Featured Research

from universities, journals, and other organizations

Pavement Sealcoat A Source Of Toxins In Stormwater Runoff

Date:
April 14, 2009
Source:
University of New Hampshire
Summary:
Driveways and parking lots may look better with a layer of sealcoat applied to the pavement, but the water running off the surface into nearby streams will be carrying more than just oxygen and hydrogen molecules. New research indicates that sealcoat may contribute to increasingly significant amounts of polyaromatic hydrocarbons entering waterways from stormwater runoff.

Sealcoat applied to pavement may be contributing to PAHs in stormwater runoff.
Credit: UNH Stormwater Center

Driveways and parking lots may look better with a layer of sealcoat applied to the pavement, but the water running off the surface into nearby streams will be carrying more than just oxygen and hydrogen molecules.

New research conducted at the University of New Hampshire Stormwater Center (UNHSC) indicates that sealcoat may contribute to increasingly significant amounts of polyaromatic hydrocarbons entering waterways from stormwater runoff.

Polyaromatic hydrocarbons, more commonly known as PAHs, are found in diesel and crude oil and are considered to be carcinogenic. Although small amounts of PAHs are typically found in the waters around the New Hampshire Seacoast, the sudden spike in the hydrocarbon concentrations in water draining from a university parking lot used for research caused Tom Ballestero, UNH associate professor of civil engineering, to be concerned about unknown impacts.

"Our society has been sealcoating pavement for decades and there are things we've never asked about," he says. "Now we're starting to probe and ask these questions."

Although it is intended to remain on the pavement surface, much of the sealcoat eventually washes or scrapes off and ends up in nearby streams and rivers, says Alison Watts, affiliate faculty member at the UNHSC. The PAHs from the sealcoat attach to organic matter, such as leaves or sediment, where they may be ingested by organisms or buried in other sediments.

As part of this N.H. Sea Grant-funded research, one-quarter acre of a parking lot located near the UNHSC was covered with coal tar-based sealcoat and one-third acre was covered with asphalt-based sealcoat. The remainder of the nine-acre lot was left unsealed. On-site stormwater drains off the parking lot and into a nearby swale. The PAH concentration was measured in the water and sediments coming from the sealcoated and unsealed parking lot sections.

Both types of sealcoat led to a surprisingly rapid increase in PAH concentrations in the initial runoff - up to 5,000 parts per billion (ppb), significantly higher than the 10 ppb levels released from the unsealed lot, although concentrations decreased after several rainstorms. The PAH concentrations in the sediments mirrored these trends; the concentrations immediately downstream of the coal tar-sealed lot increased by nearly two orders of magnitude within the first year.

Unlike other compounds, PAHs do not break down easily and thus persist in the environment for decades. Even a small amount of PAHs coming off sealcoated parking lots may overwhelm an aquatic ecological system already stressed by other contaminants.

Increased PAH concentrations in waterways could be a human health issue if people are exposed to it regularly. In addition, dust particles coming from a sealcoated driveway could potentially be troublesome for children who play on the sealed surface. Ballestero cautions that it should not be a major source of concern, but nevertheless he and Watts will be investigating PAH levels in dust from sealcoat later this year.

"You don't see people falling over from PAHs in sealcoat, it's not that big of a health issue," Ballestero says. "But it could be a cumulative exposure problem that gets uglier over time."

Ballestero says he has sensed an interest by the sealcoat industry to offer more environmentally friendly, less toxic alternatives in the future. There should be options that allow workers in the industry to continue to make a living, but without causing additional harm to the local ecosystems and human health, he notes.

"There are much bigger environmental problems out there than PAHs from sealcoats, but the bottom line is that it is easily preventable," Watts adds. "All you have to do is not apply it to pavement."

The UNH Stormwater Center, dedicated to the protection of water resources through effective stormwater management, receives continued funding from the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET) at UNH and the National Oceanic and Atmospheric Administration (NOAA).


Story Source:

The above story is based on materials provided by University of New Hampshire. Note: Materials may be edited for content and length.


Cite This Page:

University of New Hampshire. "Pavement Sealcoat A Source Of Toxins In Stormwater Runoff." ScienceDaily. ScienceDaily, 14 April 2009. <www.sciencedaily.com/releases/2009/04/090408145548.htm>.
University of New Hampshire. (2009, April 14). Pavement Sealcoat A Source Of Toxins In Stormwater Runoff. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2009/04/090408145548.htm
University of New Hampshire. "Pavement Sealcoat A Source Of Toxins In Stormwater Runoff." ScienceDaily. www.sciencedaily.com/releases/2009/04/090408145548.htm (accessed September 2, 2014).

Share This




More Earth & Climate News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Iceland Lowers Aviation Alert on Volcano

Iceland Lowers Aviation Alert on Volcano

AFP (Sep. 1, 2014) Iceland has lowered its aviation alert on its largest volcano after a fresh eruption on a nearby lava field prompted authorities to enforce a flight ban for several hours. Duration: 01:07 Video provided by AFP
Powered by NewsLook.com
Lightning Hurts 3 on NYC Beach

Lightning Hurts 3 on NYC Beach

AP (Sep. 1, 2014) A lightning strike injured three people on a New York City beach on Sunday. The storms also delayed flights and interrupted play at the US Open tennis tournament. (Sept. 1) Video provided by AP
Powered by NewsLook.com
Thailand Totters Towards Waste Crisis

Thailand Totters Towards Waste Crisis

AFP (Sep. 1, 2014) Fears are mounting in Bangkok that poor planning and lax law enforcement are tipping Thailand towards a waste crisis. Duration: 01:21 Video provided by AFP
Powered by NewsLook.com
Melting Ice Shelves Drive Rapid Antarctic Sea Level Rise

Melting Ice Shelves Drive Rapid Antarctic Sea Level Rise

Newsy (Sep. 1, 2014) A study of almost 20 years' worth of satellite images shows Antarctic sea levels are on the rise as ice shelves continue to melt. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins