Overview of ecological environment in northwest Shandong plain

I. General situation of ecological environment

(A) the status quo of the ecological environment

1. Utilization and degradation of land resources

Land is the foundation of the growth of all things, the space for human life and labor, and the basic resource for human survival. Without land, the basic conditions for survival will be lost, so protecting land is to protect human beings themselves. There are great regional differences in soil erosion in the northwest plain of Shandong Province, which are manifested in land loss, soil salinization, land desertification and the increase of non-agricultural land.

(1) Land loss

The investigation area is located in the lower reaches of the Yellow River, which is mainly soil eroded and deposited by surface water in the middle and upper reaches of the Yellow River and mountainous areas in central and southern Shandong. However, since the 20th century, due to natural factors, abundant surface water has been washed away by floods, resulting in land loss100.83x104hm2, accounting for 13.62% of the land area in the working area. The areas with soil erosion area of15×104 ~ 20×104hm2 are mainly distributed in Dongying, Binzhou and Dezhou, with Heze having the smallest soil erosion area. With the increase of forestry planting area and effective measures to protect land, after entering the 2 1 century, the land loss area in most areas decreased obviously, only Dongying and Binzhou increased slightly.

(2) Land salinization

Saline land in the survey area is mainly distributed in Dongying, Jining, Binzhou, Dezhou and other areas, with an area of about 38.85× 104 hm2, accounting for 27.73% of the saline land area in the province. The salinized land area in Binzhou City is about 15.87× 104hm2 at most. Heze City has the smallest salinized land area, about 2 100 hm2. Dongying city is also a region with frequent salinization in different degrees, and the cultivated land area is small. Overexploitation of groundwater leads to seawater intrusion, which intensifies and accelerates the process of soil salinization. From 1970 to 2000, the salinized land area in the survey area increased by 55.7× 104 hm2, with an average annual increase of about 1.86× 104 hm2. The area of salinized land in Dongying City increased the fastest, from 1986 7.78× 65438. Due to storm surge and seawater erosion, a large area of cultivated land in Dongying City was destroyed, resulting in 2283.4 hm2 of cultivated land degenerating into unused land, and another 2847.6 hm2 of cultivated land degenerating into saline-alkali land year by year due to secondary salinization of land.

(3) Land desertification

The investigation area is the Yellow River Plain, and the special topography leads to the large area of desertified land in Heze, Liaocheng, Dezhou and Binzhou, with the desertified land of 24.28× 104 hm2, accounting for 39.59% of the desertified land in the whole province. Among them, Dongying has the largest area of desertified land, which is 15.9× 104 hm2. Due to the continuous expansion of land desertification, governments at all levels have realized the importance of protecting the ecological environment. In recent years, the green area has been increased, and desertification has been controlled. The area of desertified cultivated land decreased by 5.9 1%, and the area of desertified grassland decreased by 69.49%.

(4) the increase of non-agricultural land

With the rapid development of economy, the phenomenon of land occupation is becoming more and more serious. According to the Annual Report of Comprehensive Statistics of Land and Resources in 2004, the construction land in the survey area is111×104hm2, and the residential and industrial land is 99.19×/kloc-0. Water conservancy facilities land 12.84× 104 hm2, unused land 50.98× 104 hm2, and total non-agricultural land 289.38× 104 hm2. Heze is the city with the most construction land, which is 18.86× 104 hm2. It is also a region with more residential areas, industrial and mining areas and traffic land. The areas with relatively little non-agricultural land are Jinan, Tai 'an and Zibo. But generally speaking, non-agricultural land is the main reason for the loss of cultivated land.

2. Development and utilization of water resources

Water is the source of everything's growth and the basic guarantee of life's survival. With the influence of economic development and human factors, water resources are polluted to varying degrees, which brings great inconvenience to people's normal life and restricts the development of social economy. The survey area is a water shortage area.

(1) surface water resources

The surface rivers in the survey area are controlled by geological structure and topography, and the river flow direction is generally southwest to northeast. River water quantity is the main source of water for industry, agriculture and people's normal life in this area, and the abundance of rivers directly affects the economic development and people's normal life in this area. There are many rivers in this area, including Yellow River, Tu Hai, Ma Jiahe, Xiaoqing River, Beijing-Hangzhou Grand Canal, Xinwanfu River and Dongyu River.

