Large anthropogenic nutrient and pollutant loads to the sea from small unmonitored near-coastal catchment areas

Innovations Report: A new study by [G.] Destouni and her research group at Stockholm University (SU) shows that the waterborne nutrient and pollutant loads from land to the sea may be larger from small near-coastal areas, which are left without systematic environmental monitoring of their coastal loads, than from the large, systematically monitored main rivers.

Taking Sweden and the whole Baltic Sea region as examples, the study shows also that the reported Swedish loads of nitrogen and phosphorous to the Baltic Sea are significantly smaller than expected from strong correlations between a country’s nutrient loads and its population, area and economic activity (GDP per capita) within the Baltic Sea drainage basin (BSDB), which are found for all other Baltic Sea countries.

….The near-coastal areas that are left without systematic environmental monitoring may be small, but they extend along most of the coastlines and often have a large population proportion. For the whole BSDB, for instance, these areas cover 13% of the total area and 24% of the total population of the BSDB, according to an earlier study(2) by the same research group.

…The unmonitored near-coastal catchment areas are not just forgotten when, for instance, the Swedish nutrient loads to the Baltic Sea are estimated. The data gaps are bridged with the help of computer model calculations. However, because the model results cannot be checked against representative field data for the unmonitored areas, they may be significantly wrong.

… The new study(1) synthesizes main implications of these earlier and parallel studies and suggests a concrete, improved methodology for interpreting available field data and estimating the mass loading to the sea from unmonitored near-coastal catchment areas.

The Bay of Puck on the Baltic Sea, near the town of Władysławowo, southwards, Poland, spring of 2006, shot by Krzysztof, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2