Research focuses on the effects of copper nanoparticles
The team of scientists say that these nanoparticles are now in a long list of consumer products, ranging from personal care products such as sunscreen, to paints, and they want to know what, if anything, are the consequences of exposure.
Probably the most significant finding from the study is that these copper nanoparticles inadvertently have an organism exposed to them, which is why the team chose to look at the human colon, septic tanks and zebrafish.
What’s a septic tank got to do with this?
The scientists studied the effects of nanoparticle on zebrafish embryo hatching rates, both inside a septic tank and outside, in an effort to demonstrate the impact of simulated human digested food and household water would have on the experiment.
The results showed that copper nanoparticles impacted zebrafish hatching rates at concentrations as low as 0.5 parts per million outside of the septic tank.
In contrast, the experiment showed that inside the replica septic tank, the copper nanoparticle were not bioavailable resulting in no impact on the hatching rates.
Toxicity can be eliminated using the study model
"The results are encouraging because they show with a properly functioning septic tank we can eliminate the toxicity of these nanoparticles," said Alicia Taylor, a graduate student working in the lab of Sharon Walker, a professor of chemical and environmental engineering at the University of California, Riverside's Bourns College of Engineering.
Taylor co-authored a paper: “Understanding the Transformation, Speciation, and Hazard Potential of Copper Particles in a Model Septic Tank System Using Zebrafish to Monitor the Effluent," which was published in the journal ACS Nano.
The team of researchers say they tackled the problem of replicating a suitable test model environment for the fish embryos by using a replica human colon and a two-compartment septic tank.
Simulating the digestive system
To simulate human feeding, 100 milliliters of a 20-ingredient mixture that replicated digested food was pumped into the dialysis tube at 9 a.m., 3 p.m. and 9 p.m. for five-day-long experiments over nine months, the researchers state.
Using waste water that simulates typical household grey water and the copper nanoparticles, the purpose of the experiment was to try and discover if the copper materials are disrupting the function of the septic tanks, with the possible threat of untreated waste water entering the soil and groundwater.
Effluent was emptied once a week from the septic tank and then used in combination with zebrafish embryos in a high content screening process using multiwall plate to access hatching rates.
As part of the ongoing experiment, the scientists say that the remaining effluent has been saved and sits in 30 five-gallon buckets in a closet at UC Riverside because some collaborators have requested samples of the liquid for their experiments.
