Many erosion and sediment control contractors work under urgent schedules. Whether the site is already on the critical list or impending storms will place it there, rainfall is usually the foe that forces contractors into high-speed action.
However, lack of rain – a slower, less dramatic scenario – also causes erosion. Dry, eroding soil, often less noticeable at the site than it is downwind, turns into airborne dust that can cause problems ranging from mild aggravation to chronic health ailments.
In the 1930s, before widespread erosion control, periods of drought and the resultant lack of ground cover turned the agricultural mid-South into the notorious Dust Bowl. Estimates report that thousands of tons of topsoil relocated from Oklahoma and Texas to states east; it’s not known, however, just how many respiratory problems were also caused by the dust storms.
These days, the very nature of dust makes it more noticeable – and the cause of more citizen complaints – than water-caused erosion. The degradation caused by a rain-washed site might inconvenience only direct neighbors; fugitive dust can often be seen – and complained about – for miles. The range of airborne dust also places it into the purview of local, state, and federal air-quality jurisdictions.
In addition, because EPA intends to include particulate matter in its Air Quality Indices, citizens will be made more keenly aware of dust and its possible impact upon their health, which will likely spawn more complaints and possibly more stringent local legislation.
Dust – Weather or Not
Despite the best-laid erosion control plans, weather makes the largest impact on the amount of fugitive dust whirling through the air. Drought conditions in many parts of the United States during 1996-1999 and 2002 created fugitive dust from long-vegetated but parched recreational and residential areas. Not only was the nation short on rainfall, but many communities also restricted or prohibited the lawn watering that might have suppressed some dust.
Global weather patterns also transport dust from one country, or from one continent, to another, spreading not only particulate matter but also soil pathogens that can harm plant, animal, and human life. In 2001, the National Oceanic and Atmospheric Administration reported that sediment from a dust storm in northern China reached North America, leaving a layer of dust from Canada to Arizona, while airborne dust clouded views of the Rocky Mountains.
Realizing that erosion and its fugitive dust in other countries can affect US skies, EPA coordinates environmental cooperation projects (air quality, public health, climate change) with the People’s Republic of China. US-supplied air-monitoring equipment has been established in 11 Chinese cities and provides the public with daily air-quality reports. Local officials in those cities have also been trained in air-quality monitoring and forecasting. Twenty-two additional Chinese cities are currently being equipped with air-monitoring equipment.
Not All Dust Is Dirt
Stone dust can be particularly troublesome. This spring, Cincinnati, OH, ABC-TV affiliate WCPO investigated a fugitive-dust dispute between Sterling Ventures Mine in Gallatin County, KY, and homeowners in adjacent Boone County. Although, in the past, residents of the northern Kentucky Boone, Campbell, and Kenton Counties had successfully defeated plans to locate limestone mines within their jurisdictions, in 1998 Sterling Ventures Mine won permission to mine in unzoned Gallatin County, just hundreds of yards from dozens of Boone County homes. During a packed 1997 state public hearing on the proposed mine, Sterling’s ownership promised homeowners they wouldn’t hear blasting.
Not only are the homeowners hearing blasting day and night, they’re also subjected to constant dustfall that they believe is beginning to affect their health. To prove the dust that covers their yards and homes is from the mine, homeowners not only videotaped dust leaving the mine’s property (an EPA infraction) but also hired a certified industrial hygienist to test the ambient air. It was discovered that the dust contained elevated levels of crystalline silica in the form of quartz, a known health hazard. Despite many EPA citations for airborne dust pollution, Sterling Ventures Mine’s owner insists that even his employees have no respiratory problems and “don’t need a breathing apparatus or a mask or anything.” The neighbors beg to disagree; many are now suffering from asthma, restricted breathing, and silicosis, and a few, despite being nonsmokers, have developed emphysema.
While trying to lodge complaints against the mine, homeowners have run into several jurisdictional walls, the first of which is that the polluter is in a different county than the complainants. At the state level, homeowners discovered that different types of pollution had to be reported to a variety of Kentucky government agencies. Airborne dust must be reported to the Air Quality Section of Kentucky EPA. The Division of Water monitors dust that pollutes creeks and cisterns. If fish die in affected streams, the Kentucky Department of Fish and Wildlife takes the call. Dust from uncovered trucks is the responsibility of the Kentucky Department of Transportation, blasting is overseen by the state’s Department of Mines and Minerals, and noise pollution is regulated by still another agency.