Lakes are mainly distributed in the contact zone between central and southern Shandong and northwest Shandong plain. Jining is divided into two lakes, with Nansi Lake (Nanyang Lake, dushan lake, Zhaoyang Lake and Weishan Lake) in the south, with an area of about 1 178 km2. It is one of the top ten freshwater lakes in China, with Beiwu Lake in the north, and all of them are deposited into low-lying areas with accumulated water except Dongping Lake in summer. Due to natural factors, 2002 coincided with the drought, and Nansi Lake dried up for nearly three months, which not only brought serious losses to the economy, but also seriously damaged the ecological environment of the lake area and its surrounding areas. Pollution along the lake is also very serious, with the annual pollution reaching13650×104 t. The main pollutants are suspended solids, chemical oxygen demand, biochemical oxygen demand, hexavalent chromium, phenol, cyanide, petroleum, sulfide, ammonia nitrogen and aniline, all exceeding the standard. There are 245 major polluting enterprises along the lake. In order to control polluting enterprises, the provincial government has intensified pollution control and the ecological environment has developed in a good direction.

(2) Groundwater resources

Due to the development of Cambrian and Ordovician limestone strata in the southern mountainous area of the survey area, the karst landform is beneficial to the storage of groundwater, especially in the southern mountainous area of Jinan, where thick limestone is widely distributed and karst fractures are developed, which is beneficial to precipitation infiltration. The alluvial plain of the Yellow River in northern Shandong and southwestern Shandong is flat, which is conducive to the infiltration of atmospheric precipitation. However, along the Yellow River, it is mostly replenished by the lateral seepage of the Yellow River.

In recent years, with the development of industry and agriculture and the improvement of people's living standards, the amount of groundwater exploitation is increasing. Geological disasters caused by groundwater exploitation are frequent, and environmental problems such as seawater intrusion, ground subsidence and ground fissures are more serious.

(3) Water pollution status

According to the statistics of the provincial environmental protection bureau in 2000, the total amount of wastewater discharged in the investigated area was 72 358× 104 t, and the wastewater discharge reached the standard of 66009× 104 t, with a compliance rate of 88% (compared with the 20th century 1995, the compliance rate increased by nearly 45 percentage points), among which Jining City and Zibo City. In recent years, the compliance rate of sewage and wastewater discharge in the whole region has increased year by year, from 1990 to 2000, an increase of nearly 60 percentage points. The pollutants in sewage and wastewater mainly include chemical oxygen consumption, suspended matter, volatile phenol, sulfide, cyanide, petroleum, arsenic, hexavalent chromium, lead, cadmium and mercury, among which chemical oxygen consumption, suspended matter and sulfide account for the largest proportion and belong to the main pollutants. From the industry point of view, paper and paper products, food and beverage and tobacco manufacturing, chemicals, textiles, medicine, minerals, leather, fur and its products are heavily polluted industries.

River water pollution is directly influenced by industry, agriculture and human factors. With the development of economy and the pursuit of economic benefits by enterprises, river water pollution is becoming more and more serious, and the proportion of rivers polluted in the investigation area is 100%. Shallow groundwater is not only polluted by industry but also by agriculture. Agricultural pollutants mainly include "three nitrogen", organic phosphorus and organic chlorine. The areas with serious shallow groundwater pollution are mainly distributed along the sewage river, towns and industrial concentrated areas, including Jinan, Dongying, Dezhou and Liaocheng. According to the test data, the pollution factors are mainly mercury, phenol and chemical oxygen consumption.

3. Vegetation ecological environment

(1) Forest resources

The survey area is located in the alluvial plain of the Yellow River, with agricultural production as the mainstay. In addition, before 1980s, deforestation occurred frequently, resulting in a large area without forests, and the forest coverage rate was far below the national average, which was the lowest in Shandong Province. Since the 1980s, governments at all levels have attached great importance to forestry, and the policy of returning farmland to forests has been further implemented. The forest coverage rate has increased slowly, from less than 1.9% to1.45% in 2000. Especially in Heze area, the forest coverage rate reaches 16%, and the lowest forest area in Dongying city is only 2× 104 hm2. Due to the erosion of saline soil and seawater, the survival rate of forests in Dongying City is extremely low, which greatly affects the development of forestry. 2 1 century, the policy of returning farmland to forests was further implemented, afforestation and forest protection were implemented at the grassroots level, ensuring forestry development and increasing forest area. In recent years, the awareness of environmental protection has been continuously strengthened, birds have been loved and protected, and a large number of birds have multiplied, which has increased the natural guarantee for the prevention and control of forestry pests.

