Nautical Tourism in Marine Protected Areas (MPAs): Evaluating an Impact of Copper Emission from Antifouling Coating

Abstract

Copper (Cu) has a narrow range between optimal concentrations as a micronutrient critical for phytoplankton growth and concentrations potentially toxic to living organisms. This sensitivity indicates an ecosystem vulnerability that threatens not only nature but also human health due to bioaccumulation. An important source of elevated Cu concentrations in coastal environments are biocides used as antifouling protection on ships. A pilot study conducted in the Marine Protected Area (MPA) of the Krka Estuary (Croatia) over a period of 16 months investigated the relationship between ship traffic and Cu concentrations. The aim was to contribute to more informed environmental management by assessing the associated risks. In the study presented here, Cu concentrations were monitored, analyzed, and correlated with vessel traffic. Observations revealed that the seasonal increase in maritime traffic caused by nautical tourism was associated with an increase in Cu concentrations of more than five times, posing a toxicity risk to the environment. In order to understand the distribution of copper emissions, a mapping of maritime traffic was carried out by counting transits, radar imagery, and drone photography. This approach has proven sufficient to identify the potential risks to the marine environment and human health, thus providing an effective assessment tool for marine stakeholders.

Trace Metal Partitioning in the Salinity Gradient of the Highly Stratified Estuary: A Case Study in the Krka River Estuary (Croatia)

“…Conversely, concentrations of Cd, Pb and Ni generally increased from the FWL to the SWL, showing a diluting effect of the Krka River on their concentrations, as already observed for these metals in a previous study covering longitudinal estuarine transect [8]. Concentrations of Cu in the FWL changed between seasons depending on the nautical tourism activity, which is common for this estuary [8,31]. Similar Cu concentrations were observed in the FWL and SWL in non-touristic periods (February 2019 and April 2021), in contrast to summer samplings when 2-4 times higher Cu concentrations were measured in the samples from the FWL.…”

“…Namely, due to the scarce vegetation, the absence of significant anthropogenic influence and self-purifying ability of the Krka River, the estuary, as well as the coastal sea, are unusually clean in terms of trace elements, terrigenous material and biomarkers [8,[25][26][27][28][29][30]. The only concern presents the seasonal anthropogenic pressure related to increased boat traffic and touristic activities [8,31]. The estuary is permanently stratified: the surface fresh/brackish layer (FWL) is separated from the seawater layer (SWL) by a freshwater-seawater interface (FSI) formed at a depth between 1.5 and 5 m [8,30].…”

Spatial Distribution, Ecological Risk Assessment, and Source Identification of Metals in Sediments of the Krka River Estuary (Croatia)

“…Currently, some of the sources are eliminated; wastewater has been treated and discharged in the open sea since 2007, and the electrode and ferroalloy factory (TEF factory) was closed nearly three decades ago. However, the removal of industry from the estuary resulted in the growth of nautical tourism, which poses a new anthropogenic threat to the estuarine ecosystem [28,35]. Concerning elevated concentrations reported previously in the Krka River estuary and changes in contamination sources, a detailed study was conducted in order to (1) determine the spatial distribution of metals in surface sediments, (2) evaluate the degree of recent sediment contamination, and assess the potential ecological risk of these metals to the estuarine environment, and (3) establish the relationship between metal concentrations and possible anthropogenic sources.…”

Bio‐Based Anti‐Biofoulant with Copper(II) as Intramolecular Catalyst for Radicals Formation

“…According to statistics, more than 3000 metric tons of copper are currently imported from the coating into seawater each year. [ 15 ] Especially in some bays or closed water bodies where water exchange is poor, copper‐containing antifouling coating has a significant effect on the copper content of the water body. [ 13 ] In addition to copper‐containing antifoulants, chlorothalonil, Irgarol 1051, Sea‐Nine 211, diuron, zinc dioxane, etc., are commonly used as eco‐friendly antifoulants, but these antifoulants are still required to be combined with cuprous oxide or other copper‐containing antifoulants because of their weak inhibitory effect on large fouling organisms.…”