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# Chlordecone consumption estimated by sewage epidemiology approach for health policy assessment

Damien Devault, Laurence Amalric, Sébastien Bristeau

► To cite this version:

Damien Devault, Laurence Amalric, Sébastien Bristeau. Chlordecone consumption estimated by sewage epidemiology approach for health policy assessment. Environmental Science and Pollution Research, 2018, 25 (29), pp.29633-29642. 10.1007/s11356-018-2995-x. hal-02860837

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# Chlordecone consumption estimated by sewage epidemiology approach for health policy assessment

Damien A. Devault<fnref n="1" /> · Laurence Amalric<fnref n="2" /> · Sébastien Bristeau<fnref n="2" />

## Abstract

Chlordecone is an organochlorine insecticide that was intensively used in the French West Indies to control the black weevil *Cosmopolites sordidus* in bananas. Its usage, however, resulted in the widespread pollution of the environment with heavy sanitary and social consequences, leading to population exposure mainly through food. Time-consuming and costly programs have been used to tackle this problem, and this study proposes to use the emerging sewage epidemiology approach to evaluate the current situation and the effect of such programs. The results determine the maximal value of chlordecone consumption, and considering the detection limit of the analytical protocol, the wastewater was found to have undetectable amounts of chlordecone. This value confirms the efficiency of the population protection strategy provided by French sanitary and environmental authorities. It also bolsters the usage of sewage epidemiology in pesticide assessment and relativizes the chlordecone risk compared to other chemicals of lesser concern.

**Keywords** Kepone · Back-calculation · Population exposure · French West Indies · Martinique

## Abbreviation

<table><tr><td>ADI</td><td>Admissible daily intake</td></tr><tr><td>BOD<sub>5</sub></td><td>Biochemical oxygen demand over 5 days</td></tr><tr><td>CLD</td><td>Chlordecone</td></tr><tr><td>CLD5BH</td><td>5b-Hydrochlordecone</td></tr><tr><td>CLDOH</td><td>Chlordecol</td></tr><tr><td>CLD-C13</td><td>CLD isotope-labelled</td></tr><tr><td>DTR</td><td>Drug target residue</td></tr><tr><td>FWI</td><td>French West Indies</td></tr><tr><td>GC-MS/MS</td><td>Gas chromatography-tandem mass spectrometer</td></tr><tr><td>LD</td><td>Limit of detection</td></tr><tr><td>NOAEL</td><td>No observed adverse effect level</td></tr><tr><td>PE</td><td>Population equivalent</td></tr></table>

<table><tr><td>THC</td><td>Δ-9-Tetrahydrocannabinol</td></tr><tr><td>THC-COOH</td><td>11-nor-Δ-9-Carboxytetrahydrocannabinol</td></tr><tr><td>WWTP</td><td>Wastewater treatment plant</td></tr></table>

## Introduction

Pesticide contamination of humans and ecosystems has become a major environmental concern. The impact of these products on human health and ecosystem integrity has been extensively studied, especially for persistent pesticides (Bro-Rasmussen 1996), but research is still necessary to evaluate the effects of mixtures in particular. Ecosystem contamination resulting from agricultural practices has been the subject of many studies, but for the majority of persistent organic pollutants (POPs), field or laboratory metabolisation studies are hindered by the very long half-lives of the compounds under investigation. The environmental management of the impact of such compounds is driven by POP half-life: either dilatory solutions should be found while waiting for a decrease in contamination or the professional sectors condemned by the persistent, high-level contamination of the environment should change. The latter alternative is involved in the case of chlordecone in the French West Indies (FWI) (Dubuisson et al. 2007).

<footnote>Damien A. Devault
damien.devault@martinique.univ-ag.fr</footnote>

<footnote n="1">¹ Public Health and Environment Laboratory, UMR 8079 Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 5 rue Jean Baptiste Clément, 92290 Chatenay-Malabry, France</footnote>

<footnote n="2">² Division Laboratoires, BRGM 3 avenue Claude Guillemin, 45060 Orléans, cedex 2, France</footnote>
Chlordecone (CLD, or Kepone) is an organochlorine insecticide that was applied to fight black weevil *Cosmopolites sordidus* infestation of banana plantations from 1972 to 1978 and then from 1981 to 1993 in the FWI. CLD has also been used in Europe, the USA, Africa, and Latin America (Le Déaut and Procaccia 2009). The total mass of CLD (ca 300 tons) spread across 190 km² in Martinique and Guadeloupe (FWI) led to the severe contamination of soils (Cabidoche et al. 2009), surface and ground water (respectively, Bocquené and Franco 2005 and Gourcy et al. 2009), plant products (Cabidoche and Lesueur-Jannoyer 2012), seafood (Coat et al. 2006, 2011), and livestock (e.g. Jondreville et al. 2014). Further, Mirex, an insecticide used more frequently worldwide than CLD (Hodgson 1998; Kaiser 1978), is expected to turn into CLD by photolysis (Alley et al. 1974; Ivie et al. 1974). CLD contamination has also been reported in coral fish in French Polynesia (Roche et al. 2011) and in *Chiloscyllium plagiosum* sharks fished near Hong Kong (Cornish et al. 2007). This would suggest that CLD could be much more widely distributed around the planet than initially thought. This environmental challenge needs to be tackled, but especially in the FWI since one sixth of the total 1800 tons of CLD ever produced in the world was spread across several thousand hectares in Martinique and, to a lesser extent, in Guadeloupe in the Caribbean until the mid-1990s. Such usage has led to acute pollution evoked in the scientific literature since 2000.

