What is the Right Amount of Aluminum in Our Streams?

The State Journal
24 March 2013
By Pam Kasey

Here's a hard but important question: How do we make sure the water quality criteria protecting the state's streams and lakes are neither underprotective nor overprotective?

Underprotective, and they expose aquatic life and sometimes even people to harm. Overprotective, and they impose unnecessary treatment costs on pollution discharge permittees.

It's a question that can be pretty technical but that nevertheless comes before the public every time a change to state water quality standards is proposed.

Right now, the question involves aluminum. That's because, on March 12, the secretary of state granted emergency status to a change the Department of Environmental Protection proposes to the aluminum criteria, and the proposal now heads to a March 27 public hearing.

DEP says the current aluminum criteria, recommended by the Environmental Protection Agency since 1988, can be overprotective, and that more recent science shows a way to ease up on industry while still protecting aquatic life.

Environmentalists fear the proposal would endanger aquatic life.

And a scientist very close to the issue says both may be right — and that there's a better way still.

This matters. It affects two things that are important to the state: jobs-providing mines and quarries, and the health of streams in the regions where they operate.

But how can the non-chemist public participate usefully in the dialog?

A little background

Aluminum is the third most abundant element in the Earth's crust, so it occurs naturally in rocks and soil. Mining and quarrying can release it into streams.

But too much aluminum in water can be toxic to fish and other aquatic life — both if there's a little too much on a chronic, or long-term, basis, or if there's much too much on an acute, or short-term basis. So DEP places permit limits on discharges to keep aluminum concentrations below state chronic and acute water quality criteria.

Those criteria currently are two simple numbers: 750 micrograms/liter, or ug/L, for warm water and for acute exposure in cool water, and 87 ug/L on a chronic basis in cool waters where sensitive trout live.

DEP's emergency proposal would replace that with site-specific criteria derived from an equation based on mineral content in the water. It would be applied anywhere that pH is moderate — between 6.5 and 9.0, which covers most of the state's streams most of the time — but would not incorporate pH as part of the equation.

Using mineral content, or hardness, to calculate water quality criteria is an approach the state already uses for lead, nickel and a few other metals.

The nature of the emergency                    

DEP wants to reduce treatment costs for pollution discharge permittees — coal and quarry operations — faster than it could by going through two-year legislative process, according to DEP Secretary Randy Huffman.

What are those costs?

Annual treatment for one low-volume discharger comes to $96,000 a year, in an example from Scott Mandirola, director of DEP's Division of Water and Waste Management. That discharger is expected to have no treatment cost under the proposed change.

One difficult high-volume discharge is costing another permittee $336,000 a year.

Secretary of State Natalie Tennant determined that DEP demonstrated "substantial harm to the public interest," one of the categories of justification for an emergency rule.

Tennant's decision addresses only whether the proposal qualifies as an emergency — not the validity and relevance of the science behind it.

The proposal, pro and con

The proposed change appears on its face — to non-chemists — to be almost exclusively a weakening of the criteria.

At levels of hardness below 60 milligrams/L, or mg/L, as in some of the state's headwater streams and the Cheat and Tygart Valley rivers, the proposal results in more stringent chronic and acute criteria.

But at the higher hardness levels of most of the state's larger rivers, the equation results in far more lenient criteria. The chronic standard would rise to about 2,500 ug/L aluminum at a not-uncommon hardness of 150 mg/L. It goes over 4,000 when hardness is above 220, a level measured often in, for example, the Coal River and the West Fork of the Monongahela River, both mining watersheds. It goes as high as 10,000 ug/L for the acute standards.

That's okay, according to Mandirola, because current science shows that in harder water, a higher aluminum criterion can be as protective of aquatic life as the current criteria.

It has to be noted that DEP provided no references to support the proposed equation, and that no other state uses such an equation in exactly the way the agency proposes.

An opposing view comes from Carys Mitchelmore, an associate professor at the University of Maryland Center for Environmental Science. A report she prepared documenting her opinion that the proposed change is inappropriate is being submitted by Appalachian Mountain Advocates and the Sierra Club as comments on the proposal.

Unlike for other metals, the data on aluminum toxicity and hardness are sparse and can even appear contradictory, among the concerns Mitchelmore enumerated.