(2) Grassland resources

Grassland is mainly distributed in coastal plains, inland saline-alkali sandy wasteland and rivers, lakes and swamps, mainly pasture, mainly distributed in the northwest plain of Shandong Province, especially in the sparsely populated Yellow River Delta. Most of these pastures are natural grasslands, in addition to artificial grasslands, fenced grasslands and rotational grazing grasslands.

In 1980s, in order to increase cultivated land, the occupied non-agricultural land increased and the grassland area decreased obviously, which brought losses to wetlands and ecological environment. Since the end of 1990s, the area of grassland has been increasing for returning farmland to grassland and protecting wetlands. Dongying is the most widely distributed grassland, followed by Liaocheng. According to relevant data, the increase in the number of livestock has caused different degrees of damage to the grassland. The grassland in the Yellow River Delta has been affected by rodents and industrial occupation, and the grassland area is relatively reduced.

4. Coastal ecological environment

Global temperature rise leads to the melting of glaciers and ice sheets, which leads to the rise of sea level, which makes the sea level rise at an average annual rate of 1 ~ 2 mm, which accelerates the erosion and inundation of land by seawater. Storm surge also accelerated the erosion of coastal zone by seawater. On August 20th, 1997, a storm surge occurred in Hekou District/KLOC-0, Dongying City, which caused the sea water to cross the high tide line. The northern part of Hekou District was flooded for 60 hours, and all the trees in the forest farm were destroyed. The coastline in the investigation area is about 20 1km long, and the change of coastline is directly affected by seawater intrusion.

(1) coastal erosion

Coastal erosion refers to the erosion, abrasion and dissolution of coastal waves, tidal currents and other marine forces, as well as the debris and some substances with strong chemical reactions carried by them, which are extremely harmful to residential areas and engineering facilities in coastal areas. Except for siltation within 20 kilometers near the modern estuary near the Yellow River Delta, other coastal sections are mainly eroded.

The sediment concentration of the Yellow River is the main reason for the rapid reclamation in the Yellow River Delta. Many years' observation shows that before 1980s, the Yellow River was rich in water and sediment, with an average annual inflow of 320.86× 108 m3 and an average annual inflow of 746×108m3 t. Within a certain length and width of the Yellow River estuary, the average annual reclamation was 40 km2/a, Coastal erosion10 ~15km2/a ... Since the 1990s, due to the decrease of runoff in the lower reaches of the Yellow River, the phenomenon of water cut-off has intensified, coupled with the development of soil and water conservation in the middle and upper reaches of the Yellow River and the flood control and sand retention of Xiaolangdi Reservoir Project, the sediment discharge has obviously decreased. Since 1990s, the annual sediment discharge of the Yellow River into the sea has been 3.64× 108 t, only 28% of that in 1950s. The sharp decrease in the amount of sediment discharged from the Yellow River into the sea has broken the necessary conditions for maintaining the balance between coastal siltation and erosion, and made the coast of the Yellow River Delta, which was originally dominated by siltation, become dominated by erosion under the action of marine dynamic factors. If left unchecked, the coastline of the delta will be eroded continuously, which will not only have a great impact on Shengli Oilfield and the national high-efficiency eco-economic development demonstration zone, but also have a devastating impact on the natural conditions of the entire Yellow River Delta wetland.

(2) Coastal siltation

The coastal sediment deposition in the investigation area is mainly near the Yellow River estuary. Every year, about 80% of the sediment brought into the estuary by the Yellow River is deposited on land and coastal areas, and less than 20% of the sediment is exported to the sea. Such a huge amount of sediment transport makes the Yellow River Delta famous for its rapid siltation. At present, the coastal siltation in the Yellow River Delta is mainly distributed near the estuary. During the period of 1976 ~ 1996, the land reclamation rate was 434.3 km2 and 2 1.7 km2/a, in which the land reclamation rate was 32 during the period of 1976 ~ 1985.

