Tag Archives: Ocean water quality

Ocean water condition based on water quality and other paramenters.

Contaminants

Copper and Water Quality

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A few of my readers know that I’m a sailor. My husband and I have a 32 foot sailboat, which we keep it in a marina on the Chesapeake Bay. Every year the boat gets hauled out of the water for the winter. Before the boat went back in the water this year, we had the hull painted. Copper based paints are used on boat hulls to prevent the growth of critters and sprouts. I was curious about how copper paints prevent your hull from becoming a Noah’s ark of algae and barnacles, so I have been doing a little reading on the subject. There have been a number of copper based paint studies (also grandly called Anti Fouling Systems) conducted by the U. S. Environmental Protection Agency (EPA) and the California Environmental Protection Agency (Cal-EPA). According to the two environmental organizations, the most commonly used boat paints leach copper into the water and form a toxic protective shield around the boat hull to prevent the attachment of aquatic organisms. Copper is a toxin for many aquatic plants and animals. In fact it is a toxin for many terrestrial plants and animals. Copper is a widely used pesticide in the agricultural industry where it’s employed to eliminate bacteria, fungus, and weeds.  After a few years, the leaching rate of copper from the paint on a boat hull decreases and the boat has to be painted once again. It costs a couple of thousand dollars every time, so this is not an incidental expense.

 

The most common form of copper in the antifouling paints is cuprous oxide.  I didn’t realize how much copper is actually in the paint. Cuprous oxide paint is 30 to 60 percent copper. So a lot of copper is going into the water in marinas where recreational boats spend most of their time. The Navy actually did some studies in San Diego Bay back in the 1990s and found that 98 % of the copper in the bay came from antifouling paints on boats. They calculated that each boat in the bay was releasing 1.8 pounds of copper a year just while they were sitting at the dock in the marina. According to the Navy, most of the copper in the paint was released through the leaching process. A smaller amount of copper was released during underwater cleaning of boat hulls. California does seem to have the largest problem with copper in the waters of their marinas, so much so that a marina in California has been listed as an impaired water body under 303(d) of the Clean Water Act. Once a water body is listed as impaired under the Clean Water Act, a state must institute a Total Maximum Daily Load (TMDL) for it. A TMDL basically sets the maximum amount of a particular pollutant that a water body can receive and still meet water quality standards. As you can imagine, the designation of the marina as an impaired water body has now posed a serious problem for the marina’s boaters and California’s environmental regulators. Since hull paint is considered the main contributor of copper into the marina’s waters, the Cal-EPA has instituted a study of alternate antifouling systems – hull coatings without copper – in hopes of finding one which will be effective and economical enough to be used on recreational boats so that water quality there can be improved.

 

The water quality criteria established by the EPA for copper in marine waters and estuaries is really quite low. It has been revised multiple times over the last 20 years. The revisions have sought to produce a more scientifically justified approach for the development of the water quality criteria. The latest approach in setting the copper water quality criteria was issued in the July 2016 draft guidance: Aquatic Life Ambient Estuarine/Marine Water Quality Criteria for Copper, EPA-822-P-16-001. Scientists at EPA have known for many years that the toxicity of copper in water is dependent upon the water’s salinity (the amount of dissolved solids in the water), the temperature, the pH (the measure of acidity), and the amount of natural dissolved organic carbon. EPA scientists realized variations in these parameters influence the amount of dissolved copper in water. Dissolved copper is the culprit in the metal’s toxicity to aquatic organisms. Toxicity is reduced when copper in the aquatic environment binds with other elements and organic carbon to form ligands. Ligands are a little difficult to understand but simply put, they are complexes of molecules binding together to form a new substance. So for example, if there’s a lot of natural dissolved carbon in the water, it might bind with copper to form a ligand. Copper can also form complex ions with other ions and ligands in the water. Copper tied up in ligands and complex ions is not available to plants and critters, thereby making the water less toxic to them.

 

Interestingly copper has a similar binding behavior when it interacts with aquatic organisms. It binds to the biota’s gills and surface membranes. Although biota also ingests copper in the water, the scientists at EPA do not consider it a pathway for the toxin to negatively impact the organisms. It is the binding of copper to the gills and surface membranes of marine fish and invertebrates which is the major factor in coppers toxicity to them. EPA has a name for it. They call it the biotic ligand. Therefore to take into account the complexity of the world at large which is obviously not a simple system, EPA has developed a model called the “Biotic Ligand Model” to determine based on the specific temperature, pH, salinity, and amount of dissolved carbon what the aquatic criteria is for any particular marine or estuarine environment you might encounter. This makes it a little tough for state regulators because then they must sample the waters in question for these parameters and run a complex computer model to determine the specific water quality criteria for any given water body.

 

When setting water quality criteria, EPA usually bases it on the organism in the water which is most sensitive to a given pollutant. Arthropods are pretty sensitive to copper, after all the reason boaters use copper paint is to keep barnacles from attaching to their boat hulls. Although in the grand scheme of things I don’t think anybody is really worried about barnacles. Commercial species of mollusks like mussels, oysters and abalone are also extremely sensitive to copper. EPA was able to collect acute toxicity data on 89 different estuarine and marine fish and invertebrates. In simple terms acute toxicity means that biota aren’t going to live very long when exposed to an acutely toxic concentration of a pollutant. There were far less data available on chronic toxicity. Chronic toxicity happens when exposure to a pollutant results in conditions which are not immediately fatal to an organism, for example reproductive anomalies (we call these birth defects).

