PAH's and Fish, a scary scenario

A recent article from the National Oceanic and Atmospheric Administration (NOAA) Fisheries has indicated that recent oil spill in the Gulf of Mexico affected the developing hearts of tuna (http://www.nmfs.noaa.gov/stories/2014/03/3_24_14oil_spill_effects_large_marine_fish.html). The reason for the abnormalities stems from crude oil, which contains polycyclic aromatic hydrocarbons (PAHs). Often for embryos or developing organisms the threshold for defects is much lower than that of adults. In the case of the tuna affected, the threshold is already very small, 1-15 ppb. Many of the affected fish died soon after hatching, while some may also have survived with less severe developmental issues. However those that survive will have a higher level of PAHs in their body, possibly leading to bioaccumulation and ingestion in humans. The PAHs released from crude oil spills are stored in the fatty tissues of many marine organisms which can then be consumed by humans, or build up to toxic levels and kill the organisms.

A pressing matter is the effect of these PAHs. There are shown carcinogenic properties of PAHs in test animals and is considered to be a probable human carcinogen as well.  Since PAHs are common water pollutants, bioaccumulation in organisms that become seafood is a serious issue. One of the most well known carcinogenic PAH is benzo[a]pyrene. The key feature of PAH carcinogens is a “bay region” which allows for continued reactions in the metabolic processes of the body that result in a carcinogen.

While the chemistry behind the topic is interesting I think the main point is that we, as a society, need to be more careful and conscience as to what we are polluting our environment with. Pollutants do not just affect one area, but rather spread and contaminate areas that had no influence over the contamination in the first place. We have been lulled into a tragedy of the commons mindset, whereby we stand by while animals and humans are seriously affected.

Stop Smogging Around

SMOG. A small word with a BIG effect. When I think smog I either think of industry fumes or automobile emissions. Cars and factories lead to smog, or a type of air pollution that directly affects us and our planet in the form of ozone.  The sources of ozone are Nitrogen Oxide (NOx) mixed with Volatile Organic Compounds (VOCs) and sunlight. NOx is produced during combustion from the reaction of nitrogen dioxide (NO₂) and nitric oxide (NO).  The temperature in automobiles and power plants is so high that it shifts to the products, forming these nitrogen oxides. The catalytic converter in automobiles is designed to eliminate NOx from exhaust stream. The problem with this is the lack of efficiency of the catalytic converter before the engine is completely warmed up, causing some NOx pollutant to be formed. These small solid or liquid phase particles suspended in gas, otherwise known as particulates, are also formed from this high-temperature combustion. The point of this "DIY Smog Check" experiment was to test the amount of nitrogen oxides and particulates emitted into the atmosphere as air pollution as a result of vehicle exhaust, which goes on to create ozone. The ozone that is created near the Earth’s surface in the troposphere is a major cause of negative health effects including harm to lung functions and the respiratory system, leading to lung cancer and asthma. Because of this it is important to understand the effect our cars have on our environment and it is crucial to keep up to the standards required by the California Department of Motor Vehicles. 

 

PCBs delivered fresh, daily

A 2010 study from the University of Texas School of Public Health revealed that many persistant organic pollutants  (POPs) are present in typical supermarket foods despite being banned. Among them were PFCs, PCBs, and other pesticides. The results showed that the majority of these 31 supermarket items tested contained some combination of these chemicals, including 6 of 7 types of PCBs that were found in salmon and sardines. So how is it that a food tainted with a known carcinogen is permitted to be sold in supermarkets? First of all, the levels of PCBs measured (33 ng/day) were below the total daily intake reference dose set by the EPA, which means that this is an acceptable level of pesticides to be sold in stores. This raises a philosophical question: What amount of pesticides is acceptable? While everyone has their own opinion on the matter, I’d like to cite Rachel Carson on the matter:

“Why should we tolerate a diet of weak poisons, a home in insipid surroundings, a circle of acquaintances who are not quite our enemies, the noise of motors with just enough relief to prevent insanity? Who would want to live in a world which is just not quite fatal?” 

Carson raises an interesting point. When presented with the option to ingest these known carcinogens or not in any quantities, isn’t choice an easy one? While the PCB concentrations are below EPA standards, that says nothing about possible synergistic interactions between PCBs and other chemicals, which the University of Texas study points out has not yet been researched. Granted, pesticide levels may be low on the list of issues regarding the American diet. However, it begs the question about why we’re so accepting of low levels of poison in our food.

The simple science of biodiesel production

Biodiesel is one of the big players in affordable, accessible, and safe renewable alternative fuels.  It is produced by converting animal or plant oils into a diesel fuel that can be used in internal combustion engines like automobiles or electric generators.  Most biodiesel is produced on an industrial scale.  In 2012, the biodiesel industry produced nearly 1.1 billion gallons of biodiesel, more than any other type of advanced biofuel designated by the EPA.  However, as we proved in our class’s lab, making biodiesel is not limited to large-scale production.  The procedure is relatively simple and can be performed by individuals to fuel their own vehicles.