The sanitary potential impact on the local population identified to date notably includes an increased risk of prostate cancer (Multigner et al. 2010), negative effects on the cognitive and motor development of 7-month-old infants (Dallaire et al. 2012), and increased risk of preterm birth. Contrary to the historical contamination that occurred at the CLD production plant in Hopewell where Kepone disease was due to worker exposure, the main exposure expected in the FWI is linked to food and not to occupation. The acute sanitary, environmental, economic, and social impact of CLD pollution in the FWI has led to limitations or bans on established economic and traditional activities (Joly 2010). The aim of this article is to determine whether this prophylactic strategy has effectively protected the population.

To provide short-term data that is obtained concomitantly with drug consumption, Zuccato et al. (2005, 2008) developed an estimation method based on the measurement of drug residues in wastewater, which allows for the subsequent backcalculation using metabolism data. Currently, the prevalence of illicit substance consumption in the population is mainly estimated based on population surveys, seizure data, and inquiries, but these indirect methods are imprecise, time-consuming, and limited by the intrinsic inadequacies of the investigation tools (Devault et al. 2014). Furthermore, the results are usually published 1 year after data collection. These shortcomings all complicate the reactivity of the public authorities

(Daughton 2011). Studies have already shown significant differences in the consumption of illicit drugs between countries, but the innovative dimension of this approach is now being focused on pesticides (Rousis et al. 2017). Nevertheless, the biocide use, runoff, and lixiviation of contaminated soils could interfere in the analysis. Thus, in the present study, the investigated catchment area was selected because soils and groundwater are not contaminated, and the possibility of confusing inlet is null (Baran and Arnaud 2013). Anything measured in the study is due to human ingestion of CLD through consumption of local produce and water.

To our knowledge, this study is the first to provide an estimation of the sewage concentration of CLD. The backcalculation was performed on CLD, because it is known to be toxicokinetic in human bodies (Faroon et al. 1995). Consumption was estimated using the sewage epidemiology method with CLD taken as the drug target residue (DTR), given that CLD is mostly not degraded in the human body (Faroon et al. 1995). The wastewater treatment plant (WWTP) catchment area in Martinique chosen for this study did not have any past or present banana plantations or any animal husbandry and slaughter activities, considering that animal excretions could be contaminated by CLD (Lastel et al. 2016) and confused with that of humans. The groundwater of this area was likewise free from CLD, because of its land use. Further, the area was not affected by tourist accommodation. Other factors will be discussed below such as the technical differences in sewage management and their impact on the back-calculation used in the sewage epidemiology approach.

The acceptable daily intake (ADI) of CLD is 0.5 µg/kg body weight/day for chronic exposure and 10 µg/kg body weight/day for acute exposure, i.e. respectively 100 times less than the no-observed-adverse-effect-level (NOAEL) (Faroon et al. 1995).

## Materials and methods

### Investigation site

Fort-de-France city urban area, Martinique, has a population of 110,000 inhabitants, and sewage from the entire urban area is sent to four WWTPs. However, in such rugged terrain, only half the population is connected to the sewerage system, i.e. around 50,000 inhabitants of the urban Fort-de-France area, meaning that a significant proportion of the population is not connected to the system, leading to wastewater discharge directly into the soil, rivers, and sea around the coral reef. Indeed, the WWTP catchment area selected for this study corresponds to the most connected population area. The sewer system, which is altered in Martinique on account of spontaneous uncontrolled urban sprawl, seismic activity, and human alterations such as illegal rainwater connections to collect and channel rain to the sewer network, is efficiently controlled in this residential
urban catchment area populated by the middle class with a number of high-income households. The district has already been successfully monitored and was selected for the present article because of its suitability (Devault et al. 2014, 2016b).

To link chemical consumption to a population, it is neces-
sary to know the population size in the WWTP catchment
area. Numerous models use hydrochemical parameters to cal-
culate population size (Andreottola et al. 1994) instead of
designed capacity. The estimated population based on the bio-
chemical oxygen demand over 5 days (BOD<sub>5</sub>) reported over
last year is about 19,000 inhabitants for the selected WWTP
with a maximal capacity that is four times greater. During the
experiment, BOD<sub>5</sub> was calculated each day by properly
adjusting the consumption to the associated population.

Sampling strategy

Raw wastewater sampling was conducted daily for 1 week from 1 to 7 July 2017 at the entry of the selected WWTP. Sampling was done using refrigerated autosamplers (Endress and Hauser ASP2000; Boissy-Saint-Léger, France) positioned before the bar screen to obtain 24-h flow-weighted composite influent samples with a sampling frequency at least six times per hour according to the local WWTP procedures. At the end of each sampling day, 600 mL of each sample was collected in a glass bottle with Teflon seal and transported in a cooler for immediate storage at –20 °C in the Martinique University laboratory, located 20 min from Aimé Césaire airport (Martinique). At the end of the sampling campaign, all frozen samples were transported by airplane carrier to the analytical laboratory of the Bureau de Recherches Géologiques et Minières (Orléans, mainland France).

**Analytical methods**

Chemicals

The standard chlordecone hydrate (CLD; 8% water) also
named chlordecone gem-diol (CAS 143-50-0) and chlordecol
isotope-labelled (no CAS number) (CLDOH-d1) are commer-
cially available by Cil Cluzeau (Sainte-Foy-La-Grande,
France). The standard chlordecol (CLDOH) (CAS 1034-41-9)
is commercially available by Azur isotope (Marseille, France).
The individual standards (CLD, CLDOH, and CLDOH-d1)
were prepared from solid standards dissolved in acetone
(200 mg/L) and stored at –18 °C. 5b-Hydrochlordecone
(CAS 53308-47-7) at 10 mg/L in nonane and CLD isotope-
labelled (CLD-C13) at 100 mg/L in nonane are commercially
available by LGC Standards (Molsheim, France). All of these
standards have purity greater than 98%. Analytic-grade organic
solvents (acetone, cyclohexane, and hexane) were obtained
from Fisher Scientific (Illkirch, France).

