Lab Science News

The EPA aims to reduce air emissions from certain stationary diesel engines and issued their first standards on February 17, 2010. The rule will help reduce formaldehyde, benzene, acrolein and other toxic air pollutants from diesel powered stationary reciprocating internal combustion engines (RICE), also known as compression ignition (CI) engines. The toxic air pollutants, also referred to as hazardous air pollutants or air toxics, are suspected of causing cancer and other serious health effects as well as environmental damage.

EPA estimates that the rule will reduce annual toxic air emissions by 1,000 tons, particle pollution by 2,800 tons, carbon monoxide emissions by 14,000 tons, and organic compound emissions by 27,000 tons when fully implemented in 2013.

The new emission limits apply to existing diesel engines meeting certain criteria for age, size, and use. EPA estimates that more than 900,000 of the engines generate electricity and power equipment at industrial, agricultural and other facilities. Industrial facilities such as power plants and chemical and manufacturing plants use these engines to generate electricity for compressors and pumps. They also are used in emergencies to produce electricity to pump water for flood and fire control. Emergency engines used at most residences, hospitals and other institutional facilities, and commercial facilities such as shopping centers are not covered by this rule.

To meet the emissions requirements, owners and operators of the largest engines will need to install emissions controls, such as catalysts, to engine exhaust systems that would limit air toxics emissions by up to 70 percent. Emergency engines covered by this rule need to comply with operating requirements that will limit emissions.

EPA will issue final emissions standards for similar existing stationary engines that burn gasoline, natural gas and landfill gas, known as spark ignition engines, by August 10, 2010.

EPA, in a recent study, found that concentrations of chemicals in recycled tire material were below levels considered harmful. Recycled tire material, or “tire crumb,” is commonly used in synthetic turf sports fields and children’s playgrounds.

According to EPA, public concerns have been raised in the past several years over the use of tire crumb materials, especially after high levels of lead were reported in some artificial turf fields. In 2009, the Synthetic Turf Council reported that artificial (synthetic) turf has been installed in approximately 4,500 fields, tracks and playgrounds.

EPA identified a number of chemicals that may be found in tires, although not all are contained in each tire:

EPA formed a workgroup in 2008 to consider the threat of tire crumb health effects via inhalation, ingestion, or skin contact. Laboratory studies were conducted to consider the tire material content, off-gassing, and leaching characteristics. EPA then produced a 105-page document entitled “A Scoping-Level Field Monitoring Study of Synthetic Turf Fields and Playgrounds,” released in November 2009.

Study findings

• Particulate matter, metals and volatile organic compound (VOC) concentrations were measured in the air samples and compared with areas away from the turf fields (background levels). The levels found in air samples from the artificial turf were similar to background levels found in any local air samples. One VOC associated with tire crumb materials (methyl isobutyl ketone) was detected in the samples collected on one synthetic turf field but was not detected in the corresponding background sample.
• No tire-related fibers were observed in the air samples.
• All air concentrations of particulate matter and lead were well below levels of concern.
• More than 90 percent of the lead in the tire crumb material was tightly bound and unavailable for absorption by users of the turf fields.
• Zinc, which is a known additive in tires, was found in tire crumb samples. However, air and surface wipe monitoring levels of zinc were found to be below levels of concern.
• Total extractable metal concentrations from the infill, turf blade samples and tire crumb material varied widely in the samples collected both at a given site and between sites, so it could not be determined to be a function of the presence of crumb material.
• The average extractable lead concentrations for turf blade, tire crumb infill, and tire crumb rubber were low. Although there are no standards for lead in recycled tire material or synthetic turf, average concentrations were well below the EPA standard for lead in soil (400 part per million).
• Likewise, the average extractable lead concentrations for turf field wipe samples were low. Although there are no directly comparable standards, average concentrations were well below the EPA standard for lead in residential floor dust (40 micrograms per square foot).

The results from this study along with results from other studies conducted by Federal, State, and local organizations, such as the Consumer Product Safety Commission (CPSC) and the Agency for Toxic Substances and Disease Registry, will be considered at an EPA meeting planned for Spring 2010. This meeting will help to identify steps to address public questions regarding the safety of tire crumb infill in ball fields and playgrounds.

For more information, visit EPA’s website www.epa.gov/nerl/features/tire_crumbs.html

EPA has finalized national effluent limitations guidelines (ELG) and new source performance standards (NSPS) for construction and development sites to help address improvement of water quality throughout the nation. While the standards focus on discharges occurring during stormwater events, these new guidelines affect all discharges of pollutants from construction activities into waterways, including dewatering and concrete washout.

Non-numeric ELGs: All construction and development sites will be required to meet a series of non-numeric ELGs beginning in February 2010. These are intended to minimize any discharge from a construction site to a water body, and may include:

• Strict stormwater runoff control from sites
• Minimization of steep slope disturbances, amounts of exposed soil, and soil compacting
• Stabilization of soils
• Provision and maintenance of natural buffer zones
• Discharge control from non-stormwater activities like dewatering, truck and tire washing, concrete washouts, etc.

Numeric Limits: Construction and development sites must sample stormwater discharges and comply with the numeric limitation for turbidity of 280 NTU (nephelometric turbidity units). EPA is phasing in the numeric effluent limitations over four years to allow permitting authorities adequate time to develop monitoring requirements and to allow the regulated community time to prepare for compliance with the numeric effluent limitation. These phases consist of:

• Sites that disturb 20 or more acres at one time will be required to conduct monitoring of discharges from the site and comply with the numeric effluent limitation beginning 18 months after the effective date of the final rule (August 1, 2011).
• Sites that disturb 10 or more acres at one time will be required to conduct monitoring of discharges from the site and comply with the numeric effluent limitation beginning four years after the effective date of the final rule (February 2, 2014).

Although streams and rivers naturally carry sediment loads, discharges associated with construction activity can elevate these loads to levels above those in undisturbed watersheds. Discharges from such sites may also increase the proportion of silt, clay and colloidal particles, along with other pollutants in receiving streams because these fine-grained particles may not be effectively managed by conventional erosion and sediment.

EPA stated the proposed rule is designed to achieve cleaner streams and waterways through implementation of erosion and sediment control measures and pollution prevention practices. According to EPA, sediment is one of the leading causes of water quality impairment nationwide. Activities such as clearing, excavating, and grading can lead to soil erosion into streams and other bodies of water. This discharge can cause a variety of physical, chemical, and biological impacts to water bodies.

The United States Environmental Protection Agency (EPA) will soon release its response to a 2006 National Academy of Sciences (NAS) report recommending changes to the EPA’s 2000 draft assessment of the risks posed by 2,3,7,8 Tetrachlorodibenzo-p-Dioxin.

Dioxins are environmental contaminants according to the Food and Drug Administration’s (FDA) website (September 2009). Most human dioxin exposure, however, occurs through the diet, with more than 95% coming through dietary intake of animal fats. Dioxins enter the food chain primarily in an air-to-leaf/soil-to-animal route.

In anticipation of the upcoming release, the EPA has established a special communication committee to address concerns about the safety of the food supply and other public health issues.

The EPA’s Waste Office, in response to this reassessment, is proposing lowering soil screening levels in residential areas from 1000 parts per trillion (ppt) to 72 ppt. However, given reported health risks, there are some that have been urging the EPA to adopt an even stricter 3.7 ppt-level.