.S. Only a small fraction of these (200, according to its website) have been required to be tested for their safety.
Among the chemicals on its radar screen is a group of industrial surfactants known as nonylphenol ethoxylates (NPEs). You won’t see these compounds listed as such in the many household products that contain them, and you’d need a Ph.D. anyway to track them in their many guises as detergents, wetting agents, emulsifiers, dispersants, de-icers and dust control agents.
NPEs are not removed during sewage wastewater treatment, and unlike other cleaning agents, they become more toxic and stable as they break down, meaning that aquatic organisms get higher doses and longer exposures to the more toxic degradation products.
This is recipe for environmental stress, and it explains why the Pacific Coast Federation of Fishermen’s Associations joined the Sierra Club and others in a petition requesting that the EPA tighten its regulations on NPEs.
A new CA Sea Grant project is examining the toxic effects of one NPE break-down product, called 4-nonylphenol (4-NP), an endocrine disruptor that has been detected at startlingly high levels in oysters, mussels and arrow gobies in Morro Bay, California.
The researchers will be looking at whether 4-NP exposure in Pacific oysters hurts the animal’s ability to fight bacterial disease and might explain declines in other shellfish species.
Below is a technical summary of the project published in our Program Directory.
Impacts of 4-nonylphenol on immunocompetence and disease susceptibility in Pacific oysters, Crassostrea gigas
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Sean Lema firstname.lastname@example.org
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Nonylphenol ethoxylates are industrial compounds (often surfactants) used as detergents, emulsifiers and foaming agents in a long list of household products including toilet paper, plastics, pest sprays and personal care products. In the aquatic environment, they degrade into compounds that include 4-nonylphenol (4-NP), an endocrine disruptor that has been detected at elevated levels in marine organisms in California estuaries. The scientists leading this project suspect that septic tanks and toilet paper are a main source of 4-NP in the coastal environment and in this project will examine the consequences of the compound on the Pacific oyster, focusing on how (or if) the chemical alters the shellfish’s immune system. In experiments, oysters will be injected with the bacterium Vibrio campbellii (non-pathogenic in oysters) and V. harveyi (pathogenic in oysters). Scientists will then monitor the animals’ immune response vis-a-vis total hemocyte counts, superoxide anion production levels and hemocyte lysozyme activity. Changes in protein production in gonadal tissues and hemocyctes will be examined, and there will be an effort to detect changes in the transcription profiles (number of copies of mRNA from a specific segment of DNA) for genes involved with antimicrobial defense. Results will be shared with the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment, which has identified a critical need for targeted studies of 4-NP toxicity on marine organisms.
Written by Christina Johnson, firstname.lastname@example.org