Liquid-liquid extraction

The pH of the completely thawed sample was adjusted to 2.5 using H₂SO₄ solution and spiked with two internal standards of CLD-C13 and CLDOH-d1 solution (0.5 mL each at 0.3 mg/L for 500 mL sample). A mass of 25 g NaCl was added, and the sample was blended with 30 mL of hexane/acetone mixture (85/15, v/v) for 10 min shaking. The organic phase was removed, and the solvent addition was repeated twice.

For raw wastewater, the water volume was reduced to 100 mL and diluted to 500 mL with bottled spring water to avoid emulsion formation and to optimise the separation of organic and aqueous phases. The final extract was 1 mL.

The extract was first frozen for 1 h to eliminate water traces,
then concentrated to 0.5 mL using a TurboVap® LV
Concentration Evaporator (Biotage, Uppsala, Sweden) at 40 °C
and 0.6 bar, and finally solvent-exchanged to cyclohexane.

The method has been validated in natural water samples using different surface waters. Surface waters were enriched with their own sediment (dried at 40 °C, ground a homogenised) up to 500 mg/L. The organic carbon concentration in sediment was 5.5 g/kg. Then samples were spiked with the three compounds at two concentration level (0.1 and 0.3 µg/L for each compound) and extracted after 24 h contact time, to determine the recoveries. Complementary tests were done by enriching ground water with two contaminated soils from West Indies (after grinding) to check the liquid/liquid method efficiency (Fig. 1).

Recoveries are indicated in Figs. 2, 3, and 4.

Internal standards are used and added at the beginning of the protocol, to take into account the nature of the samples. It is imperative to correct the analytical variability and thus improve the precision and accuracy of the results. It should be added before sample extraction to suppress possible side effects during its analysis (loss during process, matrix effect, etc.). We chose internal standard with similar chemical and physical properties to match those of the analyte of interest, and labelled analogues as it is recommended. CLD-C13 and CLDOH-D1 are added in each sample and allow mimicking as closely as possible the behaviour of CLD and CLDOH, respectively. In order to quantify CLD5BH, a closely related compound CLD-C13 was used.

GC-MS/MS measurement

Extracts were analysed with GC-MS/MS using a GC 450 gas chromatography apparatus equipped with an 1177 injector, a Combi Pal (CTC) autosampler, and a 300-MS triple quadrupole mass spectrometer (Bruker, Marne la Vallée, France). The injector was equipped with a 4 × 6.3 × 78.5-mm liner with fibreglass and Sky™ deactivation (Restek, Lisses, France) operated in splitless mode at 280 °C and 1 mL/min. The column, an Rxi-1MS (30 m, 0.25-mm ID, 0.25 µm) from Restek,
<figure><img src="image_3.png" /><figcaption>**Fig. 1** Chromatograms of CLD
(a) CLD standard at 0.1 µg/L, (b)
wastewater extract, and (c)
wastewater extract spiked with
CLD at 0.1 µg/L</figcaption></figure>

was heated to 50 °C for 1.1 min, then to 250 °C at a gradient of
30 °C/min, and finally to 310 °C at 10 °C/min and isothermal-
ly for 1.5 min. The transfer line was at 310 °C. The ionisation
source, using electron ionisation at 70 eV to produce positive

ions, was at 250 °C. The collision gas pressure (argon in CID)
was 1.5 mTorr.

For quantitation purposes, data from the analysis standards
from 15 to 3000 µg/L were used to plot a weighted linear

<figure><img src="image_4.png" /><figcaption>**Fig. 2** Chlordecone recovery from solid phase by liquid-liquid extraction (%). Yellow: for spiked suspended matters at 0.1 µg/L for a ± 35% uncertainty. Orange: for spiked suspended matters at 0.3 µg/L for a ± 20% uncertainty</figcaption></figure>
**Fig. 3** 5b-Hydrochlordecone recovery from solid phase by liquid-liquid extraction (%). Yellow: for spiked suspended matters at 0.1 µg/L for a ±20% uncertainty. Orange: for spiked suspended matters at 0.3 µg/L for a ±20% uncertainty

<figure><img src="image_5.png" /></figure>

calibration. CLD-C13 as the internal standard was used for CLD and 5b-hydrochlordecone, while CLDOH-d1 was used for CLDOH.

## Calculation of chemical consumption

To conduct the back-calculation of consumption, the DTR must first be selected, followed by the excretion ratio ($U_{ex}$) of the DTR. DTR stability is a pivotal characteristic, as stressed by Devault et al. (2017).

The back-calculation was carried out using the following equation defined by Zuccato et al. (2008):

$$Q = (Q_{day}/U_{ex}) \times M_{ratio}/N_{inh} \quad (1)$$

**Fig. 4** Chlordecol recovery from solid phase by liquid-liquid extraction (%). Yellow: for spiked suspended matters at 0.1 µg/L for a ±30% uncertainty. Orange: for spiked suspended matters at 0.3 µg/L for a ±25% uncertainty

