Thursday, August 17, 2017

Total Eclipse of the Sun

On Monday, August 21, 2017, all of North America will be able to see an eclipse of the sun. Anyone within the path of totality from Salem, Oregon to Charleston, South Carolina can see a total solar eclipse. The path of totality is where the moon will completely cover the sun making the sun’s corona visible.

The shadow of the moon enters the United States near Lincoln City, Oregon, at 9:05 a.m. PDT. Totality begins in Lincoln City, Oregon, at 10:16 am PDT. The total eclipse will end and hour and 2 minutes later in Charleston, South Carolina, at 2:48 p.m. EDT, though the lunar shadow will linger in the United States until 4:09 p.m. EDT. A partial eclipse will be visible throughout the United States. Here in Virginia we will see a partial solar eclipse where the moon covers about 85% of the sun's disk.

Looking directly at the sun is unsafe except during the brief total phase of a solar eclipse (“totality”), when the moon entirely blocks the sun’s bright face, which will happen only within the narrow path of totality and only during the window of complete coverage which is about 2 minutes 40 seconds. Otherwise you must protect your eyes and vision. The only safe way to look directly at a partially eclipsed sun is through special-purpose solar filters, such as “eclipse glasses or hand-held solar viewers.

Homemade filters or ordinary sunglasses, even  dark ones, are NOT SAFE for looking at the sun; they transmit thousands of times too much sunlight. Eclipse glasses and handheld solar viewers must be verified to be compliant with the ISO 12312-2 international safety standard for such products. However, there have been reports in the news of large numbers of fake solar glasses. It's not enough today to just look for the ISO 12312-2  certification, as many vendors have started printing fake glasses with ISO 12312-2  certifications. At this point, if your have not purchased solar glasses from a vendor from the approved list of the American Academy of Ophthalmology or NASA it’s probably too late and you should protect your eyes and view the eclipse on NASA’s web site or through a pinhole projector as we did when we were kids.

As described on NASA’s web site, a convenient method for safe viewing of the partially eclipsed Sun is pinhole projection. You simply pass sunlight through a small opening (for example, a hole punched in an index card) and project an image of the Sun onto a nearby surface (for example a piece of printer paper). See the NASA website for full instructions. I will be inside viewing the eclipse on-line. There is also lots of fun information about science data gathering that will take place during the eclipse.

Do not look at the  partially eclipsed sun through an unfiltered camera, telescope, binoculars, or other optical device- even if you are wearing eclipse glasses. The magnification will damage the eclipse glasses and damage your eyes. Be safe.


Monday, August 14, 2017

Conowingo Dam and the Chesapeake Bay

Last week Governor Hogan of Maryland announced that Maryland will request bids to test dredging and reuse of the dredged material from the Conowingo Dam reservoir. The test will involve removing about 25,000 cubic yards of sediment and is estimated to cost $4 million. This is the first step to remove 31 million cubic yard of sediment that have almost filled the reservoir which Maryland has estimated will cost $250 million to dredge. Dredging the reservoir is essential to protect the Chesapeake Bay.

The Conowingo Dam is a large hydroelectric dam on the Lower Susquehanna River about 10 miles upstream from where the river flows into the Chesapeake Bay at Havre De Grace, Maryland. The three dams at the downstream end of the Susquehanna River have been important in mitigating the downstream transport of nitrogen, phosphorus, and suspended sediment from the Susquehanna River watershed to the Chesapeake Bay. The Conowingo, the last dam in a series of three traps polluted sediment from the Susquehanna River in its 9,000 acre reservoir.

The U.S. Environmental Protection Agency (EPA) placed a contamination limit called the TMDL (total maximum daily load for nutrient contamination and sediment) on all the states in the Chesapeake Bay Watershed and Washington DC. The TMDL sets a total limit for the entire watershed of 185.9 million pounds of nitrogen, 12.5 million pounds of phosphorus and 6.45 billion pounds of sediment per year that represents a 25% reduction in nitrogen, 24% reduction in phosphorus and 20 % reduction in sediment from the 2011 levels. The pollution limits were then partitioned to the various states and river basins based on the Chesapeake Bay computer modeling tools and monitoring data.

When the EPA allocated the nitrogen, phosphorus and sediment reductions among the Chesapeake Bay states, the EPA believed that the Conowingo Dam would continue to trap polluted sediment for an additional quarter of a century and counted the sediment and nutrient removal of the Conowingo Dam in the design of the nutrient and sediment reductions. Subsequent studies by the U.S. Geological Survey (USGS) and the Army Corps of Engineers found that sediment was gathering at the dam at a faster rate than assumed by the EPA’s model.