 

With EPA’s Biotic Ligand Model one can pop the temperature, pH, dissolved carbon and salinity values of your local marine/estuarine water into the model and come up with a numeric value for copper which should not be exceeded. So for example, if your water is 68 degrees Fahrenheit, the pH is 8, the dissolved carbon is 1.0 milligram per liter, and salinity is 32 parts per thousand than dissolved copper shouldn’t exceed 2.0 micrograms per liter on average more than once every 3 years, and the 4 day average shouldn’t exceed 1.3 micrograms of dissolved copper per liter more than once every 3 years. Complicated right?

 

These are extremely low values. The current acute value for copper is 3.1 micrograms per liter and the chronic is 4.8. The water quality criteria are of course guidelines. They are not regulatory in nature. They are there for state regulators to use in determining protection measures for aquatic life. As mentioned above, California has already designated a San Diego area marina as an impaired water body. Other places EPA has suggested might have copper levels impacting aquatic life are certain locations within the Chesapeake Bay and some port areas of Florida. As of yet, I know of no other marinas which have been designated as impaired waters. Alternatives to copper paint are fairly expensive and can potentially double the price for applying an antifouling coating to a boat hull. The American Coatings Association and the International Copper Association have already commented on EPA’s 2016 draft guidance. The organizations submitted a number of technical comments in regard to the Biotic Ligand Model and the conservative values produced by it. They are worried that the new proposed copper water quality criteria will result in unrealistically low TMDLs for other marinas.

Contaminants

Aquatic Life Freshwater Ambient Water Quality Criteria for Selenium

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In my last post on Selenium Contamination

Selenium Contamination

I mentioned that the Environmental Protection Agency (EPA) issued a draft Aquatic Life Ambient Water Quality Criterion for Selenium in Freshwater in July 2015 (EPA 822-P-15-001). The final rule was published in the Federal Register in July 2016.  EPA has the authority to develop these type of criterion under section 304 (a) (1) of the Clean Water Act. The criteria laid out in EPA’s rule are not regulatory or enforceable until adopted by states as a water quality standard under section 303 (c) (2) of the Clean Water Act.

 

The complexity of how selenium behaves in the water environment had to be taken into account in developing the criterion. If you read my post on Selenium Contamination, you’ll know that the biggest problem with selenium is its chronic long term effects for egg laying animals. Just a tiny amount of selenium in water can get into the food chain through the algae and microbial organisms that live in water, then the invertebrates like insects, worms and so forth eat the algae and microorganisms, and they in turn are consumed by fish. Because fish don’t readily excrete selenium in urine or feces (yes, fish do poop in the water), it winds up in their tissues and it is unfortunately transferred to their offspring while they are being formed as tiny little embryos in eggs. The difference between what is an essential dietary need by fish for selenium and what is toxic to them is very small. Excess selenium ends up severely deforming the baby fish to the point they either don’t hatch or their deformities are so severe they don’t survive after hatching. The whole process of concentrating a contaminant up the food chain from microorganisms to fish and other animals is called bioaccumulation.

 

Selenium requires residency time in water for it to be bioaccumulated. Residency means it stays around in the water for a while. If you have constant low level selenium contamination going into a fast water creek or river, the velocity of that river moves much of the contaminant pretty quickly downstream, so selenium doesn’t have time to sit around and get ingested by a lot of microorganisms. Flowing waters are called lotic. Residency time increases when waters are still, like ponds, lakes and wetlands. The water with the selenium contamination stays around awhile and the microorganisms have plenty of time to suck it up and concentrate it. All the documented cases of selenium poisoning in fish have been in ponds, lakes and wetlands. Still waters are called lentic waters. Residency time is important because it takes awhile for the selenium to build up and concentrate through the food chain.

 

EPA had a tough time coming up with criterion for selenium in water because selenium toxicity depends on the food chain in a water body and if the water is moving or not. Usually scientists just do tank tests to determine water quality criterion. They’ll have one tank full of fish hanging around in contaminated water and another tank of fish, called the control, hanging around in nice clean water. The scientists generally use some abbreviated period of time like 30 days to determine what level of a particular contaminant knocks off the fish in the contaminated tank compared to the clean tank, because most water quality criterion are based on sudden death or acute toxicity not chronic long term toxicity like selenium. And they feed all the fish in the tanks nice clean fish food. There are no algae or invertebrates in the tanks concentrating the contaminant. So instead of doing tank tests, the EPA had to rely on data from laboratory and field studies. Fortunately there are a lot of studies out there, because selenium poisoning in fish has been a well known problem since the 1980’s. EPA was able to find data on a diversity of fish. Usually these studies require the use of a whole host of aquatic organisms, not just fish, because water quality is important to hosting an entire ecosystem, including fish, insects, floating crustaceans, and crawling crustaceans. But because the effects of selenium on fish are so well known and so severe, the EPA just used fish data in development of their criteria.

 

EPA looked at studies to determine what level of selenium in fish tissue and eggs caused toxicity. Then, because EPA had to come up with actual selenium water concentrations that are protective for a whole host of different fish, they got together with the U.S. Geological Survey and developed a model. It’s a complicated regression model, which the two federal agencies used to calculate actual concentration numbers protective of fish in both lotic and lentic waters if they weren’t exceeded in any 30-day period over the course of a year.

 

So, in the table below are EPA’s new Aquatic Life Ambient Water Quality Criterion for Selenium, which sets numerical criterion for selenium in fish tissue in eggs and ovaries and in whole fish or muscle and a monthly average water quality measurement for both moving water (lotic) and still water (lentic), as well as a calculation for determining a water quality criterion for intermittent exposure.

 

Summary of the Draft Freshwater Selenium Ambient Chronic Water Quality Criterion for Protection of Aquatic Life.