<figure><img src="image_6.png" /></figure>

Where $Q$ is the consumption of molecule of interest (µg/inhabitant/day in the present article), $Q_{day}$ is the load of the DTR calculated from the flow measurement and raw wastewater concentrations ($Q_{day} = Flow \times [DTR]$), $U_{ex}$ is the percentage of the DTR excretion, $M_{ratio}$ is the parent drug/DTR molar ratio (in this case $M_{ratio} = 1$ because CLD itself is DTR), and $N_{inh}$ is the number of inhabitants in the catchment area. Stability data should be taken into account to prevent DTR degradation in sewage, but CLD is a strikingly stable compound, even if the analysis was performed with all the necessary caution. CLD is so stable that CLD degradation without human induction was previously regarded as impossible (Cabidoche et al. 2009), until Devault et al. (2016a) demonstrated indirectly its slow degradation in situ at least until 5b-hydrochlordecone strengthened by in vitro results of
corroborating studies (Chaussonnerie et al. 2016). Nevertheless, the time needed to turn CLD into 5b-hydrochlordecone seems to be out of range considering the human metabolism: experiments have shown that CLD excretion half-life is ranged between 97 and 177 days in humans (Adir et al. 1978; Cohn et al. 1978; Faroon et al. 1995; Multigner et al. 2016), although CLD is mostly changed under chlordecol form (80%) (Fariss 1980). Due to this prevalence, CLDOH is selected by authors as the DTR; Fariss also proposed an excretion rate of the total body burden of CLD per day (0.36%) but these values includes CLD and CLDOH, this last representing 80% of excreta. Monitoring CLDOH, the corresponding excretion rate is 80% of 0.36%, i.e. 0.288%.

However, sewage epidemiology is based upon the fully excretion of mother drugs and metabolites generated fast (e.g. 12 to 72 h): excretion rate and daily excretion rate are close even confounded. In the case of CLD, the canonical excretion rate of 0.36% implicates a fully excreted total body burden of CLD in 278 days. This value is not consistent with results of Cohn et al. (1978) who proposed 165 days as half-life in human body but Cohn et al. only focused on blood and fat when Fariss (1980) worked on broad sense excretion. Nevertheless, Fariss studied the excretion of rodents and compared it to humans as five times faster and signalled the reach of 80% of full excretion in 3 days under a first-order kinetic. In this way, and following Fariss (1980), (1) 80% of CLD excretion is reached in the 15 first days. (2) CLDOH being the DTR excreted a 80% of total body burden, the operational excretion rate, informing about the exposition of population during the last 15 days could be estimated as 4.26%.

$$ \frac{P \times R}{N} $$

With *P* the percentage of excretion following a first-order kinetic, *N* the number of days corresponding to this first-order kinetic, and *R* the part of total body burden excreted under DTR form. Based on the limit of detection, the maximal input of CLD, i.e. the CLD consumption as if the consumption was at the limit of detection, was calculated, assuming that CLDOH concentration at the limit of detection is a way to show what the maximal extent of exposure would be when the method lacks the required level of sensitivity. The suitability of CLD as the DTR is discussed in “Chlordecone as DTR” section.

## Results

The analytical result as summarised in Table 1

Paradoxically, the present monitoring did not present quantifiable CLD, CLDOH, or 5b-hydrochlordecone (CLD5BH) concentrations (below the limit of detection).

<table><caption>**Table 1** Concentration in the wastewater samples (ng/L)</caption><thead><tr><th></th><th>Chlordecone<br>(ng/L)</th><th>Chlordecol<br>(ng/L)</th><th>5b-<br>Hydrochlordecone<br>(ng/L)</th></tr></thead><tbody><tr><td>1 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr><tr><td>2 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr><tr><td>3 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr><tr><td>4 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr><tr><td>5 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr><tr><td>6 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr><tr><td>7 July</td><td>&lt; LD</td><td>&lt; LD</td><td>&lt; LD</td></tr></tbody></table>

The back-calculated CLD expositions are summarised in Table 2a and b, with 0.288% as excretion rate and 4.26% respectively. The maximal input of CLD was estimated to be 86.8 or 5.87 µg/inhabitant/day, applying as excretion rate of 0.288 and 4.26%, respectively, based on 0.1 µg/L as the limit of detection (LD) and considering the corresponding population equivalent. With 37,382 inhabitants equivalent the July 1, the population equivalent reaches a maximum very unusually high regarding the usual results for the studied WWTP (circa 20,000 inhabitant equivalent in average). Inversely, with 13,100 inhabitants equivalent the July 7, the population equivalent reaches a minimum unusually low regarding the usual results for the studied WWTP.

## Discussion

The present article introduces chlordecol as a new DTR for chlordecone sewage epidemiology. The aim is to determine the efficiency of healthcare policy based on these sewage epidemiology results, notwithstanding the fact that CLDOH concentrations in the sampled wastewaters never reach the LD (Fig. 1). Indeed, this result should be interpreted as a daily concentration in wastewater between zero and close to the LD, even if it was never reached.

In the following discussion, the authors will study a worst-case scenario, i.e. when CLD concentration is close to the LD but without reaching it. Wastewater daily fluxes, being different each day, will be taken into account in order to provide an analysis that is as precise as possible.

The worst case of maximal CLD input was estimated to be 86.8 or 5.87 µg/inhabitant/day based on 0.1 µg/L LD, while no trace of CLD was observed in the sewage samples.

