Chapter 18
Soil Protection and Solid Waste Management

Introduction

Content

Objectives

Quiz

Links

Graphs

glossary

Corrections

Updates

Amendments

Introduction

Soil is the third environmental resource on which we critically depend, in addition to water and air. Soil is an extremely thin and sensitive "skin"on the planet. Life has developed on this skin-like layer, often only meters thick.

Soil as a resource has always been there in huge quantities and it is not until recently that it is clear that soil is a resource that we need to take care of, protect and restore. Worldwide soil is becoming a very urgent problem and destruction of soil is perhaps the largest threat against the long term productivity of the planet. Loss of soil is due to erosion, either through water or wind. Agricultural soil is impoverished through loss of organic content, the humus, by mineralization, and loss of nutrients by drainage. This is a concern in some parts of the Baltic Sea region and important worldwide. In the Baltic Sea region some forest soils are harmed by acidification as well.

Soil in industrial and urban areas is threatened by contamination and pollution. The reason is more than anything lack of an acceptable management of solid waste. The customary way to get rid of solid waste was, and too often still is, just to empty it in the nearest non-occupied area, such as a landfill or deposit. Much waste, especially industrial waste, leaks toxic substances and thus is a threat towards soil, water, and sometimes air.

Contaminated industrial sites are called "brownfields."In brownfields the soil may contain tar, fuels, oil or other hydrocarbons, not least phenols, resorcinol or collectively creosote. It may also contain chlorinated hydrocarbons, e.g. PCBs, or chloro-phenols, to mention a few of the more common contaminants. Thirdly, large amounts of heavy metals are present in some sites.

Polluted land areas constitute a risk since they may leak to ground water and pollute large parts of the environment. There are examples of old landfills, and old industries that threaten entire drainage areas. To protect human health and the environment there are thus good reasons to restore such sites. In cities, old industrial sites are also valuable e.g. as new residential areas or areas for new activities. Thus, economic development is also a reason for restoration. However, remediation of destroyed soil is difficult and costly. Technologies for soil remediation include physical, chemical, and biological methods. Today large national programs for the restoration of brownfield sites exist in many countries. In the Baltic Sea region in addition to the industrial sites there are also hundreds of former Soviet military bases that are polluted.

The waste management approach today is to avoid deposition of a material as long as possible. Waste is seen as a resource with an economic value that is to be used. Recycling and reuse strategies are thus developing.

Waste management is often a task for engineers even if much of the technologies developed for purification of water, air, and soil are based on processes in nature. In old societies very little was wasted. Now we have to return to this approach. Waste is a resource to be recycled.