This is a guest post by Chelsea Rochman. Chelsea is a post-doc at the University of California Davis. This is her fourth 

WARNING: Some content may not be acceptable for a younger audience. (Note from Miriam: It’s ok, Chelsea, nothing in this post is at all out of the ordinary for DSN. It’s salty in these here parts.)

Strange title you say? What can sex possibly have to do with the combination of fish and plastic debris? NO, this is not related to the recent news article regarding a strange object found in the stomach of a fish! Instead, it arises from a recent study performed in our laboratory whereby we were equally perplexed to find something very fishy (no pun intended!) in the testes of a male fish exposed to plastic marine debris.

Sex

Since the release of Rachel Carson’s Silent Spring in 1962, we have heard eerie stories about alligators with abnormal penises from exposure to DDT, amphibians with eggs in their testes from exposure to atrazine and snails turning hermaphroditic from exposure to tributyltin —all considered hard evidence for endocrine disruption.

Well, this all sounds frightening, depressing and/or a bit like a dark comedy sketch, BUT what is endocrine disruption really?? Well, put simply it is literally any disruption to the endocrine system. The endocrine system is the system in the body of an organism that controls our hormones. As such, it’s critical for functions we all know well including stress before a deadline, the infamous running high, the dreaded PMS, sexual pleasures and arguably most importantly, reproduction (critical to maintaining a population).

What does this have to do with fish??

Well, fish are often used in scientific research assessing the endocrine disrupting hazards of chemicals on wildlife. Fish are a) important for human consumption, b) arguably great ecological indicators of the health of aquatic habitats, c) sensitive to endocrine disruption and d) live in regions that ultimately receive our waste (ever read the phrase, “all drains lead to the ocean”). As such, fish are exposed to many of the chemicals produced and consumed by us and we must understand the hazards of the cocktail of contaminants entering our water bodies. This keeps researchers very busy, as the number of new chemicals synthesized and marketed has increased exponentially over the past fifty years.

OK… and plastic debris?

In the past, endocrine-disruption was not addressed when assessing the hazards associated with synthetic chemicals, and as a consequence chemicals once considered benign have become ubiquitous as environmental contaminants and threaten biodiversity. Similarly, hazards associated with plastic in marine habitats were also likely not addressed when assessing hazards associated with plastic products. Today, plastic debris is ubiquitous in the marine environment and is a contaminant of concern recognized by several countries and international organizations.

As I’ve mentioned before, plastic debris should be considered as a multiple stressor in aquatic habitats as a consequence of the physical toxicity and large mixture of chemical contaminants (i.e. ingredients and environmental contaminants that accumulate on plastic debris) associated with it. Several of these plastic-associated chemicals have been linked to endocrine disrupting effects. Bisphenol-A, now banned on baby products in several states including California and in Europe, can disrupt endocrine-system function. Furthermore, there is evidence that phthalates and nonylphenol, additives to several plastic types, are estrogenic. As such, plastic marine debris is likely associated with a mixture of endocrine-disrupting chemicals. As such, it is critical to assess if the plastic debris that thousands of animals associate with food could initiate any of these eerie hormonal effects described.

The story

Somebody has to do the dirty work, so we dove in and asked if fish experience endocrine disrupting effects when they eat our plastic waste for dinner. Some of you may remember this experiment from a previous blog post. What we did not share then, and will share here, are some troubling results sparked by hypotheses spun from one strange discovery: the very abnormal testes of a male fish fed marine plastic debris.

The image above shows the testes of a normal fish fed a control diet (left) next to the testes of a fish exposed to plastic marine debris (right). The testes of this adult male fish exposed to plastic marine debris has rather abnormal germ cell proliferation. We are unsure whether these abnormal germ cells will lead to intersex or reproductive impairment, but the abnormality of these gonads and the similarity to female germ cells is cause for concern.

Our results show early-warning signs of endocrine disruption in fish exposed to a mixture of plastic and sorbed contaminants, suggesting that plastic marine debris, reportedly ingested by multiple wildlife species, may alter the functioning of the endocrine system in aquatic animals.