### Chlordecone as DTR

Toxicokinetic data for CLD in human are available (Adir et al. 1978; Blanke et al. 1978; Boylan et al. 1979; Cannon et al. 1978; Cohn et al. 1978; Guzelian et al. 1981; Taylor 1982,
<table><caption>**Table 2** Chlordecone maximal consumption based on limit of detection and flux evaluation. PE, population equivalent</caption><thead><tr><th></th><th>Volume<br>(m<sup>3</sup> /<br>day)</th><th>BOD<sub>5</sub><br>(mg O<sub>2</sub> /<br>L)</th><th>Population<br>equivalent</th><th>M<sub>ratio</sub></th><th>Chlordecone<br>U<sub>ex</sub> (%)</th><th>Max flux<br>(µg/day)</th><th>Exposure<br>(µg/day /<br>inh)</th></tr></thead><tbody><tr><td colspan="8">(a)</td></tr><tr><td>1 July</td><td>4078</td><td>550</td><td>37,382</td><td>1</td><td>0.288</td><td>407,800</td><td>≤37.9</td></tr><tr><td>2 July</td><td>3006</td><td>380</td><td>19,038</td><td>1</td><td>0.288</td><td>300,600</td><td>≤54.8</td></tr><tr><td>3 July</td><td>4195</td><td>300</td><td>20,975</td><td>1</td><td>0.288</td><td>419,500</td><td>≤69.4</td></tr><tr><td>4 July</td><td>4463</td><td>290</td><td>21,571</td><td>1</td><td>0.288</td><td>446,300</td><td>≤71.8</td></tr><tr><td>5 July</td><td>3616</td><td>280</td><td>16,875</td><td>1</td><td>0.288</td><td>361,600</td><td>≤74.4</td></tr><tr><td>6 July</td><td>4074</td><td>280</td><td>19,012</td><td>1</td><td>0.288</td><td>407,400</td><td>≤74.4</td></tr><tr><td>7 July</td><td>3275</td><td>240</td><td>13,100</td><td>1</td><td>0.288</td><td>327,500</td><td>≤86.8</td></tr><tr><td colspan="8">(b)</td></tr><tr><td>1 July</td><td>4078</td><td>550</td><td>37,382</td><td>1</td><td>4.26</td><td>407,800</td><td>≤2.56</td></tr><tr><td>2 July</td><td>3006</td><td>380</td><td>19,038</td><td>1</td><td>4.26</td><td>300,600</td><td>≤3.71</td></tr><tr><td>3 July</td><td>4195</td><td>300</td><td>20,975</td><td>1</td><td>4.26</td><td>419,500</td><td>≤4.7</td></tr><tr><td>4 July</td><td>4463</td><td>290</td><td>21,571</td><td>1</td><td>4.26</td><td>446,300</td><td>≤4.86</td></tr><tr><td>5 July</td><td>3616</td><td>280</td><td>16,875</td><td>1</td><td>4.26</td><td>361,600</td><td>≤5.03</td></tr><tr><td>6 July</td><td>4074</td><td>280</td><td>19,012</td><td>1</td><td>4.26</td><td>407,400</td><td>≤5.03</td></tr><tr><td>7 July</td><td>3275</td><td>240</td><td>13,100</td><td>1</td><td>4.26</td><td>327,500</td><td>≤5.87</td></tr></tbody></table>

1985). For animals, oral exposure data prevails, most of them for acute exposure (Blanke et al. 1978; Borzelleca and Skalsky 1980; Boylan et al. 1979; Cohn et al. 1978; Egle et al. 1978; Fujimori et al. 1982; Guzelian et al. 1981; Hewitt et al. 1986; Kavlock et al. 1980; Plaa et al. 1987; Richter et al. 1979; Skalsky et al. 1980; Wang et al. 1981).

CLD is absorbed through inhalation and ingestion in the gastrointestinal tract of humans and animals, then concentrated in the liver. During its long retention time in the body of few species including humans, CLD is metabolised to chlordecol.

CLD, chlordecol, and their glucuronide conjugates are slowly excreted mainly even only in the bile then the faeces (Blanke et al. 1978; Boylan et al. 1979; Cohn et al. 1978; Guzelian, 1981) but enterohepatic recirculation occurs. Considering sewer biocoenosis, the use of CLDOH appears to be the most reliable DTR, with an excretion rate of 72% added to 9% conjugated with glucuronic acid (Fariss et al. 1980; Guzelian, 1981), with more than 97% by faeces. CLD was not detected in sweat and only in minor quantities in urine (expected to 3% of excretion), saliva, and gastric juice (Cohn et al. 1978).

Only a very limited number of studies have examined the toxicokinetics of CLD through inhalation and dermal routes. Dermal absorption does occur, but to a limited extent (Hall et al. 1988; Shah et al. 1987), and it does not seem to occur more in the FWI. We found no studies on the distribution, metabolism, or excretion of CLD following dermal exposure. Occupational studies indicate that CLD is mainly absorbed through inhalation and ingestion, and in the case of the FWI, only the oral routes seem pertinent. We did not identify any animal data on the absorption, distribution, metabolism, and excretion of CLD following inhalation exposure. Regardless

of the conclusion of the present article, additional data (acute, intermediate, and chronic) for both humans and animals are needed to adequately compare the toxicokinetic parameters across all routes of exposure.

However, CLD estimation benefits of the experience acquired in sewage epidemiology, mainly for illicit drugs whom physico-chemicals characteristics are consistent for CLD assessment (Δ-9-tétrahydrocannabinol (THC) congeners, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, methadone, respectively K<sub>OW</sub> 6.5, 5.5, 4.2, to compare to CLD K<sub>OW</sub>: 4.5). The CLD pattern in the sewer network is expected to be analogous to other molecules studied for sewage epidemiology.

Liquid-liquid extraction with hexane and acetone fully extracts CLD adsorbed on suspended matter until the suspended matter concentration reaches 500 mg/L (Fig. 2), i.e. a concentration never reached during this experiment.

## Evaluation of the population exposure

The ADI of CLD is 0.5 µg/kg body weight/day for chronic exposure and 10 µg/kg body weight/day for acute ones. Considering the human conventional weight (60 kg), the ADI would be respectively 30 and 600 µg/inhabitant/day. However, only chronic exposure ADI is pertinent considering the CLD French West Indies context. The maximal estimated exposure based on our sewage epidemiology was between 86.8 and 37.9 µg/inhabitant/day or between 5.87 and 2.56 µg/inhabitant/day depending on the use of Fariss excretion rate or operational one described in "Calculation of chemical consumption", i.e. at least the range of ADI at least five times less than the CLD ADI for chronic exposure.
This maximal value should not be misunderstood, as it
could induce an overestimation of the CLD consumption.
Indeed, the value is calculated as the maximal daily intake
per person, but there is no evidence that the real daily intake
is 86.8 or 5.87 µg/inhabitant/day, respectively. The real daily
intake is known to be between 0 and 86.8 or 5.87 µg/day/
person, even if it is not possible to determine it precisely given
the field results. This aspect highlights the next step in sewage
epidemiology: lower quantification or detection limits could
be allowed using passive samplers. Nevertheless, the popula-
tion under investigation could still be exposed to CLD al-
though at non-dangerous levels.