Studies so far have been conducted primarily in the laboratory and may not be representative of field conditions, she wrote. Other factors, especially pH, affect toxicity. And while DEP cites a similar equation in use in Colorado, that applies to total recoverable aluminum — both dissolved and suspended — and West Virginia's applies only to dissolved aluminum, so Colorado's is more stringent.

Let's just be up front about this: It's a situation perfectly designed to activate the environmental community's mistrust of anything that might benefit the coal industry.

But just because this has the appearance of an adversarial process — DEP presenting its case, and opponents coming back with their case — doesn't mean the state is getting the best solution.

Gills and metals

Both sides are right, according to Robert Santore, an environmental scientist and Environmental Chemistry Section manager at HDR/HydroQual in Syracuse, N.Y.

They just may not go far enough.

Santore has spent the last decade studying the effects of water chemistry on the toxicity of metals. He's developed a computer model that accounts for all of the important water chemistry and aims to give, as output, site-specific water quality criteria that are appropriately protective. The EPA has adopted his Biotic Ligand Model for copper and, he said, is working with it for other metals as well.

Simple numeric water quality criteria for metals are oversimplified, Santore said, in part because hardness does have an effect on toxicity.

"Hard water has two biological effects," he said. Because calcium and magnesium are plentiful in hard water, it's easier for fish to take these mineral ions in through their gills to regulate their blood chemistry. At the same time, the ions bind to gill membranes, keeping metals from binding to the tissues and inhibiting biological processes.

"That's why hardness has this effect of making metals less toxic," he said.

However, a calculation based on hardness alone also is oversimplified.

"The chemical form that aluminum is in is strongly dependent on the chemical environment that the exposure takes place in," Santore  said. "If you're a fish exposed to aluminum, the effect it's going to have on you is different in acidic water, say pH 6, than it will be at pH 7 or 8."

Dissolved organic matter in the water is important, too, and 30 years of science shows that all of these factors affect metals toxicity, he said.

The fact is, any water quality criterion for metals that relies on one number or one factor is too simplistic.

"If you're in the arid west, dealing with hardnesses of 1,500 (mg/L), you wouldn't expect metals to behave the same way they do in South Carolina, which might have very soft water of 20 (mg/L)," he said.

"And if you're looking at acid mine drainage, where the pH might be in the 5s, you need a different criterion there than you would some place where the alkalinity is high."

With this little bit of background, it's easy to see: Behaving as though water is the same everywhere results in some instances in underprotection, Santore said, and in overprotection in others.

EPA has long recognized this problem. To address it, the agency offers an alternative Water Effect Ratio for arriving at site-specific criteria. Sensitive organisms are exposed to the metal of concern at various concentrations in water directly from the site — which takes local hardness, pH and organic matter physically into account. Lower toxicity in site water justifies a less stringent site-specific criterion.

Santore's Biotic Ligand Model is designed to provide similar site-specific results more efficiently.

"We know so much about the chemical effects and the biological effects of metals that we can do a lot better today than EPA was able to do in 1988," he said.

"It is definitely time to be rethinking how we approach water quality criteria for metals and to start incorporating a wider array of good scientific principles," he added. "Understanding complexity and dealing with it is our job as scientists and regulators. The good news is, we can address it."

Back to the question

So: Given this complexity, how can the non-chemist public participate meaningfully in the public comment period for the proposed change to the aluminum criteria?

Anyone with just a little chemistry background understands the fundamental importance of pH, and anyone who knows a little about water chemistry understands that pH affects the action of metals, Santore said. At the very least, a participant who feels pH must be an important factor can make note to DEP that its effects should be taken into account.

If Santore were commenting, he said he would note that the Biotic Ligand Model that takes all of the important water chemistry into account is available for free for regulators to download and that California, Colorado and some other states have adopted its use as an alternative for some metals criteria.

The process

The public hearing on the emergency rule is scheduled for 6 p.m. on March 27 at DEP's offices in Charleston.

Comments may be e-mailed through that time to dep.comments@wv.gov.

Afterward, "Unless the comments lead the agency to refrain from proceeding with the rule, the next step after the hearing is to submit the rule change to the EPA for review and approval," said DEP spokesperson Kathy Cosco.

EPA Region 3 in Philadelphia will have 60 days to approve or 90 days to disapprove the revision. If approved, the change to the water quality criteria would be in effect, according to the practice for emergency rules, for up to 15 months.

For a permanent revision of the criteria, the changes would be included in the 2014 Triennial Review of water quality standards for legislative and EPA approval.