Media Type Fish Tissue Water Column3 Criterion
Criterion Element Element Egg/Ovary 1 Fish Whole Body or Muscle 2 Monthly Average Exposure Intermittent Exposure4

Magnitude
Magnitude 15.1 mg/kg 8.5 mg/kg whole body or  11.3 mg/kg muscle (skinless, boneless filet) 1.5 µg/L in lentic aquatic systems

 

3.1 µg/L in lotic aquatic systems

  

𝑾QC int =   𝑾QC 30 day – 𝑾C bkgrnd(𝟏−𝒇int )/ 𝒇int
Duration Instantaneous measurement5

 

 Instantaneous measurement5

 

 30 days Number of days/month with an elevated concentration
Frequency Never to be exceeded Never to be exceeded Not more than once in three years on average

 

 Not more than once in three years on average

 
1. Fish tissue elements are expressed as steady-state.

2. Egg/Ovary supersedes any whole-body, muscle, or water column element when fish egg/ovary concentrations are measured.

3. Fish whole-body or muscle tissue supersedes water column element when both fish tissue and water concentrations are measured.

4. Water column values are based on dissolved total selenium in water and are derived from fish tissue values via bioaccumulation modeling. Water column values are the applicable criterion element in the absence of steady-state condition fish tissue data.

5. Where WQC30-day is the water column monthly element, for either a lentic or lotic waters; Cbkgrnd is the average background selenium concentration, and fint is the fraction of any 30-day period during which elevated selenium concentrations occur, with fint assigned a value ≥0.033 (corresponding to 1 day).

6. Fish tissue data provide instantaneous point measurements that reflect integrative accumulation of selenium over time and space in fish population(s) at a given site.

 

Wow right? This is a pretty complex set of criteria. It is made even more complex by EPA’s allowance for states to modify all of the criterion based on site specific conditions for the exact types of fish species in a particular area instead of the ones EPA used in the development of their numbers in this table. The numbers and methods are pretty significantly different from the 5 µg/L over 4 days that has been the standard since 1999. But it is also based on a more rigorous methodology.

Contaminants

Selenium Contamination

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So many reports assessing environmental conditions erroneously list selenium under the category of heavy metals or toxic metals. Selenium is not a metal at all. On the periodic chart, it is actually located between sulfur and tellurium and is part of what is called the oxygen family. Chemically, selenium acts somewhat similar to sulfur in that it combines with a lot of metals. It is often found in metal sulfide ore deposits (for example at copper and zinc mines), which may be why a lot of environmental scientists and engineers group it in with heavy metals when they are assessing water or soil for environmental contaminants. Selenium has long been known to have environmental impacts on egg laying animals such as fish and birds, but in humans selenium toxicity is rarely seen.

 

I checked with the bible of references for toxicity: The Agency for Toxic Substance and Disease Registry’s (ATSDR) Toxicological Profile for Selenium. The reference was updated in 2003. The reference gives only a few cases of selenium toxicity, mostly from industrial chemical exposure. But there are two interesting cases in China of selenium toxicity due to long term ingestion of high levels of selenium in food. Crops in these areas of China were planted in soils with very high natural selenium content and as a result selenium became incorporated into the plants biological structure during growth. Common health effects seen by doctors examining the people who lived in these areas were brittle hair and deformed nails. Tooth loss and the loss of feeling and control of arm and legs in some people were also noted. There’s actually a name for the health effects of too much selenium in your diet. It is called selenosis. It’s found not just in humans but in other mammals as well.

 

The Toxicological Profile also noted health effects due to low selenium in people’s diets. In fact, there is a Recommended Daily Allowance (RDA) for selenium. If you take a one a day vitamin like I do, you can see selenium listed right on the label.

IMG_1476

The RDA is 0.055 milligrams per day. Selenium is a vital trace element for humans and animals, but can be harmful at levels greater than recommended. The ATSDR noted that ingesting 10 to 20 times the normal amount of selenium can result in selenosis. So there’s actually a fair amount of difference between what’s needed and what’s toxic. The average American is getting somewhere between 0.071 and 0.152 milligrams per day depending on where they live and what they are eating. You’d have to be getting 0.55 milligrams a day of selenium over an extended period to have any toxic effects. Unfortunately for birds the difference between the level of selenium essential for daily nutrition and a toxic amount is very small. Bird toxicity is often the main concern when you see high levels of selenium in water and fish. The well known results of selenium poisoning in birds are eggs that don’t hatch and deformed chicks. Both fish and birds pass the selenium they ingest to their eggs. Humans excrete most of the selenium they eat in their food. Excrete is the polite way of saying we pass it out through urine or feces. The ATSDR noted no human reproductive issues from selenium. In fact the RDA for selenium for pregnant and nursing women is actually a tiny bit higher than for other adults.

 

Selenium is everywhere. It can be found in rocks and soils all over the world at very low levels. However there are certain areas of the earth where the rocks and soils are enriched in selenium. A lot of these rocks formed back during the last days of the dinosaurs in the time period geologists call the Cretaceous. I suppose I shouldn’t say the last days of the dinosaurs, because those last days lasted for eighty million years – but hey dinosaurs were around for quite awhile before then. The Cretaceous was also when plate tectonics sort of arranged the world’s landmass in the shape, if not the position, of the familiar continents we know today. In the Late Cretaceous there were a lot of very shallow inland seas. Much of the midwestern and western parts of the United States were covered with these shallow water bodies and over the millennia they filled with rich marine organic rock and evaporite deposits. Evaporite deposits are rocks like gypsum, salt and phosphate. Organic rich rocks include oil shale and coal. Rocks formed in these shallow marine basins contain higher levels of selenium compared to other rocks. In the Cretaceous these shallow marine basins existed not only in the United States but also around the world. There are younger rocks formed under the same conditions that also have the same high selenium content; notably the phosphate rocks in southeast Idaho.