Most importantly, we report evidence at the molecular and organ level, for disruption to the endocrine system caused by the “cocktail” of contaminants associated with polyethylene deployed in an urban bay. Of major concern should be the permanent effects that exposure can have during critical early- life stages of organism development, which may impair reproductive success and harm wildlife populations. Still, chronic exposure to environmentally-relevant levels of endocrine-disrupting chemicals can have an effect after maturity as reported here. Chronic exposure is typical of marine plastic debris as it accumulates in habitats and is a persistent material that can last for decades.

Current waste-management strategies for plastics remain ineffective, and in parallel global production of plastics continue to increase at an average rate of about 9% per year. Thus the current rate of infiltration of this material into aquatic habitats is likely to increase. Because there have been several reported incidents in wildlife of population declines resulting from the release of endocrine-disrupting chemicals, our results suggest the need for future studies to test hypotheses regarding endocrine disruption in wildlife as a result of exposure to the growing accumulation of plastic debris.

The published study is found here: Rochman et al., 2014, Science of the Total Environment.

The post A story about fish, plastic debris and sex first appeared on Deep Sea News.

You may have heard me say it once, and I’ll say it again: the oceans are a toilet bowl for our waste. Throughout history, our solution to pollution has oftentimes been “dilution”. As a consequence, chemical pollution is now ubiquitous in our oceans as a result of industrialization, waste-management strategies (and/or lack thereof), natural disasters, etc….

Picture a watershed. Treated or not, our waste often finds its way into the oceans via rivers and streams, like arteries leading to the sea. As a consequence, ocean water, sediments and marine life are contaminated with pollutants (e.g., plastic debris, pesticides such as DDT, flame retardants such as PBDEs and metals such as lead and copper). Due to a large diversity of sources, all leading to our connected oceans, it can be VERY difficult to pinpoint the source of pollution when its fate is the aquatic environment.

As such, it becomes my job to try and solve this mystery and basically play detective on the open sea.  What puzzle am I trying to unravel? Well, I’ll warn you, it’s a trashy one…

Throughout my scientific career, I have been trying to understand whether marine plastic debris is a vector for chemical pollutants to accumulate in marine animals and marine food webs. Over the years I have collected several lines of evidence suggesting that it may be.

Scientific Evidence #1: Plastic is made of a large diversity of chemical ingredients, several of which can be hazardous at large concentrations (e.g., the monomers vinyl chloride and styrenes and the flame retardant PBDEs).

Scientific Evidence #2: When plastic becomes marine debris it accumulates persistent, bioaccumulative and toxic substances (e.g., the banned pesticide DDT and industrial chemical PCBs) and toxic metals (e.g., lead and cadmium).

Thus, plastic marine debris is associated with a cocktail of chemicals that can be hazardous. So, the next question is, can these chemicals accumulate in animals upon exposure?

Scientific Evidence #3: When plastic, that is allowed to soak in the ocean, is fed to fish in the laboratory, some chemicals transfer from the plastic to the fish tissue, thus bioaccumulating. We found greater concentrations of PBDEs in fish fed plastic that had been in the ocean versus fish fed no plastic at all or virgin plastic.

Scientific Evidence from other studies: Plastic ingestion occurs in hundreds of species, including 30 species of marine mammals, 41 species of fish, 119 species of seabirds and 6 out of the 7 species of sea turtles and plastic debris recovered from the oceans globally, even from remote regions, is contaminated with chemical pollutants.

ALL leading to the question: Does what we have observed in the lab occur in nature, i.e., does the plastic ingestion observed in wildlife cause the bioaccumulation of chemical pollutants found associated with marine plastic debris? As mentioned earlier, this is where it gets tricky and one must think like a detective, pulling together pieces of a puzzle to ask a greater question.

I was granted an opportunity to sail across the South Atlantic, leaving from Brazil, with 5Gyres aboard their sailboat, the Seadragon. Despite the fact that I get horribly seasick, I jumped at the opportunity and raised enough funds (from the public!) to spend 4 weeks at sea in some of the worst weather I’ve ever experienced in my life with 12 strangers cramped into a small, small space. After fixing our main sail twice, repairing our water maker several times, and almost running out of fuel we made it to Cape Town, South Africa safe and sound. The experience was a mixture of horrible and awesome all at the same time! Would I do it again? Probably.

While at sea, we sampled lanternfish, plastic debris and water. 