To produce biodiesel, first an oil source must be chosen.  In our lab, we used discarded oil from USD’s dining services, bacon grease, Crisco, and several types of plant-derived oils.  These oils exist mostly in the form of triglycerides, which are made up of a glycerol molecule bound to three fatty acids.  To convert these triglycerides to biodiesel, the fatty acids must be removed from the glycerol.  To do this, oil was reacted with methanol in a basic solution in order to perform a “transesterification” whereby each fatty acid’s bond to glycerol is replaced by a methyl group.  One of the main contaminants in biodiesel is water, so in our experiment, a great deal of time was spent heating the biodiesel to evaporate leftover water.  Additional tests were performed to determine the toxicity level of the fuel, the heat of combustion, and the chemical makeup using GC-MS.

I was shocked by how simple this process was, and was curious to find out why more vehicles don’t run on biodiesel.  One of the major barriers to widespread application is vehicle engine makeup.  In order to use fuel containing high biodiesel content in a regular diesel vehicle, modifications must be made to engine components to prevent degradation.  Some vehicles can use diesel fuels containing up to 20% biodiesel (called B20) without being modified, and lower biofuel mixes are often available such as B5 or B2.  The U.S. is lagging behind Europe in terms of biofuel adoption.  Europe accounts for about 85% of worldwide biodiesel production, and 100% biodiesel (B100) is available at many fuel stations.  Modern diesel vehicles are becoming popular for their fuel economy and environmental friendliness compared to their gasoline-powered counterparts.  I think this would be a great time to remind people that there’s a type of renewable fuel you can buy or even make yourself that is clean, domestically produced, and biodegradable with only some minor changes to your engine.

Indoor and Outdoor Ozone Level

Ozone in the upper atmosphere known as ozone layer plays an important role in protecting the organisms on the surface of earth by filtering out most biologically harmful ultraviolet (UV) light. Any significant reduction of upper atmosphere ozone can be harmful to the organisms on the surface of the earth. Overexposure to these harmful UV light can cause skin cancer in human. While the overhead ozone depletion can be harmful to organisms, the increase of ground-level ozone due to chemical reaction of pollutants is also harmful to human health. This ground-level ozone is called “an ozone layer in the wrong place” is one of the air pollutants existing in many urban centers around the world. In haling air with ozone can irritate our respiratory system and give rise to coughing, and even cause asthma.

Air pollutants are not only outdoors but also indoors, and some air pollutants are even greater indoors than outdoors. In order to determine the indoor and outdoor air quality, we used a chemical measurement to quantify ozone levels in the printer room and in outdoor environment on campus. The air was sampled by using a glass bubbler to absorb ozone, and any type of tubing to connect a pump and flow controller. In order to obtain the same volume of air samples, the sampling flow rate of the pump was set to be constant for indoor and outdoor conditions.

We found out that the ozone concentration of outdoor air was 16.8 ppb, which was slightly higher than the indoor concentration determined as 14 ppb. The results suggest that the air inside the printer room and outdoor air on campus was relatively clean in terms of the low ozone level, and the indoor air had slightly lower level of ozone than the outdoor air did. The ozone concentration reported by Downtown San Diego Today was 47 ppb which was much higher our results. The reason could be that the pre-set flow controller leads to imprecise volume of air being sampled. Since the ozone concentration was calculated based on these volumes, this could introduce errors in our results. Furthermore, the different sampling sites could also result in the consistency. If the reported ozone level was measured at downtown, the ozone concentration could be higher than our results since the higher level of vehicle exhaust in downtown could cause more ozone being formed. In addition, the inconsistency with reported value could be due to the different methods being used to determine ozone concentration as well.

Making Biodiesel

People often ask me what my dream car is, and my reply has always been a Jeep. However, as an earth conscious budding scientist I have always disliked the gas guzzling aspect of Jeeps, and therefore wanted to rebuild a Jeep with my dad to run on biodiesel.

Actually learning how to make biodiesel, test multiple oils, perform toxicity assays, determine heat content, and make soap made for a jam packed experiment that was practical and engaging. Biodiesel is currently the greenest form of renewable fuels in terms of carbon dioxide emissions. On a planet where global climate change is an important issue, research and implementation of renewable fuels such as biodiesel is a great step in the right direction.

The lab included utilizing a variety of new sills including determining the heat content, which proved to be fairly tricky. The set up included a hanging soda can and crucible with burning sample below. However there was a fair amount of error from the wick burning and heat lost to the atmosphere. Other difficulties arose in the length of time it took for the biodiesel to settle in the separatory funnel.  The toxicity assay was particularly insightful even though it was fairly tedious to count and measure 600 seeds. This aspect of the experiment was important to look at the possible impacts of biodiesel waste on the organisms that might come in contact with the waste. I particularly enjoyed the fact that we used one of the byproducts of the biodiesel, glycerin, to make soap. If we are trying to reduce carbon emissions for a better earth, there is no reason that we should not also put to good use as many byproducts as possible so as to reduce waste. Although our class is going to need to find ourselves so very good marketing majors to promote our radioactive green, unique smelling, suds!

