Types of waste

Certain types of waste, and certain issues, are central drivers to changes in our oceans. In most cases these categories of waste can be easily grouped, although they may be derived from diverse and even multiple sources. For example, wastewater can come from any location connected to the sewerage system, e.g., homes, schools, sporting, facilities, shops, business, industry, and parks.

Sediments are increasingly dominant in coastal waters. Some are natural, but others may be derived from a broad range of changes to land-use patterns, and particularly from deforestation and subsequent erosion. Nutrients may well be associated with these solid wastes, but are more usually carried in solution, and are derived from inputs ranging from agriculture to sewage. Like nutrients, but far more potent at low concentrations is a massive array of toxic pollutant. Although typically deposited directly into the oceans, or carried by rivers, some nutrients, toxins, and even fine sediments may be carried in the air to be deposited at sites very remote from human occupation.

Climate change is another issue facing life in all areas across the planet. Strictly, the waste issue here is that of greenhouse gases, but the issues these are driving are diverse, and include chemical changes to the ocean waters, warming temperatures and sea level rise.