Pesticide Pollution Found in Waterways : Environment: Mugu Lagoon and its tributaries are so contaminated that ground water could be tainted and wildlife is threatened, the state says.


Ventura County’s largest marine wetlands and wildlife sanctuary at Point Mugu and its tributaries are targeted for state cleanup because of high levels of pesticides found in the water, according to state water authorities.

Pesticide levels in the Revolon Slough and Calleguas Creek, which collect agricultural runoff before emptying into Mugu Lagoon, are so high that they could contaminate ground water beneath the streams, said Anne Saffell, chief of planning at the regional Water Resources Control Board office in Los Angeles.

In addition, the streams no longer support healthy fish populations, and the pesticide levels could harm rare and endangered species of birds at the lagoon, she said.

“We have identified those as high priority areas and will probably spend a large amount of money to clean them up,” Saffell said.


The findings of high levels of pesticides, including the now banned DDT and chlordane, along with the presence of PCBs, a type of industrial pollutant, were part of a recently released report from the state Water Resources Control Board.

Called the state’s most comprehensive report on water quality, the 1990 Water Quality Assessment evaluated rivers and streams, lakes, ground water, estuaries and harbors in Ventura County and statewide.

The assessment is the first step in the water board’s effort to discover pollution problems and set priorities for cleaning them up, Saffell said.

Contaminants in Ventura County have two predominant sources: runoff from agriculture fields and storm drains. The state board asks growers to use what are called “best management practices” when discharging runoff from their fields. But there are no specific requirements, state authorities said.

Storm drains collect street debris including rubber particles from tires and oil that leaks from crankcases along with whatever else is dumped into gutters. The Water Quality Assessment named the Mugu Lagoon, Revolon Slough and Calleguas Creek as impaired water bodies, the designation the state assigns to the most highly contaminated areas.

Neither county nor state authorities could specify whether fish taken from areas designated as impaired are safe to eat. But officials stressed that county authorities routinely monitor and post notices in areas that are considered unhealthful for fishing or recreation. No warnings are posted at the creek, the slough or the lagoon.

In addition to the three bodies of surface water designated as impaired, the report found ground water is impaired in three areas: the Santa Rosa Valley, the Santa Clara River Valley and the Simi Valley. In those areas, contaminants included pesticides, sulfates, nitrates and bacteria from sewage treatment plants upstream.

No drinking water is pumped from the Simi Valley area, but the Santa Rosa and Santa Clara River areas still produce water for drinking and agriculture, county officials said.


The county’s two major rivers, the Santa Clara and the Ventura, were designated as having intermediate water quality, indicating lower levels of contaminants than those found in impaired bodies.

According to the report, the lower Santa Clara River is suspected of containing heavy metals and pesticides. The Ventura River is suspected of contamination from pesticides and discharge from oil operations.

Piru Creek and Sespe Creek have good water quality, according to the report. The Ventura River, in the unpopulated northern part of the county, also had good water quality, the report says.

Lake Casitas, which supplies drinking water to much of the city of Ventura, was designated as intermediate quality, with suspected “elevated levels of pesticides.”


Mugu Lagoon was in the worst shape by far for area estuaries, with all 1,500 square miles considered impaired. But the McGrath Lake estuary at McGrath State Beach in Oxnard had 40 acres of intermediate quality water due to suspected pesticide contamination, the report says.

The quality of the Ventura River estuary is unknown, according to the report.

None of Ventura County’s three harbors were found to be highly polluted, but all three--the Channel Islands, Port of Hueneme and Ventura--have intermediate water quality because of suspected contamination from heavy metals. The Port of Hueneme has possible contamination from PCBs as well, according to the report.

Deborah Smith, who compiled the Water Quality Assessment for the state, said the Water Resources Control Board would like to keep waterways safe for recreation and fishing as well as for fish and wildlife habitats.


Although the contaminants may present little hazard to man in the small quantities that are found in area waterways, biologists say, the pesticides and metals pose a much greater hazard as they work their way up the food chain.

Ron Dow, who heads the environmental division at the Pacific Missile Test Center at Point Mugu, used the endangered peregrine falcon that migrates through the lagoon as an example.

As a bird of prey, it sits at the top of the food chain, eating birds that feed on fish or shellfish that eat worms that get nutrients from sediment, where the contaminants are stored.

“The terns that eat the fish may not be affected themselves,” Dow said. “But the terns taken by the peregrine have very high levels of pesticides, so their diet has high concentrations.”


Dolphins that stay near shore have high levels of pesticides in their tissues, Dow said. And even the harbor seals that loaf in the sun on the protected shores of the Mugu Lagoon could have significant levels of pesticides in their body fat, Dow said.

Dow and a team of biologists are studying the possible effects of DDT on the brittle eggs of the endangered clapper rail, a bird that nests at Mugu Lagoon. That pesticide was blamed for the decline of the peregrine and other species during the ‘70s.

Reed Smith, Southern California hazardous spill coordinator for the state Fish and Game Department, said the chemicals found at the lagoon have not yet caused deformities in animals.

“We’re not seeing the crippled critters that have shown up at Kesterson,” Smith said, referring to deformed birds found at the Los Banos area wildlife refuge that is an agricultural drain as well. “But there is a good possibility that we could end up with them here.”


The state plans to clean up the waterways that feed into Mugu Lagoon and to prevent other areas designated as intermediate quality from becoming more polluted, authorities said.

Saffell said part of the plan for cleanup and prevention will include discussions with area growers on how they can reduce the amount of pesticides that finds its way into the creeks.

“We also want to be sure nobody out there is using DDT,” Saffell said. “We don’t think it’s possible 10 years after it is no longer available, but we want to be sure.”

The state will assign contracts for the cleanup in the next five or six months and plans to finish it by 1992, she said.


Polluted Waters in Ventura County l. Lower Santa Clara River Valley: high nitrate levels. 2. Revolon Slough: high levels of pesticides. 3. Calleguas Creek: high levels of pesticides. 4. Mugu Lagoon: high levels of pesticides.