The three dams on the lower Susquehanna River (Safe Harbor, Holtwood, and Conowingo) and their associated reservoirs (Lake Clarke, Lake Aldred, and Conowingo Reservoir) have been the topic of a number of studies (Langland, 2009; Langland, 1998; Langland and Hainly, 1997), all of which generally conclude that the pools behind the dams were on a long-term trajectory to becoming filled. Recently, the USGS has concluded that the dam’s sediment reservoir is almost full. There are nearly 200 million tons of sediment, nutrients, and other pollutants from the Susquehanna River trapped behind the dam.

Analysis of water-quality data collected during the large flood in the aftermath of Tropical Storm Lee (September 2011), as well as high flows that occurred in March 2011, indicate a significant decrease in the effectiveness of the reservoir system at trapping nitrogen, phosphorus, and sediment. Rather than reaching capacity in 2030 to 2035 as originally projected by the EPA, the Conowingo Dam is already 95% full and will be full and cease protecting the bay from sediment within the next three years.

The Conowingo Dam will no longer be able to trap sediment in the Susquehanna River and prevent them from entering the Chesapeake Bay. The Susquehanna River flows 464 miles from Cooperstown, New York to Havre De Grace, Maryland collecting sediment and nutrient runoff along the way. The Susquehanna drains an area of more than 27,000 square miles and is the single largest source of fresh water flowing into Chesapeake Bay. The river currently provides nearly half of the Bay’s freshwater, 41% of its nitrogen, 25% of its phosphorus and 27% of its sediment load. Without the Conowingo removing sediments containing nitrogen and phosphorus before the waters reach the Chesapeake Bay that contamination load will increase.

EPA can’t just assign increased reductions to Maryland, Pennsylvania and New York. The sources of most of this sediment is non-point source in origin. To meet the long term goals of the Chesapeake Bay TMDL needs the Conowingo Dam to trap excess sediment from the river –it is the cheapest way to meet the goals.

Also, the Conowingo Dam cannot be left full. It will not exist in some gentle equilibrium. The Conowingo and its sister reservoirs will not be constantly filled to capacity with sediments because of short-term changes from severe storms that cause scour and a subsequent reduction in exported sediments until the scoured amount is refilled. Therefore, the amount of sediment transported out of the reservoirs will not always be in equilibrium with the amount of sediment transported into the reservoirs.

After large storm events there will be plumes of sediment and nutrients released into the river and the Chesapeake bay damaging any progress made by the TMDL program. However Governor Hogan works out who will contribute to the costs, the Conowingo Dam needs to be dredged.

Thursday, August 10, 2017

Climate Change, Rain and Nutrient Pollution

According to the National Oceanic and Atmospheric Administration (NOAA) global temperature has risen about 1 degree Celsius from pre-industrial times. Last year, reported to be the warmest year on record, was also the year that representatives from more than 175 countries gathered at the United Nations on Earth Day to sign the Paris Climate Accord.

The current administration has withdrawn the United States from the agreement. Even with the United States the Paris Accord lacked any clear path on how the nations would meet the goal to maintain global temperatures within 2 °C increase above pre-industrial temperatures. The carbon reductions committed to under the agreement are woefully inadequate to meet that goal, and neither China nor India who combined represent about a third of world greenhouse gas emissions have committed to any reductions. Instead those two nations are merely projecting when (not even at what level) their greenhouse gas emissions will peak.

If climate change progress, (and really, there are no realistic plans to stop it) most climate models are forecasting a significant increase in precipitation in the northeastern corridor of the United States including Virginia. At least we’ll have water, but all that rainfall can bring other problems. Rainfall and other precipitation washes nutrients from human activities like agriculture, lawns, septic systems and other activities into rivers and lakes. When these nutrients overload waterways, a process called eutrophication occurs. The results of this process can be dangerous to water quality when toxin-producing algae blooms develop and low-oxygen dead zones develop. We are all familiar with the annual dead zones and algae blooms in coastal regions including the Gulf of Mexico, the Chesapeake Bay and Florida.

In a recent study published in Science magazine Dr. Sinha and Dr. Michalak used models to predict how climate change might affect eutrophication. The two build on their earlier work where they found that, while land use and land management control the supply of nitrogen, precipitation controls how much of that nitrogen flows from the land into waterways. More rain more nitrogen and phosphorus pollution flows into waterways and estuaries.

In the current study, the scientists used these insights to predict how future changes to precipitation caused by climate change will, in and of themselves, affect nitrogen runoff and thereby increase the risk of water quality impairment in the United States.

Their modeling found that the mean projected increase in nitrogen loading within the continental United States is projected to be 19% with the Northeast projected to increase 28% and the Upper Mississippi Atchafalya River Basin project to increase 24%. In the Chesapeake Bay Watershed, the EPA has mandated a contamination limit called the TMDL (total maximum daily load) for nitrogen, phosphorus and sediment. The TMDL sets a total limit for the entire watershed of 185.9 million pounds of nitrogen per year which is a 25% reduction in nitrogen from 2011 levels. Increased rainfall will make meeting and maintaining those goals more challenging.