We chose lanternfish because they are known to eat plastic debris in open ocean gyres and these fish are good indicators of contamination in the local environment. They make vertical migrations to the surface to feed, which is where plastic debris accumulates and eat low on the foodchain, mostly zooplankton. As such, one might expect that chemical body burdens in these fish would be similar to patterns in the water column where they were sampled. But, if they were exposed to plastic debris and were ingesting this material, we might expect their chemical body burden to be similar to the plastic debris.

Our objective was to determine if fish living in areas with large accumulations of plastic had larger accumulations of plastic-related chemicals. Thus, we analyzed all samples for a mixture of contaminants that are known to be associated with plastic either as an ingredient and/or that accumulate from the water column (BPA, alkylphenols, PBDEs and PCBs). Each analysis revealed the contamination pattern in each sample. These patterns each provide a piece of the puzzle that could be put together to understand if we could detect the presence of chemicals from plastic in wild-caught fish.

Because this study was conducted in the open ocean, we observed a lot of variability. There was plastic and chemicals contamination in every sample, and concentrations and amounts were variable along our cruise track. Still, one pattern stood out above all else…

The flame-retardants PBDEs are added to plastic products to, as you might have guessed, keep them from going up in flames. These compounds are composed of 2 aromatic rings with differing numbers of bromines. The higher brominated compounds are often used in plastics today and can be found on some plastic products in large concentrations. We found that most of the plastic debris we sampled had a large amount of these higher brominated congeners relative to the lower brominated PBDEs. In water samples, we found an opposite pattern, that 100% of the PBDEs in water samples were these lower brominated congeners. As such, most of the fish we sampled had congener patterns similar to those in the water column. However, some fish had relatively large amounts of higher brominated PBDEs in their tissues and these fish happened to be caught in areas with relatively larger amounts of plastic debris. We found that the amount of higher brominated PBDEs in fish tissue was positively correlated with the amount of plastic sampled in the area. So, our data suggests that YES, chemicals from plastic can accumulate in fish and that higher brominated flame-retardants may be indicative of plastic ingestion in wildlife.

Adding strength to our evidence, others researchers in Japan and at CalEPA have come to the same conclusions finding similar patterns with higher brominated PBDEs and plastic debris in wild-caught fish and seabirds in the North Pacific.

So while it can be difficult to determine the sources of contaminants in nature, good detective work can lead to a greater weight of evidence to better understand sources of chemical pollutants, even in the vast open ocean. And in this case, it seems that the current state of the evidence suggests that marine plastic debris can be a vector for chemical pollutants to accumulate in marine animals and thus potentially marine food webs. So now I’m on to the next piece of the puzzle: how might this affect humans, who sit at the top of some marine foodchains, when our diet includes seafood?

The post Guest post: Playing Detective in the Great Blue Sea first appeared on Deep Sea News.

The long and windy path to a Ph.D. is lined with blood, sweat and tears. Like a roller coaster, it can be filled with joy, anxiety, fear and even nausea. This story is regarding one chapter of my dissertation, one that filled me with all these emotions and lead me to the conclusion that even in science, sh%* happens. But in this story, what we could not control lead us to better scientific conclusions with greater environmental realism. Due to what may seem like an experimental shortcoming, we were able to answer an important “so what?” question related to plastic marine debris.

Today, it’s nearly impossible to avoid the many images of marine mammals, birds and turtles entangled in plastic debris or washed up with large plastic items in their digestive tract. What we don’t see, but may question, is how the chemical pollutants associated with plastic debris interact with marine life and potentially our seafood.

When plastic becomes marine debris it accumulates several chemical pollutants swirling in seawater such as pesticides (e.g. DDT), industrial chemicals (e.g. PCBs) and metals (e.g. lead) adding to the several potentially hazardous ingredients (e.g. PBDEs and bisphenol A) already in the plastic material. Thus plastic debris presents a “cocktail” of chemical contaminants to marine animals when mistaken as a meal.

As such, it has been hypothesized that plastic debris acts as a transporter of these chemicals, several of which can be toxic at certain doses, to animals upon ingestion. While we have strong evidence that hundreds of species eat plastic debris, and several case studies showing that plastic ingestion can physically harm an animal, we have little evidence of the fate of chemicals associated with plastic debris when ingested by marine life.

