The heavy metals of many kinds of seafood off the coast of Guangdong exceed the standard of raw oyster copper by 740 times.

The fishery and aquaculture industry in Leting County, Hebei Province suffered a heavy blow as a result of oil pollution in Bohai Bay.

Guangzhou Kingboard Chemical outfall discharges sewage into the offshore, reporter Yang Hui / photo

At 5: 00 p. M. on September 28, yellow waves rolled at the sewage outlet of Guangzhou Kingboard (Nansha) Petrochemical Co., Ltd. The sewage outlet continues to discharge yellow sewage into the ocean, completely dyeing the surrounding sea area yellowish brown, and the whole bay is filled with a pungent smell.

"it's hard to catch big fish. There are so many chemical plants that many fish are gone." Lao Zhang, a fisherman nearby, told reporters.

The bay where Lao Zhang's fishing boat is located is to the east of Guangdong Huakai Oil and Gas Company, Kingboard Chemical, Development BP Oil products Co., Ltd., and a power plant, and to the north is Xiaohu Island, where the main industry is the chemical industry.

The marine bulletin recently issued by the Guangdong Marine and Fisheries Bureau shows that the content of inorganic nitrogen in the sea area adjacent to the sewage outlet of Kingboard (Nansha) Petrochemical Company has exceeded the fourth type of sea water quality standard, and the marine ecological environment quality is in a poor state. the sea water quality can not meet the requirements of the corresponding sea area use function and environmental protection target.

According to the Guangdong Marine Bulletin in 2010, 40% of the sewage discharged into the offshore outfall of Guangdong exceeded the standard, and 16% of the offshore waters are being polluted. In 2010, 1.08 million tons of petroleum hydrocarbons, arsenic, heavy metals and other pollutants were carried into the sea by the eight major estuaries of the Pearl River and the main rivers such as Rongjiang, Shenzhen River and Dongjiang River. Among them, the Pearl River accounts for 70% of the total pollutants discharged into the sea.

A large number of studies have shown that the contents of many heavy metals and persistent organic pollutants in the waters and sediments of the Pearl River Estuary exceed the standard. These pollutants will accumulate and accumulate in aquatic organisms, such as fish and zooplankton, and pose a risk of toxicity to them, and what is more serious is to enlarge the toxicity through the food chain and endanger human health. " Said Dr. Guo Pengran, associate researcher of Guangdong Provincial key Laboratory of Chemical Hazard Emergency Detection Technology.

The pollution of offshore fishing port is serious

Dr. Guo Pengran previously studied the underwater sediments of Guishan Island, a large island off the coast of the Pearl River Delta, which is located on the main channel to the east of the Pearl River Estuary. it is a docking place for large oil tankers in the Pearl River Estuary and one of the largest marine cage culture bases in Guangdong Province.

Guo Pengran's research results show that the contents of copper, lead and zinc in the seafloor surface sediments near Guishan Island exceed the estuarine background values in varying degrees. The evaluation result is that "in the mariculture base, the heavy metals in the surface sediments have potential or chronic toxic effects on benthos."

Guishan Island is an island far from the coast, and the pollution is lower than that of the fishing port near the coast. The situation in Guangdong's offshore fishing port is even more unoptimistic. Like fishermen in the waters near Kingboard (Nansha) Petrochemical Company, the marine fish salvaged by fishermen in Shenzhen Bay fishing port also smells of oil. Local restaurant owners call it "stinky oil fish".

"the contents of copper and zinc in the sediments of Shenzhen, Zhuhai and Macao fishing ports are much higher than those in domestic estuaries and bays, and the contents of cadmium are also significantly higher than those in domestic estuaries and bays. The levels of heavy metals in other fishing ports are similar to those in domestic estuaries and bays. Compared with ports around the world, the content of heavy metals in the sediments of fishing ports in the Pearl River Delta region is in the middle level, and the content of copper in the sediments of Shenzhen fishing port is among the highest in the world, only lower than the reported port of NewBedford in the United States, which is seriously polluted by heavy metals. " Zhang Gan, a researcher at the State key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, pointed out.

Researcher Zhang Gan said that the fishing ports in the Pearl River Delta have "high" or "moderate" potential ecological risks of heavy metals, among which copper and cadmium have "high" potential ecological risks. The total potential ecological risk of Guangdong fishing port is in the following order: Macao > Shenzhen > Zhuhai > Maoming.

Zhang Gan believes that the high degree of industrialization and urbanization in the Pearl River Delta has a serious environmental impact on its adjacent sea area, and the heavy metal pollution in the sediments of the fishing port is closely related to the industrialization and urbanization of the area around the fishing port.