So far Virginia is on track to meet the midpoint goals for nitrogen reduction set by the EPA. We did it by having spent about $2 billion from 1998-2017 to upgrade the waste water treatment plants in the watershed. That was expensive, but easy to achieve reductions- we knew how to do it.

The remaining areas for reducing nitrogen for the midpoint evaluation and the 2025 goals are in the agricultural, suburban and urban storm water management. These are harder targets to hit because the sources of pollution in these areas are non-point source pollution (NPS), diffuse sources of pollutionthat are carried to streams and rivers by runoff of rain and snowmelt.

The way to reduce non-point source pollution in the environment is to control stormwater and implement what is called “best management practices” (BMPs). BMPs have mostly been used in the agricultural sector. Virginia made great progress towards the EPA goal in management of livestock. A huge program carried out by the Soil and Water Conservation Districts to induce all animal operations to fence all pastures to exclude all livestock from rivers and streams and provide alternate sources of water for the animals away from rivers and streams. There are also BMP to slow storm water, limit fertilizer use and limit or eliminate tilling.

To protect our waters with the forecast increase in precipitation the Soil and Water Conservation Districts will have to introduce programs for suburban neighborhoods and communities and keep improving and expanding those programs. We can’t stop the rain, but we can prepare for it.


Monday, August 7, 2017

Montgomery Pesticide Ban Struck Down

Last week the Montgomery County Circuit Court Judge Terrence McGann struck down the county's ban of nonessential pesticide usage on private and public property. The Judge issued a summary judgment in favor of the plaintiffs; lawn care companies and private property owners who opposed the 2015 county measure. The ban, Bill 52-14 would have gone into effect Jan. 1, 2018 and would have banned the ornamental use of pesticides including Roundup and 2,4 D as well as hundreds of others.

Bill 52-14 restricted the application of pesticides on County-owned and private lawns down to 100 square feet. The law included all pesticides classified as "Carcinogenic to Humans" or "Likely to Be Carcinogenic to Humans" by the U.S. EPA; all pesticides classified by the U.S. EPA as "Restricted Use Products;" all pesticides classified as "Class 9" pesticides by the Ontario, Canada, Ministry of the Environment; all pesticides classified as "Category 1 Endocrine Disruptors" by the European Commission; and any other pesticides that are determined not to be critical to pest management in the County. Pesticides, including herbicides, insecticides, fungicides, and rodenticides, used to simply prevent blemishes and other imperfections on private and public lands are banned.

In his opinion Montgomery County Circuit Court Judge Terrence McGann said the county ordinance conflicted with state laws regarding pesticides, which would have pre-empted the county’s ability to pass pesticide regulations. Stating in the opinion: “The Ordinance prohibits the use of registered pesticide products that Maryland law permits, and in doing so, it simultaneously undermines the express purpose of State law to promote uniformity between Maryland pesticide requirements and those adopted by EPA and other states. The Ordinance prohibits and frustrates an activity intended to be permitted by State law.”

Judge McGann ORDERED that Plaintiffs’ Motions for Summary Judgment GRANTED; and further ORDERED that Bill 52-14 as it regards the use of pesticides on private property, shall not take effect, and Plaintiffs are entitled to permanent injunctive relief from the enforcement of these sections.

The Montgomery County ban on cosmetic use of herbicides and pesticides was intended to protect children based on their belief that children may be more at risk of developing health problems from pesticides because:
• Their activities lead to more exposure e.g., playing in the grass, putting their hands or toys in their mouths.
• They are closer to the ground and breathe in higher amounts of pesticides.
• Proportional to their weight, they breathe in more air and consume more food and drink than do adults.
• Their immature metabolic systems cannot break down toxins as effectively as adults.
• Their bodies are rapidly growing and developing and potentially impacted more strongly by endocrine disruptor effects.

With the exception of nitrogen, there has been no direct evidence linking pesticides to diseases in humans. Though, an increasing number of health and environmental groups are claiming that these chemicals do indeed impact human health. A wide range of chemicals are used to treat everything from pests to mold in household gardens. One of those is 2, 4-D, used by cereal crop producers and commonly found in household weed killers. It has been the subject of an extensive study by Health Canada which determined that, when used properly, it is safe. Organizations like the Sierra Club and the Canadian Cancer Society, which strongly support a ban on cosmetic use of pesticides and herbicides, disagree. However, no specific research linking the currently used ornamental pesticides to disease in humans was found.

The only documented study to find a disease link to 2,4-D was done in the United States, a 1991 National Cancer Institute study examined dogs whose owners' lawns were treated with 2,4-D four or more times per year. The study found those dogs had double the risk of developing canine malignant lymphoma than dogs whose owners do not use the herbicide.

