Trophodynamics of current use pesticides and ecological relationships in the Bathurst region vegetation‐caribou‐wolf food chain of the Canadian Arctic

Abstract

The bioaccumulation of current use pesticides (CUPs) and stable isotopes of carbon and nitrogen were investigated in vegetation-caribou-wolf food chain in the Bathurst region (Nunavut, Canada). Volumetric bioconcentration factors (BCF(v)) in vegetation were generally greatest for dacthal (10-12) ≥ endosulfan sulfate (10-11) > ß-endosulfan (>9.0-9.7) ≥ pentachloronitrobenzene (PCNB; 8.4-9.6) > α-endosulfan (8.3-9.3) > chlorpyrifos (8.0-8.7) >chlorothalonil (7.6-8.3). The BCF(v) values in vegetation were significantly correlated with the logarithm of the octanol-air partition coefficients (log K(OA)) of CUPs (r(2) = 0.90, p = 0.0040), although dacthal was an outlier and not included in this relationship. Most biomagnification factors (BMFs) for CUPs in caribou:diet comparisons were significantly less than 1. Similarly, the majority of wolf:caribou BMFs were either significantly less than 1 or were not statistically greater than 1. Significant trophic magnification factors (TMFs) were all less than 1, indicating that these CUPs exhibit trophic dilution through this terrestrial food chain. The log K(OA) reasonably predicted bioconcentration in vegetation for most CUPs but was not correlated with BMFs or TMFs in mammals. Our results, along with those of metabolic studies, suggest that mammals actively metabolize these CUPs, limiting their biomagnification potential despite entry into the food chain through effective bioconcentration in vegetation.

Current‐use pesticides in seawater and their bioaccumulation in polar bear–ringed seal food chains of the Canadian Arctic

“…and Flavocetraria sp.) and moss ( Rhytidium rugosum ), which are rootless, atmospherically dependent primary producers, had Σendosulfan profiles that were nearly identical to air . The differences in proportions of Σendosulfan in plankton between locations did however reflect the differences in water, with uptake and accumulation in plankton and algae apparently in proportion to endosulfan availability in seawater at each location (Figure ).…”

“…Extracts were analyzed by gas chromatography, negative chemical ionization, low‐resolution mass spectrometry (GC‐NCI‐MS). The GC‐MS parameters, analyses, and quantification methods are identical to those previously reported and are briefly outlined in the Supplemental Data. Mass to charge ( m / z ) ratios of ion fragments monitored for each compound are included in Supplemental Data, Table S2.…”

“…Though studies of CUPs in arctic biota are relatively rare, they have been reported in a vegetation–caribou–wolf food chain in northern Canada , in some marine organisms from Greenland , and in terrestrial biota from national parks in Alaska . Bioaccumulation hypotheses, modeling, and some (limited) field studies suggest that organic contaminants with intermediate octanol–water ( K OW ) and octanol–air ( K OA ) partition coefficients (10 2 < K OW < 10 10 and K OA ≥10 6 ), such as the CUPs, will bioaccumulate to greater degrees in mammalian food chains relative to food chains containing exclusively water‐respiring organisms (when metabolism of the contaminants is insignificant).…”

Plant–bacteria partnerships for the remediation of persistent organic pollutants

“…Due to high stability and long-range transportation characteristics, POPs find their ways from water and air into the soil ecosystem where they are taken up by plants and living organisms (Hao et al 2014;McLeod et al 2014;Morris et al 2014). They follow the usual process of bioaccumulation and biomagnification as they move up in each trophic level of the food chain.…”

Evaluation of evidence that the organophosphorus insecticide chlorpyrifos is a potential persistent organic pollutant (POP) or persistent, bioaccumulative, and toxic (PBT)

“…Only one study was found on movement of CPY in food webs. Several current-use pesticides were measured in a terrestrial food web in the Canadian Arctic [97], and CPY was detected frequently in moss and mushrooms (83% to 86%) but at lesser frequency in lichens, willow, and grass (44% to 50%). Concentrations ranged from 0.87 ng/g l. ms. in moss to 0.07 ng/g l. ms. in lichen.…”