Coastal siltation in the Yellow River Delta makes the ever-increasing shallow beaches especially suitable for the growth of marine life, and the silted land provides a broad space for the development of Shengli Oilfield. At the same time, the instability of the tail of the Yellow River has also adversely affected the production layout of the oil region. In addition, the Yellow River sediment diffusion into the sea will inevitably deposit the navigation channels of Guangli Port, Dongying Port and Yangjiaogou Port.

(3) Beach development and mariculture

In 2000, the tidal flat area of Dongying City was 48× 104 hm2, which was the largest in the whole province, increasing by 13× 104 hm2 compared with 1986, and Binzhou City increased by 25× 104 hm2. Among them, Binzhou City has the largest reclamation intensity, with an area of11.52×104hm2. Reclamation of Zero Tidal Flat in Dongying City to Protect the Yellow River Delta Nature Reserve. Mariculture is only distributed in Dongying and Binzhou, with an area of about 12.48× 104 hm2. Due to the oil development in Bohai Bay, mariculture has been restricted in recent years, and the mariculture area has increased, but the extent is small. Tidal flat development and mariculture have been seriously eroded by red tides and oil spill accidents. Red tides are concentrated in the southwest of Bohai Bay, mainly in Binzhou and Dongying. In the 1970s, red tides occurred three times. With the aggravation of pollution in the coastal waters of Bohai Sea, seawater is anoxic, the frequency of red tide is accelerated, the influence range is wide, and the duration and environmental harm are increasing. The occurrence of red tide basically lies in the serious pollution of seawater, and the oxygen content in seawater is greatly reduced. Red tide algae like to grow and develop in the anoxic and turbid polluted seawater environment. The harm of red tide is caused by seawater pollution and anoxia, so the task of harnessing the seawater ecological environment is also very arduous.

(4) seawater intrusion

Seawater intrusion is one of the geological disasters in the coastal zone, which is extremely harmful, concealed and difficult to control. The main causes of seawater intrusion are natural factors and human factors. The important hydrodynamic conditions in coastal areas have changed, which has destroyed the relatively balanced state of groundwater, fresh water and seawater, caused seawater to move inland, deteriorated groundwater quality and destroyed the ecological environment.

Apart from natural factors, seawater intrusion is mainly caused by human factors. Over-exploitation of groundwater for many years leads to the formation of groundwater funnel, which leads to salt water intrusion, depletion of upper aquifer, reduction of single well water output and increase of mining depth, which makes deep groundwater suffer from seawater intrusion to varying degrees. Seawater intrusion causes groundwater quality deterioration, soil secondary salinization and soil fertility decline, which further leads to agricultural production reduction, scrapping of motor wells and serious damage to the ecological environment of coastal plains. Many farmland in the invaded area was abandoned and became barren.

(B) the existing ecological and environmental problems

The quality of ecological environment is restricted by many factors, including geological environment, regional water pollution, land degradation, forest secondary biochemistry, meteorological conditions and other factors, as well as human factors brought about by economic development.

Under the economic tide, the development of industry and agriculture pays more attention to development than governance, and pays more attention to benefits than long-term, which has caused serious damage to the ecological environment. The development of industry and agriculture is the place where human activities have the strongest impact on the geological environment. While developing and utilizing underground minerals and water resources, human beings have also changed and destroyed the ecological environment. Industrial and agricultural production activities include mineral exploitation, industrial and agricultural sewage discharge and over-exploitation of groundwater resources. Due to the above activities, underground goaf, groundwater drainage, sewage discharge and man-made geological effects have triggered a series of geological disasters and ecological environment problems.

The main eco-environmental problems in the investigation area include land subsidence, ground fissures, land salinization, land desertification, soil erosion, seawater intrusion, water pollution, coastal erosion and coastal siltation. These ecological and environmental problems have brought great harm and inconvenience to industrial and agricultural production and human activities in this area. For example, the land subsidence in Jining area is increasing year by year, and the scope of subsidence area is also expanding accordingly. Except for large-scale agricultural areas, due to the influence of land subsidence, crops have been reduced in a large area, and soil degradation and salinization have intensified, which seriously threatens the development of agriculture. More seriously, the land subsidence in Jining city has reached 80mm, and the maximum settlement point is 140.5mm, which is located in the west of Jianshe Road, east of Taibailou West Road and east of Jiqiao 'an Road. Land subsidence directly affects urban construction, cracks appear in houses, and the road surface collapses. Even the ancient building Taibai Building has not been spared, which has caused great harm to people's normal life.