“Under the Clean Air Act, the primary delegation of responsibility lies with the state,” says David Lloyd of the Air Enforcement Section of EPA’s Region 4, which includes the state of Kentucky. “The state has various districts the inspectors work out of. They’re the front-line folks who work within the State Implementation Plan.”
There are separate regulations for fugitive emissions. What if a strong storm blew the limestone dust into the Ohio River or neighboring Ohio or Indiana? “The state of origin would be responsible for the cleanup,” Lloyd explains. “Of course, with an interstate pollution problem, then maybe we would get involved. Everything is determined on a case-by-case basis. There are two things to do in such a situation. Reasonable precautions must be taken to keep dust and emissions from being created in the first place, and then you don’t want it to cross your property boundary. Of course, the first step the Boone County homeowners should do is contact the state. However, that doesn’t mean Region 4 doesn’t touch base with the state.”
In May, WCPO-TV sent video of its investigative report to Kentucky’s top environmental official, Cabinet Secretary Hank List, who told the TV station he’d “personally investigate” the Sterling Venture Mines situation. The homeowners, who have filed suit against the mine owner, are currently in a court-ordered mediation with Sterling Venture Mines. If no settlement is reached, the suit is slated to be heard in November.
Do Erosion Control Measures Themselves Pollute?
Common erosion control techniques – straw blowing and hydroseeding – came under fire last spring in northern California’s Placer County. The county’s Air Pollution Control District (APCD) fined an erosion control contractor for creating dust in Auburn, CA, while blowing straw on a calm day. In April, Placer County enacted the “fugitive dust” Rule 228, which restricts any dust from leaving one property and entering another. The rule, which was enacted in response to continued poor air quality and a perceived need for stricter compliance rules for construction-related dust, is currently being enforced primarily after complaints have been received. However, the rule offers no objective measures of how much is “too much” dust.
During a public meeting held before Rule 228 went into effect, erosion control contractors not only informed Placer County’s APCD board that straw mulch application is a widely used erosion control best management practice specified by public and private entities alike but also pointed out that the state’s Regional Water Quality Control Boards consider straw mulch application to be one of the more effective erosion control practices. A staff member in Auburn’s Public Works Department acknowledged the dilemma of enforcing water- and air-quality standards and strongly suggested that county agencies resolve contradictory regulations. Although the Placer County APCD approved Rule 228, it established a three-month period to review options and further educate everyone affected by the rule, and it decided to forego air pollution fines for six months on straw blowing and hydroseeding operations. The APCD plans to meet with the California Department of Transportation, the Regional Water Quality Control Board, and local erosion control contractors to develop and implement local guidelines.
Dust – Soon Appearing on the Nightly News
“There are different rules for different situations,” says EPA Region 5 Environmental Scientist John Summerhays. “My section’s job is to make sure states are upholding our regulations. States submit rules, which we judge, and then we just make sure the rules are implemented.”
One of Summerhays’s areas of expertise is particulate matter. “We oversee air-quality particulate-matter standards, the regulations written for that purpose. There are two main kinds of dust – larger and smaller – and due to the concentration of the size range of particles, we’re moving our focus to particulate matter 2.5 microns and smaller. Yes, a 10-micron particle is small – the average human hair is 70 microns thick – but a 10-micron particle gets trapped higher up in the respiratory system. Particles 2.5 microns and smaller get inhaled deeper into the lungs and have a stronger correlation to health problems.
“We have been doing the Air Quality Index, which you’ll see in national newspapers and perhaps on the local weathercasts. And we’ve started to do predictions, forecasting – mainly for ozone, but we’re gearing up to do the same for particulate matter.
“Unfortunately, we can’t yet answer all the questions we’d like to answer. As it’s pretty difficult to find out exactly what’s in particulate matter, we’ll measure total mass of particles, not specific items such as sulfates/nitrates, acid rain, car emissions, agricultural burning, or some dusts. We’ll issue a report for whichever pollutant we expect to be worst. We’re hoping to introduce this new Air Quality Index in many cities nationwide sometime later this year.”
The current EPA AIRNow forecast map is available on the Web at www.epa.gov/cgi-bin/airnow.cgi?MapDisplay=FOREMAP.