In our laboratory, the Aquatic Health Program at UC Davis, we designed an experiment to determine if plastic ingestion is indeed a mechanism for persistent organic pollutants (POPs) to accumulate in marine life. Because we wanted to understand how marine plastic debris might interact with both ecology and human health, we chose to conduct our study using fish, suggested as a good indicator of ecosystem health and a common seafood item.

To do this, we devised a rigorous controlled experiment, using clean laboratory-reared Japanese medaka and a contaminant-free diet made in the laboratory. This way we could be sure any contamination in our fish was a product of plastic ingestion. We also bound the plastic to the diet in our two plastic treatments so we could be sure these fish were eating the plastic. OR SO WE THOUGHT…

Similar to nature, and even with our best efforts, sometimes controlled laboratory experiments are not as controlled as planned… Instead, all 3 diets (negative control, virgin polyethylene and polyethylene marine debris) turned out to be contaminated with POPs (as cod liver oil is an ingredient in our formulated diet). Moreover, the plastic particles completely dispersed from the diet when sprinkled into the fish tanks at each feeding.

Immediately, we began to panic. We feared our fish would not eat the plastic at all and if they did that it would be impossible to decipher contamination from plastic versus contamination from their diet. After several days of freaking out, worrying all our work had gone to waste, what seemed to be a catastrophe became a blessing in disguise. HALLELUJAH!!

DUMB LUCK #1: The oceans are a toilet bowl for chemical contaminants, including POPs. As such, these chemicals are ubiquitous in marine foodwebs in the absence of plastic debris. While it is well-known that these chemicals contaminate plastic debris, and there is some evidence that these chemicals transfer to animals (e.g. lugworms) upon ingestion, it is not clear if the source of POPs from plastic to marine animals matters in an already contaminated system. What I mean is: in the presence of plastic debris, is an organism at risk of accumulating a higher dose of POPs? As a consequence of the contamination in the cod liver oil, we were able to examine this question because our experiment included contamination in the foodchain (i.e. the diet) of all treatments with the addition of more POPs on the polytethylene in the marine-plastic treatment.

DUMB LUCK #2: The plastic did not bind to the diet and instead, upon feeding the fish, the plastic dispersed and floated independently in the water as it does in the real world. Fish were not force-fed plastic, but instead were exposed to it and had to “choose” to eat it. In this way, we were able to consider the dose of plastic to the fish in amount of plastic per volume of water. As such, the exposure concentration of plastic floating in our tanks was less than some of the largest concentrations found in the “garbage patches” of the subtropical gyres, and thus environmentally relevant. And to our surprise, the fish ate plastic and continued to do so for the entire 2 months!!

Thus, with a lot of hard work and good attitudes regarding laboratory mishaps, our experiment became ecologically relevant. Initially, we were only able to ask the mechanistic question: “do contaminants on plastic transfer to fish upon ingestion?”. Instead, we could address the more relevant question, “is plastic, at real-world concentrations, an important vector of contaminants to the foodweb, despite widespread and global contamination of these chemicals in seawater, sediment and the marine food chain?”.

After a 2-month exposure to plastic, the concentrations of POPs in the fish demonstrated that despite contamination in the diet, concentrations of POPs were greater in fish fed plastic with sorbed chemical pollutants. For some chemicals, this significantly greater concentration in fish suggests that plastic debris can be an important vector of POPs into marine life and thus potentially into the seafood we put on our own plates.

For more information, check out the published study, and feel free to ask questions in the comment section.

The post Guest post: The invisible consequences of mistaking plastic for dinner first appeared on Deep Sea News.

“Oh NOOO!” you say, “Not another article about plastic in the ocean??? What can possibly be invisible about it?” We see plastic litter just about everywhere we go. However, what you don’t see is the toxic contaminants associated and attracted to plastic debris once it hits the marine environment. This is what I work on—I am a graduate student in a joint Ecology program with San Diego State University and UC Davis studying some ecotoxicological aspects of plastic debris.

Plastics contain many chemicals upon manufacturing such as flame-retardants, aromatic hydrocarbons (from the oil plastic is made out of), Bisphenol A, and phthalates. All of these can be toxic at certain concentrations, as we know the dose makes the poison. Once in the ocean they adsorb (attract to its surface) concentrations of pesticides, fuel contaminants, and industrial chemicals at 1 million times the level in the water column (Mato et al., 2001).

