Aluminum producers are backing EPA’s effort to update its water quality criteria for the ubiquitous metal, calling the current approach “overly simplistic,” though the producers are urging the agency to allow use of a model to translate the risk-based criteria into regulatory limits, saying this will ensure consideration of site-specific factors.
The producer’s initial support for EPA’s revision is especially significant given growing domestic use of the metal — especially in the auto industry as many manufacturers increase their use of the substance as a lighter-weight alternative to steel, a key factor for compliance with federal fuel efficiency and greenhouse gas requirements.
But mining and coal interests are strongly opposing the agency’s effort, saying it is not justified and will result in overly strict regulatory requirements. Mining industry representatives have been advocating for less stringent state aluminum standards for years, and say they are wary of any potential changes EPA will make to the national criteria–which they fear will make standards more stringent than necessary.
The industry comments come in response to news that early data that EPA has gathered suggests the agency will likely strengthen its water quality criteria and force some states to adopt new approaches to regulate the substance.
In a recent letter to West Virginia officials, EPA Region III all but rejected the state’s request to approve proposed new criteria for aluminum — which sought to use water hardness as a factor in calculating the criteria even though the agency had already approved such approaches in Colorado and New Mexico (Inside EPA, Feb. 14).
Aluminum is toxic to aquatic life in both its dissolved and solid states. It is naturally occurring but also is released into the environment from coal mining and finishing operations, coal-fired power plants, and waste water treatment plants, among other sources.
EPA’s current criteria — set in 1988 — measures aluminum in terms of total recoverable metal (TRM) in water based on an average pH scale. The agency set an acute criteria of 750 micrograms per liter (ug/L) and 87 ug/L for chronic exposures.
EPA and state regulators use such criteria — risk-based concentration limits — to craft enforceable standards in permits, water quality standards and other regulatory levels for limiting harms to human health and aquatic species. Based on its current criteria, EPA says that 6,610 miles of rivers and streams are currently considered impaired because of excess levels of aluminum.
EPA limited its 1988 criteria to apply within the 6.5 to 9 pH range because it found that aluminum is “substantially less toxic at higher pH and hardness, but the effects of pH and hardness are not well quantified at this time.”
Despite its initial uncertainty over the use of hardness in measuring aluminum, over the past few years, EPA has approved new state criteria in New Mexico and Colorado that account for both pH and hardness as factors in setting aluminum criteria. Industry and states have pushed such an approach, arguing it is a more precise method of measurement than the current recommendation, using EPA’s findings that aluminum tends to be less toxic in harder waters.
But based on the new data it has gathered, EPA appears to be considering strengthening the current national criteria. Region III officials said in their recent letter to West Virginia that the agency will consider the new information it is gathering to ensure that any new criteria “will be protective of all aquatic life, including mussels, at various pH and [water] hardness levels.”
An official with The Aluminum Association, the trade group that represents aluminum producers, backs EPA’s effort to revise its criteria. “It’s widely regarded that the previous approach that used a simple pH model [as the sole risk factor] was probably over simplistic,” the official says.
While the association official agrees with the need to revise the criteria, the group is nevertheless pushing EPA in ongoing meetings to allow for the use of the Biotic Ligand Model (BLM)–a model that considers a series of site-specific factors when setting standards and providing flexibility.
“It would result in a much more reasonable and local water quality standard,” the aluminum association official says. “It’s not a one-size-fits-all approach. We do see the issues that this introduces in the regulatory process, but science seems to be backing the model.”
EPA has already allowed the use of the BLM in 2007 when it set criteria for copper. The model uses 10 parameters to calculate a freshwater criterion including pH, temperature and dissolved inorganic carbon, but not hardness.
According to those who support the method, BLM is beneficial in that it would better account for site-specific conditions when setting aluminum criterion–essentially setting localized standards for each body of water. But it is much more cumbersome to operate than a single standard because of it’s specificity.
While the aluminum group appears open to revising the standard, coal and mining groups are strongly opposing it. “We see no reason for re-regulating impacts on streams because current rules are effective in protecting water quality while balancing that important objective with maintaining a vibrant industry,” the National Mining Association said in a statement.
And representatives at the West Virginia Coal Association (WVCOAL) warn that a new EPA criteria that doesn’t incorporate hardness would be a step in the wrong direction, “I think the overwhelming majority of evidence indicates that aluminum toxicity is tied to hardness, and other states have already been approved and implemented by the EPA for a number of years,” an official with the group says. “In West Virginia we clearly think it’s a hardness based issue. We have been struggling with the aluminum criteria in West Virginia and I think a number of years ago we collectively agreed that the hardness base was the way to go.” — Miranda Green