Biomonitoring of nutrient and toxic element concentrations in the Sarno River through aquatic plants.

The Sarno River is considered the most polluted river in Europe and one of the ten most polluted rivers in the world. So far, its quality has been usually evaluated by water and sediment analyses of either inorganic or organic pollutants. However, a biomonitoring approach would be of paramount importance in the evaluation of river quality, since it integrates pollutant temporal fluctuations, as in the case of discontinuous inputs from urban, industrial and agricultural activities. To this end, a passive biomonitoring study of the Sarno River was carried out, using two native aquatic plants accumulators of inorganic pollutants. The spring area was monitored analysing the roots of the semi-submerged Apium nodiflorum, whereas the whole river course was monitored analysing the shoots of the submerged Potamogeton pectinatus. The information on the four macronutrient (Ca, K, Mg, P), the six micronutrient (Cu, Fe, Mn, Na, Ni, Zn) and the four toxic element (Cd, Cr, Pb, V) concentrations were separately combined in the Nemerow Pollution Index. Results evidenced a severe pollution degree of the Sarno River, attributable to toxic elements > micronutrients > macronutrients. In particular, the spring area showed high K concentrations, as well as high concentrations of several micronutrients and toxic elements. A generalized Zn contamination and a progressive macronutrient (above all Ca and P), micronutrient (above all Ni, Cu and Fe) and toxic element (above all Cr and Pb) accumulation toward the mouth was related to pollution from agricultural and urban activities. Industrial sources, especially tanneries along the Solofrana tributary, accounted for high Mn concentrations, whereas the volcanic origin of the substrate accounted for a generalized V contamination.

Aquatic macroinvertebrate community responses to pollution of perfluoroalkyl substances (PFAS): Can we define threshold body burdens?

The pollution of per- and polyfluorinated alkyl substances (PFAS) in aquatic environments is a worldwide concern of which the ecological impact is still not well understood. Especially field-based effect studies in aquatic ecosystems are generally lacking, creating a knowledge gap that goes along with monitoring and regulatory challenges. Therefore, this study examined if bioaccumulated PFAS concentrations could be related to ecological responses assessed by changes in the macroinvertebrate community structure. In addition, threshold body burdens that are protective of ecological damage were estimated. Aquatic macroinvertebrates were sampled in 30 streams across Flanders (Belgium) and 28 PFAS target analytes were measured in three resident taxa (Gammarus sp., Asellus sp. and Chironomus sp.) and translocated zebra mussels (Dreissena polymorpha). The macroinvertebrate community structure was assessed by calculating the Multimetric Macroinvertebrate Index Flanders (MMIF). Primarily long-chain perfluorinated carboxylic acids (PFCAs) were detected in both resident taxa (passive biomonitoring) and zebra mussels (active biomonitoring). Based on a 90th quantile regression model, safe threshold body burdens could be calculated for PFTeDA (7.1 ng/g ww) and ΣPFAS (2264 ng/g ww) in Gammarus sp. and for PFOA (5.5 ng/g ww), PFDoDA (1.7 ng/g ww), PFTrDA (0.51 ng/g ww), PFTeDA (2.4 ng/g ww), PFOS (644 ng/g ww) and ΣPFAS (133 ng/g ww) in zebra mussel. An additional threshold value was calculated for most compounds and species using the 95th percentile method. However, although these estimated thresholds are pertinent and indicative, regulatory applicability requires further lines of evidence and validation. Nevertheless, this study offers first-time evidence of associations between accumulated PFAS concentrations in invertebrates and a reduced ecological water quality in terms of macroinvertebrate community structure and highlights the potential of Gammarus sp. and zebra mussels to serve as reliable PFAS biomonitoring species.

Comparative biomonitoring of airborne potentially toxic elements using mosses (Hypnum cupressiforme, Brachythecium spp.) and lichen (Evernia prunastri) over remote areas.