The fragile natural ecological environment is disturbed and destroyed by multiple factors. The ecological environment has seriously endangered the normal work and life of human beings, and it is urgent to control the ecological environment.

Second, the distribution of endemic diseases.

According to relevant data, there are four kinds of endemic diseases related to the environment in this area: endemic goiter (goiter), endemic fluorosis (endemic fluorosis), Keshan disease and Kaschin-Beck disease.

Onychomycosis

Endemic goiter is a global disease, which is mainly caused by iodine deficiency or excess in geological environment and related to geochemical elements. When iodine intake is unbalanced, it will lead to disorder of biochemical function and abnormality of physiological function. It is characterized by goiter, neck thickening, physiological development stagnation, abnormal cell metabolism and central nervous system hypoplasia. In severe cases, there will be symptoms such as short stature and paralysis, which will seriously endanger human health. As an essential trace element for human body, iodine must remain stable within a certain range. The urine iodine of the population is lower than 100μg/L, which is called iodine deficiency. Urine iodine 100 ~ 200μ g/L is the most suitable state for iodine nutrition. Urine iodine exceeding 300 μ g/L is called "exceeding the appropriate amount"; When urinary iodine exceeds 500 μg/L, the incidence of hyperthyroidism caused by iodine increases. According to the etiology, goiter can be divided into iodine deficiency endemic goiter and iodine excess goiter.

1. iodine deficiency endemic goiter

This disease is caused by long-term iodine deficiency. Under normal circumstances, each person can take iodine 100 ~ 250 mg every day, which can meet the needs. If it is lower than 100~250 mg/L, cretinism patients with mental retardation, deafness and dwarfism will appear. The disease is mainly distributed in middle and low hills and alluvial plains. According to the relevant data in 2000, the survey area is mainly distributed in Guangrao County and northern Weifang. The total number of patients is 28,800, including 8 1 person with cretinism, which also occurs in Jining area.

2. Iodine goiter

According to the national standard "Delineation of Water-borne High Iodine Areas and Endemic High Iodine Goiter Areas" (GB/T 19 380—2003), the concept of high iodine areas is that in a specific natural environment, people consume more iodine than their physiological needs for a long time through drinking water, but it is not enough to cause the prevalence of high iodine goiter. The standard is that the iodine content of drinking water for residents is >150μ g/l; The concept that the median urinary iodine of children aged 8 ~ 10 is more than 400μ g/L in high iodine area is that in a specific natural environment, people take too much iodine through drinking water for a long time, which causes goiter and forms an endemic area of high iodine goiter. The demarcation standard (in towns and villages) is that the iodine content of residents' drinking water is > 300μ g/L; The median urinary iodine of children aged 8 ~ 10 is more than 800μ g/l; The goiter rate of children aged 8 ~ 10 is more than 5%.

Excessive iodine causes changes in thyroid morphology and function, and causes thyroid autoimmune diseases, such as goiter, hyperthyroidism, hypothyroidism and Hashimoto thyroiditis. The harm of high iodine has become a serious public health problem in China.

Shandong province is one of the provinces most seriously affected by high iodine. According to the survey conducted by Shandong Institute of Endemic Disease Prevention and Control in 2003 ~ 2004, the iodine-high endemic areas and regions were distributed in 288 townships in 7 cities and 38 counties (cities, districts), with the threatened population140,000. As far as the distribution range of high iodine areas is concerned, the investigation area is located in two large-scale high iodine areas in Shandong Province. One is the alluvial, marine and lake plain area near the Yellow River Estuary, adjacent to the Bohai Sea in the east, including Hebei and Shandong provinces 12 county, which is a deep-water iodine-rich area. Second, the area between the Yellow River and the old course of the Yellow River, including parts of northern and southwestern Shandong, is a shallow water high iodine area. Both high iodine areas and high iodine areas in Shandong Province are located in this investigation area.

