GAZA CITY - Countless fruit groves across the Gaza Strip are now gone, entire farms bulldozed. The remains of thousands of destroyed homes emit toxic asbestos, while dilapidated infrastructure dumps raw sewage into the Mediterranean Sea. An already deepening environmental crisis in the besieged Gaza Strip has been further compounded by the recent war.

A Palestinian wheels a cart loaded with bottles filled with water from a public tap in Khan Younis in the southern Gaza Strip April 20, 2009. Israelis have access to more than four times more water than do Palestinians in the West Bank and Gaza Strip, the World Bank said in a report on Monday. (REUTERS/Ibraheem Abu Mustafa) Throughout the three-week Operation Cast Lead, Israel targeted almost every aspect of the coastal territory's infrastructure. Homes, businesses, factories, power grids, sewage systems and water treatment plants were reduced to piles of rubble across the Gaza Strip.

According to a preliminary assessment of environmental and infrastructural damage made by the United Nations Development Programme (UNDP), Israel's assault not only exacerbated Gaza's existing hazards, but created new ones by contaminating both land and urban environments and leaving unprecedented amounts of debris in its wake.

The United Nations Environmental Programme (UNEP) announced last month it would send a team of post-conflict experts to the Gaza Strip in May to follow up on the issues that pose the greatest threats to the Gaza population.

Prior to the war, Gaza's infrastructure languished under three years of sanctions and a further 18 months of a joint Israeli-Egyptian blockade that prohibits the import of all but "essential" goods into the Gaza Strip.

Many areas of Gaza, particularly the sprawling refugee camps, lacked proper sewage systems. Where they did exist, they often ran on generators or rationed electricity. A ban on materials required for their maintenance, including cement, steel and pipes, left them in a state of disrepair.

A report released by the UN Office for the Coordination of Humanitarian Affairs (OCHA) just ten days before the launch of Operation Cast Lead stated that at least 80 percent of the water supplied in Gaza "does not meet the World Health Organisation standards for drinking.

"Much needed maintenance is impeded by a lack of pipes, spare parts and construction materials. The resulting degradation of the system is posing a major public health hazard," the report reads.

Restrictions on materials and goods left at least 70 percent of Gaza's agricultural land without irrigation, according to the Food and Agricultural Organisation (FAO), while local authorities were being forced to dump approximately 70 million litres of raw sewage into the sea each day. Fuel shortages made garbage collection infrequent at best.

During the assault, Israeli bombs hit the already fragile sewage and water treatment systems, causing drinking water and raw sewage to mix across some of the most populated areas of Gaza.

Tank shells hit the strip's largest wastewater plant in the Sheikh Aljeen area of Gaza City, sending sewage cascading directly into neighbourhoods, farms and into the sea.

Forty percent of the rooftop water tanks in Khan Younis were damaged or destroyed, and four water wells were destroyed completely in Gaza City, Beit Hanoun and Jabaliya, according to the Water, Sanitation and Hygiene (WASH) cluster group that works under OCHA.

"After the war, the major impact is being felt in the northern areas of Gaza, where most of the water networks were destroyed," says Najla Shawa, WASH's information manager in Gaza. "In Khan Younis as well, only 30 percent of the governorate is being served by a sewage network."

Ten million more litres of raw sewage is now being dumped into the Mediterranean Sea each day than was prior to the war, WASH says, posing a threat to coastal marine life and Gaza's fisheries.

Israeli missiles also targeted factories in urban-residential and rural areas, releasing potentially toxic chemicals into both the air and soil. The piles of rubble that continue to mark Gaza's landscape are said to contain large quantities of asbestos, a carcinogenic mineral fibre used commonly in construction.

"The demolition waste created by the latest hostilities potentially contain hazardous materials such as asbestos," a representative of the UNEP's Post- Conflict and Disaster Management branch told IPS on telephone from Geneva. "High levels of exposure to asbestos have been linked to lung cancer."

Over 20,000 buildings and 5,000 homes were destroyed, according to local authorities. Some 600,000 metric tonnes of rubble has yet to be cleared as a result of the siege, with much of the debris having been bulldozed into the soil by Israeli tanks.

Gaza's soil will also be affected in the long-term by Israel's use of white phosphorus shells throughout the war, says Sameera Rifai, representative of the International Union for the Conservation of Nature in the Occupied Palestinian Territories.

"The soil of the agricultural land is now polluted by the weapons the Israelis used, particularly white phosphorus," Rifai told IPS.

White phosphorus, a chemical incendiary agent, can remain unchanged in soil sediments and in the bodies of fish for many years, according to the U.S. Agency for Toxic Substances and Disease Registry.

Samples of Gaza's soil tested positive for white phosphorus in February, according to studies done at Yildiz Technical University in Istanbul, Turkey.

The war weakened even further the capability of municipalities to collect rubbish, says Palestinian environmental activist and researcher for Friends of the Earth Middle East, Basil Yasin. Refuse and solid waste continue to line the streets of Gaza, and the strip's three major dumping sites are at full capacity, the UN reports.

As long as the blockade is in place, however, and Gaza is deprived the proper materials it needs to rebuild, environmentalists are sceptical much can be done to address the strip's increasing environmental problems.

"It is a continuous crisis, not just the one war, that is constantly preventing the Palestinians from developing sustainable projects," Shawa told IPS. "Mainly this includes a lack of access to materials, which prevents the water networks and sewage plants from being constructed."

"In the last two months, just two or three containers of water pipes were allowed into Gaza by the Israelis," she said.

Shawa also says the so-called "buffer zone" Israel has created unilaterally inside Gaza is hindering environmental clean-up and assessment in the post- war period.

"People just cannot access areas in the east and northern parts where most of the sewage plants are located," she says. "Municipal authorities are unable to reach areas to test the water or soil for sewage levels."

The UNEP says environmental stability is crucial to establishing long-term peace in any conflict.

"Significant progress in terms of the environment cannot be made as long as the borders remain closed," says Rifai.

"If we want to develop Gaza and sustain its natural resources, the closure should end and there should be free movement of people and materials," says Rifai. "Otherwise, there is no point."

(This story is part of a series of features on sustainable development by IPS - Inter Press Service, and IFEJ -- the International Federation of Environmental Journalists.)