The selection of the appropriate biomonitor species is a crucial criterion for biomonitoring on a broad spatial scale. Mosses Hypnum cupressiforme and Brachythecium spp. and lichen Evernia prunastri were sampled at 22 remote sites over Serbia aiming interspecies comparison of their bioconcentration capacities. The concentration of 16 potentially toxic elements (PTEs), Al, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, P, Pb, S, Sr, V, and Zn, was measured in the samples. Between the co-located mosses, linear regression analysis (type II) showed significant determination coefficients only for a couple of the elements (Cd and S), while for H. cupressiforme vs. lichen, significant regression lines were obtained for a broader set of elements (Ba, Cd, Fe, Hg, Mn, Ni, Sr). The ratio of the PTEs in the mosses discovered higher concentrations in H. cupressiforme than in another moss at some sites and vice versa at other sites. According to the PTE ratios, H. cupressiforme accumulated much more element content than the lichen, but followed a similar spatial pattern. In addition, principal component analysis (PCA) pointed out a different grouping of the PTEs depending on the species tested. The poor correlation of the moss-moss data is perhaps because several species of the genus Brachythecium were sampled, which possibly influenced the average genus accumulation capacity. In addition, morphological features of the mosses (concave vs. flat leaflets, creeping vs. cushiony life form) presumably delegate differences in PTE accumulation. To conclude, it should be careful with using more biomonitor species, even of the same genus, within the same study.

Biomonitoring of Airborne Microplastic Deposition in Semi-Natural and Rural Sites Using the Moss Hypnum cupressiforme.

We show that the native moss Hypnum cupressiforme can be used as a biomonitor of atmospheric microplastics (MPs). The moss was collected in seven semi-natural and rural sites in Campania (southern Italy) and was analyzed for the presence of MPs, according to standard protocols. Moss samples from all sites accumulated MPs, with fibers representing the largest fraction of plastic debris. Higher numbers of MPs and longer fibers were recorded in moss samples from sites closer to urbanized areas, likely as the results of a continuous flux from sources. The MP size class distribution showed that small size classes characterized sites having a lower level of MP deposition and a high altitude above sea level.

Spatial and seasonal use of biomarkers in dreissenids: implications for biomonitoring.

In addition to pollution, organisms are exposed to natural variations of the biotic and abiotic factors of their environment. A battery of sub-cellular biomarkers has been measured seasonally in several populations of both Dreissena polymorpha and Dreissena rostriformis bugensis. To observe and understand the variability associated with biomarker responses, water physicochemistry, sediment contamination, and internal concentrations of contaminants in soft tissues were also considered. Results evidenced seasonal, inter-specific, and inter-populational variability of the measured responses, highlighting the needs (1) to acquire long-term data on the studied populations and (2) to incorporate environmental parameters and contamination in the interpretation of biological responses. From a biomonitoring perspective, significant relationships were identified between biomarkers, internal concentrations of contaminants in soft tissues, and sediment contamination in D. r. bugensis and, to a lesser extent, in D. polymorpha. The detailed interpretation of each biomarker of the battery measured is complex, but a global analysis of all biomarkers at once allows to obtain this signature of the contamination of the studied sites.

Platyhypnidium aquaticum as Bioindicator of Metal and Metalloid Contamination of River Water in a Neotropical Mountain City.

Water contamination is a major environmental problem in many cities of the world. Most water contamination results from industry and human activities that generate toxic substances (e.g., metals). Rheophilic and aquatic mosses are found in lotic ecosystems, and their morphological and physiological traits are responsive to ecological and pollution gradients. Here we hypothesized that the native rheophilic moss Platyhypnidium aquaticum (A. Jaeger) M. Fleisch exposed to polluted waters can bioaccumulate greater amounts of metals, and a metalloid, than P. aquaticum exposed to pollution-free water. To this aim, we tested the bioindicator capacity of the aquatic P. aquaticum for 15 metals (Cd, Pb, Zn, Fe, K, Ca, Na, Mn, V, Co, Ba, Cr, Al, Sr, and Mg) and one metalloid (As), in twelve river samples coming from three urban and one control zone along the Zamora river in the city of Loja. When compared to the control, our results showed that P. aquaticum in the Southern, Central, and Northern zones of the city bioaccumulated higher concentrations of Ba, Cd, Co, Fe, Mg, Mn, Na, Sr, Zn, and the metalloid As. On the other hand, concentrations of Al, Ca, Cr, Pb, and V in P. aquaticum tended to be lower in the control zone, but these differences were not significant. We suggest that the presence of these contaminants may be related to water pollution (e.g., residual discharges and a lack of treatment systems) along urban zones of the river. We report for the first time the utility of P. aquaticum as a model species for development of long-term biomonitoring programs of water contamination in South America. Passive biomonitoring with P. aquaticum can be a simple and low-cost method to obtain reliable data of the current state of water contamination with metals and metalloids in tropical regions.