 

These rocks are the source of a lot of trouble for the fish and bird populations of the world. The problem was first noticed way back in the 1970’s at a place called Belews Lake in North Carolina. Belews is not a natural lake. It is a man made reservoir that is essentially a cooling basin for a power plant – a coal fired power plant. One of the sources of water to the reservoir was a fly ash settling pond. When you burn coal you get fly ash. It’s what’s left over after the organic content is burned to create electric energy. It looks a lot like the ash you get in the bottom of your grill after barbequing with charcoal, except charcoal is made from wood. Coal is essentially a rock with a lot of organic matter. You have all sorts of elements in coal that are rock like – silica, aluminum, iron, and calcium. You also have arsenic, cadmium, chromium, molybdenum, mercury and the subject of this blog post – selenium. Some of these elements go up the stack of the power plant as air pollutants but the majority is left behind in the fly ash.

 

There are lots of accounts of what happened at Belews Lake, but in my opinion, William Frankenberger and Richard Engberg did the best review of the incident in the 1998 publication: Environmental Chemistry of Selenium published by Marcel Dekker, Incorporated. According to their report, the water entering the reservoir from the fly ash settling pond contained 150 to 200 micrograms per liter (parts per billion) of selenium. Doesn’t sound like much does it? In fact, in Belews Lake itself the selenium concentrations in the water were on average only 10 micrograms per liter. But when wildlife scientists started looking at why fish populations were disappearing in the lake, they found up to 70 percent of the fish in the lake had reproductive abnormalities and 16 fish species once found in the lake were totally gone. By 1978 only four species of fish were left in the lake and when their tissues were analyzed for selenium, they were found to exceed 100 milligrams per kilogram (parts per million).  Instead of excreting the selenium, the fish were storing the selenium in their bodies and passing it on to their eggs. Were the fish drinking the water? Of course not, the selenium in the water was being taken up by algae and other microorganisms and entering the food chain, which for fish include a lot of insects, worms, and the like who thrive on algae and microorganisms. In upstream reaches of Belews Lake unaffected by the water from the fly ash pond, normal fish communities were found. There the water contained less than 5 micrograms per liter of selenium. Noting the difference, scientists could pretty much conclude selenium is not good for fish. This was such a notable account of poisoning of fish from low selenium concentrations in water that in 1987 the Environmental Protection Agency changed their selenium freshwater criteria for the protection of aquatic from 35 micrograms per liter to 5 micrograms per liter.

 

The other landmark environmental account of selenium poisoning is that of the Kesterson Reservoir in the San Joaquin Valley of California. People often speak with reverence about the studies conducted there and scientists talk about the Kesterson Syndrome. Messieurs Frankenberger and Engberg also describe the Kesterson studies in the Environmental Chemistry of Selenium. Remember those Cretaceous marine rocks I described earlier? There are a lot of those exposed at the surface in the San Joaquin Valley in California. I think all Americans know the San Joaquin as a fertile agricultural valley in California, but like all agriculture in the dry western states, they water the heck out of it. There is a lot of agricultural drainage as a result and back in the 1970’s the state of California got the idea to build large shallow impoundments to serve as evaporation basins for the drainage, which could also be managed as a wetland in order to benefit wildlife. Sounds like a win/win right? In fact it looked like it was going to work. The ponds at first received all sorts of good quality agricultural water and a large size marsh with thriving wetland plant communities was established. Wildlife populations began to flourish. Then the impoundments started receiving the saline subsurface drainage from the agricultural irrigation. By 1981 all of the flow into the impoundments was this saline drainage and by 1982 scientists started seeing deterioration of the wildlife in the marsh.

 

When scientists measured the amount of selenium discharging into the marsh from the irrigation drainage, the water averaged 300 micrograms per liter. The many different fish species that once populated the marsh were gone. The only species left were the mosquito fish which is known to tolerate pollution pretty well, but even they were suffering from reproductive abnormalities and unhatched eggs. Mosquito fish had as much as 120 milligrams per kilogram selenium in their body tissue. Eggs of water birds in the marsh were analyzed by scientists and ranged from 4 to 70 milligrams per kilogram selenium, depending on what type of bird egg it was. I think Kesterson is where scientists first recognized that even among birds there were variations in tolerance for selenium. Scientists checked nests for eggs that failed to hatch. In one count of 578 nests, 39 percent of eggs in the nests had one or more eggs that did not hatch. Up to 15 percent of the egg embryos examined had deformities. Now I was going to include a photo from a U.S. Geological Survey report on bird deformities due to selenium, but I know some of my readers are a little sensitive. So I’m just going to provide a link. If you get queasy looking at road kill, do not click on this link:  http://www.nwhc.usgs.gov/publications/field_manual/chapter_44.pdf .

Fortunately drainage to the Kesterson Reservoir was stopped in 1986.

 

There are dozens more examples of where low levels of selenium have resulted in environmental damage. There has been a lot of research on selenium since the incidence at Belews Lake and in July of 2015, the Environmental Protection Agency issued a draft proposal for further updating the selenium water quality criterion for protection of aquatic life.

Water Quality

Ocean Condition: Assessing the Fish

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Questions, questions, there are always questions. The big question about my review of the Environmental Protection Agency’s (EPA) January 2016 “National Coastal Condition Assessment 2010” report was “how did the EPA determine the majority of coastal fish in the United States were in fair to poor condition?” My last blog post (if you didn’t catch it, here’s the link https://waterblogger.org/water-quality/ocean-condition/) said EPA rated the majority of fish in coastal waters as fair (26.4 % of fish) to poor (49 % of fish) due to the amount of selenium in the fish tissue. It is a fair question about what constitutes such a rating. So I went back to EPA’s technical report which provides all the methodologies for the data produced during the study. It was also released in January 2016, as a companion piece to the “National Coastal Condition Assessment 2010” report.

