Utility of a multi-tracer approach as a component of adaptive monitoring for municipal wastewater impacts

Distinguishing municipal wastewater effluent (MWWE) from other industrial effluents or through an urbanized watershed can be challenging. In complex receiving environments, linking environmental responses to specific compounds or effluents is not always straight forward. In order to characterize the inherent complexity of tracing MWWE in aquatic systems influenced by multiple stressors, a proposed multi-tracer suite is intended to highlight areas of potential biological concern. Characterization and quantification of effluent exposure to aquatic biota in this manner is essential to shape policies intended to encourage wastewater infrastructure development (i.e. treatment plant upgrade) and broader environmental management. This paper describes the use of a comprehensive suite of tracers that includes isotopes in support of a core surveillance program, demonstrating its effectiveness both empirically and with respect to diagnostic value contributed to monitoring programs.Natural Sciences and Engineering Research Council (NSERC

An Assessment of the Spatial and Temporal Variability of Biological Responses to Municipal Wastewater Effluent in Rainbow Darter (<i>Etheostoma caeruleum</i>) Collected along an Urban Gradient

<div><p>Municipal wastewater effluent (MWWE) and its constituents, such as chemicals of emerging concern, pose a potential threat to the sustainability of fish populations by disrupting key endocrine functions in aquatic organisms. While studies have demonstrated changes in biological markers of exposure of aquatic organisms to groups of chemicals of emerging concern, the variability of these markers over time has not been sufficiently described in wild fish species. The aim of this study was to assess the spatial and temporal variability of biological markers in response to MWWE exposure and to test the consistency of these responses between seasons and among years. Rainbow darter (<i>Etheostoma caeruleum</i>) were collected in spring and fall seasons over a 5-year period in the Grand River, Ontario, Canada. In addition to surface water chemistry (nutrients and selected pharmaceuticals), measures were taken across levels of biological organization in rainbow darter. The measurements of hormone production, gonad development, and intersex severity were temporally consistent and suggested impaired reproduction in male fish collected downstream of MWWE outfalls. In contrast, ovarian development and hormone production in females appeared to be influenced more by urbanization than MWWE. Measures of gene expression and somatic indices were highly variable between sites and years, respectively, and were inconclusive in terms of the impacts of MWWE overall. Robust biomonitoring programs must consider these factors in both the design and interpretation of results, especially when spatial and temporal sampling of biological endpoints is limited. Assessing the effects of contaminants and other stressors on fish in watersheds would be greatly enhanced by an approach that considers natural variability in the endpoints being measured.</p></div

Data from - An assessment of the spatial and temporal variability of biological endpoint responses of rainbow darter collected along an urban gradient.

Municipal wastewater effluent (MWWE) and its constituents, such as chemicals of emerging concern, pose a potential threat to the sustainability of fish populations by disrupting key endocrine functions in aquatic organisms. While studies have demonstrated changes in biological markers of exposure of aquatic organisms to groups of chemicals of emerging concern, the variability of these markers over time has not been sufficiently described in many wild fish species. The aim of this study was to assess the spatial and temporal variability of biological markers in response to MWWE exposures and to test the consistency of these same responses between seasons and among years. Rainbow darter (<i>Etheostoma caeruleum</i>) were collected in spring and fall seasons over a five-year period in the Grand River, ON, Canada. In addition to surface water chemistry (nutrients and selected pharmaceuticals), measures were taken across levels of biological organization in rainbow darter. The measurement of hormone production, gonad development, and intersex severity were temporally consistent and suggested impaired reproduction in male fish collected downstream of MWWE outfalls.  In contrast, ovarian development and hormone production in females appeared to be influenced more by urbanization than MWWE.  Measures of gene expression and somatic indices were highly variable between sites and years respectively, and were inconclusive when determining the impacts of MWWE overall. Robust biomonitoring programs must consider these factors in both the design and interpretation of results, especially when spatial and temporal sampling of biological endpoints is limited.  Assessing the effects of contaminants and other stressors on fish in watersheds would be greatly enhanced by an approach that considers natural variability in the endpoints being measured

Liver somatic index is variable through the urban watershed.

<p>Liver somatic index of (A, C) female and (B, D) male rainbow darter collected through an urban gradient in the (A, B) fall of 2007 (red triangles), 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles) and in the (C, D) spring of 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles). The dashed line indicates the 25% critical effect size calculated from the mean of the data from the rural reference site (R), and the solid line indicates the 95% confidence interval from the pooled R.</p

Condition factor increases downstream of MWWTP outfalls in fall, but not spring.

<p>Condition factor of (A, C) female and (B, D) male rainbow darter collected through an urban gradient in the (A, B) fall of 2007 (red triangles), 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles) and in the (C, D) spring of 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles). The dashed line indicates the 10% critical effect size calculated from the mean of the data from the rural reference site (R), and the solid line indicates the 95% confidence interval from the pooled R.</p

Comparison of significant changes observed in male rainbow darter downstream of the Waterloo (DSW) and Kitchener (DSK) MWWTPs in relation to either the rural reference site (R) or the immediate upstream (USW, USK respectively) reference site.

<p>Comparisons are made for fall and spring field collections.</p

Canonical analysis of principal coordinates (CAP) ordination with biological variables as vectors.

<p>(A) Female and (B) male biological measures collected from a reference site (green squares), sites upstream of municipal wastewater treatment plant (MWWTP) outfalls (red downward triangles), or downstream of MWWTP outfalls (blue triangles).</p

Properties of Waterloo and Kitchener municipal wastewater treatment plants from 2007 to 2011 [51].

<p>Properties of Waterloo and Kitchener municipal wastewater treatment plants from 2007 to 2011 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164879#pone.0164879.ref051" target="_blank">51</a>].</p

Intersex incidence and severity are consistently higher at sites downstream of MWWTP outfalls.

<p>Intersex (A, C) incidence and (B, D) severity of male rainbow darter collected through an urban gradient in the (A, B) fall of 2007 (red triangles), 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles) and in the (C, D) spring of 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles). The dashed line indicates the upper 25% critical effect size calculated from the mean of the data from the rural reference site (R), and the solid line indicates the upper 95% confidence interval from the pooled R.</p

Impact of MWWE on gonad development is clear in males, but not females.

<p>Proportion of advanced cell types in (A, C) female and (B, D) male gonads of rainbow darter collected through an urban gradient. The proportion of all cell types was assessed through histological analysis of female and male gonads collected in (A, B) fall and (C, D) spring field seasons in 2007 (red triangles), 2009 (grey circles), 2010 (green squares), 2011 (yellow diamonds), and 2012 (blue down-facing triangles). The dashed line indicates the upper 25% critical effect size calculated from the mean of the data from the rural reference site (R), and the solid line indicates the upper 95% confidence interval from the pooled R.</p