In addition, glyphosate (N-phosphonomethylglycine), the active ingredient in the herbicide Roundup and the most popular herbicide in use today in the United States was labeled a probable carcinogen by the International Agency for Research on Cancer, IARC, in 2015. Americans spray an estimated 180-185 million pounds of the weed killer, on their yards and farms every year. All the acute toxicity tests have found that glyphosate is nearly nontoxic to mammals; however, there have been for some time a minority of scientists and experts who believes that glyphosate may be more toxic than is claimed and pushed for additional  studies impacts to human health from low level constant exposure to glyphosate.

Thursday, August 3, 2017

Human Waste and Disease

Human excrement can carry disease such as cholera, diarrhea, dysentery, hepatitis A, typhoid and polio. In the developing world, a case of diarrhea can be life threatening. Sanitation is what makes modern cities and towns possible without the consequences of disease and possibly death. There are 7.5 billion people on earth. In 2015, only 40% of the earth’s population (2.9 billion people) had the use of a toilet or improved latrine with a system in place to ensure that excreta are treated or disposed of safely. Though 68% of the world’s population (5.0 billion people) used at least a basic sanitation service, that leaves 2.3 billion people who still do not have the most basic sanitation facilities such as toilets or latrines. 

Of these, almost 900 million still defecate in the open, in open fields, street gutters, behind bushes or into open bodies of water. Open defecation perpetuates a vicious cycle of disease and poverty. In the countries where open defection is most widespread they have the highest number of deaths of children under 5 years old as well as the highest levels of malnutrition and poverty.

Open defecation is as old as humankind. As long as population densities were low and the earth could safely absorb human wastes, it probably caused few problems. As more people gathered in towns and cities diseases spread. Mankind gradually learned the link between hygiene and health and, in particular, the importance of avoiding contact with feces. Today open defecation is declining worldwide, but of the nearly 900 million people still defecate in the open, over 550 million of them are reported to live in India. In India it is reported that almost 120,000 children under 5 years old die each year from diarrhea. Children are dying from diarrhea. Untold numbers suffer with chronic intestinal infections that reduce nutrient absorption and result in stunting.

In India and worldwide open defecation perpetuates a vicious cycle of disease and poverty. Globally most of the people who engage in open defecation live in rural areas, and that is true in India also. However, in India there is reported to be over 150 million urban slum dwellers that lack sanitation facilities and the number is rising. The situation of the urban poor poses a growing challenge as they live increasingly in slums where sewerage is precarious or non-existent and lack clean and safe water.

In the rural areas of India, in particular, cultural taboos and beliefs seem to perpetuate open defecation even when latrines have been installed. Since 1990 India has been engaged in various missions to build latrines in rural India and end open defecation. Under Prime Minister Modi there has been $40 billion allocated for latrine-building and education. The current program is called Swachh Bharat Abhiyan (Clean India Mission). This program follows the Nirmal Bharat Abhiyan (Total Sanitation Campaign) is a program in India to provide subsidies ($190 per pit latrine) for the construction of household toilets for those at and near the poverty level to prevent diarrhea, soil-transmitted helminth infection, and child malnutrition and stunting of growth.

From May 2010 until December 2013 the Bill and Melinda Gates Foundation funded a study to assess the effectiveness of installing rural household latrines in India under the Nirmal Bharat Abhiyan in preventing diarrhea, soil-transmitted helminth infection, and child malnutrition. The study attempted to investigate the effect of the installing latrines as actually delivered by the foundation and its local partners working in India within the Nirmal Bharat Abhiyan.

The study findings cast doubt on the health effect of the Nirmal Bharat Abhiyan that focus only increasing latrine construction but do not end open defecation or address other sanitation issues that might reduce other possible sources of exposure fecal contamination. Although latrine coverage increased substantially in the study villages to levels targeted by the campaign, many households did not build latrines and others were not functional at the time of the follow-up.

The study findings showed no evidence that the Nirmal Bharat Abhiyan program in rural Odisha reduced exposure to fecal contamination or prevented diarrhea, soil-transmitted helminth infection, or child malnutrition. The study found that the program was a failure and had no impact on health. These findings are consistent with another study performed in India in the Indian state of Madhya Pradesh, but in contrast to results found with improved sanitation and hygiene in other world programs.

The study found that householders with access to latrines did not always use them. Open defecation remained practiced by widely practiced by men and children in homes with latrines. The problem experienced were unique to India. Before any program can succeed India needs to address the underlying cultural acceptance of open defecation, before they can make any progress in improving childhood health and the eliminating the widespread stunting of growth in Indian children. Latrine use was nearly five times higher for women than for men or children in the study, but the study results show that the health benefits generally associated with sanitation cannot be assumed simply by construction of latrines.