EPA has been using a standard process for examining toxicity in fish for the two decades they have been producing reports on coastal conditions. The method used examines the whole body tissue of a fish. When I used to work on ecological risk assessments, we referred to this method as the bassamatic. EPA of course refers to the process as homogenization. Basically you put the fish in a blender or other sort of grinder. I know this presents an unpleasant image, but it is important that your sample for analysis is going to represent what the wildlife out there is actually eating. My understanding is the fish are generally in a frozen state before they are blended and these are not your kitchen blenders anyway, as they typically have titanium blades to prevent laboratory contamination of the sample. Once the fish samples are prepared, they are tested for a number of natural contaminants, including selenium, mercury, cadmium, and arsenic. They are also analyzed for a number of persistent organic contaminates like the pesticides toxaphene, mirex, lindane, endrin, endosulfan, dieldren, DDT, and chlordane. They are also analyzed for other persistent organic contaminants hexachlorobenzene (a fungicide), heptachlorepoxide (a degradation compound of the pesticide heptachlor), and different molecular weight hydrocarbons. Persistent is “environment talk” for organic chemicals that don’t readily degrade and stick around causing endless problems. Fortunately most of these are no longer used in the United States.

Next EPA sorted through a multitude of scientific laboratory studies conducted to establish contaminant concentrations that pose risks to birds, mammals, and fish. There’s currently a huge body of scientific work in this area. EPA wrote the guidelines for conducting ecological risk assessments way back in the 1990s and scientists have been developing data on fatal and sub-lethal contaminant exposure to wildlife ever since. You know that old saying “Whatever kills you makes you stronger?” Well it is definitely not true in the world of toxic contaminants. Sub-lethal in the case of toxic contaminants can have a variety of very nasty consequences for wildlife. Here’s your word for today: teratogen. A teratogen halts or deforms the development of an embryo or fetus. This is a sub-lethal effect.

Environmental scientists don’t use the terms lethal and sub-lethal. They use the terms acute for lethal and chronic for sub-lethal. The concentration of a contaminant known to have a toxicological effect on a wildlife species is called the Toxicity Reference Value or TRV for short. Because nobody wants to have a toxicological effect on wildlife, scientists generally look at only the exposure concentrations that show no observed adverse effects (NOAEL) on wildlife or the low observed adverse effects (LOAEL) on wildlife.

For the national coastal study, EPA looked at a variety of wildlife that all eat fish and developed a generalized NOAEL and LOAEL for the contaminants analyzed. I’m going to use two of the contaminants for comparison: selenium and arsenic. Most people when they think of arsenic, they’re thinking poison, right? Well look at this:

 

Birds Marine Mammals Marine Fish

 

Selenium NOAEL 0.27 0.15 11.04
LOAEL 0.53 0.24 14.75

 

Arsenic NOAEL 3.39 0.08 0.06
LOAEL 8.51 0.4 0.3

 

The numbers you see are in milligrams per kilogram or parts per million (ppm). For a bird the low observed adverse effect of selenium is at 0.53 ppm, while the low observed adverse effect of arsenic is 8.51 ppm. Selenium has a more toxic effect on birds than arsenic does. Marine mammals also have a low TRV for both selenium and arsenic.

But remember now, EPA is examining the condition of the fish and what the toxic impacts are on the birds, mammals and fish that are eating them, not at what level a particular wildlife species starts having toxic effects. They had to calculate what amount of a contaminant in a fish would pose a risk to birds, marine mammals, and marine fish. So they got their fish tissue NOAEL and LOAEL for the toxic impacts by taking the TRV for wildlife species, multiplying it by the general body weight and dividing it by the general amount of fish ingested. Yes they really did this. I know it sounds complicated and frankly the whole process makes my head hurt, but they came up with some figures they could screen fish for and say whether they were in good, fair or poor condition.

Here are the selenium numbers EPA developed for their report:

 

Contaminant Bird Marine Mammal Marine Fish
Fish Tissue Fish Tissue Fish Tissue
NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL
Selenium 0.29 0.57 259.68 428.48 11244.05 15016.72

These figures are again in milligrams per kilogram. Marine mammals like dolphins and seals and marine fish like tuna, shark and swordfish have larger body weights than birds so they can eat fish with a lot more selenium in them before they begin to have toxic effects. Birds also have a greater ingestion rate – they eat more just to keep their body weight up. I guess it takes more calories to fly than to swim around or walk.

So there you have it. EPA established their screening criteria for what constituted fair and poor fish quality based on the consumption of fish by birds.

Water Quality

Ocean Condition

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For a while now, I have been writing about changes to the earth’s oceans as a result of climate change. I’ve felt adrift in the ocean environment, having primarily worked on terrestrial surface and groundwater issues. So I prepared to launch myself into a vast number of research papers on ocean water conditions to update myself on the current science. Fortunately for me, EPA’s “National Coastal Condition Assessment 2010” was published in January of 2016. The report, although issued somewhat tardily, is a great snapshot of coastal water conditions in the U.S. and saved me from months of reading dry, poorly written journal papers. I was able to shift with the wind and set sail on a short excursion of only 103 pages to find out the condition of coastal waters in the U.S. EPA defines coastal waters as the estuaries, bays, wetlands, swamps, and open waters along the coastlines of the U.S.