Cooking Oil --> Biodiesel + Soap

As a class, we synthesized biofuel from our school’s cooking oil. Although biofuel is a renewable resource, waste products are still formed. To purify our biofuel, we separated the desired product from the waste product, glycerin. As a way to be completely resourceful in our biodiesel synthesis, we made soap out of the glycerin. We performed this procedure by first heating the glycerin at 70 °C for about an hour in order to drive off the methanol used in the synthesis of our biofuel. We then allowed it to cool to 60 °C, at which point the original brown liquid began to congeal. We expected this to happen, as we were making solid soap. While making the catalyst solution, which consisted of water, potassium hydroxide, and citric acid, we brought the glycerin temperature back up to 70 °C, mixing throughout the heating process. At 70 °C, we added the catalyst solution and allowed it to stir for 10 minutes. While it was stirring we added green food coloring in order to make the soap more appealing than its’ original brown color. We also added hops and jasmine for texture and aroma. Each group added their own scent and color, but all other steps were followed as a class. During these 10 minutes, we also tested the pH of the soap to ensure that it was not acidic and therefore would be safe for human use. This ten-minute heating and stirring period was followed by 10 minutes of just stirring without heat, and then poured into a round mold to allow to solidify overnight. Each group’s soap seemed to have a different consistency before we allowed them to solidify, as the pictures below show. This was strange because we all used the same procedure and adding food coloring or scent should not produce such disparity in consistency. When we returned to our soap, none of the soaps seemed to have solidified; they all had a gummy consistency. The consistency was a mix between solid and liquid soap, but the goal was to synthesize solid soap. We are unsure why this occurred, but it may have to do with how much fat was in the original biomass. We used vegetable based biomass, which is mostly unsaturated fats, whereas animal fat is saturated and therefore congeals more easily. This is solely a hypothetical possibility and needs to be experimentally tested to prove. Another odd observation of the soap products was that some of them produced suds, while others did not. I am unsure why this happened but it could possibly be because the starting glycerin had too much water in it or not all the methanol was driven off.

What are you smoking?

Many people know that smoking is bad for them. But did you also know that smoking can actually lead to an increase in NOx emisisons, which when reacted with volatile organic compounds (VOCs) in the presence of sunlight can create ozone? Ozone in the stratosphere helps shield us from harmful UV radiation from the sun, but in the troposphere can actually lead to increased damage of lung tissue and a decrease in lung function in people of all ages.

In our lab, we were interested in determining the NOx concentrations emitted from both cigarettes and cigars. To do so, we used a syringe which had a 25 mL NO2 solution inside that was attached to a filter using plastic tubing. The filter was also fitted to a holder that would contain the unlit end of a cigar/cigarette using plastic tubing. Once the cigarette/cigar was lit, we drew a 35 mL puff into the 60 mL syringe and allowed it to sit. Not only did most groups collect a great deal of particulate matter on the filter paper, but most of the NO2 solutions in the syringes changed color, which it should do in the presence of NOx. After running a few calculations, the class average for the NOx emissions from cigarettes/cigars was 4.5*10^-6 M and the particulate matter collected on the filter paper averaged to 6.5*10^-4 g/275 mL of exhaust.

All that particulate matter is being inhaled into the lungs, causing lung damage. The smoke emitted, though the number may not seem that high, actually does a lot of damage in small amounts to both the environment and human health - like we all needed another reason to not smoke.

Biodiesel, soap, and... Hops?

Biodiesel fuel can be a “green” alternative in more ways than one! Not only was our biofuel synthesized from used cooking oil, but the byproducts of this synthesis were used to create soap.

           During the synthesis of biodiesel, two major products are formed – Biodiesel, the fuel we are seeking to create and glycerin. The glycerin in this lab was a dark color and had the consistency of thick syrup. Glycerin is a molecule that has a wide variety of application, however, the most appropriate application of our glycerin was soap due to its low purity.  

            The general scheme of our soap making procedure was to first heat the glycerin to remove any methanol, which is the contaminant we are primarily concerned with in this reaction. Once free of methanol, the warm glycerin was reacted with potassium hydroxide/citric acid solution. At this point, oils and colors could be added to make the soap more pleasant. We decided to add a few grams of ground cascade hops in an attempt to take advantage of the hops’ aroma and antimicrobial properties. Because the hops didn’t make as large of an aromatic impact as we’d hoped, we opted to add some jasmine oil as well to give the soap a more familiar scent. We thought it was appropriate to color the soap green to emphasize the “green” nature of this project.

            After allowing the soap to harden for a week during spring break, we came back to find our soap wasn’t exactly what we had hoped. The soap was unpleasant in color and scent. The jasmine scent did not compliment the earthy scent of the hops and the bright green color we had hoped for was very, very dark. To make matters worse, the soap didn’t lather very well, but it was an excellent learning experience!