There are 17 high iodine areas in the survey area, including: gaoqing county, Decheng District, Laoling City, Ling County, Ningjin County, Xiajin County, Wucheng County, Liangshan County, Linqing City, Shenxian County, Chiping County, guanxian, Peony District, County, Shan County, Juye County and Jia County. Coastal areas are mainly concentrated in the Bohai Plain in northern Shandong, while inland areas are mainly concentrated in the Southwest Shandong Plain, the lower reaches of the Yellow River and the banks of the Beijing-Hangzhou Grand Canal.

(2) Endemic fluorosis

Endemic fluorosis is a geochemical disease that occurs in a specific geographical environment. Under natural conditions, people live in high-fluorine environment for a long time, mainly through drinking water, air or food, which leads to chronic cumulative poisoning of the whole body, commonly known as "rhubarb teeth", "dry teeth", "sugar bone disease" and "black bone wind". Shandong province is one of the provinces with the most serious endemic fluorosis in China, with a wide area, serious illness and great harm. People in endemic fluorosis areas drink high-fluorine water, which can cause dental fluorosis, skeletal fluorosis, even paralysis and loss of working ability, seriously endangering the health of people in this area and directly affecting the economic and social development in this area. Shandong province is a drinking water endemic fluorosis area, and endemic fluorosis areas in the province are distributed in 17 cities, 1 13 counties (cities, districts) and 1656 villages. There are 9.79 million people in endemic fluorosis areas, 2.9 million people with dental fluorosis and 230,000 people with skeletal fluorosis.

Endemic fluorosis in this area is mainly distributed in Dezhou, Binzhou, Jining, Zibo and Weifang, involving 48 counties (cities, districts) in 9 cities. * * * There are 670 endemic fluorosis villages1village, including 3935 villages with mild fluorosis (water fluoride 1.0 1 ~ 2.00 mg/L), 2437 villages with moderate fluorosis (water fluoride 2.00 ~ 4.00 mg/L) and severe fluorosis villages.

Since the early 1980s, Shandong Province has carried out the prevention and control of endemic fluorosis with improving water and reducing fluoride as the main measures (mainly drilling wells), and achieved certain results. 4 188 affected villages in the survey area improved water and reduced fluoride, benefiting more than 3.54 million people; Gaishui village accounts for 62.50% of endemic fluorosis villages in the survey area, and the beneficiary population accounts for 62.60% of the endangered population in the survey area. The investigation results in recent years show that the rejection rate of water improvement projects is above 30%, and the fluoride in water of basically normal operation projects is above 30%. In fact, less than 50% of the water improvement projects meet the sanitary standard of drinking water, that is, less than half of the sick villages with improved water can really drink low-fluorine sanitary water, and the prevention and control situation is still very serious.

(3) Keshan disease

Keshan disease is an endemic cardiomyopathy, and its etiology is not completely clear. The epidemic area of the disease is wide and the mortality rate is high, which seriously endangers people's lives and health. The survey area has a small distribution range and a low incidence rate, mainly distributed in parts of Jining and Weifang. At present, there are 1500 cases in Jining city, and the incidence rate has a downward trend, mostly distributed in the surrounding areas of Nansi Lake. Keshan disease in Weifang is mainly distributed in the contact zone between low hills and plains. According to the data of Weifang endemic disease office in 2000, there were only 14 people.

Kaschin-Beck disease

Kaschin-Beck disease does great harm to human skeleton and joint system. The patient's joints are swollen, he walks left and right, he has difficulty in moving, even his limbs are short and deformed, and even he is disabled. The occurrence of Kaschin-Beck disease is mainly caused by drinking heavily polluted kiln water for a long time. Calcium deficiency, magnesium deficiency, selenium deficiency, high humic acid and Fusarium in grain may all be directly related to the onset of Kaschin-Beck disease. There are few places where the disease was found in the investigation area, only Weifang. According to the data provided by the office of endemic diseases, there were 856 patients in 2000, including 2 newly discovered patients, and the incidence rate was mainly in childhood.

The occurrence of endemic diseases is closely related to the water environment, and has a great causal relationship with the content of elements in water and the lack of some elements. Changing the quality of drinking water is the key factor to solve this problem, so creating an excellent water quality ecological environment is the foundation to eradicate endemic diseases.