Study Says Testing Itself Made Effluent at Encina Plant Toxic

Times Staff Writer

A year ago, fathead minnows testing toxicity in the effluent produced by the Encina sewage plant began dying off in unprecedented numbers.

The death rate of the tiny freshwater fish caused considerable concern among Encina officials, who feared it meant that the treated waste water being dumped off the Carlsbad coast was unacceptably toxic. Environmental concern escalated to financial concern in February when the Regional Water Quality Control Board ordered the plant to further clean its effluent within a year or face strict sanctions.

Now, five months and $74,000 later, the sewage treatment plant has discovered the source of the problem: faulty testing.

Tests by an independent consultant showed the effluent being pumped through the plant’s ocean outfall is in fact not above the accepted limit of toxicity. “What it comes down to is the procedure they were using was creating the toxicity,” Gregory Lorton of ERC Environmental and Energy Services Co. told the Encina board members Wednesday. Lorton said the false test results were caused by too much air being pumped into the waste water that was being sampled.


The excessive aeration stripped the carbon dioxide from the samples, which in turn raised the toxic level of the waste water and created excess ammonia--which killed the fish, Lorton said. He suggested that the laboratory technicians had errantly pumped more air into the samples in an attempt to keep the fish alive, not realizing they were skewing the test results.

‘Cease and Desist’

Encina has used the fathead minnow method of testing effluent for years, paying Kinnetic Laboratories of Carlsbad to run the tests. All was well until last summer, when the toxicity of the samples inexplicably shot up.

In response, Encina brought in another laboratory to run concurrent tests, which showed no unusual level of toxins. In February, shortly before the Regional Water Quality Control Board issued its “cease-and-desist” order, the Encina board voted to spend up to $74,000 to get to the root of the problem.


Lorton, head of the chemical engineering division of the San Diego consulting firm that was hired to find a solution, was careful to point out that Kinnetic Laboratory employees were the first to notice that the problem was caused by their testing procedures. Speculation about the detrimental effects of aeration was confirmed by officials from the Goleta Sanitary District near Santa Barbara, which had experienced similar faulty test results, Lorton said.

The unusual chemical reaction was also documented in a 1979 paper published by the Los Angeles County Sanitation District, he said.

Encina general manager Rick Graff said Wednesday that a letter has already been mailed to the Regional Water Quality Control Board, explaining the situation and asking them to lift the order. The regional board is expected to address the request at its Aug. 24 meeting, Graff said.

Encina’s board is now considering legal action against Kinnetic Labs. Encina attorney Roy H. Gann said Kinnetic could be made to reimburse the facility the $74,000 it spent on identifying the problem if the laboratory can be proven negligent.