Trace element concentrations in the moss Hypnum cupressiforme growing in a presumably unpolluted area.

In this study we determined the concentrations of As, Cd, Hg, Ni and Pb in samples of the moss Hypnum cupressiforme collected during 5 different sampling surveys (2006-2014) in a presumably unpolluted area in northern Spain (25 sampling sites). We then applied factor analysis (FA) to the data to explore the factors underlying the spatial and temporal variability in the concentrations. The percentage of variance explained by the FA ranged between 34 and 98%, and was usually higher than 70%. The FA yielded 5 factors that explained the variance in the concentrations of Cd, As, Hg and Pb in all sampling surveys and also a single factor that explained the variance in Hg and Pb concentrations in 2006. Although the lack of obvious sources of pollution in the study region (at least for the elements considered) suggests that most elements (except perhaps Ni) probably originated from long-range atmospheric transport, this would not explain the results of the FA. We suggest that rather than being due to the origin of the pollutants (as frequently assumed), the spatio-temporal variability in the concentrations of these elements is probably determined by a series of other factors: the physicochemical characteristics of the pollutants and of the moss binding surfaces, physiological processes (e.g. moss growth), and the characteristics of the sampling sites (e.g. vegetation cover, elevation, slope, aspect). We therefore conclude that the assumption that variations in element concentrations in moss tissues are due to the origin of the pollutants is an oversimplification that leads to erroneous interpretation of the results of biomonitoring studies with terrestrial mosses.

A critical review of protocols for moss biomonitoring of atmospheric deposition: sampling and sample preparation.

Currently, the most important guideline for the application of the moss technique to monitor the atmospheric deposition of heavy metals is the "Heavy metals, nitrogen and POPs in European mosses: 2015 survey" published by the UNECE ICP Vegetation. Two main problems have been identified with this guideline: i) some of the recommendations regarding the methodological aspects involved in the application of the moss technique are not based on scientific criteria; and, ii) some recommendations in the manual are very vague and some aspects are even left out (e.g., elevation, distance to the coast). As a result there exists a high variability in the application of the protocol and many scientists adapt it to the specific conditions in the studied areas without evaluating how changes affect the results obtained. Therefore, in this article a total of 369 studies were reviewed including both methodological and application studies of the passive biomonitoring of the atmospheric deposition of heavy metals with terrestrial mosses. The results of this review have shown on the one hand, that none of the articles completely accomplished the ICP-Vegetation protocol suggestions, either because the information regarding some aspects was lacking or simply because the authors did not follow the manual suggestions. On the other hand, it was found that the results of methodological studies sometimes contradicted the ICP Vegetation manual recommendations. Thus, a new protocol in which each suggestion has been carefully and rigorously contrasted with the available literature has been proposed in this paper. In addition, practical and economic issues have also been considered and much more concise suggestions have been proposed which would facilitate its fulfilment in a more objective way.

Searching for native tree species and respective potential biomarkers for future assessment of pollution effects on the highly diverse Atlantic Forest in SE-Brazil.

This study summarizes the first effort to search for bioindicator tree species and respective potential biomarkers for future assessment of potential mixed pollution effects on the highly diverse Atlantic Forest in SE-Brazil. Leaves of the three most abundant species inventoried in a phytosociological survey (Croton floribundus, Piptadenia gonoacantha and Astronium graveolens) were collected in four forest remnants during winter and summer (2012). Their potential bioindicator attributes were highlighted using a screening of morphological, chemical and biochemical markers. The leaf surface structure and/or epicuticular wax composition pointed the accumulator properties of C. floribundus and P. gonoacantha. C. floribundus is a candidate for assessing potential accumulation of Cu, Cd, Mn, Ni, S and Zn. P. gonoacantha is a candidate to monitor polycyclic aromatic hydrocarbons. Increased levels of secondary metabolites and decreased antioxidant capacity in leaves of A. graveolens may support its value as a bioindicator for oxidative pollutants by visible dark stipplings.