Petroleum and Salt a Deadly Mix for Maracaibo Lake
By Humberto Márquez*
South America's largest lake "is contaminated, but stable," say officials, who are also confident that the aquatic ecosystem can recover.
CARACAS - A forest of metal towers rise throughout nearly half of the 12,000 square km of Maracaibo Lake, in northwest Venezuela, testimony to 90 years of continued extraction of crude in South America's largest oil field and the result of a choice between sustainable development and unremitting degradation.
The lake, connected to the Caribbean Sea via a natural canal with the Gulf of Venezuela, suffers the multiple onslaught of salinity, oil spills and sewage, phenomena that local authorities are confronting with optimism that they can change the situation.
"The lake is very contaminated, but stable. Its waters are renewed every five years and it is recoverable as a source of sustainable development for the millions of inhabitants living in the Maracaibo basin," biologist Gonzalo Godoy, president of the regional management commission, said in a conversation with Tierramérica.
Fifty years ago, when the oil industry deemed it necessary to create a route for tanker ships, the canal was dredged. As a result, the salinity of the lake rose form 1.0-1.5 grams per liter in the first half of the 20th century to nearly five grams/liter in surface water samples, and up to 15 grams/liter during the dry season.
"The fish we used to catch, particularly the 'lisa' (Mugil labrosus, a type of mullet), have disappeared, and now the fish we sell to the restaurants around the lake we get in the gulf, especially corvina (Sciaempus ocellatus) and shrimp," fisherman Getulio Nava told Tierramérica.
"Nobody swims in the lake anymore, and that water can't be used for irrigation. When I was a boy, my grandfather told me about 'augadores', who carrying it on the backs of donkeys would sell lake water in Maracaibo. Now it's only good for looking at," he said.
The extent of the salinity problem became evident in April, when Caribbean sharks were caught in the southern part of the lake, more than 100 km from the islet-studded bay that communicates it to the gulf.
"We would like to help with environmental protection, here next to the gulf, but I don't have any option," the mayor of the municipality, Hely Espina, told a recent press conference.
"To fish, the nets should measure seven inches between threads, according to environmental rules. But the fishing communities use 2.5-inch nets in order to catch what they can. There is hunger. And I am not going to stop them," he said.
The oil industry also contaminates Maracaibo. Thousands of wells have been dug into the lake bottom and the shores. For decades, petroleum output surpassed two million barrels a day. Today it is somewhat less, standing at 1.4 million 159-liter barrels a day.
Furthermore, "there are 42,700 km of pipes connecting the wells to the storage tanks, the distribution and transport pipelines, the ports and the refineries," Jorge Hinestroza, an expert from the University of Zulia, told Tierramérica.
In recent years, 30 to 50 oil spills have been reported each month, "Although the volumes are never known for certain because the phenomena have always been a shadowy part of operations," said Hinestroza.
During the recent December-January strike against the Hugo Chávez government, a protest led in part by managers of the state-run giant Petróleos de Venezuela (PDVSA) the strikers accused the personnel who continued to operate the oil wells and refineries of causing accidents.
But Hinestroza and the Federation of Zulia State Fishing Communities believe that a large portion of the accidents during that two-month period were due to "the sabotage by the striking managers and direct attacks on certain installations."
Also of political origin are the dozens of oil spills in the past decade caused by insurgents in neighboring Colombia who dynamite the Colombian Caño Limón-Coveñas pipeline, which then leaks crude into the Catatumbo, Escalante and Tarra rivers, which flow into the southern Maracaibo.
The most recent attack, Apr. 19, dumped 2,500 barrels of petroleum. PDVSA has designated specialized teams to clean up the affected areas.
The lakeshore communities themselves are responsible for another problem, as the sewage they produce is dumped into the lake at the rate of 9,000 liters per second.
Only a portion of Maracaibo's sewage is treated, coming from more than a million residents, and from cities like Cabimas and Lagunillas, with hundreds of thousands of inhabitants, meaning that untreated wastewater is dumped in the lake, absorbing oxygen and asphyxiating the ecosystem's flora and fauna.
Nevertheless, "the lake can be restored for future generations," says Godoy, president of the lake management commission.
To clean up the lake in the first half of the 21st century, so that its shoreline can be enjoyed, its water can be used for irrigation, requires a three-pronged effort, according to Godoy.
First, the closure of the current navigation canal would reduce salinity within just a few years and would move the heavier, oxygen-rich water to the lake's depths.
This requires moving the petroleum shipment operations to the sea coast, building sewage treatment plants in at least six lakeshore cities, and reducing oil spills and the flow of wastewater from industry, farming and livestock into the lake.
Furthermore, states Godoy, it is essential to control deforestation and agricultural expansion because they produce runoff into the rivers that feed the lake.
"There is room for optimism," says the official, "It is a big lake and its potential for recovery is big too."
* Humberto Márquez is an IPS correspondent.