It is only possible to compare our results of CLD exposure
to the literature with the pan-European analysis of Rousis et al.
(2017) conducted in eight major cities in Italy, the UK, the
Netherlands, Belgium, Spain, Denmark, and Norway, and per-
formed on pre-emergent herbicides banned since 2003 (atra-
zine, simazine) as well as authorised pesticides whether used
(terbuthylazine) or not (propazine). Such results are interest-
ing because, like CLD, atrazine is persistent in the environ-
ment. Moreover, CLD is an insecticide, as the other pesticide
exposures back-calculated by Rousis et al., i.e. pyrethroids
and organophosphates.

Considering operational excretion rate results, i.e. Table 2b,
CLD maximal exposure range is similar to the *s*-triazines and
organophosphates observed by Rousis et al. (2017), lower than
pyrethroids (range up to 125 µg/inhabitant/day) and much low-
er than alkyl phosphates (range up to 2000 µg/day/person).
Permethrins ranged between 12 and 108% of ADI, while
CLD maximal exposure ranged between 19.6% and 289% con-
sidering CLD ADI chronic exposure and “operational” excre-
tion rate deducted from Fariss (1980) and adapted to sewage
epidemiology, i.e. 4.26%, and the excretion rate directly pro-
posed by Fariss (1980) corrected by CLDOH part, i.e. 0.288%.

Authors highlight also that results have been reached using
a 0.1 µg/L limit of detection, corresponding to a 0.3 µg/L limit
of quantification. Such analytical performance could be
surpassed, including because protocol is primarily designed
for surface water, not for wastewaters. Chlordecone analysis
is has been recently proposed with limit of detection two or-
ders below the one reached in the present article.

Evaluation of sanitary framework results

The present study could be usefully compared to illicit drug
consumption, which involves a willingly consumption of haz-
ardous chemicals. Since 2013, the illicit drug consumption in
the population connected to studied WWTP has been success-
fully monitored for SCORE (Sewage Analysis CORe group
Europe) (Devault et al. 2014 and 2016b); cannabis and co-
caine consumption reached 23,000 and 1300 µg/inhabitant/
day, respectively. Even if the toxicological impact of each
molecule should be taken into account, such previous works

on the sampled WWTP backs up the application to other mol-
ecules than illicit drugs.

The results of the present study could help to objectivise
the sanitary efforts of the public authorities and provide guid-
ance to decision makers regarding the critical level of illicit
drug consumption in Martinique and the corresponding ab-
sence of a plan equivalent to the “chlordecone plans”.
Indeed, the present results highlight the success of the
“chlordecone plans” of the past decade, which have allotted
94 million euros to the CLD threat. To the best of the authors’
knowledge, CLD content in sludge has never been assessed.

It is worthwhile noting that the absence of CLDOH detec-
tion in the local sewage is a sort of evaluation of the sanitary
efforts initiated to limit CLD use. Indeed, the present results
show that sanitary and environmental managers have
succeeded in preventing population contamination by
conducting soil analysis and then limiting the cropping of
roots and tubers in polluted areas and fishing in contaminated
bays as well as by providing populations with safety instruc-
tions for suitable cooking and gardening. As the studied area is
urban, housing rarely allows for significant-sized vegetable
gardens, while informal markets could limit the need for su-
permarkets. That said, produce from both supermarkets and
informal markets have been surveyed without highlighting
prevalent contaminated food (2.7% of samples from
Martinique, mainly from self-production in the contaminated
area far from studied one). Moreover, the local context, un-
derstanding the spread of CLD (and subsequent pollution) as a
contemptible colonial remnant, has helped to raise awareness
and change behaviour (Joly 2010). Yet the same negative per-
ceptions do not apply to illicit drug consumption, which ob-
tains similar results pointing to the anecdotic consumption of
illicit drugs. Tackling the drug problem will thus probably
require more time, persuasion, and money.

Conclusions

Sum of CLDOH should be suitably used as a DTR in order to
back-calculate the population exposure to this pesticide.
Considering the area under investigation, the population ex-
posure was demonstrated to be minimal and non-threatening.
However, this study could to be usefully extended to other
areas, including contaminated area, ideally with better detec-
tion limit. In this study, sewage epidemiology was successful-
ly applied to a propitious context regarding the stability of
CLD, which lends support to the previous studies conducted
in the same area.

**Acknowledgements** The present study is part of the QUINQUEREME program funded by the Water Office of Martinique (Office de l'Eau), the Regional Health Agency of Martinique (Agence Régionale de Santé de
Martinique), and Odysse, which also supported the program through the kind involvement of its staff and site accompaniment.

The authors wish to thank the WWTP teams, Hervé Macarie, Marc W. Fariss, Yves Lévi and Sara Karolak for their support and review, Benoît Vittecoq and Anne-Lise Tailame for their logistical support, and Victoria Grace (English Publications) for her English editing.