Are these chemicals such as BPA and phthalates leaching off of the plastic into the ocean water? Or even worse, are they leaching off of the plastic into marine organisms upon ingestion? Scientists love to ask questions and a popular one is often, “SO WHAT?” This is a question I would like to attack. If sea life is living among this plastic debris, and we know it is, then “SO WHAT?”  I aim to answer this question from the perspective of an eco-toxicologist: what is the fate of contaminants to and from plastic debris in the ocean and how are these contaminants moving through the food web? What are the negative effects of this movement to marine life?

In San Diego, I measure how plastics adsorb organic contaminants to their surface in the San Diego Bay. By deploying contained samples of virgin plastic pellets from the factory into the water we can look at the type, amount of pollutant and concentration over time in a more controlled setting. This allows us to better understand how plastics adsorb pollutants and if different plastics behave differently. We can also get an idea of what pollutants are in the San Diego Bay by using plastics as a monitoring tool. In Davis, I am working on laboratory experiments to better understand what happens when trash becomes food. Upon exposing fish to plastic debris included in their diet we can look at certain toxic endpoints such as survival, weight loss, body burden, histopathology, and immunochemistry.

My favorite aspect of my research is the time I get to go out into the field, the big open ocean. As you may know, there are large accumulations of plastic in the open ocean which have been given several nicknames such as “the great garbage patch”, “the gyre”,  “toxic soup”, and “ocean landfill.”  Last August I got the opportunity to be one of the scientists on the SEAPLEX cruise to the North Pacific Subtropical Gyre led by Miriam Goldstein.  This November I am planning to set sail across the South Atlantic to investigate plastic pollution in the South Atlantic Gyre region.

On this cruise I am planning to deploy a brand new instrument by Aqualytical that can capture a wide range of contaminants in the water. This device can retain both polar and non-polar compounds in one sweep. I will be looking for both chemicals associated with the plastics such as Bisphenol A and phthalates as well as persistent organic contaminants such as pesticides, aromatic hydrocarbons and PCBs.

I also plan to collect salps and fish tissue to measure bioaccumulation of chemicals associated with the plastic debris. In addition plastic samples will be collected to see what pollutants are adsorbing to the plastics in this location. Upon collecting samples, I have to be very careful in order to avoid contaminating the samples with chemicals from the boat or other equipment we may have. This is done with certain techniques such as baking all glassware and foil that will be used to collect samples at 450 degrees C for six hours and never allowing the samples to come in contact with your skin. All samples will also be stored at -20 degrees C in order to preserve the chemicals in the samples until analysis.

While this cruise will be full of lots of exciting research it will also be filled with adventure! We will be on a sailboat (can anyone say seasick!) exploring the waters of the South Atlantic. The organization running the cruise, 5 Gyres, is a nonprofit that focuses on the issue of marine plastic pollution. They work in collaboration with Algalita Marine Research Foundation, and through education and outreach they are responsible for alerting the masses about this environmental issue. Throughout the past year they have visited the North Atlantic and Indian Ocean, and you can follow along on this upcoming voyage across the South Atlantic on their blog.

I am currently working hard to help fund this cruise. Analytical Chemistry is not cheap, and as a PhD student the money is not always flowing. However, researching the toxicological aspects of this issue is extremely important in order to understand how this debris might be affecting the marine life. 5 Gyres has offered to pay for my trip, and I am scavenging supplies for my research from my existing research funding. So I’m all set – if I can just get to Brazil and back from South Africa.

My goal is to raise $2,350 in order to to cover my flight as well as carbon offset credits ($200). Any funding over the goal will be used for sample analyses. (You can learn more about my research here.) Any help is greatly appreciated and I will reward those who can help pitch in for a cleaner ocean! To see more please visit my Kickstarter page.

References
Mato, Y., Isobe, T., Takada, H., Kanehiro, H., Ohtake, C., and T. Kaminuma. 2001. Plastic resin pellets as a transport medium for toxic chemicals in the marine environment. Environmental Science and Technology. (35) 318-324.

The post Guest Post: The Invisible Side of Plastic Marine Debris first appeared on Deep Sea News.