 

This is EPA’s third assessment of the ocean waters of the U.S. The first two assessments were conducted in 1999/2000 and 2005/2006. So now, there is a ten year history of coastal water condition assessments. You can do a lot with this kind of data. You can see what the trends in water quality are. Is water improving or getting worse? If so why is that happening? And if it is getting worse, what further water programs do we need in the U.S. to stop coastal water degradation. After all it’s the activities here on terra firma that are affecting our coastal waters. We all learned rivers drain into oceans years ago in elementary school. Everything we do here on the ground eventually ends up in the ocean. Our wastewater treatment plants dump the treated sewage water back into our rivers, which then flow into the oceans. Our agricultural runoff and city storm water drainage all end up in the river and flow down to the sea.

 

EPA measured the condition of coastal waters using four different methods. First they looked at the health of biological communities living in coastal waters. Specifically they collected and counted the number of benthic organisms. Benthic organisms are the creepy crawlies hanging out in the sediment at the water’s bottom. You know these guys – worms, clams, that sort of thing. If they exist in large quantities then you have good coastal water conditions; ditto for surface water too. If you go into a stream and turn over a few rocks and don’t find some creepy crawlies underneath them, you probably have water quality problems. The existence of benthic organisms is an important indicator of the overall health of any water body.

 

Second they looked at the water quality itself and they used all those parameters which are used on terrestrial surface waters to determine if they are in good condition – nitrogen, phosphate, dissolved oxygen, water clarity – and additionally something called chlorophyll a. Chlorophyll a is the stuff that makes plants green. If you have a lot of chlorophyll a in coastal waters, it’s because you have a lot of algae. Too much algae means too many nutrients. It also means you probably have low dissolved oxygen at the bottom of the water where dead algae accumulate and start to “stank”.

 

The EPA also looked at sediment quality in their report. They had two measures for determining sediment quality: sediment contaminants and sediment toxicity. You’d think if you had the one, you’d have the other right? Well it doesn’t necessarily work that way. You can have low amounts of contaminants, but if you have contaminants the creepy crawlies really don’t like (especially in the fatal range of don’t like) that’s all it takes to end up with poor sediment quality. EPA collected sediment samples from the bottom of coastal waters and sent them to laboratories to be analyzed for metals, polyaromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs), organochlorine pesticides, and total organic carbon. The results are EPA’s measure of sediment contaminants in coastal waters. EPA also took the sediment and put it in a tank with ocean water in the laboratory. They then threw into the tank some different kinds of amphipods to see how they fared. Amphipods are these nearly microscopic creatures that look like shrimp but aren’t. They are scavengers which means they grub around in the sediment looking for dead things to eat. Basically the amphipods hang out for about 10 days in the tank. Some of their friends and family are put into another tank in the laboratory with nice clean sediment (this tank of amphipods is called the control.) After the 10 days, scientist count how many amphipods are left in the tank with the contaminated sediment and in the control tank. There are measurement standards for this sort of thing and the scientists can calculate based on the mortality rate of amphipods what the sediment’s toxicity is.

 

For its fourth and final measure of coastal water conditions, EPA analyzed fish tissue for contaminants. Not for the level of contaminants that are of concern to humans who eat fish, but for the level of contaminants of concern for wildlife that eat fish.  Humans eat fish just a few times a week, if at all.  Wildlife like otters, osprey, minks, and herons are eating fish all day long, every day of the year. Fish are their main food source.

 

EPA’s report covers the total coastline of the U.S., including the Great Lakes. Unfortunately this is the first year the Great Lakes were included in the study, so I’m excluding the Great Lakes’ data from this post, because there is really nothing to which the current condition of the coastal waters of the Great Lakes can be compared. For their report, EPA has divided the coastline into the Northeast Coast (from Maine to Virginia), the Southeast Coast (North Carolina to Biscayne Bay in Florida), the Gulf Coast (west coast of Florida all the way to the border of Texas with Mexico), and the West Coast which includes Washington, Oregon and California. That’s a lot of coast line; 35,400 square miles to be precise. And only 1,104 sites were sampled. When I saw that low number, I gave the whole study a wary eye. How could data from such a small number of sites adequately reflect coastal condition? Here’s how EPA does it: a statistical method is used which is similar to those used in political surveys. This kind of sampling methodology provides a statistically valid estimate with a known confidence level. Coastal sites can’t just not answer their phone, right? So such a survey should be even more precise than a political poll. Well not exactly. Unfortunately there is a lot of missing data, where scientists went out and tried to catch a fish at a particular study site, but couldn’t get one. Or a scientist couldn’t collect a sediment sample at a site because the site location was on a rocky coast. It depends on the coastline as to how much data is missing. EPA is working on improvements in data collection for their current 2015 report. But even with missing data there are still some clear trends, especially if you look at the individual coasts.

 

For example along the Northeast Coast only about 44% of waters were rated as having good quality, mainly because of the amount of phosphorous in the water. The amount of phosphorous in the water has increased on the Northeast Coast since the last survey in 2005/2006. Sediment quality has also deteriorated since 2005/2006, mostly due to sediment toxicity. Only 60% of the sediment sites sampled were rated as good quality sediments. However, the sediment toxicity doesn’t seem to be affecting much of the biological communities which have stayed about the same.

 

Coastal water in the Southeast is only rated good for about 21% of the sites sampled in 2010/2011. Frankly coastal water quality in the Southeast is just not very good due to the amount of phosphorous in the water. These waters are actually worse than those in the Northeast. Sediment quality has also decreased in the Southeast because of an increase in the amount of contaminants found in samples during 2010/2011 sampling. The Southeast sediment quality is rated good at about 65% of the sites sampled. Biological communities are only rated good at about 60 % of the sites sampled and really they haven’t changed much in the last 10 years.