## References

Adir J, Caplan YH, Thompson BC (1978) Kepone serum half-life in humans. Life Sci 22(8):699-702

Alley EG, Layton BR, Minyard JP (1974) Identification of the photo-products of the insecticides Mirex and Kepone. J Agric Food Chem 22:442-445

Andreottola G, Bonomo L, Poggiali L, Zaffaroni C (1994) A methodology for the estimation of unit nutrient and organic loads from domestic and non-domestic sources. Europ Water Poll Control 4(6):13-19

Baran N, Arnaud L (2013) Cartography of contamination risk of groundwater by pesticides in Martinique. BRGM/RP-61976-FR, 103 p., 41 ill., 3 ann., CD. http://www.eaumartinique.fr/IMG/pdf_RP_61976-FR_ODE_CartoPhytos_vf-3.pdf In French

Blanke RV, Fariss MW, Guzelian PS, Paterson AR, Smith DE (1978) Identification of a reduced form of chlordecone (Kepone) in human stool. Bull Environ Contam Toxicol 20:782-785. https://doi.org/10.1007/BF01683600

Bocquené G, Franco A (2005) Pesticide contamination of the coastline of Martinique. Mar Poll Bull 51(5-7):612-619

Borzelleca JF, Skalsky HL (1980) The excretion of pesticides in saliva and its value in assessing exposure. J Environ Sci Health B 15(6): 843-866

Boylan JJ, Cohn WJ, Egle J, Blanke RV, Guzelian PS (1979) Excretion of chlordecone by the gastrointestinal tract: evidence for a nonbiliary mechanism. Clin Pharmacol Ther 25:579-585

Bro-Rasmussen F (1996) Content by persistent chemicals in food chain and human health. Sci Tot Env 188(1):S45-S60

Cabidoche Y-M, Lesueur-Jannoyer M (2012) Contamination of harvested organs in root crops grown on chlordecone-polluted soils. Pedosphere 22(4):562-571

Cabidoche Y-M, Achard R, Cattan P, Clermont-Dauphin C, Massat F, Sansoulet J (2009) Long-term pollution by chlordecone of tropical volcanic soils in the French West Indies: a simple leaching model accounts for current residue. Environ Poll 157(5):1697-1705

Cannon SB, Veazey JM Jr, Jackson RS, Burse VW, Hayes C, Straub WE, Landrigan PJ, Liddle JA (1978) Epidemic Kepone poisoning in chemical workers. Am J Epidemiol 107(6):107529-107537

Chaussonnerie S, Saaidi P-L, Ugarte E, Barbance A, Fossey A, Barbe V, Gyapay G, Brüls T, Chevallier M, Couturat L, Fouteau S, Muselet D, Pateau E, Cohen GN, Fonknechten N, Weissenbach J, Le Paslier D (2016) Microbial degradation of a recalcitrant pesticide: Chlordecone. Front Microb 7:2025

Coat S, Bocquené G, Godard E (2006) Contamination of some aquatic species with the organochlorine pesticide chlordecone in Martinique. Aquat Liv Res 19(2):181-187

Coat S, Monti D, Legendre P, Bouchon C, Massat F, Lepoint G (2011) Organochlorine pollution in tropical rivers (Guadeloupe): role of ecological factors in food web bioaccumulation. Environ Poll 159: 1692-1701

Cohn WJ, Boylan JJ, Blanke RV, Fariss MW, Howell JR, Guzelian PS (1978) Treatment of chlordecone (Kepone) toxicity with cholestyramine. Results of a controlled clinical trial. New Engl J Med 298: 243-248. https://doi.org/10.1056/NEJM197802022980504

Cornish AS, Ng WC, Ho VCM, Wong HL, Lam JCW, Lam PKS, Leung KMY (2007) Trace metal and organochlorines in the bamboo shark

*Chiloscyllium plagiosum* from the southern waters of Hong Kong, China. Sci Tot Env 376:335-345

Dallaire R, Muckle G, Rouge F, Kadhel P, Bataille H, Guldner L, Seurin S, Chajés V, Monfort C, Boucher O, Pierre Thomé J, Jacobson SW, Multigner L, Cordier S (2012) Cognitive, visual, and motor development of 7-month-old Guadeloupean infants exposed to chlordecone. Env Res 118:79-85

Daughton CG (2011) Illicit drugs: contaminants in the environment and utility in forensic epidemiology. Rev Environ Contam Toxicol 210:59-110

Devault DA, Néfau T, Pascaline H, Karolak S, Levi Y (2014) First evaluation of illicit and licit drug consumption based on wastewater analysis in Fort de France urban area (Martinique, Caribbean), a transit area for drug smuggling. Sci Tot Env 490:970-978

Devault DA, Laplanche C, Pascaline H, Bristeau S, Mouvet C, Macarie H (2016a) Natural transformation of chlordecone into 5b-hydrochlordecone in French West Indies soils: statistical evidence for investigating long-term persistence of organic pollutants. Environ Sci Poll Res 23(1):81-97

Devault DA, Néfau T, Levi Y, Karolak S (2016b) The removal of illicit drugs and morphine in two waste water treatment plants (WWTPs) under tropical conditions. Environ Sci Poll Res 1-11 In Press

Devault DA, Néfau T, Levi Y, Karolak S (2017) The removal of illicit drugs and morphine in two waste water treatment plants (WWTPs) under tropical conditions. Environ Sci Poll Res 24(33):25645-25655

Dubuisson C, Héraud F, Leblanc J-C, Gallotti S, Flamand C, Blateau A, Quenel P, Volatier J-L (2007) Impact of subsistence production on the management options to reduce the food exposure of the Martinican population to chlordecone. Regul Toxicol Pharmacol 49(1):5-16

Egle JL Jr, Fernandez SB, Guzelian PS, Borzelleca JF (1978) Distribution and excretion of chlordecone (Kepone) in the rat. Drug Metab Disp 6(1):91-95

Fariss, M.W. Comparative metabolism of chlordecone (Kepone) in mammals. Virginia Commonwealth University /Medical College of Virginia, Ph.D Thesis, 152pp.

Faroon O, Smith L, Derosa C, Kueberuwa S (1995) ATSDR evaluation of health effects of chemicals: II. Mirex and chlordecone: health effects, toxicokinetics, human exposure, and environmental fate. Toxicol Indust Health 11(6):1-195 https://www.atsdr.cdc.gov/toxprofiler/tp66.pdf

Fujimori K, Benet H, Mehendale HM, Ho IK (1982) Comparison of brain discrete area distributions of chlordecone and mirex in the mouse. Neurotoxicol 3(2):125-129

Gourcy L, Baran N, Vittecoq B (2009) Improving the knowledge of pesticide transfer processes using age-dating tools (CFC, SF6, 3H) in a volcanic island (Martinique, French West Indies). J Contam Hydrol 108:107-117

Guzelian PS (1981) Therapeutic approaches for chlordecone poisoning in humans. J Toxicol Environ Health 8:757-766

Hall LL, Fisher HL, Sumler MR (1988) Dose response of skin absorption in young and adult rats. ASTM Special Technical Publication, Perf Prot Cloth 989:177-194

Hewitt LA, Caille G, Plaa GL (1986) Temporal relationships between biotransformation, detoxication, and chlordecone potentiation of chloroform-induced hepatotoxicity. Can J Physiol Pharmacol 64(4):477-482

Hodgson E (1998) Toxicology of environmentally persistent chemicals: Mirex and chlordecone. Rev Toxicol 2:477-499

Ivie GW, Dorough HW, Alley EG (1974) Photodecomposition of Mirex on silica gel chromatoplates exposed to natural and artificial light. J Agric Food Chem 22:933-935

Joly P-B (2010) Chlordecone saga in French West Indies. Chronological reconstruction 1968-2008. INRA/SenS and IFRIS, Paris, pp 82 (In French)

Jondreville C, Lavigne A, Jurjanz S, Dalibard C, Liabeuf JM, Clostre F, Lesueur-Jannoyer M (2014) Contamination of free-range ducks by
chlordecone in Martinique (French West Indies): a field study. Sci Tot Env 493:336-341

Kaiser KLE (1978) Pesticide report: the rise and fall of Mirex. Environ Sci Technol 12:520-528

Kavlock RJ, Chernoff N, Rogers E, Whitehouse D (1980) Comparative tissue distribution of mirex and chlordecone in fetal and neonatal rats. Pestic Biochem Physiol 14(3):227-235

Lastel M-L, Lerch S, Fournier A, Jurjanz S, Mahieu M, Archimède H, Feidt C, Rychen G (2016) Chlordecone disappearance in tissues of growing goats after a one month decontamination period—effect of body fatness on chlordecone retention. Environ Sci Poll Res 23(4): 3176-3183

Le Déaut J-Y, Procaccia C (2009) Impact of chlordecone and pesticide uses in French West Indies: assess and perspectives. OPECST report no. 487 (2008-2009). French Senat. ISBN: 9782111267688. pp. 223 In French

Multigner L, Ndong JR, Giusti A, Romana M, Delacroix-Maillard H, Cordier S, Jégou B, Thome JP, Blanchet P (2010) Chlordecone exposure and risk of prostate cancer. J Clin Oncol 28(21):3457-3462

Multigner L, Kadhel P, Rouget F, Blanchet P, Cordier S (2016) Chlordecone exposure and adverse effects in French West Indies populations. Environ Sci Poll Res 23(1):3-8

Plaa GL, Caille G, Vezina M, Iijima M, Côté MG (1987) Chloroform interaction with chlordecone and mirex: correlation between biochemical and histological indexes of toxicity and quantitative tissue levels. Fund Appl Toxicol 9:198-207

Richter E, Lay JP, Klein W, Korte F (1979) Enhanced elimination of Kepone-14 C in rats fed liquid paraffin. J Agric Food Chem 27(1): 187-189

Roche H, Salvat B, Ramade F (2011) Assessment of the pesticides pollution of coral reefs communities from French Polynesia. Rev Ecol 66(1):3-10

Rousis NI, Gracia-Lor E, Zuccato E, Bade R, Baz-Lomba JA, Castrignanò E, Causanilles A, Covaci A, de Voogt P, Hernández F, Kasprzyk-Hordern B, Kinyua J, McCall A-K, Plósz BG, Ramin P, Ryu Y, Thomas KV, van Nuijs A, Yang Z, Castiglioni S (2017) Wastewater-based epidemiology to assess pan-European pesticide exposure. Water Res 121:270-279

Shah PV, Fisher HL, Sumler MR, Monroe RJ (1987) Comparison of the penetration of 14 pesticides through the skin of young and adult rats. J Toxicol Environ Health 21(3):353-366

Skalsky JL, Wrenn JM, Borzelleca JF (1980) In vitro and in vivo evaluation of the movement of Kepone in the rat submaxillary gland. J Environ Pathol Toxicol Oncol 3(5-6):529-536

Taylor JR (1982) Neurological manifestations in humans exposed to chlordecone and follow-up results. Neurotoxicol 3(2):9-16

Taylor JR (1985) Neurological manifestations in humans exposed to chlordecone: follow-up results. Neurotoxicol 6(1):231-2361

Wang TPH, Ho IK, Mehendale HM (1981) Correlation between neurotoxicity and chlordecone (Kepone) levels in brain and plasma in the mouse. Neurotoxicol (Park Forest South, Ill) 2(2):373-381

Zuccato E, Chiabrando C, Castiglioni S, Calamari D, Bagnati R, Schiarea S, Fanelli R (2005) Cocaine in surface waters: a new evidence-based tool to monitor community drug abuse. Environ Health: Glob Acc Sci Source 4:14

Zuccato E, Chiabrando C, Castiglioni S, Bagnati R, Fanelli R (2008) Estimating community drug abuse by wastewater analysis. Environ Health Persp 116(8):1027-1032