 

It gets worse when you look over at the Gulf Coast. The Gulf coast hands down has the worst water quality in the U.S.  Only about 16 % of the sites sampled have good water quality. The culprit again is phosphorous. Water quality has declined significantly over the last 10 years because of increasing amounts of phosphorous. And the Gulf must be absolutely wracked with algae based on the chlorophyll a amounts, which are the highest of all coastal waters in the U.S. Not surprisingly sediment toxicity increased for the 2010/2011 assessment. A rather notable event occurred in April of 2010 when the Deep Water Horizon exploded and leaked oil into the Gulf for almost 3 months. There was a 15 % decline in good sediment quality among the samples taken in 2010 compared to the samples taken in 2005/2006. The EPA report states the biggest decreases in sediment quality in the Gulf were in the oil spill area as a result of sediment toxicity. However the EPA report can’t directly link the oil spill to the increase in sediment toxicity because of the limited contaminants the Agency samples for in these periodic coastal assessments. It’s a head scratcher, but then there are probably better studies out there related to the impacts of the Deep Water Horizon oil spill. One of the interesting findings is that biological communities on the Gulf floor actually increased from 2005/2006 to 2010/2011 – by a lot. The good rating went from 24% to 60 %. That is a significant change which is explained in the report as being a result of missing data from 2005/2006. Apparently 47% of sites were not sampled for benthic data during that timeframe.

 

The West Coast has the best water quality in the U.S. Some 64% of coastal waters there were in good condition. Again the big contributor to water degradation was phosphorous. There was a lot of missing sediment data; 19 % of sites were not sampled. In my book, that is probably too much missing data to really say much about the overall quality of sediments on the West Coast. There are a lot of mixed results from year to year for the West Coast. For example there was a 25% decline in water quality rated good between the 1999/2000 and the 2005/2006 event and then a 15 % increase in waters rated good quality from 2005/2006 to 2010/2011. Biological communities rated good showed a big decrease in 2010/2011 from 2005/2006, but then again there was a lot of missing data from 2010/2011; 21 % of sites were not sampled. So I find the changes a little suspect.

 

The other measure EPA looked at was fish. There were no coastal areas rated good for fish. Basically most of the fish were rated in poor condition: 42 % on the West Coast, 69 % in the Gulf, 57 % from the Southeast Coast, and 33 % on the Northeast Coast. The fish on every coastline of the U.S. are contaminated with selenium, mercury and arsenic to such an extent that they are simply not good for the wildlife in those areas to eat. EPA made the surprising assessment that it is selenium which is the most widespread contaminant exceeding fish tissue contaminant levels harmful to wildlife.

 

There are a couple of serious take aways from this report. One, all of our coastal water have a serious problem with phosphorous levels. Two, significant numbers of coastal fish have so much selenium in them that they are not healthy for the wildlife to eat.

 

Both phosphorous and selenium are natural elements which are widely distributed in soils and rocks. Phosphorous also comes from phosphate rock which is mined and processed for phosphate fertilizer. Phosphate fertilizer is applied to lawns and agricultural fields and without sufficient water management is carried into our streams and rivers as runoff. Interestingly selenium is also found in phosphate rock. Selenium runoff has been of great concern at the phosphate mines in Idaho. But selenium has many other sources too, including coal. EPA does not speculate on the source of the selenium found in the fish tissue.

General

Ocean Acidification – Climate Change

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When I took my first graduate level physical chemistry class many years ago, I had a professor who spent several lectures demonstrating how the human emission of carbon dioxide through the burning of fossil fuel could not contribute to the accumulation of greenhouse gases in the atmosphere and cause atmospheric temperatures to rise. His chemical equations showed how ocean water reacts with carbon dioxide in the atmosphere and essentially removes it.  The chemical equations for this exchange are actually very simple and quite well known. Carbon dioxide, which is CO2 (carbon and oxygen), reacts with water, which we know is H2O (hydrogen and oxygen), to form carbonic acid (H2CO3). Carbonic acid then further reacts with ocean water to produce bicarbonate (HCO3) and free hydrogen ions.

You’re thinking, we’re saved! We don’t have to worry about those carbon dioxide emissions from power plants and cars anymore. Let’s pump more oil and gas out of the ground and to heck with driving a Prius. Where’s my Hummer?

Well not so fast. My physical chemistry professor forgot to explain to us what happens to the ocean after this chemical exchange. What do we remember about free hydrogen ions? They are a measure of acidity. Remember pH? It is a scale of measurement from 1 to 14 where 7 is neutral. Anything below 7 is acidic and anything above 7 is basic. The pH of a solution is simply a measure of free hydrogen ions. The more free hydrogen you have, the more acidic your solution. So when the ocean reacts with carbon dioxide from the atmosphere, it is becoming more acidic. This is what is known as ocean acidification.

The pH of the oceans range from 7.8 to 8.4. So right now seawater is mildly on the basic side. The pH of the oceans is something scientists have been measuring for a long time. The change in the pH of the ocean can also be calculated based on man’s carbon dioxide emissions. Scientists have made an inventory of greenhouse gas emissions dating as far back as the start of the industrial age. Such inventories are not your most accurate of measures, especially when you are looking at emissions from several hundred years ago, but if anything they are probably undercounting emissions. The International Panel on Climate Change in their 2013 Report “The Physical Science Basis” states that currently the amount of total carbon dioxide from human emissions being stored in the ocean is 30 %. According to calculations using such inventories there has been a 0.08 decrease in pH in the ocean’s surface water between 1765 and 1994.

Direct measurement of pH taken since 1991 in the North Atlantic and North Pacific have shown a steady decrease ranging between ‾0.0014 and ‾0.0024 per year. These numbers reflect regional variations in pH decreases. The IPCC report states the variability in the decline of pH is a reflection of high latitude oceans not as effectively absorbing carbon dioxide.

The pH decreases seem tiny don’t they? But think about this. Oceans cover almost three-fourths of our planet; that is a lot of water. The fact that carbon dioxide emissions can change the pH of the entire surface water of the ocean every year by even these tiny amounts is phenomenal. Say you took the mid-range of this yearly decrease (‾0.0019) and multiply it by 1000 years. You would be looking at almost a pH decrease of 2 by the year 3016. You would be going from slightly basic ocean water to slightly acidic ocean water, just from human carbon dioxide emissions.

On the short term there are a lot of scientific researchers who are studying the impacts that these slight yearly decreases may be causing. None other than the National Academy of Sciences has weighed into the impacts of ocean acidification by developing  “A National Strategy to Meet the Challenges of a Changing Ocean (2010).” Ocean Acidification is a big concern of scientists, after all humans are changing the very chemistry of the earth’s oceans.

General

Ocean Salinity – Climate Change

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Have you ever read the folktale “Why the Sea is Salt?” It’s a cute little story about a magic handmill spirited away from Satan himself by an unfortunate thief. While hiding behind the door to hell, the thief sees the devil order the handmill to produce all sorts of lavish food and objects. Once he gets his hands on the magic handmill, the thief escapes by boarding a boat and setting sail. The devil had directed the handmill by simply saying “handmill grind…,” so the thief proceeds to tell the magic handmill to grind gold. Unfortunately for the thief, only Satan can make the handmill grind luxuries. For everyone else, the magic handmill just grinds salt. Once the handmill starts grinding salt, the thief realizes he’s forgotten the words the devil used to get the handmill to stop. The salt from the handmill overloads the boat and it sinks to the bottom of the ocean where the handmill keeps on grinding out loads of salt even today.

It’s a nice legend, but in reality we all know the main mechanism causing the sea to be salty is the erosion of minerals from rocks and soils. The eroded minerals are flushed down rivers and streams and deposited in the oceans. There’s also some contribution of minerals to the oceans from volcanic eruptions both above and below sea level. (Yes there are volcanic eruptions from the ocean floor.) The minerals in the ocean are concentrated by evaporation of freshwater from the ocean’s surface. Some of these minerals like calcium and carbonate are used by organisms to form shells. Other minerals are used as nutrients. Only the minerals which are not actively used by organic life in vast amounts are left behind. As you might guess the largest component of the dissolved solids left in the oceans are chloride and sodium, the components of salt. Useful for seasoning French fries but not much else.

With all you’ve heard in the media about the melting glaciers and the polar ice sheets, you would think the ocean was getting less salty, right? After all, the freshwater from all this ice is going into the ocean and scientists say that at least half of sea level rise is being caused by melting ice. Surely this addition of freshwater is having an impact.  In reality though the contribution of melting glaciers to salinity changes in the oceans is not as great as you might think, because there are a whole lot of other things going on between the oceans and the atmosphere which are far more influential on how salty the water is. The International Panel on Climate Change (IPCC) in their 2013 report “The Physical Science Basis” states that the oceans are getting saltier in some locations and less salty in others. For example the Atlantic Ocean is becoming saltier and the Pacific Ocean is becoming fresher.  Interestingly enough, the Atlantic has always been saltier than the Pacific. Why? It is that old hydrologic cycle of evaporation and precipitation. It just rains more in the Pacific.  Low salinity is found in areas where precipitation exceeds evaporation and runoff from rivers and streams. High salinity is found where evaporation exceeds precipitation and runoff.

Increases in atmospheric temperature as part of climate change increases this overall hydrologic cycle. Think about it. Warmer air holds more moisture than dry air. The IPCC cites that the atmosphere can actually hold about 4 % more water vapor for each degree Fahrenheit the temperature increases. Scientists have been recording atmospheric vapor since the 1970s and the data show increases in atmospheric water vapor. So essentially, it is raining more in warm areas of the Pacific Ocean and raining less in mid latitude areas of the Atlantic Ocean. The IPCC report notes that surface salinity of the tropical Pacific Ocean has declined by 0.1 – 0.3 parts per thousand over 50 years in the western equatorial regions and by up to 0.6 – 0.75 in the intertropical and southern Pacific. The subtropical Atlantic is saltier by 0.1 – 0.3. Polar regions also get more precipitation in the form of both ice and snow, so the ocean water in the arctic regions is becoming fresher as well, although I didn’t see an exact number in the IPCC report.

Interesting right? But exactly how vital is the role of salinity in the oceans? Colder water is denser than warmer water. Denser water sinks. In the arctic, cold fresh water sinks and spreads toward the equator, supplying the deeper ocean with freshwater and reducing salinity. It is a process that impacts the oceans circulation and ocean circulation impacts our climate. Fresh water is less dense than salty water. Will the freshening of the waters in the arctic impact the movement of polar waters in some way? Will increasingly dense salty water in the subtropics result in changes to the composition of deeper water? Now we are entering the realm of speculation. Other scientists don’t hesitate to speculate on possibilities. No less an august organization as the National Science Foundation speculates that based on research they funded back in the early first decade of the 21st century  fresher water at the northern pole could impact ocean circulation in the North Atlantic, in particular the Gulf Stream, and consequently weather in the Northern Hemisphere.

The impact of the Gulf Stream on North Atlantic climate appears to be as much of a myth as the thief’s magic handmill, according to the Lamont Doherty Earth Observatory at Columbia University. Here is a link to an article on why the Observatory says it is a myth:

http://www.ldeo.columbia.edu/res/div/ocp/gs/.

So I will leave speculation about the impacts of changes in ocean salinity to earth’s climate for someone else.